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Bool, Lawrence E. III. "The partitioning of iron during the combustion of pulverized coal." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186374.
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The presence of pyrite in coal has long been known to affect the slagging propensity of the coal when burned in industrial boilers. In particular it has been found that molten pyrite bonds very well to steel furnace tubes. In addition, it has been found that the amount of chemically bound iron greatly influences the slag contact angle and stickiness on steel heat transfer tubes. The goal of this research, which is part of a larger project headed by the PSI Technology Company to study mineral matter transformations during combustion, is to explore and model the mechanisms dominating the fate of iron during combustion. To achieve this goal a well characterized suite of coals was burned in a 17kW downfired laboratory combustor. Fly ash was extracted from the flue gas and size classified. These ash samples were then subjected to a number of analytical techniques including Atomic Absorption Spectroscopy (AA), Energy Dispersive X-Ray (EDX), Computer Controlled Scanning Electron Microscopy (CCSEM), Transmission Electron Microscopy (TEM), and Mossbauer Spectroscopy to determine the ash bulk composition and morphology. Of these techniques, Transmission Electron Microscopy and Mossbauer, were instrumental in determining the iron-silicate interactions during combustion. Utilizing the information gleaned from the fly ash analysis, and work in the literature, it was possible to propose a pathway for iron interactions during combustion. A mechanistic model was then proposed to quantify the competition between processes governing iron oxidation/crystallization and those promoting iron-silicate mixing/reaction. This model described the partitioning of iron between chemically bound and physically bound phases. By utilizing kinetic parameters from the literature and fundamental transport phenomena, this model was able to successfully correlate data from several coals burned under a range of combustion conditions. The model can also be used to quantify the effect of combustion modifications and fuel property changes on iron partitioning.
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Kothari, Ankit. "Effects of Fly Ash on the properties of Alkali Activated Slag Concrete." Thesis, Luleå tekniska universitet, Geoteknologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-63534.
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This master thesis presents the effects of fly ash on the properties of alkali activated slag concrete, commonly referred as Geopolymer concrete (GPC). Cement manufacturer are major producers of CO2 which negatively affects the environment. Due to the increased construction activities and environmental concern, it is necessary to introduce alternative and eco-friendly binders for concrete. Slag and fly ash based concrete, which is by-product from industrial waste, is probably the best replacement for OPC concrete due to less or nil environmental issue. Most of the researchers have already concluded that slag and fly ash can be used as binders in concrete by activating them with alkali activator solution (e.g. by sodium silicate or sodium carbonate). In the present work concretes were produced by varying the proportion of slag to fly ash (40:60, 50:50, 60:40 & 80:20); amount of alkali activators (5, 10 & 14) and chemical modulus of sodium silicate (Ms) (0.25, 0.5 & 1). Setting times and compressive strength values were evaluated. Results showed that decrease in fly ash content irrespective of % of alkali activators and alkali modulus (Ms), the compressive strength was increasing and setting time was getting shorter. The produced concretes showed increasing compressive strength with increase in % of alkali activator for Ms 0.5 and 1, while for Ms=0.25 the strength was decreasing with increase in % of alkali activators. From this it can be concluded that, Ms=0.5 was the optimum point below which the reaction got slower. Based on the initial investigations, mix S8:F2-SS10(1) and S8:F2-SS10(0.5) showed most promising results in terms of fresh and hardened concrete properties and were easy to handle. Consequently, the above mentioned mixture was chosen to be studied in more detail. The experimental program for these mixes included determination of slump flow, compressive strength (7, 14, 28 days) and shrinkage (drying and autogenous). The results shows that, strength increased with time and comparatively mix with Ms=0.5 showed higher compressive strength than mix with Ms=1, due to higher alkalinity of the pore solution. Mix with Ms=1 showed higher drying shrinkage compared to mix with Ms=0.5, which was explained by higher alkalinity of the solutions (Ms=0.5) leading to rapid formation of aluminosilicate gel. Autogenous shrinkage appeared to be higher for mix with Ms=0.5. This was associated with lower modulus which leads to densification of concrete microstructure at early ages. Pore diameter decrease and the water trapped in the pores exerted increasing tensile stress resulting for higher autogenous shrinkage.
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Talefirouz, Davood. "Use Of Granulated Blast Furnace Slag, Steel Slag And Fly Ash In Cement-bentonite Slurry Wall Construction." Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615432/index.pdf.
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Slurry walls have been widely used for more than 25 years to control the migration of contaminants in the subsurface. In the USA, vertical barriers are mostly constructed of soil-bentonite using the slurry trench method of construction. In this method, sodium bentonite is mixed with water to form a viscous slurry that is pumped into a trench during excavation to maintain the trench stability. The stable trench is then backfilled with a mixture of soil and slurry having a consistency of high slump concrete. These barriers have been designed primarily for low permeability, generally less than 10&minus9 m/s. Some investigations have pointed toward improved performance using admixtures that would provide low permeability. In this study, Soma thermal power plant fly ash, granulated blast furnace slag, lime, and steel slag are used as admixture to improve the performance of slurry walls. Permeability, compressive strength, slump, compressibility properties of the mixtures were found and checked for the minimum requirements. According to the findings of this study, granulated blast furnace slag (GGBS), fly ash and steel slag can be used at certain percentages and curing periods as additive in cement-bentonite barrier wall construction. Permeability of specimens having fly ash decreases by increasing fly ash content. Mixtures having 50 % of GGBS type I with 5 % of lime and 9% bentonite content gave acceptable results in 28 days of curing time. Specimens including 50 % of GGBS type II with 5 % of lime and 9% bentonite content gave the higher permeability value in 28 days of curing time with respect to GGBS type I. In addition, most of the mixtures prepared by steel slag gave the acceptable permeability values in 28 days of curing period. Unconfined compressive strength of all mixtures increase by increasing curing time. Cc, Cr, Cv, kcon values were found from consolidation test results. Permeability values found from consolidation tests are 10 times to 100 times higher than flexible wall k results for the same effective stress of 150 kPa. Generally, mv values are decreasing with increasing curing time. As mv decreases, D increases.
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Topbas, Selim. "Effect Of Trass, Granulated Blast Furnace Slag And Fly Ash On Delayed Ettringite Formation." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612494/index.pdf.
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Properly proportioned, placed and cured concrete can be durable under most conditions. However, deterioration of concrete does occur under certain environments. One of the problems that affect the durability of hardened concrete is delayed ettringite formation (DEF) which is an important problem encountered in precast concrete industry where high temperature curing is applied. Although there had been many researches on DEF, there are still many uncertainties about its chemistry and mechanism.
In this study, the effects of partial cement replacement by different mineral admixtures (trass, blast furnace slag and fly ash), SO3/Al2O3 molar ratio and specific surface area of cement on DEF were investigated. For this purpose, 9 groups of control cements were prepared with 3 different specific surface areas and 3 different SO3/Al2O3 molar ratios. Different amounts of mineral admixtures were blended with the control cements. High temperature curing was applied to the cement pastes and the expansions of these pastes were measured periodically for 240 days.
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The experimental results obtained were interpreted for a comparative analysis of the effects of the afore-mentioned parameters.
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Ryno, Barnard. "Mechanical properties of fly ash/slag based geopolymer concrete with the addition of macro fibres." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/95866.
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Thesis (MEng) -- Stellenbosch University, 2014.ENGLISH ABSTRACT: Geopolymer concrete is an alternative construction material that has comparable mechanical properties to that of ordinary Portland cement concrete, consisting of an aluminosilicate and an alkali solution. Fly ash based geopolymer concrete hardens through a process called geopolymerisation. This hardening process requires heat activation of temperatures above ambient. Thus, fly ash based geopolymer concrete will be an inadequate construction material for in-situ casting, as heat curing will be uneconomical. The study investigated fly ash/slag based geopolymer concrete. When slag is added to the matrix, curing at ambient temperatures is possible due to calcium silicate hydrates that form in conjunction with the geopolymeric gel. The main goal of the study is to obtain a better understanding of the mechanical properties of geopolymer concrete, cured at ambient temperatures. A significant number of mix variations were carried out to investigate the influence that the various parameters, present in the matrix, have on the compressive strength of fly ash/slag based geopolymer concrete. Promising results were found, as strengths as high as 72 MPa were obtained. The sodium hydroxide solution, the slag content and the amount of additional water in the matrix had the biggest influence on the compressive strength of the fly ash/slag based geopolymer concrete. The modulus of the elasticity of fly ash/slag based geopolymer concrete did not yield promising results as the majority of the specimens, regardless of the compressive strength, yielded a stiffness of less than 20 GPa. This is problematic from a structural point of view as this will result in large deflections of elements. The sodium hydroxide solution had the most significant influence on the elastic modulus of the geopolymer concrete. Steel and polypropylene fibres were added to a high- and low strength geopolymer concrete matrix to investigate the ductility improvement. The limit of proportionality mainly depended on the compressive strength of the geopolymer concrete, while the amount of fibres increased the energy absorption of the concrete. A similar strength OPC concrete mix was compared to the low strength geopolymer concrete and it was found that the OPC concrete specimen yielded slightly better flexural behaviour. Fibre pull-out tests were also conducted to investigate the fibre-matrix interface. From the knowledge gained during this study, it can be concluded that the use of fly ash/slag based geopolymer concrete, as an alternative binder material, is still some time away as there are many complications that need to be dealt with, especially the low modulus of elasticity. However, fly ash/slag based geopolymer concrete does have potential if these complications can be addressed.
AFRIKAANSE OPSOMMING: Geopolimeerbeton is ‘n alternatiewe konstruksiemateriaal wat vergelykbare meganiese eienskappe met beton waar OPC die binder is, en wat bestaan uit ‘n aluminosilikaat en ‘n alkaliese oplossing. Vliegas-gebaseerde geopolimeerbeton verhard tydens ‘n proses wat geopolimerisasie genoem word. Hierdie verhardingsproses benodig hitte-aktivering van temperature hoër as dié van die onmiddellike omgewing. Gevolglik sal vliegas-gebaseerde geopolimeerbeton ‘n ontoereikende konstruksiemateriaal vir in situ gietvorming wees, aangesien hitte-nabehandeling onekonomies sal wees. Die studie het vliegas/slagmentgebaseerde geopolimeerbeton ondersoek. Wanneer slagment by die bindmiddel gevoeg word, is nabehandeling by omliggende temperature moontlik as gevolg van kalsiumsilikaathidroksiede wat in verbinding met die geopolimeriese jel vorm. Die hoofdoel van die studie was om ‘n beter begrip te kry van die meganiese eienskappe van geopolimeerbeton, wat nabehandeling by omliggende temperature ontvang het. ‘n Aansienlike aantal meng variasies is uitgevoer om die invloed te ondersoek wat die verskeie parameters, aanwesig in die bindmiddel, op die druksterkte van die vliegas/slagmentgebaseerde geopolimeerbeton het. Belowende resultate is verkry en sterktes van tot so hoog as 72 MPa is opgelewer. Daar is gevind dat die sodiumhidroksiedoplossing, die slagmentinhoud en die hoeveelheid water in die bindmiddel die grootste invloed op die druksterkte van die vliegas/slagmentgebaseerde geopolimeerbeton gehad het. Die styfheid van die vliegas/slagmentgebaseerde geopolimeerbeton het nie belowende resultate opgelewer nie. Die meeste van die monsters, ongeag die druksterkte, het ‘n styfheid van minder as 20 GPa opgelewer. Vanuit ‘n strukturele oogpunt is dit problematies, omdat groot defleksies in elemente sal voorkom. Die sodiumhidroksiedoplossing het die grootste invloed op die styfheid van die vliegas/slagmentgebaseerde geopolimeerbeton gehad. Staal en polipropileenvesels is by ‘n hoë en lae sterke geopolimeer beton gevoeg om die buigbaarheid te ondersoek. Die die maksimum buigbaarheid het hoofsaaklik afgehang van die beton se druksterkte terwyl die hoeveelheid vesels die beton se energie-opname verhoog het. ‘n OPC beton mengsel van soortgelyke sterkte is vergelyk met die lae sterkte geopolimeerbeton en daar is gevind dat die OPC beton ietwat beter buigbaarheid opgelewer het. Veseluittrektoetse is uitgevoer om die veselbindmiddel se skeidingsvlak te ondersoek. Daar kan tot die gevolgtrekking gekom word dat, alhoewel belowende resultate verkry is, daar steeds sommige aspekte is wat ondersoek en verbeter moet word, in besonder die styfheid, voordat geopolimeerbeton as ‘n alternatiewe bindmiddel kan optree. Volgens die kennis opgedoen tydens hierdie studie, kan dit afgelei word dat die gebruik van vliegas/slagmentgebaseerde geopolimeerbeton, as 'n alternatiewe bindmiddel, nog 'n geruime tyd weg is, as gevolg van baie komplikasies wat gehandel moet word, veral die lae elastisiteitsmodulus. Tog het vliegas/slagmentgebaseerde geopolimeerbeton potensiaal as hierdie komplikasies verbeter kan word.
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Chibulu, Chizya. "The influence of fly ash and ground granulated blastfurnace slag on restrained shrinkage cracking of bonded overlays." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/20521.
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The concrete repair industry is driven by deterioration of, damage to, and defects in concrete structures. The impact of deterioration or damage is a reduction in the service life of the concrete structure. One of the common methods used to repair and rehabilitate damaged concrete structures is the bonded overlay technique. However, bonded overlays are prone to restrained shrinkage cracking which impairs their performance. The mechanism leading to restrained shrinkage cracking of bonded concrete overlays is complex and depends on material properties, such as shrinkage, tensile strength, elastic modulus, and tensile relaxation. In order to reduce the risk of cracking in bonded concrete overlays, one or a combination of the following is required: lower shrinkage strains, higher tensile strength, lower elastic modulus, and increased stress relaxation. The development of these material properties depends on the degree of hydration of the binder material. Fly ash (FA) and slag (GGBS) are known to influence the hydration reaction when added to the binder material. This change in hydration reactions affects the development of the mechanical properties of the concrete, which ultimately affects the outcome of restrained shrinkage. An increase in age at cracking with the use of fly ash and slag in bonded concrete overlays was hypothesised. The research aimed at investigating the influence of fly ash and slag on the performance of bonded concrete overlays with regards to restrained shrinkage cracking. The research also aimed at using the influence of fly ash and slag on the specific material properties governing restrained shrinkage to analyse and predict the performance of the overlay materials
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Zheng, Yong Chu. "Shrinkage behaviour of geopolymers /." Connect to thesis, 2010. http://repository.unimelb.edu.au/10187/7157.
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Naalisvaara, M. (Mikko). "Mechanical properties and drying shrinkage of fibre-reinforced alkali activated fly ash/slag binder s using ceramic waste aggregate." Bachelor's thesis, University of Oulu, 2018. http://urn.fi/URN:NBN:fi:oulu-201805221855.
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Ordinary Portland Cement (OPC), one of the most used construction materials, is a significant contributor to greenhouse gas emissions, such as carbon dioxide. The manufacturing process of OPC requires large amounts of energy and it consumes Earth’s natural resources at a high rate. New methods to replace OPC have been developed for a few decades now, and one of the promising method is a class of materials known as alkali-activated materials (AAM). AAM’s require less raw resources to manufacture, due to utilizing various industrial by-products, such as blast furnace slag and fly ash. One-part alkali-activated binders require only dry materials that can be mixed and water is being added to the binder as the last step. This makes them easy to handle and transport. In this thesis, experiments regarding the mechanical properties and drying shrinkage were conducted on a set of different samples, including different fly ash-slag mix compositions and fibre combinations. Crushed ceramic waste was used as an aggregate, because it is currently a form of waste with very little use. It was found that using 40% slag and 50% fly ash was a desirable mix composition, and so it acted as the reference for fibre-reinforced mix compositions. Polypropylene (PP), basalt (Ba) and polyvinyl alcohol fibres (PVA) were tested in different combinations, with the total amount of fibres in each specimen at 1.5% (total volume). Results showed that generally the addition of fibres increased the total flexural strength. Freeze-thaw test results showed that flexural strength loss was lower with fibre-reinforced samples, and compressive strength generally isn’t negatively affected. Hybrid fibre mixtures showed the most promising results in terms of reducing drying shrinkage ratePortlandsementti, eräs yleisimmistä rakennusmateriaaleista, on merkittävä kasvihuonekaasupäästöjen aiheuttaja. Portlandsementin valmistusprosessi käyttää paljon energiaa, ja se kuluttaa maapallon luonnonvaroja hälyttävällä tahdilla. Uusia materiaaleja, joilla Portlandsementti voitaisiin korvata, ollaan tutkittu ja kehitelty jo vuosikymmeniä, ja eräs lupaavista ehdokkaista on alkali-aktivoidut materiaalit. Näiden valmistaminen ei vaadi paljoa luonnonvaroja, sillä useita teollisuuden sivutuotteita voidaan hyödyntää lähes suoraan raaka-aineina, kuten masuunikuonaa ja lentotuhkaa. Lisäksi alkali-aktivaatioreaktio on huomattavasti Portlandsementin valmistuksessa tarvittavia kemiallisia reaktioita ympäristöystävällisempi. Yksi-osaiset alkali-aktivoidut sideaineet ovat kiinteässä muodossa veden lisäämiseen asti, joten niitä on helppoa ja turvallista käsitellä ja kuljettaa. Tässä työssä suoritettiin kokeita, joiden avulla mitattiin erään alkali-aktivoiduista sideaineista valmistetun betonin mekaanisia ominaisuuksia, sekä kuivumisen aiheuttamaa kutistumista. Kokeissa tutkittiin optimaalista lentotuhkan ja masuunikuonan välistä suhdetta, sekä kolmen erilaisen kuidun vaikutusta lisäaineena. Rakenneaineena käytettiin keraamista jätettä, eli posliinia, joka murskattiin haluttuun raekokoon leukamyllyllä. Jätteenä posliini on huono kierrätettävä, joten sille mahdollisten käyttötarkoituksien löytäminen on tärkeää. Tulosten perusteella betonin pohjaksi valittiin lentotuhka-masuunikuonasuhteeltaan 40/50 koostuva variantti. Polypropyleeni- (PP), basaltti- (Ba) ja polyvinyylialkoholikuituja (PVA) testattiin eri suhteissa niin, että niiden kokonaisosuus aineen tilavuudesta oli 1,5 %. Tulosten mukaan yleisesti kuitujen lisääminen lisäsi näytteiden taivutuslujuutta. Jäätymis-sulamissyklit heikensivät kuidullisia näytteitä enemmän kuin kuiduttomia taivutuslujuustestissä, mutta puristuslujuudessa vaikutusta ei juurikaan havaittu. Kuivumisen aiheuttama kutistuminen vaihteli eri kuituyhdistelmien välillä, mutta yleisesti ottaen kuituyhdistelmät yksittäisten kuitujen sijaan aiheuttivat vähiten kutistumista
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Almuwbber, Omar Mohamed. "The effect of different Ordinary Portland cement binders, partially replaced by fly ash and slag, on the properties of self-compacting concrete." Thesis, Cape Peninsula University of Technology, 2015. http://hdl.handle.net/20.500.11838/1040.
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Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Civil Engineering in the Faculty of Engineering at the Cape Peninsula University of TechnologySelf-compacting concrete (SCC) is a flowable self-consolidating concrete which can fill formwork without any external vibration. A self-compacting concrete mix requires the addition of superplasticiser (SP), which allows it to become more workable without the addition of excessive water to the mixture. The effect of different CEM I 52.5N cements produced by one company at different factories on self-compacting concrete was investigated. The properties of SCC are highly sensitive to changes in material properties, water content and addition of admixtures. For self-compacting concrete to be more accepted in South Africa, the effect that locally sourced materials have on SCC, partially replaced with extenders, needs to be investigated. The European guidelines for SCC (2005) determined the standard, through an extensive study, for the design and testing of self-compacting concrete. Using these guidelines, the properties of self-compacting concrete with the usage of local materials were investigated. The effect on SCC mixes was studied by using four cements; two types of SPs – partially replaced with two types of fly ash; and one type of slag. Mix design and tests were done according to the European Specification and Guidelines for Self-Compacting Concrete (2005). Using locally sourced materials (different cements, sand, coarse aggregate, fly ashes and slag), mixes were optimised with different SPs. Optimisation was achieved when self-compacting criteria, as found in the European guidelines, were adhered to, and the binders in these required mixes were then partially replaced with fly ash and slag at different concentrations. Tests done were the slump flow, V-funnel, L-box, sieve segregation resistance as well as the compressive strength tests. The results obtained were then compared with the properties prescribed by the European guidelines. The cements reacted differently when adding the SPs, and partially replacing fly ash and slag. According to the tests, replacing cement with extenders – in order to get a sufficient SCC – seemed to depend on the chemical and physical properties of each cement type, including the soluble alkali in the mixture, C3A, C3S and the surface area. The range, in which the concentration of these chemical and physical cement compounds should vary – in order to produce an acceptable SCC partially replaced by extenders – was determined and suggested to the cement producer. The main conclusion of this project is that cement properties vary sufficiently from factory to factory so as to influence the performance of an SCC mix. The problem becomes even bigger when such cements are extended with fly ash or slag, and when different SPs are used. When designing a stable SCC mix, these factors should be taken into account.
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Watterson, Scott Michael. "Strength of Concrete Masonry Prisms Constructed with Non-Traditional Grout and Type-M Mortar." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2909.
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The Concrete Masonry Association of California and Nevada in conjunction with Brigham Young University devised a masonry prism testing scheme to aid in the determination of whether prisms constructed with grouts possessing high levels of supplemental cementitious materials could meet minimum masonry compressive strength requirements. ASTM standards, identical to that of concrete, place restrictions on quantities, by weight, of supplemental materials that can replace ordinary Portland cement. For an all fly ash replacement, up to 40% of Portland cement can be replaced while up to 70% can be replaced by a fly ash-slag combination. Research is focused on class F fly ash and ground granulated blast furnace slag replacing Portland cement in larger quantities. Manufacturing grouts with increasing incremental amounts help to establish higher use limitations associated specifically with masonry grout. Masonry prisms, concrete masonry units, type M mortar, and variations of grout were tested for their respective compressive strengths at age intervals of 14, 28, 42, 56, and 90 days. Grouts were designed to support the discussion of whether non-traditional grouts can achieve acceptable masonry compressive strength in prisms while not possessing adequate grout compressive strength. The control grout consisted of one mix design containing a cementitious materials content of 100% Portland cement. Three grouts replaced Portland cement with fly ash and three grouts replaced Portland cement with a fly ash-slag combination without modifying the cementitious material weight contribution. Class F fly ash replaced Portland cement at rates of 45%, 55%, and 65%. Class F fly ash-ground granulated blast furnace slag combinations replaced Portland cement at rates of 65%, 75%, and 85% where the combinations consisted of 25% fly ash and 40%, 50%, and 60% slag. Results indicate that all prisms exceeded the 10.3 MPa (1500 psi) minimum compressive strength requirements before the mandated 28-day age period. Neither 55% and 65% fly ash replacements nor the 85% fly ash-slag combination achieved grout strength minimums at the typical specified age. The grout mixtures manufactured with exceeding addition rates which attained greater than the minimum strength at the 28-day age were the 45% fly ash and 65% and 75% fly ash-slag combination. All grouts did, eventually, extend their strength gain beyond 13.8 MPa (2000 psi) through the course of testing and all but 65% fly ash achieved this strength within 42 days.
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Bateman, Eric. "Performance of No Vibration/No Admixture Masonry Grout Containing High Replacement of Portland Cement with Fly Ash and Ground Granulated Blast Furnace Slag." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1163.
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When hollow concrete masonry is used for construction in high seismic regions, structural designs typically require fully grouted walls. The grouting process is labor-intensive, time-consuming and has a high energy demand due to requirements of consolidation in each and subsequent grout lifts. Self-consolidating grout with admixtures has been successfully used without segregation in walls of up to 12.67 ft. in height. Investigation of self-consolidating grout mixes without admixtures has potential for sustainability improvement.
This thesis reports on the compression strength and consolidation observations of self-consolidating characteristics of no vibration/no admixture grout made by substituting various proportions of Portland cement with Type F fly ash and/or ground granulated blast furnace slag (GGBFS). The percentages of Portland cement replacement evaluated were 0%, 50%, 60%, and 70% for Type F fly ash. The percentages of Portland cement replacement evaluated were 0%, 60%, 70% and 80% for Type F fly ash and GGBFS.
Grout compressive strengths were evaluated from individually filled grout specimens constructed in concrete masonry hollow core units, dry cured, and tested after 7, 14, 28, 42, 56, and 130 days. Also, hollow concrete masonry walls were built 12.67 ft. tall and grouted. The relative performance was assessed by comparing to conventional grouted masonry and evaluating consolidation characteristics around mortar fins and reinforcement; compressive strength tests after 130 days of curing, and rebar pull-out tests were taken from various wall heights.
All experimental grouts had acceptable consolidation characteristics but fly ash replacement grouts did not meet the compressive strength requirements.
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Blanchard, Ryan P. "Measurements and Modeling of Coal Ash Deposition in an Entrained-Flow Reactor." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2376.pdf.
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Cherki, El Idrissi Anass. "Géopolymérisation et activation alcaline des coulis d’injection : structuration, micromécanique et résistance aux sollicitations physico-chimiques." Thesis, Ecole centrale de Nantes, 2016. http://www.theses.fr/2016ECDN0015/document.
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La nécessité de construire de manière durable, rationnelle et écologique incite à l’innovation et la recherche d’alternatives, telles que la géopolymérisation et l’activation alcaline, qui suscitent un intérêt croissant. Dans ce sens, ces technologies permettent de valorise rdes matières premières à plus faible impact environnemental pour le développement d’une nouvelle famille de matériaux. Cependant, ces mécanismes réactionnels sont complexes et il est encore nécessaire de lever plusieurs verrous avant leur implémentation : la confusion entre les deux processus, l’absence d’approches de formulation rationnelles, la méconnaissance de certaines vulnérabilités, etc. La thèse s’intègre dans cette dynamique et a pour objectif une meilleure connaissance des géopolymères et des matériaux alcali-activés. Le cadre de travail est le développement de coulis d’injection. Un programme expérimental basé sur une sélection de compositions est établi afin de caractériser leurs principales propriétés. Les différences entre les deux processus de structuration sont relevées à travers une étude physico-chimique (DRX, RMN) et liées aux évolutions macroscopiques au jeune âge. Un travail d’optimisation de formulation est mené afin de répondre à des critères d’application et définir les paramètres influençant le comportement rhéologique et mécanique des coulis. Une méthodologie basée sur l’analyse micromécanique et l’homogénéisation multi-échelles a permis d’évaluer le module élastique des matériaux et peut servir de plateforme pour une analyse globale du comportement mécanique. Enfin, une étude de la durabilité est entamée en évaluant la sensibilité au séchage et à la lixiviation en milieu acideThe need for more durable, rational and ecological constructions encourages innovation and the search for alternatives, such as geopolymerization and alkali-activation, with a growing interest. These technologies allow the use of resources with a lower environmental impact in developing a new class of materials. However, both reaction mechanisms are complex and some issues need further investigation before a proper implementation: the confusion between these processes, the absence of a rational design approach, the lack of knowledge concerning some mechanisms of degradation, etc. The present thesis joins this dynamic and aims at a better understanding of geopolymers and alkali activated materials to design soil injection grouts. An experimental program has been established based on selected mix designs to study their main properties. The differences between both structuration processes were determined through a physicochemical study (XRD, NMR). They were correlated to the macroscopic phenomena observed at early age. An optimization of the mixtures was carried to satisfy the application criteria and define the parameters controlling the rheological and mechanical behavior of the grouts. Using a micromechanical characterization and multiscale homogenization, a methodology has been designed to determine the elastic modulus of the materials.This can be used as a first tool to analyze the global mechanical behavior. Finally, the sensitivity to drying and exposure to acid environments was assessed
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Schöler, Axel [Verfasser], Horst-Michael [Akademischer Betreuer] [Gutachter] Ludwig, Barbara [Gutachter] Lothenbach, and Yuanzheng [Gutachter] Yue. "Hydration of multi-component cements containing clinker, slag, type-V fly ash and limestone / Axel Schöler ; Gutachter: Horst-Michael Ludwig, Barbara Lothenbach, Yuanzheng Yue ; Betreuer: Horst-Michael Ludwig." Weimar : F. A. Finger-Institut für Baustoffkunde, 2016. http://d-nb.info/1117091201/34.
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Nilsson, Daniel, and Dennis Lundgren. "Betongens hållfasthetsutveckling vid användning av olika ersättare för portlandklinker : En laborativ studie." Thesis, KTH, Byggteknik och design, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-101677.
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Tillverkning av portlandklinker står för ungefär fem procent av världens totala koldioxidutsläpp. Det finns därför ett allmänt intresse att minska användandet av portlandklinker. Klinkern kan antingen ersättas av andra cementerande material, eller så kan nya cementsnåla recept utformas. I den här rapporten har två cement med inmald flygaska respektive slagg från Cementa AB undersökts. För att undersöka klinkerersättnings-materialens potential har tester för tryckhållfasthet, uttorkningskrympning, bindetid, värmeutveckling och arbetbarhet utförts. Resultaten visar att skillnaderna mellan försökscementen och byggcementet är så pass små att båda bör kunna användas som byggcement. Ytterligare har ultrafiller av kalksten använts som ersättare för att minska cementhalten i betongen. Det går lika bra att delvis ersätta försökscementen med ultrafiller som det gör för byggcementet. Med cementsnåla recept och större del ersättningsmaterial finns det stora möjligheter att spara på energi och miljö. Detta borde i framtiden kunna leda till ett bättre och mer miljövänligt byggmaterial.Manufacture of clinker is responsible for about five percent of the total global carbon dioxide emissions. Therefore, there is a general interest in reducing the use of clinker. Clinker can either be replaced by other cementitious materials, or reduced by using lean-cement recipes. This report examines two experimental cements, one with fly ash and one with slag, developed by Cementa AB. To examine the potential of clinker replacement materials, tests for compressive strength, drying shrinkage, initial setting, heat generation and workability, were performed. The results show that the differences between the experimental cements and the reference are so small that both are useable as building cements. In addition, an ultrafine filler of limestone is used as a replacement material for further reduction of the clinker content in concrete. It was also found, that it is just as efficient to partly replace the experimental cements with ultrafine filler as in the reference cement. There are great opportunities to save energy and the environment impact with both clinker-saving cement recipes and with cement replacement materials. This should lead to a better, more environmentally friendly, building material in the future.
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Brizola, Rodrigo Matzenbacher. "MICROESTRUTURA DO COBRIMENTO DE CONCRETOS COM ALTOS TEORES DE ESCÓRIA E CINZA VOLANTE ATIVADAS POR CIMENTO PORTLAND E CAL HIDRATADA." Universidade Federal de Santa Maria, 2007. http://repositorio.ufsm.br/handle/1/7882.
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In the history of the concrete structures there was a time in which the mechanical resistance was the most important property for the designers. However due to amount of pathologies in the concrete structures and your respective worn-out amounts in recovery, other feature is being prioritized: the durability. And for environmental reasons as global heating, pollution and the raw materials decrease, the sustentability is prioritized. Aiming at collaborate to these
factors these paper has as objective analyzes the microstructure of the covercrete with substitution in mass of 90% of cement for mineral additions. Were researched three types of concretes reference concrete (100%CPV-ARI), concrete with 70%Slag+20%FlyAsh and other similar mixture with addition of 20% of hydrated lime with the intention of partially restoring the hydroxide of calcium consumed by the pozzolanics reactions - named respectively of R, EV and EVC. Aims at, more specifically, to establish the differences
microstructures of the covercrete of the prototypes(beams-70x20x15cm), through the tests of combined water, x-ray diffraction and scanning electron microscopy. For comparison effect, compressive strength test were also accomplished in molded cylinders(10x20cm) and cured in humid camera and in the cylinders(10x20cm) extracted of the cured prototypes in
environmental conditions after 7 days of humid cure. Were studied three relationships a/ag: 0.40, 0.60 and 0.80 for the concrete R and 0.30, 0.40 and 0.50 for the concretes with
additions, obtaining resistance between 20 and 70MPa. The tests of the microstructure were accomplished in the 91 and 300 days, with samples starting from the surface of the
prototypes, in layers, in the depths of: 0-1.0cm(C1), 2.0-3.0cm(C2) and 4.5-5.5cm(C3). Evolution of the strength was accompanied in the ages of 28, 91, 182 and 300 days. Results
were analyzed in equality of a/ag and compressive strength. For a/ag 0.40 and 0.50, to 28 days of age, in relation to reference concrete, the strength of the concrete EV was 54.0% on average of this, and the concrete EVC it was 68.5%. In the final age of 300 days, the percentile are of 72.5% and 76%. In both tests ages, with the increase of the depth of the layer occurs: decrease in the intruded volume total mercury, decrease in the tenor of combined water for the reference concrete and increment in the concretes with additions, decrease in the intensity of pick of the hydroxide of calcium in the three mixtures, decrease in the intensity of
pick of the hydrated silicate for the reference concrete and increment in the concretes with mineral additions. Analysis on scanning electron microscopy showed refinement in the size of
the grains, larger compact and uniformity in the mixtures with additionsNa história das estruturas de concreto houve período no qual a resistência mecânica foi a propriedade mais importante para os projetistas. Porém, devido ao surgimento de manifestações patológicas nas estruturas de concreto e seus respectivos montantes gastos em recuperação, outro aspecto também está sendo considerado: a durabilidade. Por motivos ambientais como aquecimento global, poluição e diminuição das matérias-primas, prioriza-se também a sustentabilidade. Visando colaborar com estes fatores o presente trabalho tem como objetivo analisar a microestrutura da camada de cobrimento de concretos com substituição em massa de 90% de cimento Portland por adições minerais. Foram pesquisadas três misturas: concreto de referência (100%CPV-ARI), concreto com 70%Escória+20%CinzaVolante e outra mistura similar com adição de 20% de cal hidratada com o intuito de repor parcialmente o hidróxido de cálcio consumido pelas reações pozolânicas as quais foram nomeadas respectivamente de R, EV e EVC. Objetiva, mais especificamente, estabelecer as diferenças microestruturais da camada de cobrimento de protótipos (vigas 70x20x15cm), através dos ensaios de porosimetria por intrusão de mercúrio, água combinada, difração de raios-X e microscopia eletrônica de varredura. Para efeito de comparação, também foram realizados ensaios de resistência à compressão em corpos-de-prova (10x20cm) moldados e curados em câmara úmida e em testemunhos (10x20cm) extraídos dos protótipos curados em condições ambientais após 7 dias de cura úmida. Foram estudadas três relações a/ag: 0.40, 0.60 e 0.80 para o concreto R e 0.30, 0.40 e 0.50 para os concretos com adições, obtendo resistências entre 20 e 70MPa. Os ensaios da microestrutura foram realizados aos 91 e 300 dias, com amostras a partir da face dos protótipos, em três camadas, nas profundidades: 0-1cm(C1), 2- 3cm(C2) e 4.5-5.5cm(C3). A evolução da resistência foi acompanhada nas idades de 28, 91, 182 e 300 dias. Os resultados foram analisados em igualdade de relação a/ag e resistência à compressão. Para as relações a/ag 0.40 e 0.50, aos 28 dias de idade, em relação ao concreto de referência, a resistência do concreto EV foi em média 54.0% deste, e o concreto EVC foi 68.5%. E na idade final de 300 dias, os percentuais são de 72.5% e 76%. Em ambas as idades de ensaio, com o aumento da profundidade da camada ocorreu: decréscimo no volume total intrudido de mercúrio, decréscimo no teor de água combinada para o concreto de referência e acréscimo nos concretos com adições, decréscimo na intensidade de pico do hidróxido de cálcio nas três misturas, decréscimo na intensidade de pico do silicato de cálcio hidratado para o concreto de referência e acréscimo nos concretos com adições minerais. A análise das micrografias mostrou refinamento no tamanho dos grãos, maior densificação e uniformidade nas misturas com adições
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Fialová, Barbora. "Rehydratace alkalicky aktivované strusky po vysokoteplotním namáhání." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-239940.
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Ground granulated blast furnace slag is a by-product of the steel industry and is often used in combination with ordinary Portland cement as a binder in concrete. When concrete is exposed to high temperatures, physical and chemical transformations lead to significant loss of mechanical properties. This study aims to investigate the effect of high temperatures and rehydration on the mechanical properties, microstructure and phase composition of alkali activated slag. The results of the research could make an important contribution to decisions made concerning the reconstruction of structures affected by fire. In suitable cases it would be possible to regenerate parts of a structure instead of totally rebuilding it.
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Eckl, Ondřej. "Využití některých velkoobjemově produkovaných druhotných surovin k přípravě pojiv a kompozitů na bázi geopolymerů." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2009. http://www.nusl.cz/ntk/nusl-216460.
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Lisztwanová, Ewa. "Kompozitní materiály se silikátovou matricí do prostředí vysokých teplot." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265581.
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This thesis deals with the study and design of composite materials based on silica matrix suitable for extreme conditions, eg. for the repair of concrete structures with anticipated increased risk of fire. The theoretical part summarizes basic knowledge concerning the fire resistance of structures and the behavior of the composite system during extreme conditions. Theoretically oriented section also contains information on alkali-activated materials and their use in high temperature environments. Based on the evaluation of the theoretical part of the experiment were designed and tested different types of composite materials with increased content of raw materials from alternative sources. Laboratory research has been based on testing of basic physico-mechanical parameters including phase composition and microstructure of the proposed formulations before and after thermal exposure of 1200 ° C. Also considered was the effect of different cooling conditions.
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Munhoz, Flávio André da Cunha. "Efeito de adições ativas na mitigação das reações álcali-sílica e álcali-silicato." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/3/3146/tde-10012008-100734/.
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A reação álcali-agregado é uma manifestação patológica diretamente ligada à seleção dos materiais (cimento, agregados miúdo e graúdo, água e aditivos) que pode comprometer a durabilidade das estruturas de concreto, uma vez que a interação desses materiais e as condições ambientais é que vão conferir ao concreto determinadas propriedades ligadas à sua vida útil. A reação entre os hidróxidos alcalinos solubilizados na fase líquida dos poros dos concretos e alguns agregados reativos é lenta e resulta em um gel que, ao se acumular em vazios do concreto e na interface pasta-agregado, na presença de água, se expande, exercendo pressão interna no concreto. Ao exceder a resistência à tração do concreto, a pressão interna pode promover fissurações. A reação álcali-agregado requer a atuação conjunta de água, agregado reativo e álcalis. Sua prevenção pode ser feita a partir da eliminação de um dos fatores, ou seja, a partir do emprego de agregados inertes ou de cimentos com baixos teores de álcalis ou isolamento da umidade. Na impossibilidade de eliminar um dos fatores, medidas preventivas devem ser tomadas para o emprego de agregados reativos em obras de construção civil. Entre essas, destacam-se a utilização de cimentos com baixos teores de álcalis ou a de cimentos com adições ativas mitigadoras da reação álcali-agregado: escória de alto-forno, cinza volante, metacaulim e sílica ativa, que foi o objeto de pesquisa do presente trabalho. No programa experimental foram analisados dois tipos de agregado potencialmente reativos com os hidróxidos alcalinos: EDVDOWR e PLORQLWR_ JUDQtWLFR. O primeiro, proveniente de rocha ígnea, tem como constituintes deletérios vidro, clorofeíta, calcedônia (sílica criptocristalina), que dará origem à reação do tipo iOFDOL_VtOLFD. O agregado milonito granítico provém de rocha metamórfica, tem como constituintes deletérios quartzo microgranular, quartzo recristalizado, quartzo com extinção ondulante e quartzo e feldspato deformados, que dará origem ao tipo de reação iOFDOL_VLOLFDWR. Com o objetivo de avaliar a eficiência de adições ativas em mitigar as reações, os agregados foram combinados com 16 cimentos com adições ativas. Escória de alto-forno foi adicionada a 15%, 30%, 45% e 60% e cinza volante, a 10%, 15%, 25% e 35%, teores normalmente encontrados nos cimentos brasileiros. Metacaulim foi adicionada a 5%, 10%, 15% e 20%, e sílica ativa, a 5%, 10% e 15%, teores representativos da faixa normalmente adicionada diretamente a concretos. Todos os materiais utilizados foram caracterizados química, física e mineralogicamente, incluindo a análise petrográfica dos agregados. As barras de argamassa foram analisadas ao MEV, microscópio óptico de luz transmitida, realizaram-se ensaios de porosimetria por intrusão de mercúrio e análises térmicas para quantificar a teor de portlandita residual, e determinou-se o teor de álcalis dentro das barras após a realização dos ensaios para verificar a migração de íons de sódio. Os resultados indicam que a eficiência das adições ativas varia de acordo com a composição química e mineralógica das adições, da proporção desse material no cimento, e do grau de reatividade do agregado.The alkali-aggregate reaction is a pathologic manifestation that can induce the premature distress and loss in serviceability of concrete structures affected. It is directly associated to the selection of materials (cement, coarse and fine aggregates, water and additives), as the interaction between these materials and environmental condition will grant the concrete some of the properties related to its service life. The slow reaction between alkali hydroxides soluble in the liquid phase within concrete pores and reactive aggregates gives rise to a gel that piles up within concrete voids and the aggregate-paste interface. In presence of water, the gel expands and exerts internal pressure in the concrete. When the internal pressure exceeds the tensile strength, cracking may come up as result. The alkali-aggregate reaction requires the action of water, reactive aggregate and alkalis altogether. Prevention can be carried out by eliminating one of these factors, i.e. employing either inert aggregates or lowalkali cements, or keeping the concrete away from moisture. Otherwise, preventive measures must be taken when reactive aggregates are used in civil construction works, such as the use of low-alkali cements or composite cements bearing alkaliaggregate- reaction mitigating admixtures: blast-furnace slag, fly ash, metakaolin and silica fume, which are the object of the present research. The experimental work included the analysis of two potentially reactive aggregates to alkali hydroxides: basalt and granite milonite. The igneous basalt carries deleterious constituents such as glass, chloropheite (cryptocrystalline silica), that will give rise to the DONDOL_VLOLFD type reaction while the metamorphic granite milonite carries micro granular, recrystallized, undulate-extinction-bearing quartz and deformed feldspar grains, that give rise to DONDOL_VLOLFDWH type reaction. Aiming at evaluating how efficient in mitigating these reactions the active admixtures are, these aggregates were mixed with 16 composite cements. The contents of admixtures followed those usually found in Brazilian industrial cements for blast-furnace slag (15%, 30%, 45%, 60%) and fly ash (10%, 15%, 25%, 35%), and those generally added directly to concrete for metakaolin (5%, 10%, 15%, 20%) and silica fume (5%, 10%, 15%). All materials were characterized for their chemical composition, physical properties and mineralogy. Petrography was carried out on the aggregates. The mortar bars were analyzed at the scanning electronic and transmitted-light optical microscopes. Mercury-intrusion porosimetry and thermal analyses were carried out to quantify residual portlandite. The alkali content within the bars was determined in order to verify migration of Na+ ions. The results show that the efficiency of active admixtures varies according to their chemical and mineralogical composition and proportioning in cement, and to the aggregate reactivity.
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Indra, Ivo. "Kompozitní materiály na bázi alkalicky aktivované vysokopecní strusky s přídavkem elektrárenských popílků." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2010. http://www.nusl.cz/ntk/nusl-216595.
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This thesis concerns on substitution of blast furnace slag or its part with fly ash in alkali-activated systems based on aluminosilikates. Classic, fluid bottom and fluid filter fly ashes will be tested. The goal is to prepare geopolymer with required mechanical properties, but with maximal admixture of alternative raw materials. In composites with substitutioned slag or its part the thesis focuses mainly on workabilityof fresh mixture, pressure and bending strenght. Use of secondary raw materials has advantages in the economic point of view and it´s friendly to enviroment, too.
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Kalina, Martin. "Podlahové systémy na bázi druhotných surovin z energetického průmyslu." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2014. http://www.nusl.cz/ntk/nusl-217076.
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This thesis deals with the possibility of using secondary raw materials from the energy industry especially the solid residues of high temperature combustion of coal. These materials should be now seen as a material with wide usage especially in the construction industry. One possibility of their usage is a replacement of binding parts in floor systems. The aim is to find the optimal composition of the mixture, which fits all the technical requirements and at the same time reduces the cost of its production. An advanced methods of powder X-ray diffraction analysis, particle size laser diffraction analysis and X-ray fluorescence analysis were used to determine the raw materials. Based on these analysis the experiments were designed focusing on the mechanical properties, the observation of the evolution of hydration’s heat in prepared mixtures and their time of setting and hardening.
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Kejík, Pavel. "Low-Cost Filtration Barriers for Ultrafine Particles Separation." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-401605.
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V mnoha oborech jsou stále využívána anorganická filtrační media založená na materiálech, jejichž výroba využívá primární suroviny. Jejich výroba je tedy energeticky náročná a v důsledku nákladná a neohleduplná k životnímu prostředí. Cílem této práce je ověřit možnost využití alkalicky aktivovaných materiálů na bázi sekundárních surovin, především vysokopecních strusek (BFS) a popílků z uhelných elektráren (FA), pro výrobu porézních médií schopných v budoucnosti nahradit keramické a jiné anorganické filtry. Výzkum je rozvinut skrze experimentální design založený na výpočetním schématu samostatně vyvinutém s pomocí programu MATLAB. Toto schéma počítá vhodná složení směsí na základě poměrů obsahu nejdůležitějších oxidů ve vstupních surovinách. Tak je zajištěno zohlednění proměnlivého složení vstupních surovin a práce je tím hodnotnější, že její výsledky jsou skrze početní nástroj zohledňující základní oxidové složení surovin zobecnitelné. Zároveň byly však pro srovnání a lepší názornost závislostí vlastností na složení navrhnuty a připraveny i série vzorků založené vždy pouze na jedné ze surovin. Z výsledků vyplývá, že pevnost vzorků z těchto směsí (vytvrzených 24 hodin při 70 °C) ve čtyřbodové ohybové zkoušce dle ČSN EN 12390 5 může přesáhnout 7,6 MPa. Dosažením co možná nejvyšší porozity však zákonitě negativně ovlivňuje pevnost materiálu a výsledný materiál tedy dosahuje pevnosti těsně nad hranicí 6,3 MPa. Výsledky obecně dokazují, že nejvíce je pevnost materiálů ovlivněna poměrem SiO2/Al2O3 a množstvím alkalického aktivátoru. Z výsledků vyplývá, že alkalicky aktivované materiály (AAM) na bázi strusky dosahují i více než dvojnásobné pevnosti analogických materiálů na bázi elektrárenského popílku. Velikost pórů materiálů připravených z tříděných surovin s velikostí zrna od desítek po lehce přes sto mikronů se ve většině případů pohybuje v rozmezí desetin ž jednotek mikronů, v případě výsledného materiálu je to pak přibližně 0,2 mikronu. Celková porozita lisovaných těles se pohybuje těsně pod 40 %, což je v tomto případě téměř dvojnásobek ve srovnání s totožnými materiály na bázi netříděných surovin. Výsledky rovněž ukazují, že materiály na bázi strusky vykazují nižší porozitu než ty na bázi popílku, což je patrně způsobeno rozdílnou morfologií částic obou materiálů – částice strusky jsou nepravidelně hranaté a částice popílku kulaté. V průběhu experimentální činnosti byla pozorována tvorba výkvětů u materiálů na bázi elektrárenských popílků. Pomocí Energo-disperzní spektroskopické analýzy (EDS) byly výkvěty identifikovány jako hydroxid sodný procházející karbonatací za účasti vzdušného CO2. Test permeability vyžadoval, kvůli velmi jemné povaze porézní struktury, přípravu asymetrických filtračních přepážek. Tyto přepážky dosáhli propustnosti 138 L/h.m2.bar pro vodu a 1320 L/h.m2.bar pro vzduch.
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Cantarelli, Gustavo Martins. "PERCOLAÇÃO DE ÁGUA EM CONCRETOS COM ELEVADOS TEORES DE ESCORIA E CINZA VOLANTE COM ADIÇÃO DE CAL." Universidade Federal de Santa Maria, 2007. http://repositorio.ufsm.br/handle/1/7678.
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Conselho Nacional de Desenvolvimento Científico e TecnológicoThe study of concrete structures durability necessarily passes by the study of covercrete and by the understanding of the factors that affect the features of this superficial layer. The use of high contents of mineral addictions on the concrete influences meaningfully the resistance of the covering layer to the chemical attack and on the pores structure. This dissertation aimed to analyze, through the obtained results in the tests of capillary water absorption, according to the RILEM TC 116 PCD Recommendation, and to the diffusion of water held following the directives DAN et al (1988) presented by Isaia (1995), based on publications of CSTB, the percolation of water on concrete covering layer, besides co-relating with the resistance to 50 MPa, the total volume of intruding mercury and the critical diameter of the pores. To these analysis perform, prototypes specimens of 75 cm x 20cm x 15cm have been molded with high contents of mineral additions, 70 % of slag and 20% of fly ash, in replacement to the cement mass, with or without addition of 20% of hydrated lime, in mass, and w/cm relationships 0,3 ; 0,4 ; 0,5 besides the reference mix proportion, only with cement and w/cm relationships 0,4; 0,6 e 0,8. The tests of capillary absorption and water diffusion were held, on the 91 and 300 days to execute the comparative study between these two ages, extracted specimens of 10 cm x 20 cm, from the prototypes had been accomplished, being closed to 0, 2,5 e 5,0cm of depth from the surface. After performing the analysis, it has been noticed that the replacement of cement by mineral additions causes a strength reduction to the compression, being it more accentuated in the initial ages and eased as the time passes by. In relation to the coefficients of water absorption and diffusion of the concretes with mineral additions compared to the reference concretes in equality of w/cm and ages, being analyzed the use of additions, meaningful reductions that get to 79% in the absorption and 69% in the diffusion, on the 300 day. When analyzed considering the depth (in equality of w/cm) the layer reduction 3 (5cm) in relation to 1(0,5cm) gets to 55% in the absorption and 31% in the diffusion, on the 300 day, and in the mix proportion with addition of hydrated lime, justifiable by the fact of the hydrated lime stored water helping in the hydrating process producing a more compact matrix. In equality of 50 Mpa compressive strength, the reductions are 86% to the absorption and 70% to the diffusion. It s been noticed, as to the absorption as to the diffusion, a strong co-relation with the intruding total volume and the pores diameter on the 300 day.
O estudo da durabilidade das estruturas de concreto passa, necessariamente, pelo estudo do concreto de cobrimento e pelo entendimento dos fatores que afetam as características dessa camada superficial. O uso de altos teores de adições minerais no concreto influencia significativamente a resistência da camada de cobrimento ao ataque químico e a estrutura dos poros. Esta dissertação tem por objetivo analisar, através dos resultados obtidos nos ensaios de absorção capilar de água, conforme a norma RILEM TC-116 PCD, e de difusão de água, realizado seguindo as diretrizes de Dan et al (1988), apresentadas por Isaia (1995), baseadas em publicações de CSTB, a percolação de água na camada de cobrimento do concreto, além de correlacionar com a resistência a 50 MPa , o volume total de mercúrio intrudido e o diâmetro crítico dos poros. Para realização dessas análises, foram moldadas peças protótipos de 75 cm x 20 cm x 15 cm, que permaneceram em exposição ambiental até a data de realização dos ensaios. Os protótipos foram moldados com altos teores de escória, 70% e cinza volante 20%, em substituição à massa de cimento, com e sem adição de 20% de cal hidratada, em massa, e uma relação a/mc 0,3, 0,4, 0,5, além do traço de referência, somente com cimento e relação a/c 0,4; 0,6 e 0,8. Os ensaios de absorção capilar e de difusão de água foram realizados aos 91 e 300 dias. Para executar o estudo comparativo entre essas duas idades, foram extraídos testemunhos 10 cm x 20 cm dos protótipos sendo cerrados a 0, 2,5 e 5,0 cm de profundidade a partir da superfície. Após a realização das análises, observou-se que a substituição de cimento por adições minerais acarreta uma diminuição na resistência à compressão, sendo mais acentuada nas idades iniciais e amenizada com o passar do tempo. Em relação aos coeficientes de absorção e de difusão de água dos concretos com adições minerais, comparados com os concretos de referência, em igualdade de a/mc e idades analisadas, o uso de adições resultou em significativas reduções nesses coeficientes, que chegam a 79% na absorção e de 69% na difusão, aos 300 dias. Quando analisados em função da profundidade (em igualdade de a/mc), as reduções da camada 3 em relação à camada 1 chegam a 55% na absorção e 31% na difusão, aos 300 dias e nos traços com adição de cal hidratada. Esse comportamento é justificável pelo fato de a cal hidratada armazenar água auxiliando nos processos de hidratação, produzindo uma matriz mais compacta. Em igualdade de resistência, as reduções são de 86% para a absorção e de 70% para a difusão. Observa-se, tanto para a absorção como para a difusão, uma forte correlação com o volume total intrudido e o diâmetro dos poros aos 300 dias.
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Mizerová, Cecílie. "Binární alkalicky aktivované kompozitní materiály s cihelným prachem." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-372259.
Full textAbstract:
The thesis is focused on the application of brick powder in production of binary alkali-activated binders with metakaolin, slag and fly ash. The theoretical part summarizes recent fields of use of the ceramic waste in construction and binder industry and prerequisite properties of the brick powder for alkaline activation. Brick powder based geopolymers made in the experimental work were tested for their mechanical properties, porosity and microstructure, flow properties of the fresh geopolymers were evaluated by rheometric measurements. In accordance with the results it can be concluded that brick powder could be a suitable precursor for blended binders with metakaolin and slag, these samples exhibited good mechanical properties and microstructure characteristics. The combination with fly ash was less applicable due to a rapid setting, hardening retarder used in these binders caused significant deterioration of the mechanical properties of the material.
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Novák, Václav. "Vliv velikosti částic odpadního skla na vlastnosti alkalicky aktivovaných aluminosilikátových kompozitů." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392355.
Full textAbstract:
The diploma thesis is focused on the use of the waste glass with different fineness on alkali - activated composites, mainly based on slag and fly ash. The theoretical part is focused on materials that are most used for alkaline activation - slag, fly ash and their composites with waste glass. The theoretical part also deals with the alkaline activation of composites from these materials and the factors that influences the microstructure and properties of these composites. In the experimental part were prepared composites from slag and fly ash with a waste glass as substitute. These composites then have been examined on mechanical properties and microstructure, also how different fineness of glass influences these properties. Then it will be decided whether it is economically advantageous grinding waste glass to finer fractions
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Khokhar, Muhammad Irfan. "Optimisation of concrete mix design with high content of mineral additions: effect on microstructure, hydration and shrinkage." Doctoral thesis, Universite Libre de Bruxelles, 2010. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209985.
Full textAbstract:
The cement being used in the construction industry is the result of a chemical processlinked to the decarbonation of limestone conducted at high temperature and results in a
significant release of CO2. This thesis is part of the project EcoBéton (Green concrete) funded
by the French National Research Agency (ANR), with a purpose to show the feasibility of
high substitution of cement by mineral additions such as blast furnaces slag, fly ash and
limestone fillers. Generally for high percentages of replacements, the early age strength is
lower than Portland cement concrete. To cope with this problem, an optimisation method for
mix design of concrete using Bolomey’s law has been proposed. Following the encouraging
results obtained from mortar, a series of tests on concretes with different substitution
percentages were carried out to validate the optimisation method. To meet the requirements of
the construction industry related to performance of concrete at early age, which determine
their durability, a complete experimental study was carried out. Standard tests for the
characterization of the mechanical properties (compressive strength, tensile strength, and
setting) allowed to validate the choice of mix design on the basis of equivalent performance.
We focused on the hydration process to understand the evolution of the mechanical
properties. Setting time measurement by ultrasound device at different temperatures (10°C,
20°C and 30°C) showed that ground granulated blast furnace slag (GGBFS) and fly ash
delayed the setting process, while use of limestone filler may accelerate this process.
Calorimetric studies over mortars and concretes made possible to calculate the activation
energy of the different mixtures and a decrease in heat of hydration of concretes with mineral
additions was observed which is beneficial for use in mega projects of concrete. Scanning
Electron Microscopy observations and thermal analysis have given enough information about
the hydration process. It was observed that the hydration products are similar for different
concrete mixtures, but the time of their appearance and quantity in the cement matrix varies
for each concrete mix.
Last part of the thesis was dedicated to the study of main types of shrinkage. First of all,
deformations measured were correlated to hydration, capillary depression and porosity
evolution. Results allowed concluding that the use of mineral additions has an actual effect on
the plastic shrinkage behaviour, but its impact is not proportional to the percentage of
additions. Substitution of cement by the additions seems to have a marked influence on the
kinetics of the shrinkage without any effect on its long term amplitude. The study of
restrained shrinkage under drying conditions by means of ring tests showed that concretes
with high percentage of slag addition seem more prone to cracking than the Portland cement
concretes.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
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Chung-HoTsai and 蔡宗和. "Alkali-activated Slag Binders with BOF Slag and Fly Ash." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/86526443069730108431.
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"Kinetics of Alkaline Activation of Slag and Fly ash-Slag Systems." Master's thesis, 2012. http://hdl.handle.net/2286/R.I.15972.
Full textAbstract:
abstract: Alkali-activated aluminosilicates, commonly known as "geopolymers", are being increasingly studied as a potential replacement for Portland cement. These binders use an alkaline activator, typically alkali silicates, alkali hydroxides or a combination of both along with a silica-and-alumina rich material, such as fly ash or slag, to form a final product with properties comparable to or better than those of ordinary Portland cement. The kinetics of alkali activation is highly dependent on the chemical composition of the binder material and the activator concentration. The influence of binder composition (slag, fly ash or both), different levels of alkalinity, expressed using the ratios of Na2O-to-binders (n) and activator SiO2-to-Na2O ratios (Ms), on the early age behavior in sodium silicate solution (waterglass) activated fly ash-slag blended systems is discussed in this thesis. Optimal binder composition and the n values are selected based on the setting times. Higher activator alkalinity (n value) is required when the amount of slag in the fly ash-slag blended mixtures is reduced. Isothermal calorimetry is performed to evaluate the early age hydration process and to understand the reaction kinetics of the alkali activated systems. The differences in the calorimetric signatures between waterglass activated slag and fly ash-slag blends facilitate an understanding of the impact of the binder composition on the reaction rates. Kinetic modeling is used to quantify the differences in reaction kinetics using the Exponential as well as the Knudsen method. The influence of temperature on the reaction kinetics of activated slag and fly ash-slag blends based on the hydration parameters are discussed. Very high compressive strengths can be obtained both at early ages as well as later ages (more than 70 MPa) with waterglass activated slag mortars. Compressive strength decreases with the increase in the fly ash content. A qualitative evidence of leaching is presented through the electrical conductivity changes in the saturating solution. The impact of leaching and the strength loss is found to be generally higher for the mixtures made using a higher activator Ms and a higher n value. Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) is used to obtain information about the reaction products.Dissertation/Thesis
M.S. Civil Engineering 2012
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Wei, Rui-Jun, and 魏睿君. "Properties of alkali-activated slag-fly ash concrete." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/2d6p5e.
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Wnag, Yu-He, and 王郁賀. "Study for Transport Behavior of Slag-Fly Ash Concrete." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/53001781534744354335.
Full textAbstract:
碩士國立臺灣海洋大學
材料工程研究所
103
In this study, concrete containing different slag-fly ash ratios (30%,40%,50% and 60%) of mineral admixtures with different water-to-binder ratios (0.45, 0.55 and 0.65) are made and test with the rapid chloride permeability test (RCPT), accelerated chloride ion transport test (ACMT) and Chloride migration coefficient from non-steady-state migration experiments (RCM) etc. After the test got total charge, penetration depth, steady-state migration coefficient (MS) and non- steady-state migration coefficient (MR 、Mn) to evaluate the durability and the correlation among each test. Compressive results show strength decrease with increasing W/B, but there is no rise or declining trend with increasing slag-fly ash amount of cement replacement, only with the W/B=0.45 substitution ratio 30% and 40% ,higher than the control group (group C); RCPT results show that the total charge decrease with increases W/B,that it increases with slag-fly ash amount of cement replacement less,and penetration depth,and the total content of chloride ion are also the same result. ACMT results showed that in 91 days of curing age, steady state and non-steady state migration coefficient increases due to W/B rises, and they become less with an increases with slag-fly ash amount of cement replacement less; RCM test results show that the migration coefficient with non-steady falls with slag-fly ash amount of cement replacement increasing.When the slag-fly ash amount replace 60%, non-steady-state migration coefficient is higher than 50%. The test about RCPT penetration depth and the total charge showed that, because slag-fly ash replace part of the cement, hydration reaction at 28 days of age than control group (Group C) and produce intercept difference. It may need to adjust the charge.The test also show that at the age of 91 days compared to 28 days, the hydration reaction more complete and the two groups showed a good linear relationship (R2=0.93), which does not need to adjust charge. RCM non-steady state migration coefficient and ACMT steady migration coefficient show that in the age of 28 days showed a linear relationship (R2=0.97);Both MR,MS and RCPT penetration depth show that the deeper RCPT penetration depth, the higher and MR,MS.They show a linear relationship.
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Lu, Cheng-Young, and 呂澄洋. "STABILIZATION OF SWINE MANURE WITH FLY ASH,SLAG AND LIME." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/32988424431164030087.
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Hwang, Wha-Shi, and 黃惠香. "STABILIZATION OF SWINE MANURE WITH FLY ASH,SLAG AND LIME." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/79040977554575538665.
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Chen, Hsi-An, and 陳璽安. "Binding Mechanism and Properties of Alkali-Activated Fly Ash/Slag Mortar." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/96656137703531384279.
Full textAbstract:
碩士國立臺灣海洋大學
河海工程學系
100
This study presents an investigation into binding mechanism and properties of alkali-activated fly ash/slag mortars. Two levels of sodium oxide (Na2O) concentrations of 4% and 6% of mineral material weight and liquid sodium silicate (SiO2) with modulus ratio of 1 ( mass ratio of SiO2 to Na2O ) were used as activators to activate various ratios of fly ash to slag. The liquid/binder ratios of 0.35, 0.5 and 0.65 were used, respectively. Compressive strength test, flexural strength test, water absorption test, drying shrinkage test, scanning electron microscopy (SEM) and X-ray diffraction analysis were performed and their performance was discussed and compared with reference mortars produced by ordinary Portland cement mortars. At the same liquid/binder ratio, higher compressive strengths have been observed in alkali-activated fly ash /slag mortars (except alkali-activated fly ash mortars) than comparable ordinary Portland cement mortars at the age of 28 days. Meanwhile, the compressive strength of alkali-activated fly ash/slag mixing ratio of 50/50 is higher than that of the other ash/slag mixing ratios, and the compressive strength of alkali-activated fly ash/slag increases with an increase dosage of Na2O. A similar trend is observed for the specimens in flexural strength test. As the level of Na2O concentrations of 6% and the fly ash/slag mixing ratio of 50/50, alkali-activated fly ash/slag mortars have the lower water absorption and least drying shrinkage. the gap between the fly ash particles are calcium aluminum silicate compounds can be seen from the microscopic analysis, and when the hydration of slag growth steady, the densification of specimens will increase substantially. Thus, the fly ash/slag mixing ratio of 50/50 alkali-activated with the level of Na2O concentrations of 6% may be considered as the optimum mix design based on the results.
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Fang, Ming-Yi, and 方銘毅. "Theoretical Modelling Chloride Diffusion in Concretes Containing Fly Ash and Slag." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/29033972234500818386.
Full textAbstract:
碩士國立臺灣海洋大學
河海工程學系
99
The main purpose of this thesis is to study the modelling of chloride diffusion in fly ash and slag concretes exposed to chloride environments. The capacity of the concrete cementations system to bind chloride ions has an important effect on the rate of chloride ionic transport in concrete. This thesis reviews four mathematical models used for stating chloride binding in concrete. The analytical solutions of Fick’s second law of linear (diffusivity = constant) and nonlinear (diffusivity constant) diffusion equations associated with initial and boundary conditions are used as predictive models, respectively. The experimental data obtained by Thomas and Bamforth [Modelling chloride diffusion in concrete: Effect of fly ash and slag. Cement and Concrete Research 1999; 29: 487-495] was cited as input parameters. The results at the present study show as follows: 1. In the case of linear model, the chloride profiles in the Portland cement (PC), fly ash, and slag concretes predicted by the model of no binding is in good agreement with that of experimental data. Furthermore, the ranking of chloride concentration content in these concretes for four mathematical models is (1) no binding (2) linear binding (3) Langmuir isotherm, and (4) Freundlich isotherm. 2. The nonlinear model in conjunction with four mathematical models related to chloride binding in concretes is not suitable to predict the transport mechanism of chloride diffusion in concretes containing fly ash and slag. Further research of fly ash or slag blended cement hydration is needed and suggested.
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Jiun-HauTu and 涂俊豪. "Binding Mechanism and Durability of Alkali-Activated Slag/Fly Ash Concrete." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/vw2rpm.
Full textAbstract:
碩士國立臺灣海洋大學
河海工程學系
102
There are two models of alkali-activated cements, one is the case of activation of slag (Si + Ca) and the other is activation of fly ash (Si + Al). The major chemical product for alkali-activated slag is C-S-H gel while for alkali-activated fly ash it is amorphous hydrated alkali-aluminosilicate. This study investigates the binding mechanism and durability of alkali-activated slag/fly ash concrete with various slag/fly ash ratio, liquid/binder ratio, alkali modulus ratio, Na2O concentration and curing temperature. Setting time, length change, compressive strength, splitting strength, rapid chloride penetration test and sulfate resistance were performed. Test results reveal that the slag/fly ash ratio and alkali modulus ratio are two key factors influencing the compressive strength of alkali-activated mortars. The optimal combination ratio of alkali-activated mortar with 0/100 of fly ash/slag, 0.5 of liquid/binder ratio, 1.23 of alkali modulus ratio, 8% Na2O concentration,and cured at the temperature of 65℃ has the highest compressive strength performance by Taguchi method. The compressive strength of alkali-activated concrete (AAC) is higher than that of ordinary Portland cement concrete (OPCC). Meanwhile, the higher the slag/fly ash ratio is, the higher the compressive strength was observed. In durability, the total charge passed of AAC is higher than that of OPCC due to the high concentration of ionic species, mainly Na+ and OH- which influence the results of the RCPT. The weight loss of AAC is lower than that of OPCC and the compressive strength of AAC increases after the sulfate resistance test. SEM micrograph of AAC at the age of 28 days show that the surface of alkali-activated slag forms the rod-like crystals of ettringite and C-S-H gel which are the major hydration products, while for alkali-activated fly ash it is higher proportion of un-reacted fly ash spheres remain in the matrix and the amorphous microspheres surrounded by a glassy crust of reaction products.
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Yang, Chang-Yo, and 楊長祐. "Research on Cost-Effective Mixing Design of Slag-Fly Ash Concrete." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/362hdd.
Full textAbstract:
碩士國立高雄第一科技大學
營建工程系碩士班
106
This study is the application of cost-effective concrete mixing design, for the domestic common ACI concrete mixing design model to do some changes, in order to meet the strength and Workability of concrete materials, to achieve the highest economic benefits. This study is based on the type I of Portland cement, 100 blast furnace slag and fly ash as the main binder, with the cooperation of the premixing plant commonly used coarse, fine aggregate and chemical composition of the composition of concrete mix, build of different water and cement than the strength of the development of predictive, And according to the cost-effective concrete mixing design concept, Set the concrete unit volume cost as the objective function, Composition material prices, the minimum material consumption and the nature of concrete indicators for the constraints, The above-mentioned ratio of the cemented material and the ideal gradation curve of the aggregate, with the ready-mixed conctete plant commonly needs mixed with the concrete, has good work and low cost of economic benefits. Laboratory test results verify, the cost of the concrete unit is designed according to the design method, only about 41-50% of the actual turnover of the market. While the actual pre-mixing plant applications can be profits from 10% to 22.5%. Enough to prove that this mixing design model with practical benefits. The Cost-Effective Concrete Mixing Design in this study is applied to the proportioning process of Slag-Fly Ash Concrete, compared with the traditional model of Cost-Effective Concrete Mixing Design, the economic ratio proposed in this study is applied to the proportioning process of furnace-stone concrete, compared with the traditional model of economic matching, adding pozzolanic materials to replace part of the cement,In line with the trend of modern concrete science,Simple matching process and calculation, can make all the cooperation ready-mixed concrete plant can give full play to its advantages, and make reference to the data to make up for the deficiencies.Today may be deeply rooted in the traditional concept of ready-mix plant,provide an effective integration of concrete material,analysis of design patterns quickly calculate the ratio.
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Ma, Yi-Chun, and 馬逸群. "Effects of Circulated Fluidized-Bed Fly Ash, Ground Granulated Blast-Furnace Slag and Coal Fly Ash on properties of Mortar." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/96250885673719756345.
Full textAbstract:
碩士國立臺灣海洋大學
河海工程學系
104
Circulated Fluidized Bed Combustion Technology (CFBC) fly ash, Ground Granulated Blast-Furnace Slag (GGBFS) and Coal Fly Ash (CFA) all belong to the industrial by products. Using them as the mineral admixtures in concrete can effectively reduce the amount of cement and sustainable construction can be achieved. Based on this, the mixture proportion of CFBC fly ah, GGBFS and CFA in mortar mixtures are examined to evaluate their influences on the properties of fresh mortar, and physical properties, mechanical properties, durability and micro-scale properties of harden mortar. Experimental results showed that adequate amount of CFBC fly ash increased the flowability of cement paste especially for the group with the replacement percentage of cement being 10%. While the amount of cement and GGBFS was insufficient, the setting time became longer. When the replacement percentage of GGBFS was 60%, the setting time could be effectively reduced. Adequate amount of CFA and GGBFS could inhibit the expansion problem from CFBC fly ash. For CFA, 20% replacement percentage had the best performance while for CFBC fly ash 40% replacement percentage had the best performance. When the replacement percentage of CFBC fly ash was lower than 20% and the replacement percentage of CFA was lower than 20%, the compressive strength became higher. For GGBFS, it can effectively replace cement without reducing the compressive strength. When the replacement percentage of blended mineral admixtures (using CFBC fly ah, GGBFS and CFA at the same time) was higher, the capability to resist sulfate increased. While the replacement percentage of blended mineral admixtures was lower than 40%, the amount of GGBFS should be high in order to prevent possible damage. When the replacement percentage of CFBC fly ash was 10%, needle shape ettringite was observed which explained the reason of expansion. When the replacement percentages of CFBC fly ash and CFA were 10%, nonreactive fly ash powder and ettringite were found.
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nan, Chen chun, and 陳純男. "Study of Soil Improvement Using Fly Ash and Slag in Grouting Method." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/49789155055038786432.
Full textAbstract:
碩士國立海洋大學
河海工程學系碩士在職專班
90
ABSTRACT Soil improvement using Grouting method has become very popular and widely accepted in recent years. It uses simple machine which can be operated easily and installed quickly. The machine can be practiced in small area. The setting material is cement. It is very popular material and very easy to obtain. The project of this study is to evaluate the performance of grouting by using a few Fly Ash or Slag instead of Cement. Fly Ash and Slag are the industrial residuals, if they can be reused, not only the cost of installation can be cut down but also the amount of residuals be reduced. It is also good for environmental consideration. In this study, the proportion of setting material is shown as follows: (A) 1. Water : Cement 10:10 (B) 2. Water : Cement : Fly Ash 10:9:1 (C) 3. Water : Cement : Fly Ash 10:8:2 (D) 4. Water : Cement : Slag 10:9:1 (E) 5. Water : Cement : Slag 10:8:2 The test results show that the compression stress of (B) is 82.60% to 97.67% that of (A). The compression stress of (D) is 81.17% to 86.42% that of (A). Therefore, compression strength of grouting with 10% fly ash or slag by weight instead of cement could be accepted.
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Wu, Chung-sheng, and 吳崇聖. "Study on Properties of Reactive Powder Concrete with Fly Ash and Slag." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/akms6y.
Full textAbstract:
碩士國立臺灣科技大學
營建工程系
94
This research discusses the properties of reactive powder concrete (RPC) with different replacing amounts of fly ash (15%, 30%, 45%) at 0% slag replacement, different replacing amounts of slag (10%, 20%, 30%) at 0% fly ash replacement and different replacing amounts of slag (0%, 12.5%, 25%) at 53% replacement of fly ash, at 25℃ and 85℃ curing temperatures. The experimental variances include slump flow, mechanical property, and durability. A control set of traditional RPC mix proportion was also used for comparison. The results show that: (1) The slump flow can achieve 190 mm and is better than the control set of traditional RPC mix proportion; (2) The mechanical properties of RPC by using water curing are more stable. Using fly ash and slag with steam curing can improve pozzolanic reaction and also get better mechanical property in early stage; (3) Using steel fiber can improve bending and splitting strength such that the RPC can have high strength and toughness, suitable for retrofit; (4) The test results of ultrasonic pulse velocity, electrical resistance and carbonation for RPC show that RPC has good durability and corrosion resistance; (5) Using RPC for retrofit can improve the strength of cylindrical specimen. The failure mode does not the pop-up flake due to the confining effect of steel fiber, and only some continuous cracks found on surface.
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"FTIR Analysis of Alkali Activated Slag and Fly Ash Using Deconvolution Techniques." Master's thesis, 2014. http://hdl.handle.net/2286/R.I.25964.
Full textAbstract:
abstract: The studies on aluminosilicate materials to replace traditional construction materials such as ordinary Portland cement(OPC) to reduce the effects caused has been an important research area for the past decades. Many properties like strength have already been studied and the primary focus is to learn about the reaction mechanism and the effect of the parameters on the formed products. The aim of this research was to explore the structural changes and reaction product analysis of geopolymers (Slag & Fly Ash) using Fourier transform infrared spectroscopy (FTIR) and deconvolution
techniques. Spectroscopic techniques give valuable information at a molecular level but not all methods are economic and simple. To understand the mechanisms of alkali activated aluminosilicate materials, attenuated total reflectance (ATR) FTIR has been used where the effect of the parameters on the reaction products have been analyzed. To analyze complex systems like geopolymers using FTIR, deconvolution techniques help to obtain the properties of a particular peak attributed to a certain molecular vibration.
Time and temperature dependent analysis were done on slag pastes to understand the polymerization of reactive silica in the system with time and temperature variance. For time dependent analysis slag has been activated with sodium and potassium silicates using two different `n'values and three different silica modulus [Ms- (SiO2 /M2O)] values. The temperature dependent analysis was done by curing the samples at 60C and 80C. Similarly fly ash has been studied by activating with alkali hydroxides and alkali silicates. Under the same curing conditions the fly ash samples were evaluated to analyze the effects of added silicates for alkali activation.
The peak shifts in the FTIR explains the changes in the structural nature of the matrix and can be identified using the deconvolution technique. A strong correlation is found between the concentrations of silicate monomer in the activating position of the main Si-O-T (where T is Al/Si) stretching band in the FTIR spectrum, which
gives an indication of the relative changes in the Si/Al ratio. Also, the effect of the cation and silicate concentration in the activating solution has been discussed using the Fourier self deconvolution technique.Dissertation/Thesis
Masters Thesis Civil and Environmental Engineering 2014
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QIU, ZONG-XIAN, and 邱宗弦. "Preparation of fly ash/slag based geopolymer concrete by different retardation methods." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/4vspdf.
Full textAbstract:
碩士國立臺北科技大學
資源工程研究所
107
Herein study, geopolymer concrete was prepared by using fly ash and slag. The first stage is the slurry retardation test. It is found that sucrose and Terminalia chebula can effectively delay the hardening time. Besides, the reduction of SiO2/Na2O and the reduction of SiO2/Al2O3 can effectively delay the hardening time. As found in the ready-mixed plant test, the moisture content of the fine granules has a significant influence on the geopolymer. Therefore, the second stage of the study will test the fine granules. The moisture content of the material is controlled from 0% to 10%. The second stage is the mortar retarding test. The mortar is prepared by using fine particles with a water content of 10% and a liquid-solid ratio of 0.7, which can effectively delay the hardening time. The initial setting time is about 2 to 11 hours, and the final setting time is about 23 to 31. Hours and the compressive strength can reach 30MPa or more. Since the ready mixing plant cannot control the moisture content of the fine granules and the moisture content of the fine granules is 5%, there is no effect of delaying the hardening time. Therefore, the water content of the fine granules is controlled to be more than 5%, and it is expected to be delayed hardening time. In the third stage, the concrete is prepared by using fine granules with a moisture content of 8% or higher and a liquid/ash ratio of 0.7 or 0.75, which can effectively delay the hardening time. The initial setting time is about 18 to 63 hours, and the final setting time is about 31. ~97 hours, and the compressive strength can reach 21MPa or more.
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Wang, Hsuan-Feng, and 王暄豐. "Investigation of fly ash / slag concrete durability using rapid chloride permeability test." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/27254160790006597213.
Full textAbstract:
碩士國立臺灣海洋大學
材料工程研究所
92
Abstract In this study is to investigate the effect of fly ash and slag on durability of concrete. The water to binder ratios are 0.35, 0.45, 0.55 and 0.65, fly ash replacement with 0%, 15%, 35% and 45%, and slag replacement with 0%, 35%, 45% and 55%. Rapid chloride penetration test, and compressive strength test were performed. Testing results show that the compressive strength of fly ash replacement and slag replacement lower than 35% will be increase 10% with water to binder ratios 0.35, 0.45. The compressive strength of fly ash replacement and slag replacement lower than 15% , 45% will be increase 6% with water to binder ratios 0.55, 0.65. Results of repid chloride penetration test present that the concrete’s ability to resist chloride penetration of fly ash replacemene and slag replacement with 45%, 55% will be have low to Moderate for all kind of water to binder ratios. Anyway, the results show the compressive strength and the concrete’s ability to resist chloride penetration doesn’t have linearly correlated.
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Hsiao, LI-Jen, and 蕭李仁. "Effects of Circulated Fluidized-Bed Fly Ash, Ground Granulated Blast-Furnace Slag and Coal Fly Ash on Durabilities and Micro-Characteristics of Concrete." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/27992226867736410715.
Full text
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Chang-HengTsai and 蔡長亨. "Study on the Application of Slag-Fly Ash Materials to the Concrete Products." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/3d4zye.
Full text
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Chang, Yi-Kuo, and 張益國. "The Feasibility of Wastewater Sludge Stabilization with Fly Ash and Water Quenched Slag." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/56475381337341659096.
Full textAbstract:
碩士國立成功大學
環境工程學系
84
THE FEASIBILITY OF WASTEWATER SLUDGE STABILIZATION WITH FLY ASH AND WATER QUENCHED SLAGJuu-En Chang and Yi-Kuo ChangDepartment of Environmental EngineeringNational Cheng Kung UniversityABSTRACTWastewater sludges contain nutrients and organic matters which make them suitable for reclaiming and improving marginal soils. But when the quantities used are not properly controlled, the sludge can be harmful to the lands and plants both. Fly ash and slag contain a predominant fraction of pozzolanic materials (Si, Ca, and Al oxides) which have the pollutant stabilization ability and they benefit soil. Therefore, the fly ash and slag can be useful for stabilization of organic matters in the wastewater sludge, and the mixture can be applied to land with a minimal environmental impact. In this study, fly ash and slag were used as additives to stabilize the organic matters, ammonia and phosphate in wastewater sludge. The sludge was obtained from an industrial park wastewater treatment plant, the fly ash was from a power plant, and the water quenched slag was from a steel plant. To determine the optimal operating conditions, parameters such as curing time, curing temperature, additive dosages, water content and pH value were varied. Leaching tests were performed to evaluate the stabilization efficacy of the additives at designed dosages, water content and curing conditions. Experimental results show that both fly ash and slag could effectively reduce the leaching-out rates of DOC and NH3-N of the wastewater sludge, and the leached out DOC decreased with increased additive dosages. The adsorption capacity for DOC and NH3-N of the fly ash was higher than slag, because the fly ash had a larger specific surface area. The optimal operating conditions for the stabilization of wastewater sludge by fly ash and slag are : leaching out ratio (Lr) of DOC was 0.43 with slag as additive only for 7-day curing; Lr of NH3-N was 0.17 with slag as additive only for 14-day curing; while Lr of PO43- was 0.50 with slag or fly ash as additive for 3-hour curing. SEM-EDX and XRD microanalysis show that the adsorption performance was better than encapsulation at the beginning of curing, but the stabilization mechanism turned into fixation/stabilization as a result from Pozzolanic reaction when curing time increased. Also, curing at low temperature could inhibit sludge biodegradation and resulted in a decrease in leaching-out rates of DOC, NH3-N and ortho-P.Key words : wastewater sludge, stabilization, fly ash, slag
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Huang, Jyun-Jie, and 黃俊傑. "Study on Fresh Properties of Alkali-activated Concrete with Slag and Fly Ash." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/92482171932003818373.
Full textAbstract:
碩士國立臺灣科技大學
營建工程系
104
In this study, the sodium silicate and sodium hydroxide were used as the alkali activator. After trial mixes, the liguid-solid ratio was fixed as 0.5, and the experimental parameters including different dosages of activator, silicon-sodium ratio and proportions of slag-fly ash mixtures were used to investigate the effects of various combinations of parameters on the fresh, physical, durable and microstructural properties of the alkali-activated concrete with slag and fly ash. The research results show that: (1) For the fresh properties, the slump of alkali-activated slag-fly ash concrete were in the range from 220 to 270 mm, and the slump flow were in the range from 360 to 600 mm, and the initial and finial setting times of concrete were from 529 to 684 and 556 to 745 min, respectively. Increase of dosages of activator could not significantly change the workability and setting times. (2) The air content of alkali-activated slag-fly ash concrete was in the range from 0.3 to 2.8 %. Increase of dosages of activator and silicon-sodium ratio could decrease the air content. (3) The increase of dosages of activator could enhance the material strength such that the compressive strength of all mixture at 28 days were in the range from 21.43 to 48.03 MPa. However, when the slag powder mixed with fly ash being the inert ingrident, the concrete had lower compressive strength at 28 days by a decreaseof 13.1 to 38.3% if the amount of fly ash replacement replaced 50 wt. % of slag. (4) The thermal conductivities of all mixtures were in range from 1.227 to 1.854 w/m•k, which were lower than these of normal concrete by 18.2 to 47 %, that in turn showed that thealkali-activated slag-fly ash concrete had much better insulation properties. In addition, the properties of thermal conductivity were primarily controlled by composition of powder material rather than by the mixing liquid. (5) The increase of dosages of activator and and silicon-sodium ratio could increase the drying shrinkage of alkali-activated slag-fly ash concrete. (6) The increase of dosages of activator and and silicon-sodium ratio could increase the surface resistivity of alkali-activated slag-fly ash concrete. (7) The increase of dosages of activator and and silicon-sodium ratio could reduce the water absorption of alkali-activated slag-fly ash concrete. The higher the water absorption is, the higher the internal voids of concrete will be.
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Wu, Tsung-han, and 吳宗翰. "Study on Bonding Behavior of Reinforcement in Alkali-Activated Slag-Fly Ash Mortar." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/39288957652931366671.
Full textAbstract:
碩士國立臺灣科技大學
營建工程系
102
In this study, the sodium hydroxide and sodium silicate were used as the alkali activator. The slag and fly ash were used to produce alkali activated slag mortars and alkali activated slag-fly ash mortars. Two different dosages of alkali activator (N3% and N6 %) were used to cast 150?e150?e150 mm3 cubic mortar specimen. The experimental parameters include two different concentrations of sodium hydroxide (3 %, 6 %), four different diameters of reinforcement (? = 10 mm, 13 mm, 16 mm and 19 mm), two different embedment lengths (75 mm, 150 mm). The pullout test was used to investigate the bonding behavior of reinforcement in the alkali activated slag-fly ash mortars. The research results show that:(1) For the failure modes of bond slip, the bonding properties of reinforcement have a close relationship with the compressive strength of mortar, the higher the compressive strength of mortar is, the better bond performance of reinforcement will get. The alkali activated slag mortar with 6 % activator not only has the highest compress strength (60.18 MPa) but also the higher bonding stress (17.87 MPa) than those of other mixtures at the same ages. Mortar specimens with fly ash had lower bond stress by about 38.59 % lower than that of alkali activated slag mortars. In splitting failure mode, the bond stress of alkali activated slag-fly ash mortars with 6 % activator is higher than that of alkali activated slag mortars. It shows that adding fly ash has good performance in later ages. (2) When the embedded length of reinforcement is 75 mm, all the specimens fail in pullout type, but when the embedded length becomes 150 mm, the mode of failure is decided by diameter of reinforcement. The larger the size of reinforcing bar is, the higher bonding stress it will obtain. If the specimen doesn’t have enough confining force to carry the bonding stress, the specimens would fail in splitting mode. (3) The increase of the diameter of reinforcing bar also increases the bonding strength due to the increase of the height of rib and contact area. (4) For the same failure mode, the different of bond strengths among reinforcements with various bar diameters is not obvious. The bar of smaller diameter would get a little bit higher bonding stress for mortar specimens with same size. (5) The reinforcing bar with D10 mm yielded in alkali activated slag mortars with 3 % activator, embedded length of 75 mm at 7 days. The reinforcing bar of D13 mm yielded in alkali activated slag mortars with 6 % activator, embedded length of 150 mm at 7 days. The reinforcing bar of D16 mm yielded in alkali activated slag mortars with 3 % and 6 % activators, embedded length of 150 mm at 28 days. (6) The specimens of cement mortars and cement-fly ash mortars have better bonding performance than those of alkali activated slag mortars. At the same failure mode, the specimens of cement mortar with D19 mm reinforcing bar and embedded length of 150 mm have an average slip value of 1.2 mm, which is higher than 0.86 mm for the specimens of alkali activated slag mortar at same ages. The bonding stress of cement mortar is also higher than that of alkali activated slag mortar. The reason is that the microstructures of cement mortar show more dense hydrate than that of alkali activated slag mortar at the same magnification.
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Cheng, Pai-jung, and 鄭百榕. "Engineering Properties of Slag-Fly Ash Composite Geopolymer at Room and Elevated Temperatures." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/11609867045471656474.
Full textAbstract:
碩士國立臺灣科技大學
營建工程系
101
In this study, the sodium hydroxide and sodium silicate were used as the alkali activator to activate the powder activity. Under the condition of fixed modulus of sodium silicate, experimental parameters including different dosages of activator, water-solid ratios, amounts of sand and proportions of slag-fly ash mixtures were used to investigate the effects of various combinations of parameters on the fresh and hardened properties. The second is to investigate the effects of exposure tovarious elevated temperatures for one hour on the properties of of composite geopolymer. Finally, the variations of composition and microstructures of geopolymer were examined by the X-Ray Diffraction analyzer and Scanning Electron Microscopy. The research results show that: (1) Both the water-solid ratio and the amount of fly ash replacement have close correlation with the workability of fresh paste. At the fixed activator of 3 %, the increases of water-solid ratios from 0.35 to 0.40 and amount of fly ash replacement from 0 to 50 %, the flowability of paste increases by 25 % to 80 %, the setting times extends to 39 to 97 minutes, and the temperature of hydration is relatively lower. (2) When amount of fly ash replacement is 30 %, the compressive strength of specimen decreases about 19 %, other engineering properties, ultrasonic pulse velocity, dynamic elastic modulus and dynamic shear modulus were slightly decreased by 5 % to 7 %. (3) Both the increase of dosages of activator and decrease of water-solid ratio can enhance the engineering properties, but overdosage tends to easily cause the fragile and fragmentation problems. (4) The drying shrinkage of specimens with the addition of fly ash significantly decreases by about 80 %. (5) The addition of fly ash only causes a slight increase of the thermal conductivity (6) The addition of fine aggregates can get better engineering properties and volume stability, but no apparent effects on the strength and volumetric stability exposed to elevated temperatures for one hour. (7) The additon of fly ash can significantly increase the strength of specimen with a best increae of 40 % when the elevated temperature is 400 oC for one hour. (8) The result of SEM indicates that although a large number of unreactive fly ash particles exist at room temperature, they apparently help the suppression of drying shrinkage and crack. The structure of geopolymer becomes denser to enhance the strength of specimen exposed to elevated temperatures.
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Luo, Yong-Lin, and 羅永麟. "Study on the Microstructure and Property of Concrete Containing Slag and Fly Ash." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/06790239230191139130.
Full textAbstract:
碩士國立中興大學
土木工程學系所
96
This research aims to investigate the pore structures and the interfacial transition zone （ITZ）of concrete containing both slag and fly ash. In this research, three water / binder ratios （0.35 0.5 0.7）and five substitute ratios of cement with pozzolanic material（0% 20% 30% 50% 60%）. The pozzolanic concrete was tested for compressive strength, MIP porosity measurement, microhardness and scanning electron microscope（SEM）. Test results show that concrete containing slag and fly ash produce evident filling effect and pozzolanic reaction in concrete after 28 days age. At the age of 91 days the pozzolanic material has provided eminent contribution to the strength, the porosity and the ITZ of concrete, making the total pore volume lower and ITZ property of pozzolanic concrete better than that of normal concrete. As for the correlation coefficients between compressive strength and either porosity or ITZ microhardness, the compressive strength has the most ideal relationship with the total pore volume. Thus, we use the total pore volume to predict the compressive strength of pozzolanic concrete and establish a prediction model as follow: S=-662.68Vt+87.29.