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Relevant bibliographies by topics / Concrete; Pozzolanic additives

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Academic literature on the topic 'Concrete; Pozzolanic additives'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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Journal articles on the topic "Concrete; Pozzolanic additives"

1

Golewski, Grzegorz Ludwik. "Changes in the Fracture Toughness under Mode II Loading of Low Calcium Fly Ash (LCFA) Concrete Depending on Ages." Materials 13, no. 22 (November 19, 2020): 5241. http://dx.doi.org/10.3390/ma13225241.

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This study investigated the influence of the curing time on the fracture toughness of concrete produced with different content of low calcium fly ash (LCFA). During the study, the amounts of 20% and 30% of pozzolanic additive were used. In order to observe the effect of the applied pozzolanic additive on the analyzed concrete properties, the obtained results were compared with the values obtained for the reference concrete. Compressive strength—fcm and fracture toughness, by using mode II loading—KIIc (shearing), were determined between the 3rd and 365th days of curing. In the course of experiments, changes in the development of cracks in individual series of concrete were also analyzed. In addition, the microstructures of all composites and the nature of macroscopic crack propagation in mature concretes were assessed. It was observed that the greatest increase in fracture toughness at shear was in the case of reference concrete during the first 28 days, whereas, in the case of concretes containing LCFA, in the period of time above 4 weeks. Furthermore, concrete without the LCFA additives were characterized by a brittle fracture. In contrast to it, concretes with LCFA additives are mainly characterized by a quasi-plastic process of failure. Moreover, most of the samples showed a typical pattern of the destruction that occurs as a result of shearing. The presented test results may be helpful in selecting the composition of concrete mixtures containing LCFA to be used in concrete and reinforced concrete structures subjected to shear loads.

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2

Justs, Janis, Genadij Shakhmenko, Diana Bajare, and Nikolajs Toropovs. "Comparison of Pozzolanic Additives for Normal and High Strength Concrete." Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference 2 (August 5, 2015): 79. http://dx.doi.org/10.17770/etr2011vol2.979.

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Microsilica is widely recognized as a “benchmark” for pozzolanic products. Although microsilica is an industrial byproduct, it has recently become very expensive. Four different pozzolanic additives were compared by the authors of this study. Two of the additives were commercially available products – microsilica by Elkem and Centrilit NC by MC Bauchemie. The other two additives were produced under laboratory conditions. Both of them were clay-based materials. Compressive strength was determined after 7, 28 and 155 days. The objective of this research was to determine alternatives to microsilica and evaluate pozzolanic additives performance in normal and high-strength concrete.

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Sētiņa, Janīna, Inna Juhņeviča, Jānis Baroniņš, and Liene Gulbe. "Minerālo saistvielu pētījumi Silikātu materiālu institūtā." Materials Science and Applied Chemistry 35 (November 1, 2018): 134–59. http://dx.doi.org/10.7250/msac-2018-0006.

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Parādīti pēdējās desmitgades pētījumi minerālo saistvielu jomā. Pētīta dažādu aktīvo ķīmisko piedevu ietekme uz betona struktūru, mehāniskajām un fizikālajām īpašībām. Novērtēta iegūto betonu korozijas izturība pret sulfātu sāļu šķīdumiem. Pētīta dažādu rūpniecisko blakus produktu – pelnu – kā pucolānu piedevas ietekme uz betona īpašībām.Investigation of Mineral Binders in the Institute of Silicate MaterialsThe influence of natural and artificial pozzolanic and micro-filler additives on the cement paste hydration process, structure, properties was studied. Different additives and chemical compositions were used: micro- and nano-silica, amorphous silicon dioxide synthesized by sol-gel method, glass powder, highly disperse sand, different types of ash. The pozzolanic activity of additives mainly depends on quantity and specific surface area, i. e., the dispersity of active SiO2 and Al2O3. Depending on the pozzolanic activity chemical additives can be used as concrete aggregates or as active additives.The influence of superplasticizer Semflow MC (SP) on microstructure and properties of concrete was investigated. The compressive strength of concrete with SP increased to 154 MPa, corresponding to HPC. The capillary absorption of water and solutions containing sulphate ions into HPC depends on amount of SP. The depth of penetration of solution in the samples decreases consistently by increasing the amount of SP. The formation of crystalline phase during maturation was analysed, and it was found that by increasing testing time the amount of portlandite decreased and calcium hydrosilicate formed. The concrete samples with low W/C ratio, pozzolanic additives and SP up to 2.5 % according mechanical and chemical properties conform to the characteristics of HPC. The investigated concrete has high chemical resistance to solutions containing sulphate ions.Keywords – binders, concrete, pozzolanic additives, ash, concrete corrosion

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Konkol, Janusz. "Fracture Toughness and Fracture Surface Morphology of Concretes Modified with Selected Additives of Pozzolanic Properties." Buildings 9, no. 8 (July 26, 2019): 174. http://dx.doi.org/10.3390/buildings9080174.

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Modern methods of designing and testing concrete must be extended to appropriate material engineering approaches. It is then crucial to link the properties of concrete with its structure described in a quantitative way. The aim of the article was to present the results of research on concretes modified with three additives: Silica fume (SF), activated fluidal ash (FA), and metakaolinite (MK). The concretes were tested for compressive strength, fracture toughness (determining critical stress intensity factor KIcS and elastic modulus E). Also, stereological and fractal tests were performed. The research program covered three separate experiment plans, adopting the water/binder ratio and the additive/binder mass ratio as the independent variables. The results of experiments and their analysis proved a statistically significant relationship between fracture morphology (fractal dimension D) and concrete composition and fracture toughness. A higher fractal dimension was found in concretes with a higher content of cement paste and a lower content of additive. No significant effect of the type of additive used in the above dependence was found. An original method enabling the determination of mechanical properties of concrete with no need for destructive testing has been developed.

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5

Setina, Janina, Alona Gabrene, Inna Juhnevica, and Ieva Ose. "Effect of Siliceous Pozzolanic Additives on the Hydration Process of Cement." Key Engineering Materials 604 (March 2014): 110–13. http://dx.doi.org/10.4028/www.scientific.net/kem.604.110.

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The given study investigates the influence of pozzolanic admixtures both micro- and nanosize silica and biomass ashes on microstructure and properties of hydration process of cement paste. The investigations were carried out by - XRD, SEM and FTIR. Pozzolanic activity of the concrete admixtures strongly depends on their chemical composition, content of reactive silica as well as the specific surface area. The micro- and nanosilica pozzolanic additives demonstrated the higher values of pozzolanic activity. Those activate the process of mineralization and are acting both as the cementitious admixture as well as the fine filler.

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6

Larsen, O., O. Aleksandrova, V. Naruts, A. Polozov, and A. Bakhrakh. "STUDY OF THE PROPERTIES OF ACTIVE MINERAL ADDITIVES FOR USE IN HYDRAULIC ENGINEERING CONSTRUCTION." Bulletin of Belgorod State Technological University named after. V. G. Shukhov 5, no. 8 (August 4, 2020): 8–17. http://dx.doi.org/10.34031/2071-7318-2020-5-8-8-17.

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Improving the technology of construction production contributes to improving the quality of construc-tion of hydraulic structures and their reliability. In recent decades, rolled compacted concrete has be-come widespread in the construction of dams in our country and in world practice. The technology of rolled compacted concrete in hydraulic engineering projects has a number of advantages: it reduces labor costs and expenses, allows fully mechanization the concreting process with implement of high-performance equipment, and thereby increases the rate of construction of massive structures. The use of mineral fillers in rolled concrete will reduce heat generation, contribute to a reduced adiabatic rise in the temperature of concrete, improve its performance and increase durability. The test method for assessing pozzolanic activity of volcanic scoria, fly ash, crushed powder of basalt and volcanic tuff by degree of absorbed lime from a saturated calcium hydroxide solution with a simultaneous change in volume is described. The studies have shown that volcanic scoria and crushed powder of basalt are additives with the lowest volume increase at the age of 30 days, they show the high pozzolanic proper-ties and can be selected as initial pozzolanic materials for production rolled compacted concrete with significant economic and environmental advantages.

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Koťátková, Jaroslava, Dana Koňáková, Eva Vejmelková, Pavel Reiterman, and Jamal Akhter Siddique. "Mechanical and Water Transport Properties of HSC with Different SCMs." Materials Science Forum 824 (July 2015): 105–10. http://dx.doi.org/10.4028/www.scientific.net/msf.824.105.

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Pozzolanic materials and their usage in concrete production are nowadays widely spread. Their application as additives is inherent especially for the purpose of high strength concrete. This article deals with evaluation and comparison of the influence of two different supplementary cementitious materials on the properties of high strength concrete: natural pozzolana (NP) and finely crushed brick (FCB). The studied characteristics are basic physical properties with connection to mechanical parameters, and next to this, characterization of water transport. In the scope of this study results revealed better pertinence of finely crushed brick, as the appropriate replacement of cement was found out to be up to 30%, whilst for natural pozzolana only 10% of cement substitution is favourable. The open porosity as the first indicator of both mechanical and water transport properties appeared to be lower in all studied mixtures with FCB than in the case of NP. With increasing ratio of the additive to cement there is significant worsening of mechanical and water transport parameters when NP is involved. The behaviour of mixtures with FCB is better even when high amount of cement is substituted.

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Setina, Janina, Alona Gabrene, and Inna Juhnevica. "Effect of Pozzolanic Additives on Structure and Chemical Durability of Concrete." Procedia Engineering 57 (2013): 1005–12. http://dx.doi.org/10.1016/j.proeng.2013.04.127.

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9

Vitola, L., G. Sahmenko, D. Erdmane, G. Bumanis, and D. Bajare. "The effect of various pozzolanic additives on the concrete strength index." IOP Conference Series: Materials Science and Engineering 251 (October 2017): 012038. http://dx.doi.org/10.1088/1757-899x/251/1/012038.

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10

Yener, Engin. "The effect of pozzolanic mineral additives on the strength and durability properties of structural lightweight concrete." CEBEL Vol 2 Issue 2 April 2021 2, no. 2 (February 18, 2021): 35–40. http://dx.doi.org/10.36937/cebel.2021.002.005.

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Structural lightweight concretes have the potential to be used in road pavements and bridge decks due to their properties such as sufficient wear resistance, high impermeability, superior freeze-thaw resistance and ductile behavior. However, road pavements are directly exposed to nitric acid and sulfuric acid solutions created by the exhaust gases of transportation vehicles in humid environments. Therefore, the concrete to be used in road pavements must be resistant to these acid effects. In addition, sufficient strength must be guaranteed when used as pavement material. The aim of this study is to produce lightweight concrete suitable for road pavements and other structures exposed to acid effects. For this, the effect of silica fume (SF) and fly ash (FA) on acid resistance and strength development of lightweight concrete with perlite aggregates was investigated. Five different lightweight concrete mixtures were produced by substituting 0%, 5%SF, 10% SF, 10%FA, 20% FA instead of cement by weight. Natural perlite rock has been used as an aggregate source in order to provide high strength and lightness. The cylindrical samples produced were kept in lime saturated water cure for 120 days and their compressive strength was measured on the 28th, 56th, 90th and 120th days. In addition, in order to monitor the acid resistance, the strength changes of the samples exposed to 5% sulfuric acid and 5% nitric acid solution after 28 days of standard curing were followed until the 120th day. Results show that, SF and FA additives increase the compressive strength especially at older ages. In case of 10% SF, the 120-day strength value increased by 18.6% and reached 34.5 MPa. Also, lightweight perlite concrete is highly resistant to nitric acid and sulfuric acid effects. In the case of 92 days of nitric acid and sulfuric acid exposure, the strength losses are only 5.2% and 13.4%, respectively. In order to fully benefit from SF and FA, concretes must be adequately cured before acid attack. It has been concluded that it is possible to produce high-strength and acid-resistant lightweight concretes suitable for road pavements and many other structural elements by using natural perlite aggregate.

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Dissertations / Theses on the topic "Concrete; Pozzolanic additives"

1

Tank, Suresh Bhagwanji. "The use of condensed silica fume in Portland cement grouts." Thesis, University College London (University of London), 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307794.

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Ahmed, Mohammad Sharfuddin Aerospace Civil &amp Mechanical Engineering Australian Defence Force Academy UNSW. "Effects of systematic increase in pozzolanic materials on the mechanical, durability, and microstructural characteristics of concrete." Awarded by:University of New South Wales - Australian Defence Force Academy. School of Aerospace, Civil and Mechanical Engineering, 2007. http://handle.unsw.edu.au/1959.4/38645.

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The use of high performance concrete in construction has been enhanced by the use of pozzolanic materials. However, the use of these materials has not been optimized. Such optimization may be achieved by a systematic increase in the amount and combination of pozzolanic material additions, with accompanying studies of their effects on the mechanical, durability and microstructural characteristics of blended concrete. This work evaluated various concrete durability issues by studying systematic increases of pozzolanic materials such as fly ash and blast furnace slag (BFS) in the range of 25, 50 and 70%, and silica fume at 10% of total cementitious materials, forming various binary and ternary concrete blends. The concrete specimens were cured for a period of seven days after demoulding in line with widely practiced commercial curing procedures. The research explored the role and effectiveness of various binary and ternary blends of pozzolanic materials on the mechanical, durability and microstructural characteristics of concrete. Durability was evaluated by two independent rapid chloride permeability tests measured as charge passed and chloride conductivity from the RCPT and UCT tests respectively. These two rapid tests were coupled with long-term ponding tests to evaluate chloride ingress and the extent of corrosion for a period of two years. Further durability tests such as carbonation, drying shrinkage and porosity of these blends were also undertaken. This study also utilized micro-analytical techniques such as X-ray diffraction and Scanning Electron Microscopy to follow the hydration mechanism in various binary and ternary blends. Statistical significance testing was used to analyse and confirm all experimental results and conclusions. It is well known that a level of caution is exercised in the construction industry in the use of ternary blends. This study aims to evaluate the durability aspects of ternary concrete blends, in addition to binary blends, for resistance to chloride, corrosion, carbonation attacks and provide recommendations relating to the limits of blending level, as well as exposure conditions for blended concretes, based on the results of this study. It is expected that this will fill a major knowledge gap observed in the concrete industry. A comparison of two rapid chloride permeability tests such as UCT and RCPT indicates that the UCT test is easy and practicable, and does not contradict results obtained in the standard RCPT. However, the statistical significance of results obtained for some blends was only able to be established by using the RCPT. This effect can be attributed to the larger size specimens compared to UCT. The recommended blend to acquire both early-age and long-term strength development in fly ash is the ternary blends comprising 10% silica fume and 25% fly ash cast using lower w/b ratio. In addition, the same blend exhibited lower carbonation depth, lower charge passed from RCPT, lower chloride ingress and higher corrosion resistance characteristics from long-term ponding test compared to other blends of fly ash. In BFS blends, an increase in compressive strength was observed only in the specimens of 25% BFS compared to other higher percentage blends, while the higher addition of 50 and 70% replacement showed no significant difference in compressive strength between them and their corresponding ternary blends with addition of silica fume. The results of this study indicate that control (OPC) specimens cast with increased w/b ratio of 0.48 showed higher chloride ingress compared to both binary blends of 70% fly ash and 70% BFS specimens. This indicates that (OPC) cast using higher w/b ratio is to be avoided in chloride environments. On the other hand, though, the ternary blends of 10% silica fume and up to 50% fly ash exhibited lower chloride ingress compared to their respective binary blends of fly ash. However, these ternary blends exhibited lower compressive strength, more negative corrosion potential and higher corrosion rate, compared to the respective binary blends of 25% fly ash and its ternary blends. Therefore, the recommended blend observed in the long-term ponding test is the ternary blend of 25% fly ash and 10% silica fume. The recommended level of corrosion resistance in slag specimens is achieved by the use of ternary blends comprising silica fume at 10% added to the blend that contains up to 70% slag. However, the recommended level of slag for a lower carbonation effect is the use of a ternary blend comprising 50% slag and 10% silica fume (3B5S1) which showed a carbonation depth of 10.8 mm and a compressive strength of 53.2 MPa after 365 days of exposure. The drying shrinkage of concrete increased with the increase in fly ash and the same trend was observed in BFS specimens. However, the results were not significantly different between their respective blends. The extent of carbonation in fly ash specimens was higher compared to BFS blends specimens. This can be attributed to the formation of dusty and weak surfaces on the outer surface in addition to the excessive leaching of sodium chloride solution from the long-term ponding test in the former specimens compared to later. The high volume pozzolanic materials, irrespective of fly ash or BFS and addition of silica fume (70% fly ash and 10% silica fume, and 70% BFS and 10% silica fume), showed higher cumulative pore volume indicating that these blends with seven days of curing were not beneficial. These high volume ternary blends required prolonged curing to release portlandite from the hydration of cement to continue the pozzolanic reaction. This study has shown that 7-days curing of the pozzolanic concrete is inadequate if pozzolanic activity is to be invoked. This is particularly the case when it is expected that the concrete is likely to be subjected to a harsher than usual environment characterised by a dry atmosphere.

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Books on the topic "Concrete; Pozzolanic additives"

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International, Conference on Fly Ash Silica Fume Slag and Natural Pozzolans in Concrete (7th 2001 Madras India). Seventh CANMET/ACI International Conference on Fly Ash, Silica Fume, Slag and Natural Pozzolans in Concrete. Farmington Hills, Michigan: ACI International, 2001.

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2

International Conference on the Use of Fly Ash, Silica Fume, Slag, and Natural Pozzolans in Concrete (4th 1991 Istanbul, Turkey). Fly ash, silica fume, slag, and natural pozzolans in concrete: Proceedings, fourth international conference, Istanbul, Turkey, May 1992. Edited by Malhotra V. M, Canada Centre for Mineral and Energy Technology., and American Concrete Institute. Detroit, Mich: American Concrete Institute, 1993.

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3

Fly ash, silica fume, slag, and natural pozzolans in concrete: Proceedings third international conference, Trondheim, Norway, 1989. Detroit: American Concrete Institute, 1989.

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4

Fly ash, silica fume, slag, and natural pozzolans in concrete: Proceedings, second international conference, Madrid, Spain, 1986. Detroit (P.O. Box 19150, Redford Sta., Detroit 48219): American Concrete Institute, 1986.

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5

M, Malhotra V., and International Conference on Fly Ash, Silica Fume, Slag, and Natural Pozzolans in Concrete (5th : 1995 : Milwaukee, Wis.), eds. Fly ash, silica fume, slag, and natural pozzolans in concrete: Proceedings, fifth international conference, Milwaukee, Wisconsin, USA, 1995. Detroit: American Concrete Institute, 1995.

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Book chapters on the topic "Concrete; Pozzolanic additives"

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Du, Hongjian, Anjaneya Dixit, and Sze Dai Pang. "Potential of Marine Clay for Cement Replacement and Pozzolanic Additive in Concrete." In RILEM Bookseries, 57–65. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-2806-4_7.

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2

"Properties of GFRC mortars with different pozzolanic additives." In Fibre Reinforced Cement and Concrete, 136–47. CRC Press, 1992. http://dx.doi.org/10.1201/9781482271225-17.

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"Properties of GFRC mortars with different pozzolanic additives." In Fibre Reinforced Cement and Concrete, 136–47. CRC Press, 1992. http://dx.doi.org/10.1201/9781482271225-17.

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Conference papers on the topic "Concrete; Pozzolanic additives"

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Larsen, Oksana, Oksana Larsen, Svetlana Samchenko, Olga Aleksandrova, and Boris Bulgakov. "POZZOLANIC ACTIVITY ASSESSMENT OF SOME MINERAL ADDITIVES USED IN ROLLER COMPACTED CONCRETE FOR DAM CONSTRUCTION." In 20th International Multidisciplinary Scientific GeoConference Proceedings SGEM 2020. STEF92 Technology, 2020. http://dx.doi.org/10.5593/sgem2020/6.1/s26.055.

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Setina, Janina, Inna Juhnevica, and Janis Baronins. "The effect of ashes on the properties of cement mortar and typical concrete fillers." In The 13th international scientific conference “Modern Building Materials, Structures and Techniques”. Vilnius Gediminas Technical University, 2019. http://dx.doi.org/10.3846/mbmst.2019.031.

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The production of heat and electricity from shale and biomass is leading to a significant increase in the amount of the combustion residues i.e. ashes. The utilization of ashes as the pozzolanic additive in the production of Portland cement mortar and concrete for the construction of lightweight structures is the most popular way. The interaction of ashes with other typical concrete fillers also can affect the final relative short-term and long-term properties of fresh and hardened concrete when designing the concrete mixture. The influence of wood and shale ashes on the properties of cement mortar and typical concrete fillers (sand, limestone, dolomite) – fresh mortar, hydration process, and hardened mortar were researched and assessed for their applicability in the production of concrete. The best results of mechanical strength, frost resistance and water absorption were measured in case of shale ashes containing samples in combination with cement and selected concrete additive – sand. Shale ashes can be recommended for application as the active additive. Since wood ash was exhibiting lower activity, it can also be applied as a filler to produce building materials.

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McQueen, Mark T. "Energy and High Surface Area Siliceous Ash From the Combustion of Rice Hulls." In 17th International Conference on Fluidized Bed Combustion. ASMEDC, 2003. http://dx.doi.org/10.1115/fbc2003-018.

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Biomass combustion is an attractive energy production method since it is a zero net emitter of carbon dioxide. Rice hulls are a significant source of biomass fuel: approximately 100Mt of rice hulls are produced yearly from the processing and milling of paddy rice. Previous studies have shown that the ash produced from the combustion of rice hulls possesses pozzolanic properties. When used as a concrete additive, the ash can behave similar to silica fume and improve the strength and porosity of the finished concrete. In such cases, the surface area attributed to the pozzolan is related to the residual carbon content of the ash, which is often well in excess of 5%. The excessive carbon level stems from the awkward geometry of the hulls combined with the low melting point and heat sensitive nature of the ash minerals: these create problems for commercial combustion devices. As a result, the ash produced at these facilities contains either high residual carbon or a high proportion of crystalline silica, both of which renders the ash unattractive for use as a concrete additive. However, if the ash is of sufficient quality to be sold as a concrete additive, the economics of energy generation from the rice hulls can be improved. Test work conducted in Mississauga, Canada has produced an ash with less than 3% residual carbon, and greater than 90% silica, nearly all of which is amorphous. This work was done at temperatures higher than those in conventional operations without significant conversion of the siliceous component from the amorphous state to crystalline forms such as crystobalite or quartz. The key to this unexpected result is an enhanced combustion environment in which the solids residence time at elevated temperatures, and therefore the opportunity for silica phase changes, is minimized. In this instance, the total measured surface area of this ash is lower than that of the other ashes due to the reduced residual carbon content, but the siliceous surface area is equal or greater due to the high amorphous content. Consistent with this fact, the rice hull ash performed well in a number of standard concrete tests, in which the ash replaced 7.5% to 12.5% of the Portland cement for similar water to cement mixture ratios. With proper application of a TORBED process reactor as a combustor, a high value and high surface area siliceous ash can be produced as energy is simultaneously recovered from the system.

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Reports on the topic "Concrete; Pozzolanic additives"

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Al-Chaar, Ghassan K., Mouin Alkadi, David A. Yaksic, and Lisa A. Kallemeyn. The Use of Natural Pozzolan in Concrete as an Additive or Substitute for Cement. Fort Belvoir, VA: Defense Technical Information Center, December 2011. http://dx.doi.org/10.21236/ada558534.

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