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1
Md Zain, M. R., C. L. Oh, and L. S. Wee. "Performance of Eco Engineered Cementitious Composites Containing Supplementary Cementitious Materials as a Binder and Recycled Concrete Fines as Fine Aggregate." IOP Conference Series: Materials Science and Engineering 1200, no. 1 (November 1, 2021): 012004. http://dx.doi.org/10.1088/1757-899x/1200/1/012004.
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Abstract Engineered cementitious composites (ECC) mixtures demand a large cement content, which is detrimental to their sustainable development because mass cement production is hazardous to the environment and human health. Thus, this paper investigates the mechanical performance of eco engineered cementitious composites (ECC) under axial compressive loading and direct tensile strength tests. The eco ECC used in this investigation was comprised of cement, superplasticizer, fly ash (FA) or ground granulated blast furnace slag (GGBS), polypropylene (PP) fibre, water and recycled concrete fines (RCF). Two (2) eco ECC mixture series were designed and prepared. GGBS70 (70 percent GGBS + 30 percent cement), FA70 (70 percent Fly Ash + 30 percent cement), GGBS80 (80 percent GGBS + 20 percent cement), and FA80 (80 percent Fly Ash + 20 percent cement) are the four Cement-GGBS and Cement-Fly Ash combinations examined in this study. Also every combination had two different RCF percentages, R0.2 (0.2 percent RCF) and R0.4 (0.4 percent RCF). The main objective of this research is to determine the optimum mix design for eco ECC that contains supplementary Cementitious Materials (SCMs) such as GGBS or FA. Additionally, recycled concrete fines (RCF) were used as a substitute for sand. The influence of different cement replacement materials and RCF content on compressive and tensile strength was experimentally investigated. The inclusion of GGBS as a partial replacement of cement in the eco concrete mixture results in greater compressive strength than Fly Ash (FA). The test results revealed that increasing the RCF content in the ECC mixture resulted in higher compressive and tensile strength. When the sand to binder ratio was adjusted between 0.2 and 0.4, the compressive and tensile strength of the ECC mixture increased.
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Arularasi, V., P. Thamilselvi, Siva Avudaiappan, Erick I. Saavedra Flores, Mugahed Amran, Roman Fediuk, Nikolai Vatin, and Maria Karelina. "Rheological Behavior and Strength Characteristics of Cement Paste and Mortar with Fly Ash and GGBS Admixtures." Sustainability 13, no. 17 (August 26, 2021): 9600. http://dx.doi.org/10.3390/su13179600.
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A cement paste or mortar is composed of a mineral skeleton with micron to millimeter-sized grains, surrounded by water filaments. The cohesion or shear resistance in the cement paste and mortar is caused by capillary forces of action. In the case of mortar mixes, there is friction between the particles. Therefore, the mortar mixture shows both friction between particles and cohesion, while the paste shows only cohesion, and the friction between particles is negligible. The property of the cement paste is greatly influenced by the rheological characteristics like cohesion and internal angle friction. It is also interesting that when studying the rheology of fresh concrete, the rheological behavior of cement paste and mortar has direct applicability. In this paper, the rheological characteristics of cement paste and mortar with and without mineral admixtures, that is, fly ash and ground granulated blast-furnace slag (GGBS), were studied. A cement mortar mix with a cement-to-sand ratio of 1:3 was investigated, including fly ash replacement from 10% to 40%, and GGBS from 10% to 70% of the weight of the cement. A suitable blend of fly ash, GGBS, and ordinary Portland cement (OPC) was also selected to determine rheological parameters. For mortar mixtures, the flow table was conducted for workability studies. The flexural and split tensile strength tests were conducted on various mortar mixtures for different curing times. The results indicate that in the presence of a mineral mixture of fly ash and GGBS, the rheological behavior of paste and mortar is similar. Compared with OPC-GGBS-based mixtures, both cement with fly ash and ternary mixtures show less shear resistance or impact resistance. The rheological behavior of the mortar also matches the rheological behavior in the flow table test. Therefore, it is easy to use the vane shear test equipment to conduct cohesion studies to understand the properties of cement paste and mortar using mineral admixtures. The strength results show that the long-term strength of GGBS-based mixtures and ternary mixed mixtures is better than that of fly-ash-based mixtures. For all mixtures, the strength characteristics are greatest at a w/b ratio of 0.6.
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Salih, Moslih Amer, Shamil Kamil Ahmed, Shaymaa Alsafi, Mohd Mustafa Al Bakri Abullah, Ramadhansyah Putra Jaya, Shayfull Zamree Abd Rahim, Ikmal Hakem Aziz, and I. Nyoman Arya Thanaya. "Strength and Durability of Sustainable Self-Consolidating Concrete with High Levels of Supplementary Cementitious Materials." Materials 15, no. 22 (November 11, 2022): 7991. http://dx.doi.org/10.3390/ma15227991.
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Self-consolidating concrete (SCC) has been used extensively in the construction industry because of its advanced characteristics of a highly flowable mixture and the ability to be consolidated under its own weight. One of the main challenges is the high content of OPC used in the production process. This research focuses on developing sustainable, high-strength self-consolidating concrete (SCC) by incorporating high levels of supplementary cementitious materials. The overarching purpose of this study is to replace OPC partially by up to 71% by using fly ash, GGBS, and microsilica to produce high-strength and durable SCC. Two groups of mixtures were designed to replace OPC. The first group contained 14%, 23.4%, and 32.77% fly ash and 6.4% microsilica. The second group contained 32.77%, 46.81%, and 65.5% GGBS and 6.4% microsilica. The fresh properties were investigated using the slump, V-funnel, L-box, and J-ring tests. The hardened properties were assessed using a compressive strength test, while water permeability, water absorption, and rapid chloride penetration tests were used to evaluate the durability. The innovation of this experimental work was introducing SCC with an unconventional mixture that can achieve highly durable and high-strength concrete. The results showed the feasibility of SCC by incorporating high volumes of fly ash and GGBS without compromising compressive strength and durability.
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A. H. HASSAN and H.B. MAHMUD. "Mixture Proportioning Of Self Compacting Concrete (SCC) Containing Fly Ash, Rice Husk Ash and Blast Furnace Slag." Electronic Journal of Structural Engineering 13, no. 2 (June 1, 2013): 16–20. http://dx.doi.org/10.56748/ejse.131682.
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Self-compacting concrete is a new generation of high-performance concrete with the aim of building durable concrete structures without any skilled laborers for concrete placement. This paper displays mixture proportion of self-compacting concrete and briefly discusses the effects of addition of rice husk ash (RHA), fly ash (FA) and ground granulated blast furnace slag (GGBS) to fresh properties, compressive strength and durability performance of self- compacting concrete.
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Kumar Vishal, Manish Kumar Yadav, Punit Kumar, and Manish Kumar. "Study of mechanical behavior of Fly Ash based geopolymer concrete." International Journal of Science and Research Archive 8, no. 1 (February 28, 2023): 788–92. http://dx.doi.org/10.30574/ijsra.2023.8.1.0127.
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Construction materials that are friendly to the environment are now being researched and developed all over the globe in an effort to limit the use of natural resources that are depleting at an alarming rate and to cut down on the production of greenhouse gases. In this respect, geopolymer plays an extremely important function, and a large number of researchers have investigated the numerous dimensions of its viability as a material for binding. In order to alter the geopolymerisation reaction of fly ash, ground granulated blast furnace slag (abbreviated as GGBS) has been used into fly ash-based geopolymer concrete (abbreviated as GPC). In this paper, the influence of various proportions of GGBS (0-100%) on Fly Ash based GPC, as well as the effect of the amount of Alkaline Activated Solution (AAS) in the mixture of GPC, is studied to determine how it affects the compressive strength of the GPC under conditions of ambient temperature. It was observed from the results of the experiments that the compressive strength of the GPC increases both with an increase in the percentage of GGBS and also with an increase in the amount of the sodium silicate solution in which the concentration of sodium hydroxide in the aqueous solution is fixed at a constant value of 10M. This was the case even though the amount of sodium hydroxide that was present in the solution remained the same.
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Ahmed, Hemn U., Azad A. Mohammed, and Ahmed Mohammed. "Soft computing models to predict the compressive strength of GGBS/FA- geopolymer concrete." PLOS ONE 17, no. 5 (May 25, 2022): e0265846. http://dx.doi.org/10.1371/journal.pone.0265846.
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A variety of ashes used as the binder in geopolymer concrete such as fly ash (FA), ground granulated blast furnace slag (GGBS), rice husk ash (RHA), metakaolin (MK), palm oil fuel ash (POFA), and so on, among of them the FA was commonly used to produce geopolymer concrete. However, one of the drawbacks of using FA as a main binder in geopolymer concrete is that it needs heat curing to cure the concrete specimens, which lead to restriction of using geopolymer concrete in site projects; therefore, GGBS was used as a replacement for FA with different percentages to tackle this problem. In this study, Artificial Neural Network (ANN), M5P-Tree (M5P), Linear Regression (LR), and Multi-logistic regression (MLR) models were used to develop the predictive models for predicting the compressive strength of blended ground granulated blast furnace slag and fly ash based-geopolymer concrete (GGBS/FA-GPC). A comprehensive dataset consists of 220 samples collected in several academic research studies and analyzed to develop the models. In the modeling process, for the first time, eleven effective variable parameters on the compressive strength of the GGBS/FA-GPC, including the Activated alkaline solution to binder ratio (l/b), FA content, SiO2/Al2O3 (Si/Al) of FA, GGBS content, SiO2/CaO (Si/Ca) of GGBS, fine (F) and coarse (C) aggregate content, sodium hydroxide (SH) content, sodium silicate (SS) content, (SS/SH) and molarity (M) were considered as the modeling input parameters. Various statistical assessments such as Root Mean Squared Error (RMSE), Mean Absolute Error (MAE), Scatter Index (SI), OBJ value, and the Coefficient of determination (R2) were used to evaluate the efficiency of the developed models. The results indicated that the ANN model better predicted the compressive strength of GGBS/FA-GPC mixtures compared to the other models. Moreover, the sensitivity analysis demonstrated that the alkaline liquid to binder ratio, fly ash content, molarity, and sodium silicate content are the most affecting parameter for estimating the compressive strength of the GGBS/FA-GPC.
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Le, Tri H. M., Dae-Wook Park, Jin-Yong Park, and Tam M. Phan. "Evaluation of the Effect of Fly Ash and Slag on the Properties of Cement Asphalt Mortar." Advances in Materials Science and Engineering 2019 (July 10, 2019): 1–10. http://dx.doi.org/10.1155/2019/1829328.
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The application of cement asphalt mortar (CAM) in modern high-speed railways has been gaining attention due to its combined merits between asphalt and cement hydration product characteristics. To promote sustainable development, it is promising to utilize by-products in the making of new CAM instead of using only cement. In this research, the cement content was partly replaced by fly ash or ground-granulated blast furnace (GGBS) slag to achieve this objective. Then, laboratory experiments were conducted to determine the effect of these admixtures on the fresh and hardened characteristics of CAM. The test results revealed that the CAM mixture with slag received better fresh properties compared to the controlled mixture. However, the poor pozzolanic property of these by-product materials may lead to the low strength development. Meanwhile, although the mixture with fly ash suffered from slow strength establishment compared to the control mix at an early age, the strength of this condition increases dramatically after 28 days. Based on the findings, the application of appropriate fly ash content in the CAM mixture will not only provide ideal workable time and mixing stability but also ensure the required strength for the design target. This combination also serves as a cost-effective and environmental solution.
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Procházka, Lukáš, Jana Boháčová, and Barbara Vojvodíková. "Influence of Fly Ash Denitrification on Properties of Hybrid Alkali-Activated Composites." Crystals 12, no. 5 (April 28, 2022): 633. http://dx.doi.org/10.3390/cryst12050633.
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This article deals with the possibility of partial replacement of blast furnace slag (GGBFS) with fly ash after denitrification (FAD) in alkali-activated materials. Physical-mechanical and durability properties were tested, hydration reaction was monitored, and infrared spectroscopy was performed. Results were compared between mixtures prepared with fly ash without denitrification (FA), and also with a mixture based only on GGBFS. The basic result is that hybrid alkali-systems with FAD show similar trends to FA. The significant effect of fly ash is manifested in terms of its resistance to freeze-thaw processes. Reactions in a calorimeter show a slower development of reactions with increasing replacement of GGBFS due to the lower reactivity of the fly ash. Through testing the leaching resistance, a decrease in flexural strength was found. This may be due to the descaling of the main hydration product, C–(A)–S–H gel. After 28 days of maturation, compressive strengths of all monitored mixtures ranged from 96 to 102 MPa. The flexural strengths ranged from 6.8 to 8.0 MPa. After 28 days of maturation, the higher strengths reached mixtures without replacing GGBFS. In terms of resistance to freeze-thaw processes, the largest decrease (almost 20%) of flexural strength was achieved by a mixture with 30% of GGBFS replacement by FA. No fundamental differences were found for the mixtures in the FTIR analysis.
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Srinivas Prabhu, R., R. Anuradha, and S. Vivek. "Experimental Research on Triple Blended Self-Compacting Geo Polymer Concrete." Asian Journal of Engineering and Applied Technology 5, no. 2 (November 5, 2016): 15–21. http://dx.doi.org/10.51983/ajeat-2016.5.2.804.
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Self-compacting concrete (SCC) represents one of the most outstanding advances in concrete technology during the last decade. self compacting concrete is a flowing concrete mixture that is able to consolidate under its own weight. The highly fluid nature of SCC makes its suitable for placing in difficult situation and in sections with congested reinforcement. The aim of the study is to make use of Fly Ash, Ground Granulated Blast Furnace Slag and Silica Fume as replacements of cement and understand its effect on the fresh properties and hardened properties of concrete. The investigation includes the concept of triple blending of Fly ash, GGBS and Silica Fume, this triple blend exploits the beneficial characteristics of Pozzolanic materials in producing a better concrete.
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Kanagarathinam, L., Venkatesan Govindaraj, V. Gokul, V. Muthukumaran, and Yalam Nikhil Sai. "Laboratory Evaluation of Stabilising Components for Effective Treatment of Expansive Soil." Asian Journal of Water, Environment and Pollution 20, no. 4 (July 21, 2023): 87–91. http://dx.doi.org/10.3233/ajw230055.
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The experimental study is to understand the mix ratio of fly ash and GGBS (ground granulated blast-furnace slag) in improving the shrink-swell characteristic of soil. The strength of the soil improved considerably after the addition of these stabilisers. In this study, experiments were conducted to observe the influence of the soil stabilisers in the improvement of the strength of the subgrade in expansive soil regions. This influential study will reveal the percentage of Flyash and GGBS mixture. Then the Standard Proctor Compaction test is used to determine the optimum moisture content required to compact the soil with Flyash and GGBS to attain the maximum dry density. The soil’s California Bearing ratio (CBR) was computed to understand the behaviour of improved soil if used as a subgrade. Hence the existing soil can be used as a subgrade with effective treatment of soil.
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Lian, Oh Chai, Lee Siong Wee, and Mohd Raizamzamani Md Zain. "Mechanical Properties of Engineered Cementitious Composites Using Local Ingredients." Journal of Mechanical Engineering 16, no. 2 (August 1, 2019): 145–57. http://dx.doi.org/10.24191/jmeche.v16i2.15332.
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This research focuses on the mechanical properties of Engineered Cementitious Composites (ECC). Few ECC mixtures were designed and tested under direct tensile test and compression test. The novelty of this research is the utilization of available local materials in Malaysia, which is significantly different from the ingredients employed by previous researchers in the US, Japan and other countries. The ingredients used for ECC mixtures in this research were Ordinary Portland Cement (OPC), ground granulated blast-furnace slag (GGBS), sand, water, superplasticizer (SP) and polypropylene (PP) fibers. Local ingredients such as river sand and GGBS were used to replace micro silica sand and fly ash in the standard mix of ECC. Test results demonstrated that tensile ductility and compressive strength in ECC improved as compared to normal concrete. The effect of cement replacement ratio and fibres content are discussed based on the performance in both tensile and compressive properties. Comparison with previous studies was carried out to identify the weaknesses of the current ECC mixture, so that improvement can be done in future studies. The best ECC mixture is proposed according to the performance in mechanical properties.
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Arya, Saresh, and V. Niranjan. "Experimental Investigation on Strength and Durability Characteristics of Multi Blended Cement Concrete." Asian Review of Civil Engineering 6, no. 2 (November 5, 2017): 20–22. http://dx.doi.org/10.51983/tarce-2017.6.2.2872.
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The main aim of the present study is to determine the strength of concrete mix of M30 grade, with partial replacement of cement with Silica fume, Rice husk ash and FLY-ASH. Portland cement is the most important ingredient of concrete and is a versatile and relatively high cost material. Large scale production of cement is causing environmental problems on one hand and depletion of natural resources on other hand. Hence, the researchers are currently focused on use of waste material having cementing properties (such as fly ash, GGBS, metakaloin, silica fume, rice husk ash) which can be added in concrete as partial replacement of cement, without compromising on its strength and durability, which will result in decrease of cement production thus reduction in emission in greenhouse gases, in addition to sustainable management of the waste. This paper presents a study on mechanical and durability properties of ternary blend is a mixture of three products (i.e. portland cement and two SCMs ) and quaternary blend is a mixture of four products (i.e. portland cement and three SCMs ). The pozzolanic material such as fly ash, silica fume, rice husk ash were used as a cement replacing materials in conjuction with ordinary Portland cement. This paper presents a study on mechanical and durability properties of concrete made with multi component cement. Study includes concept of multi blended cement exploits the beneficial characteristics of all pozzolanic materials in producing better concrete.
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Lindh, Per, and Polina Lemenkova. "Effects of GGBS and Fly Ash in Binders on Soil Stabilization for Road Construction." Romanian Journal of Transport Infrastructure 11, no. 2 (December 1, 2022): 1–13. http://dx.doi.org/10.2478/rjti-2022-0010.
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Abstract In this paper we propose a new technique of soil stabilization for road construction based on using new alternative binders. The project aims to evaluate the effects of alternative additive materials in soil stabilization contexts for road construction. The alternative binders (slag, energy ash and bio ash as new alternative road construction material) have been used to complement the traditional binders (cement and lime). The project used five binders and evaluated their effects on soil strength. The proposed method comprises advantages of using the alternative binders which are the residual products contributing to a lower environmental impact. The results have shown that only slag has significant effects on the strength of the stabilized soil, while bio ash and energy ash make a marginal contribution to the increase of strength. This is caused by the twofold reasons. First, the effects of the amount of ashes that should reach a certain threshold with respect to the total amount of binder that must be exceeded to have the effect of the soil mixture. Second, the bio fly ash was stored and it was not completely fresh which may have contributed to the carbonation during the storage period and results in a lower hardening ability. Based on the results of the study we recommend the use of bio fly ash as a supply material andfor its amount to be adjusted so the storage period is not too long. This study verified the effects of slag, cement and lime on stabilization of soil for road construction.
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Reddy, Bijivemula Kiran Kumar, and Mattur C. Narasimhan. "Corrosion of steel rebars embedded in One-part Alkali activated concrete mixes." E3S Web of Conferences 405 (2023): 03024. http://dx.doi.org/10.1051/e3sconf/202340503024.
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To reduce CO2 emissions and turn a variety of industrial/agricultural wastes into valuable cementitious products, alkali-activated materials (AAM) are recognized as suitable substitutes for regular Portland cement (OPC). However, the concentrated aqueous alkali solutions used in conventional two-part alkali activated materials are highly corrosive, viscous, and are difficult to handle in direct field applications. As a result, the potential for developing so-called "just add water" type one-part AAMs, as compared to traditional two-part AAM, is being explored, particularly in cast-in-situ applications. In the present study on corrosion of reinforcing steel bars in fly ash-slag (FA-GGBS) based one-part AAC mixtures, three parameters—the total binder content, the relative proportions of GGBS and Fly-ash and the percentage of sodium oxide (Na2O) - are recognized as the key factors in determining the strength and durability performance (including corrosion of rebars embedded in it) of a given AAC mix. Accordingly, experiments were conducted on AAC mixes with three binder contents (440, 460, and 480 kg/m3), three Slag/FA ratios (80/20, 70/30 and 60/40, by volume) and three alternate Na2O percentages (5, 6, and 7%, by weight of total binder content). Prismatic cylindrical test specimens of reinforced geopolymer concrete were prepared and half-cell potential and corrosion rate measurements were made after 28-, 56-, and 90 days of continuous exposure to 3% of NaCl solution, to accelerate the corrosion process. Measured corrosion current density and corrosion rates using a Electro-chemical Corrosion Analyser have indicated that the AAC mixture having a total binder content 440 kg/m3, GGBS/FS ratio of 70/30 and 6% Na2O content, exhibits best corrosion resistance amongst the various mixes tested herein, as measured up to the end of 90-days.
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Mousavinezhad, Seyedsaleh, Gregory J. Gonzales, William K. Toledo, Judit M. Garcia, Craig M. Newtson, and Srinivas Allena. "A Comprehensive Study on Non-Proprietary Ultra-High-Performance Concrete Containing Supplementary Cementitious Materials." Materials 16, no. 7 (March 25, 2023): 2622. http://dx.doi.org/10.3390/ma16072622.
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Ultra-high performance concrete (UHPC) is a novel cement-based material with exceptional mechanical and durability properties. Silica fume, the primary supplementary cementitious material (SCM) in UHPC, is expensive in North America, so it is often substituted with inexpensive class F fly ash. However, future availability of fly ash is uncertain as the energy industry moves toward renewable energy, which creates an urgent need to find cost-effective and environmentally friendly alternatives to fly ash. This study investigated replacing cement, fly ash, and silica fume in UHPC mixtures with ground granulated blast-furnace slag (GGBFS), metakaolin, and a natural pozzolan (pumicite). To identify acceptable UHPC mixtures (28-day compressive strength greater than 120 MPa), workability, compression, and flexural tests were conducted on all mixtures. Then, durability properties including shrinkage, frost resistance, and chloride ion permeability (rapid chloride permeability and surface resistivity tests) were evaluated for the acceptable UHPC mixtures. Results showed that 75, 100, and 40% of fly ash in the control mixture could be replaced with pumicite, metakaolin, and GGBFS, respectively, while still producing acceptable strengths. Flexural strengths were greater than 14.20 MPa for all mixtures. For durability, UHPC mixtures had shrinkage strains no greater than 406 μstrain, durability factors of at least 105, and “very low” susceptibility to chloride ion penetration, indicating that these SCMs are suitable candidates to completely replace fly ash and partially replace silica fume in non-proprietary UHPC.
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Kumar, Piyush. "Strength Evaluation of High Strength Concrete by Using Fly Ash and Silica Fume as A Partial Replacement of Cement." International Journal for Research in Applied Science and Engineering Technology 10, no. 8 (August 31, 2022): 1564–70. http://dx.doi.org/10.22214/ijraset.2022.46463.
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Abstract: Presently large amounts of fly ash are generated in thermal industries with an important impact on environment as well as humans. In recent years, many researchers have established that the use of supplementary cementitious materials like fly ash (FA), GGBS, blast furnace slag, silica fume, metakaolin, and rice husk ash, hypo sludge etc. can, not only improve the various properties of concrete, but also can contribute to economy in construction costs. This research work describes the feasibility of using Fly ash and Silica Fume as partial replacement of cement. The cement has been replaced by fly ash accordingly in the range of 0%, 10%, 20%, 30%, 40%, 50%, and 60% by weight of cement and 10% of silica fume in common for M30 grade of Concrete. Concrete mixtures produced, tested and compared in terms of compressive strength and split tensile strength with the conventional concrete for 7, and 28 days. It is found that, 30% of fly ash and 10% of silica fume can be replaced and good strength obtained is comparable to the conventional concrete mix.
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Zheng, Chuji, Jun Wang, Hengjuan Liu, Hota GangaRao, and Ruifeng Liang. "Characteristics and microstructures of the GFRP waste powder/GGBS-based geopolymer paste and concrete." REVIEWS ON ADVANCED MATERIALS SCIENCE 61, no. 1 (January 1, 2022): 117–37. http://dx.doi.org/10.1515/rams-2022-0005.
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Abstract A novel method is developed for reusing the waste glass fiber-reinforced polymer (GFRP) powder as a precursor in geopolymer production. Several activation parameters that affect the workability and strength gain of GFRP powder-based geopolymers are investigated. The results of an experimental study reveal that the early strength of GFRP powder-based geopolymer pastes develops slowly at ambient temperature. The highest compressive strength of GFRP powder-based geopolymer pastes is 7.13 MPa at an age of 28 days. The ratio of compressive strength to flexural strength of GFRP powder-based-geopolymers is lower than that of fly ash and ground granulated blast furnace slag (GGBS)-based geopolymers, indicating that the incorporation of GFRP powder can improve the geopolymer brittleness. GGBS is incorporated into geopolymer blends to accelerate the early activity of GFRP powder. The binary geopolymer pastes exhibit shorter setting times and higher mechanical strength values than those of single GFRP powder geopolymer pastes. The GGBS geopolymer concrete mixture with 30 wt% GFRP powder displayed the highest compressive strength and flexural strength values and was less brittle. The developed binary GFRP powder/GGBS-based geopolymers reduce the disadvantages of single GFRP powder or GGBS geopolymers, and thus, offer high potential as a building construction material.
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Khartabil, Ahmad, and Samer Al Martini. "Thermal Transmission Properties of Sustainable Concrete with Supplementary Cementitious Materials." Key Engineering Materials 853 (July 2020): 142–49. http://dx.doi.org/10.4028/www.scientific.net/kem.853.142.
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Understanding the thermal properties of a construction material is necessarily to evaluate its heat transfer resistance that has a major contribution to the energy-efficiency required to achieve sustainable structure. Thermal properties are evaluated through three main parameters namely: thermal conductivity, thermal resistivity and thermal transmittance. The aforementioned parameters are commonly referred as K-value, R-value, and U-value respectively. Recent regulations by Dubai municipality enforced to use sustainable concrete in construction. This is by replacing cement with supplementary cementitious materials (SCMs), such as grand granulated blast furnace slag (GGBS) and fly ash. The use of grand granulated blast furnace slag (GGBS) at relatively high percentage replacement became a typical practice in ready-mixed concrete industry in Dubai. As such, it is essential to characterize the thermal properties of this sustainable concrete. The current paper investigates the thermal properties of sustainable concrete mixtures incorporating supplementary cementitious materials, air entrainment additives, polypropylene and hybrid synthetic fiber. K-value, R-value and U-value are evaluated in accordance with ASTM C518. Additionally, hardened density of all investigated mixtures are measured. The results show that the foamed concrete has better heat transfer resistance than that for the non-air entrained mixture.
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Procházka, Lukáš, Jana Boháčová, and Barbara Vojvodíková. "Effect of Admixtures on Durability and Physical-Mechanical Properties of Alkali-Activated Materials." Materials 15, no. 6 (March 8, 2022): 2010. http://dx.doi.org/10.3390/ma15062010.
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The results of ground granulated blast furnace slag (GGBS) tests in alkali-activated systems show that, with its use, it is possible to produce promising materials with the required properties. Unfortunately, GGBS is becoming a scarce commodity on the market, so the effort is to partially replace its volume in these materials with other secondary materials, while maintaining the original properties. This paper focuses on a comparison of two basic types of mixtures. The first mixture was prepared only from ground granulated blast furnace slag (GGBS) and the second type of mixture was prepared with admixtures, where the admixtures formed a total of 30% (15% of the replacement was fly ash after denitrification—FA, and 15% of the replacement was cement by-pass dust—CBPD). These mixtures were prepared with varying amounts of activator and tested. The experiment monitored the development of strength over time and the influence of different types of aggressive environments on the strength characteristics. Thermal analysis and FTIR were used in the experiment to determine the degradation products. The paper provides an interesting comparison of the resistance results of different composites in aggressive environments and at the same time an evaluation of the behavior of individual mixtures in different types of aggressive environment. After 28 days of maturation, the highest strengths were obtained with mixtures with the lowest doses of activator. The difference in these compressive strengths was around 25% in favor of the mixtures with only GGBS; in the case of flexural strength, this difference was around 23%. The largest decreases in strength were achieved in the XA3 environment. This environment contains the highest concentration of sulfate ions according to the EN 206-1 standard. The decreases in compressive strength were 40–45%, compared to the same old reference series. The surface degraded due to sulfate ions. Calcium sulphate dihydrate was identified by FTIR, thermal analysis and SEM as a degradation product.
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Long, Hoang Vinh. "Optimizing Mixtures of Alkali Aluminosilicate Cement Based on Ternary By-Products." Civil Engineering Journal 7, no. 7 (July 1, 2021): 1264–74. http://dx.doi.org/10.28991/cej-2021-03091724.
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Portland cement is a popular binder but causes many adverse effects on the environment. That is due to the large consumption of raw materials and energy during production while emitting vast amounts of CO2. In recent years, Alkali Aluminosilicate Cement (AAC) has drawn much attention in research and development and promises to become a binder that can replace the traditional cement. In many studies of this binder, the content of the ingredients is often gradually changed to determine the optimal composition. The object of this paper is to optimize the composition of AAC using a combination of three by-products as the primary raw material, including Rush Husk Ash (RHA), Fly Ash (FA), and Ground Granulated Blast-Furnace Slag (GGBS). The investigation was conducted based on the critical parameter SiO2/Al2O3, and the D-optimal design. The FA and the GGBS were industrial product form, while the RHA was ground in a ball mill for 2 hours before mixing. The results show that this type of binder has setting time and soundness to meet standard cement requirements. While comparing to Portland cement, the AAC has a faster setting time, slower development of compressive strength in the early stages but a higher strength at the age of 56 days. According to the highest compressive strength at 28 days and high fly ash content, the optimal composition was RHA of 27.8%, FA of 41.8%, and GGBS of 15.4%, corresponding to the ratio SiO2/Al2O3 of 3.83. In addition, compressive strength at 28 days of the mortar specimens with the optimal binder and the ratio of water/ cement at 0.32 reached 63 MPa. Doi: 10.28991/cej-2021-03091724 Full Text: PDF
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Verma, Somesh. "Experimental Investigation on Waste Utilization of Steel fiber and SCBA in Concrete with Partially Replacement of Cement." International Journal for Research in Applied Science and Engineering Technology 9, no. 12 (December 31, 2021): 1048–51. http://dx.doi.org/10.22214/ijraset.2021.39396.
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Abstract: This work presents the determination of the mechanical properties (compression, split tensile and flexural) of the specimens (cubes, cylinders and beams). The test specimens are M60 high strength concrete which includes ground granulated blast furnace slag (0%,10%, 20%, 30% and 40%) and fly ash (0% 10%, 20%, 30% and 40%) to obtain the desired resistances and properties. Finally, we used granulated blast furnace in different percentages as cement and concrete were replaced. We prepared concrete cubes, beams and cylinders and stored them for a 28-day cure. The tests are performed after 7, 21 and 28 days. To achieve the desired strength that cannot be achieved with conventional concrete and the current method, a large number of test mixtures with different percentages of fly ash and different percentages of ground granulated blast furnace slag are needed to select the combination of materials. Keywords: Fly Ash (FA), Ground Granulated Blast Furnace Slag (GGBS), Compressive strength, Tensile strength, Flexural strength, Ordinary Portland Cement (OPC)
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Ding, Xinxin, Mingshuang Zhao, Xue Qiu, Yupu Wang, and Yijie Ru. "The Optimization of Mix Proportion Design for SCC: Experimental Study and Grey Relational Analysis." Materials 15, no. 4 (February 10, 2022): 1305. http://dx.doi.org/10.3390/ma15041305.
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The optimization of mix proportions based on the targeted fresh and hardened performances of self-compacting concrete (SCC) is a foundation for its transition from laboratory research to industrial production. In this paper, the mix proportions of various SCC mixtures were designed by the absolute volume method with changes in the content of river sand and manufactured sand, the content of fly ash and granulated ground blast furnace slag (GGBS) and the maximum particle sizes of coarse aggregates. This experimental study was carried out to verify the workability, density and cubic compressive strength of SCC. The results show that SCC demonstrated good performance with appropriate mix proportions of manufactured sand and river sand. A hybrid effect of fly ash and GGBS appeared on the fresh performance of SCC with a constant strength, and the coarse aggregate with a smaller maximum particle size was beneficial to the workability but detrimental to the compressive strength of SCC. Finally, the optimization of the mix proportion of SCC was evaluated by grey relational analysis, in which the weight of the indicators was determined by the entropy method to improve the evaluation credibility. As a result, the optimal mix proportions of SCC were selected.
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Susilowati, Anni, and Iqbal Yusra. "KUAT TEKAN BETON CAMPURAN GGBFS DAN FLY ASH MENGGUNAKAN RETARDER." PROKONS Jurusan Teknik Sipil 15, no. 1 (February 28, 2021): 51. http://dx.doi.org/10.33795/prokons.v15i1.281.
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Abstract One of the world's construction needs is casting in large volumes that require concrete with low hydration heat, and one of the problems is that the concrete has a setting during the casting queue. Therefore, a research was conducted on adding retarder to concrete with a mixture of GGBFS and Fly Ash. The purpose of this research was to analyze the physical and mechanical properties of concrete, the effect of adding retarder and obtain optimal retarder levels. This research used an experimental methods to make concrete specimens of 75% cement mix: GGBFS 15%: Fly Ash 10% with a water cement ratio of 0.5 using mix design SNI-03-2834-2000. Variations of the retarder added to the concrete mixture were 0%, 0.2%, 0.4%, and 0.6% by weight of cement with the Naptha RD 31 type. Analysis of the effect of the retarder used statistical regression test methods on SPSS. The results of research obtained the longest setting time in this researchwas 1890 minutes at a variation of 0.6% with a slump of 168 mm. The compressive strength of the concrete increased by 12.07% - 52.36% by using a retarder added material. Based on the research results, it was obtained that the optimum level of use of retarder in mixed concrete GGBFS and Fly Ash was 0.2% because it has the best physical and mechanical properties. Keywords: Fly Ash, GGBFS, Compressive Strength, Retarder
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Aruntaş, Hüseyin Yilmaz, Erkan Yildiz, and Gökhan Kaplan. "The engineering performance of eco-friendly concretes containing diatomite fly ash and ground granulated blast furnace slag." Acta Polytechnica 62, no. 5 (October 31, 2022): 505–21. http://dx.doi.org/10.14311/ap.2022.62.0505.
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Approximately 10 % of CO2 is emitted from an ordinary Portland cement production. In cement and concrete production, CO2 emissions can be greatly reduced by using Supplementary Cementitious Materials (SCMs). In addition, the microstructure and durability properties of concrete are greatly improved when silica-rich SCMs are used. In this study, Eco-Friendly concrete design was carried out using three different SCMs. Diatomite, ground granulated blast furnace (GGBFS) and fly ash (FA) were used as the SCM in the concrete mixtures. SCMs were used instead of cement at ratios of 5, 10, 15, and 20 wt %. When diatomite was used at the rate of 20 %, the standard consistency water increased 1.7 times as compared to the reference mixture. With the increase in the replacement ratio, the final setting times of the pastes increased. The high active SiO2 content of diatomite shortened the initial setting time and increased the compressive strength. The use of 5 % diatomite reduced the slump value by 57 % as compared to the reference mixture. The slump and Ve-Be tests of GGBFS and FA mixtures showed similar properties to the reference mixture. The 28-day compressive strength of concrete varied between 29.2–34.6 MPa. With the increase in the curing time of the concrete mixtures, up to 50 % improvements were observed in the compressive strength. Especially on the 180th day, a compressive strength of 44.1 MPa was obtained in concrete mixtures with a 10 % replacement ratio. While using the FA in the mixtures improved the abrasion properties, the opposite result was observed in the case of the GGBFS. It was observed that the mixtures with 5 % FA showed the closest properties to the reference mixture. As a result, it was determined that SCMs with different properties could be used in environmentally friendly concrete mixtures by up to a 20 % replacement ratio.
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Ngo, Si-Huy, and Trong-Phuoc Huynh. "Effect of paste content on long-term strength and durability performance of green mortars." Journal of Science and Technology in Civil Engineering (STCE) - HUCE 16, no. 1 (January 26, 2022): 113–25. http://dx.doi.org/10.31814/stce.huce(nuce)2022-16(1)-10.
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This study uses densified mixture design algorithm (DMDA) to design the mixture proportions green mortars incorporating fly ash and ground granulated blast furnace slag (GGBFS). Three green mortar mixtures with various paste contents were designed using the DMDA method while a control cement-based mortar mixture was designed using the conventional method for comparison. The effect of different paste contents (n = 1.1, 1.3, and 1.5) on the changes of porosity, thermal conductivity, compressive strength, chloride ion penetration, resistance to sulfate attack, and ultrasonic pulse velocity (UPV) of both the green and control mortars was studied. The procedures of DMDA mix design for green mortar mixtures were also presented in this study. Test results reveal that all three green mixtures show a better performance than the control mixture, especially for long-term properties. On the other hand, increasing paste content increased porosity and compressive strength, however, it reduced thermal conductivity and UPV of the green mortars. All of the green mortars exhibited good performance with low porosity and compressive strength values of above 40 MPa after 28 days of curing. Moreover, the green mortars also demonstrated excellent ability to resist chloride (with RCPT values significantly lower than the threshold of 1000 coulombs) and sulfate attacks. As a result, the quality of these mortars was classified as very good level with UPV values of above 4000 m/s. This study proves the effectiveness of using the DMDA method to design the green mortar mixtures in the combination of using fly ash and GGBFS.
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Hussein, Sarah Sameer, and Nada Mahdi Fawzi. "Influence of Using Various Percentages of Slag on Mechanical Properties of Fly Ash-based Geopolymer Concrete." Journal of Engineering 27, no. 10 (October 1, 2021): 50–67. http://dx.doi.org/10.31026/j.eng.2021.10.04.
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In order to implement the concept of sustainability in the field of construction, it is necessary to find an alternative to the materials that cause pollution by manufacturing, the most important of which is cement. Because factory wastes provide siliceous and aluminous materials and contain calcium such as fly ash and slag that are used in the production of high-strength geopolymer concrete with specifications similar to ordinary concrete, it was necessary for developing this type of concrete that is helping to reduce CO2 (dioxide carbon) in the atmosphere. Therefore, the aim of this study was to study the influence of incorporating various percentages of slag as a replacement for fly ash and the effect of slag on mechanical properties. This paper showed the details of the experimental work that has been undertaken to search and make tests the strength of geopolymer mixtures made of fly ash and then replaced fly ash with slag in different percentages. The geopolymer mixes were prepared using a ground granulated blast-furnace slag (GGBFS) blend and low calcium fly ash class F activated by an alkaline solution. The mixture compositions of fly ash to slag were (0.75:0.25, 0.65:0.35, 0.55:0.45) by weight of cementitious materials respectively and compared with reference mix of conventional concrete with mix proportion 1:1.5:3 (cement: sand: coarse agg.), respectively. The copper fiber was used as recycled material from electricity devices wastes such as (machines, motors, wires, and electronic devices) to enhance the mechanical properties of geopolymer concrete. The heat curing system at 40 oC temperature was used. The results revealed that the mix proportion of 0.45 blast furnace slag and 0.55 fly ash produced the best strength results. It also showed that this mix ratio could provide a solution for the need for heat curing for fly ash-based geopolymer.
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Al Martini, Samer, Ziad Hassan, and Ahmad Khartabil. "Compressive Strength of Sustainable Concrete Mixes with Different Maximum Size Aggregates." Key Engineering Materials 803 (May 2019): 228–32. http://dx.doi.org/10.4028/www.scientific.net/kem.803.228.
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The current study investigates the effect of aggregate’s maximum size on the compressive strength of sustainable flowable concrete. The concrete mixtures were mixed for 2 hours under lab controlled environment. The purpose of the prolonged mixing was to simulate concrete in a transit truck during transportation to a construction site. The mechanical properties of the mixes were investigated through compressive strength test. Three groups of concrete mixes were prepared: the first one with 20 mm maximum size aggregates, the second group with 10 mm maximum size aggregates and third group with 5 mm max size. The concrete mixes incorporated GGBs and fly ash (FA) in binary blends. To maintain consistent initial slump for all mixes, polycarboxylate based high-range water-reducing admixture (HRWR) was used. The concrete compressive strength was measured at 1, 3, 7, and 28 days. The results showed that the mechanical properties of sustainable flow mixtures investigated were highly affected by FA, GGBS, and maximum size aggregates.
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Syzdykov, Daniyar, Chang Seon Shon, Saken Sandybay, Islam Orynbassarov, Di Chuan Zhang, and Jong Ryeol Kim. "Preliminary Investigation of Geopolymer Mixture Using GGBFS and Off-ASTM Class F Fly Ash." Materials Science Forum 1053 (February 17, 2022): 309–14. http://dx.doi.org/10.4028/p-mx9n06.
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Recently developed geopolymer concrete is considered a promising alternative for ordinary Portland cement (OPC) concrete. It accounts for green and durable civil infrastructure because the geopolymer concrete is made of industrial by-products and an alkali activator. This paper presents the investigation of a geopolymer mixture (paste) made of a combination of off-ASTM fly ash (FA) and ground granulated blast furnace slag (GGBFS) produced in a steel-making plant, Kazakhstan. The effect of water/binder ratios (w/b=0.32 and 0.35), alkaline activator solution/binder ratios (AAS/b=0.20 and 0.40), and GGBFS/fly ash ratio (S/FA=50/50 and 25/75) on geopolymer concrete’s properties were evaluated. These include workability, compressive strength, and drying shrinkage. The test results showed that increasing water content increases compressive strength and drying shrinkage of the geopolymer specimen. Decreasing alkaline content resulted in a drop in compressive strength and workability but positively minimized drying shrinkage. The mixture containing 50% GGBFS and 50% FA tends to have higher strength than the GGBFS/FA ratio of 25/75.
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Wang, Ying, Wen Ni, Siqi Zhang, Jia Li, and Prannoy Suraneni. "Optimal Mixture Designs for Heavy Metal Encapsulation in Municipal Solid Waste Incineration Fly Ash." Applied Sciences 10, no. 19 (October 4, 2020): 6948. http://dx.doi.org/10.3390/app10196948.
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Mixing municipal solid waste incineration fly ash (MSWIFA) with industrial by-products such as ground granulated blast furnace slag (GGBFS) and ladle furnace slag (LFS) can lead to a hardened system which can encapsulate the heavy metals present in the MSWIFA. The objective of this study is to find optimal mixture designs to effectively encapsulate these heavy metals. The nature of the hydrates and the strength of the mixtures are studied to develop a sustainable and practical construction material incorporating MSWIFA. Heavy metals including Cr, Cu, Zn and Cd are safely encapsulated in several developed mixtures with leachate concentration below EPA drinking water limit. The encapsulation behavior is complex and depends on metal type, age of testing, and hydration products. In general, mixtures containing LFS have more aluminate hydrates, and show greater encapsulation capacity for most heavy metals. However, they also generally show significant Sb leaching. Mixtures which show satisfactory encapsulation for all ions and adequate strength development are identified. Three ideal mixtures, including one containing zero cement, are identified which satisfy both leaching and strength requirements.
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Karolina, Rahmi, Johannes Tarigan, Harianto Hardjasaputra, and Roy Andre Daniel Silalahi. "Analysis of Geopolymer Mortar Compressive Strength Based on Fly Ash and GGBFS as Patch Repair Material." IOP Conference Series: Earth and Environmental Science 1195, no. 1 (June 1, 2023): 012032. http://dx.doi.org/10.1088/1755-1315/1195/1/012032.
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Abstract Damages that often emerge in concrete include cracks, delamination, spalling, wear, fracture, porous, voids (perforated). These damages need to be repaired, one of which is by patch repair. With consideration of strength and frugality, a self-made repair material was developed using mortar as a base material, i.e., geopolymer mortar. Geopolymer mortar is a mortar with natural materials and materials that have a high content of silica oxide and alumina (such as Fly Ash and GGBFS) as a binder that must be activated with an alkaline activator in the form of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). The use of Fly Ash and GGBFS as a binder to replace cement in geopolymer mortar has a positive impact from an environmental point of view because it can reduce the use of cement and can reduce environmental pollution due to Fly Ash and GGBFS waste. In this research, the effect of variations in Fly Ash and GGBFS and variations in the molarity of NaOH on the compressive strength of geopolymer mortar were investigated, in order to obtain the optimum composition of the geopolymer mortar mixture that meets the requirements of compressive strength as a repair material. From the results of the research, the maximum compressive strength occurred in GF91 16 M mortar at 56 days of 73.77 MPa was obtained. Geopolymer mortar has a higher compressive strength and a cheaper price when compared to Sika Grout mortar so that the use of geopolymer mortar as a patch repair material is better than Sika Grout mortar in terms of strength and frugality.
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Kuszhanova, Assem, Moldir Raiymbek, Aliya Abzal, Chang Seon Shon, Saken Sandybay, Aizhan Tukaziban, and Jong Ryeol Kim. "Compressive Strength and Expansion Characteristics of Mortar Mixtures Incorporating Chronologically Aged-Basic BOFS Aggregates Blended with GGBFS and Fly Ash." Materials Science Forum 1077 (December 15, 2022): 237–42. http://dx.doi.org/10.4028/p-bd348b.
Full textAbstract:
During the steelmaking process, many by-products, such as blast-furnace slag (BFS), basic oxygen furnace slag (BOFS), and ladle slag (LS), are generated. Unlike BFS, utilizing BOFS is limited due to its expansive volumetric characteristics by the transformation process of free lime (f-CaO) and free magnesia (f-MgO) to portlandite (Ca(OH)2) and brucite (Mg(OH)2). The natural aging process may help BOFS used as an aggregate in mortar or concrete because harmful elements such as f-CaO and f-MgO could be consumed during this stage. This study evaluated compressive strength and expansion characteristics of mortar mixtures incorporating chronologically aged-BOFS aggregates blended with ground granulated blast furnace slag (GGBFS) and ASTM class F fly ash (FFA). Test results revealed that the longer aged BOFS aggregate, the lower compressive strength, regardless of mixture types. The aging process of BOFS aggregate reduced the expansion of mortar mixtures. Incorporating GGBFS or FFA into mortar mixtures containing BOFS aggregate even more reduced the expansion of the mixture.
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Hussan, Ali, Daniel Levacher, Salim Mezazigh, and Louis Jardin. "Valorization of a Highly Organic Sediment: From Conventional Binders to a Geopolymer Approach." Journal of Composites Science 6, no. 5 (May 19, 2022): 147. http://dx.doi.org/10.3390/jcs6050147.
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The objective of this research is to investigate the possible reuse of dredged sediments from the port of Cherbourg, France, as an alternative material in road engineering and as a backfill material. These dredged sediments contain high percentages of organic matter (OM), and the presence of OM in the sediment, even in small amounts, can affect the engineering properties of sediments. This research was carried out in two series: the sediment was treated with traditional hydraulic binders (ordinary Portland cement (OPC), calcium sulfo-aluminate (CSA) cement, quarry sand (QS), lime, and a combination of them) in the first series, and with pozzolanic binders in the second series (ground-granulated blast-furnace slag (GGBS) and fly ash (FA)), along with the introduction of an activator. According to French legislation, these two pozzolanic binders (GGBS and FA) have no carbon footprint as they are industrial by-products, and therefore, the second series of this research is considered to be highly eco-friendly and economical. Sediment treated with hydraulic binders yielded a maximum value of unconfined compressive strength (UCS) of 1 MPa at 28 days. Out of eight formulations made using traditional binders, only one formulation barely met the French criteria to be used in the sub-base layer of roads. The development of geopolymer using alkali-activated GGBS and then the incorporation of 30% sediments yielded a UCS value above 2 MPa at 28, 60, 90, and 180 days. Furthermore, the addition of 5% lime and 3% granular calcium carbonate in the same mixture (geopolymer + 30% sediments) increased the UCS by up to 60% and 90%, respectively.
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Karthik, Sundaravadivelu, and Kaliyaperumal Saravana Raja Mohan. "A Taguchi Approach for Optimizing Design Mixture of Geopolymer Concrete Incorporating Fly Ash, Ground Granulated Blast Furnace Slag and Silica Fume." Crystals 11, no. 11 (October 22, 2021): 1279. http://dx.doi.org/10.3390/cryst11111279.
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In recent decades, geopolymer concrete (GPC) has been extensively researched as a potential substitute sustainable building material that may reduce CO2 emissions due to its utilization of industrial by-products. Fly ash (FA) and ground-granulated blast-furnace slag (GGBFS) are preferred geopolymer raw materials due to their obtainability and high alumina and silica concentrations. GGBFS-FA based GPC offers a clean and sustainable development technology alternative. In this study, the Taguchi method was used to optimize the mixed proportions of geopolymer concrete to achieve desired strength criteria. Four factors and four levels were considered: binder content, including four combinations of FA and GGFBS dosage, dosage of superplasticizer (0.5, 1.0, 1.5 and 2%), Na2SiO3/NaOH ratio (1.5, 2.0, 2.5 and 3), and molarity (6, 8, 10 and 12). Using these ingredients and factors, the effect of compressive strength was examined. The Taguchi approach using an L16 orthogonal array was employed to find the optimum condition of every factor while limiting the number of experiments. The findings indicated that the optimum synthesis conditions for maximum compressive strength obtained from the binder comprised 45% of FA, 45% of GGBFS and 10% of silica fume, 1.5% dosage of superplasticizer, Na2SiO3/NaOH ratio = 1.5, and 12 molar contents.
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Liu, Yushi, Xiaoming Zhou, Chengbo Lv, Yingzi Yang, and Tianan Liu. "Use of Silica Fume and GGBS to Improve Frost Resistance of ECC with High-Volume Fly Ash." Advances in Civil Engineering 2018 (2018): 1–11. http://dx.doi.org/10.1155/2018/7987589.
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Fly ash (FA) has been an important ingredient for engineered cementitious composite (ECC) with excellent tensile strain capacity and multiple cracking. Unfortunately, the frost resistance of ECC with high-volume FA has always been a problem. This paper discusses the influence of silica fume (SF) and ground-granulated blast-furnace slag (GGBS) on the frost resistance of ECC with high volume of FA. Four ECC mixtures, ECC (50% FA), ECC (70% FA), ECC (30% FA + 40% SL), and ECC (65% FA + 5% SF), are evaluated by freezing-thawing cycles up to 200 cycles in tap water and sodium chloride solution. The result shows the relative dynamic elastic modulus and mass loss of ECC in sodium chloride solution by freeze-thaw cycles are larger than those in tap water by freeze-thaw cycles. Moreover, the relative dynamic elastic modulus and mass loss of ECC by freeze-thaw cycles increase with FA content increasing. However, the ECC (30% FA + 40% SL) shows a lower relative dynamic elastic modulus and mass loss, but its deflection upon four-point bending test is relatively smaller before and after freeze-thaw cycles. By contrast, the ECC (65% FA + 5% SF) exhibits a significant deflection increase with higher first cracking load, and the toughness increases sharply after freeze-thaw cycles, meaning ECC has good toughness property.
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Fitriani, Heni, Ash Ahmed, Olonade Kolawole, Fraser Hyndman, Yakni Idris, and Rosidawani Rosidawani. "Optimizing Compressive Strength Properties of Binary Blended Cement Rice Husk Concrete for Road Pavement." Trends in Sciences 19, no. 9 (April 30, 2022): 3972. http://dx.doi.org/10.48048/tis.2022.3972.
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Different supplementary cementitious materials are often blended with cement to produce sustainable concrete. More often than not, the strength of blended concrete is compromised, if the constituent materials are not carefully selected. In this study, optimization of strength properties of blended cement-rice husk ash (RHA) was carried out to determine the best mix ratio that produced binary blended concrete of high strength. Different mix ratios of cement and RHA were studied at a water cement ratio of 0.4 to produce concrete specimens. RHA was produced by burning 700 ℃ for an hour and its chemical composition was determined using the X-Ray Fluoresce (XRF) technique. RHA produced was used to replace cement at replacement levels of 2.5, 5, 7.5, and 10 %, and was used as binder. The compressive strength of each concrete mix was determined at 7, 28, and 56 days. Approximately 250 concrete cubes were tested and the results were subjected to statistical analysis. The results showed that compressive strength and internal structure varied with RHA as a replacement for cement. Optimal strength was achieved for a concrete mixture, prepared at a water: cement: aggregate ratio of 1:1.5:3, respectively, and a RHA replacement ratio of 5 %.
HIGHLIGHTS
Cement is the most utilized construction material. The energy-intensive processes that are involved in its production contribute up to 10 % of total global CO2emissions, with potentially adverse environmental implications. It is however possible, that energy and cost efficiency can be achieved by reducing on the amount of clinker, and in its place utilising supplementary cementitious materials (SCMs) or pozzolans
Currently, most sustainable concrete uses either GGBS (slag) or PFA (fly ash) to reduce the quantity of cement used in construction and highways applications. GGBS and PFA come from industries (steel and coal waste respectively) which are in decline that should not be relied upon in the long term. Therefore, for long term sustainability it is imperative to focus attention on other alternative pozzolans
This report shows that cement in concrete can also be replaced with rice husk ash (RHA) which actually enhances the mechanical properties. Findings show the usage of up to 5 % rice husk ash as a partial cement replacement can enhance the strength of concrete whilst reducing the embodied CO2
GRAPHICAL ABSTRACT
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Oleiwi, Safie M., Jinan L. Abbas, Yahyia M. Hameed, Abbas H. Mohammed, and Ali K. Hussein. "Effect of Different Proportions of Fly Ash and GGBFS on the Compressive Strength of Geopolymer Mortar." Annales de Chimie - Science des Matériaux 46, no. 5 (December 14, 2022): 229–33. http://dx.doi.org/10.18280/acsm.460501.
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Nowadays, geopolymer plays a significant role in developing eco-friendly materials to avoid the pollution caused by the Portland cement industry. Geopolymer is a developed industrial by-product-based alternative concrete binder. The aim of this study to evaluate the effect of different proportions of Fly Ash (FA) and Ground Granulated Blast Furnace Slag (GGBFS) on the strength properties of geopolymer mortar. In this study, GGBFS was added as 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% of the total binder with NaOH concentrations 12 M and sodium silicate to sodium hydroxide ratio 2.5. The compressive strength was investigated experimentally in this study. The combination of FA and GGBFS were tested in a total of eleven geopolymer mix mortars, and the results show that combining the above constituents at 70℃ improves the compressive strength of geopolymer mortar. The result show that the mixture with 100% GGBFS replacement have maximum compressive strength (78.25 MPa) at 7-days age.
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Zhang, Pu, Yiliang Huang, Yongqi Li, Jun Zhao, Hengqian Dong, and Tao Chen. "Influence Factors on the Properties of Ultrahigh-Performance Fiber-Reinforced Concrete Cured under the Condition of Room Temperature." Advances in Civil Engineering 2018 (July 11, 2018): 1–9. http://dx.doi.org/10.1155/2018/2754735.
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Ultrahigh-performance fiber-reinforced concrete (UHPFRC) is a new type of concrete with excellent performance and good application prospects. However, expensive heat curing or high-pressure curing was often adopted to ensure the sufficient compressive strength. This study focuses on improving the compressive strength and workability of UHPFRC by changing the composition materials and the mixture ratios under standard curing conditions. The 0-1 mm and 1∼3 mm sintered bauxite was adopted as coarse aggregate. UHPFRC with high compressive strength and good workability was developed by changing the water-binder ratios, by adding ground-granulated blast furnace slag (GGBFS) or fly ash, and by changing the bauxite content of different particle sizes. When the volume ratio of steel fiber was 3%, the recommend water to binder ratio was 0.194 according to this experiment, the dosage of GGBFS-replaced cement is recommended as 20%, the dosage of fly ash instead of silica fume is recommended as 30%. The recommend ratio of 0-1 mm and 1∼3 mm sintered bauxite was 1.51 : 1. Finally, a kind of UHPFRC material with a compressive strength of 152.4 MPa and a slump of 120 mm was developed under the standard curing conditions.
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Yombi Anne, Matutu, and Jagdish Chand. "Geo-polymer concrete- a concrete for sustainable environment." IOP Conference Series: Earth and Environmental Science 1110, no. 1 (February 1, 2023): 012049. http://dx.doi.org/10.1088/1755-1315/1110/1/012049.
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Abstract The production of the cement concrete industry has grown in this modern world and is considered one of the major contributors to global pollution. The production of cement used as a binder in cement concrete requires a high-temperature combustion process which contributes to the increase of the amount of CO2 in the atmosphere leading to major threats to the planet such as climate change and depletion of natural resources. Many countries begin to impose carbon taxes as raw materials deplete over time. To reduce and eliminate greenhouse gas emissions, numerous studies have been conducted to develop an innovative and environmentally beneficial building material names Geo-polymer concrete (GC). It is vital to substitute cement with a by-product substance abundant in silicon and aluminium like red mud, fly ash (FA), rice husk ash (RHA), silica fume (SF), ground granulated blast furnace slag (GGBS), etc. activated by a high alkaline solution (AS) to connect coarse aggregates (CA), fine aggregates (FA), and other substance in GC for the purpose of making a progress in qualities of concrete and reduce natural resource uses. The current study focused on the impact of various factors such as the effect of superplasticizer, Na-OH molarity (8, 10, 12, 14 and 16M), and curing temperature (30-900C) on different mechanical characteristics such as workability, tensile and compressive strength of GC. Results obtained show that the higher strength is obtained with a molarity of 14M after both 7 and 28 days as with 16M excess Na+ ions lower the strength and affect the process of polymerisation. The curing temperature at 900C for all mixtures gives higher strength as compared to 600C which in return gives higher strength than 300C at 28 days of testing. The results also show that the addition of superplasticizer (1, 1.5, 2 and 3 % of mass of fly ash) improves the workability of geopolymer fresh concrete. In current research work, Naphthalene superplasticizer was used and its addition beyond 1.5% of the mass of fly ash improved workability but slightly decreased the strength of concrete. Its optimum value was found as 68.05KN/m2 at 900C curing temperature when 14M NaOH and 1.5% superplasticizer were added.
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Ashveenkumar, P., M. Preethi, and P. Prashanth. "Mechanical properties of geopolymer concrete with varying cement content using flyash and ground granulated blast furnace slag." International Journal of Engineering, Science and Technology 13, no. 4 (May 30, 2022): 57–64. http://dx.doi.org/10.4314/ijest.v13i4.7.
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In the recent past, the importance of geopolymer concrete as an eco-friendly product to replace portland cement concrete is continuously increasing over time. Yet less research effort has been invested in this area compared with some topical issues in civil engineering. Thus, the objective of this article is to analyse the mechanical properties of geopolymer concrete where the cement is replaced by fly ash and ground granulated blast-furnace slag (GGBS). Sodium silicate and sodium hydroxide 8 molarity solution was used. The compressive strength of a cube in an 8 molarity solution was measured for various mixtures (i.e. G50F50 where G and F stand for GGBS and flyash, respectively while the numerical value denotes the cement percentage) and the cement contents (i.e. 0, 10, 20, 30, 40%). The cube specimens are 100mmx100mmx100mm with the ambient curing at 35- 400C. In total, 9 cubes, 3 beams and 3 cylinders are cast at 7days, 14days and 28days while the compressive strengths of different mixes and cubes are calculated. For 28days, beams and cylinders are measured for flexural and tensile strength. The compressive strength at 7,14 and 28 days nearly doubled the target strength by using geopolymer concrete instead of normal concrete. Compressive strength is about 10% higher at 7 and 14days and 20% higher at 28days after replacing 40% of the cement. Flexural strength increased by 50% when 40% of the cement was replaced but split tensile strength only increased by 1%.
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Salas Montoya, Andres, Loth I. Rodríguez-Barboza, Fabiola Colmenero Fonseca, Javier Cárcel-Carrasco, and Lauren Y. Gómez-Zamorano. "Composite Cements Using Ground Granulated Blast Furnace Slag, Fly Ash, and Geothermal Silica with Alkali Activation." Buildings 13, no. 7 (July 21, 2023): 1854. http://dx.doi.org/10.3390/buildings13071854.
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In recent decades, alkali activated and blended cements have attracted great interest worldwide due to their advantages of low energy cost, high strength, and good durability. This study evaluated the effects of replacing 50% of Portland cement with a mixture of three waste materials: ground granulated blast furnace slag (GGBFS), fly ash (FA), and geothermal waste (GS), with and without external alkaline activation, and activated with different alkali agents: 4 and 7% Na2O equivalent of sodium hydroxide, sodium silicate (water glass), and sodium sulfate. After 90 days of curing, samples were characterized using compressive strength tests, scanning electron microscopy, X-ray diffraction, and thermogravimetric analyses. The results showed that sodium hydroxide caused an alkali–silica reaction and reduced the strength, while sodium silicate and sodium sulfate improved the strength and hydration products formation. Moreover, the addition of fly ash decreased the compressive strength but increased the workability, while the addition of slag and geothermal waste increased strength and densified the matrix with the formation of additional hydration products. The blended cements without activation also showed better performance than pure cement and a more compact matrix of hydration products. The study demonstrated the feasibility of using waste materials to produce blended cements with low energy costs and high durability.
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Kozhageldi, Nurtay, Chang Seon Shon, Gulfairuz Kareken, Aizhan Tukaziban, Madiyar Mardenov, Di Chuan Zhang, and Jong Ryeol Kim. "Properties of Geopolymer Mortar Mixtures Containing Waste Glass Aggregates and River Sand." Key Engineering Materials 945 (May 19, 2023): 93–99. http://dx.doi.org/10.4028/p-67b121.
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This paper evaluates the properties of fly ash (FA) and ground granulated blast furnace slag (GGBFS) based geopolymer mortar mixtures with waste glass sand (WGS) obtained by crushing glass bottles. A total of seven mixtures, including the partial substitution of river sand (RS) with WGS (0%, 15%, 30%, and 45%) with two alkali activator solution to binder (AAS/b) ratio groups (0.4 and 0.3), were designed. Sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) were used as the alkali activators. The experimental program evaluated compressive strength, hardened density, alkali-silica reaction (ASR), drying shrinkage, and thermal conductivity of geopolymer mortar mixtures. Test results indicated that the compressive strength of the geopolymer mortar increased with the addition of WGS for AAS/b = 0.4, but it had a negative effect for AAS/b = 0.3. The FA and GGBFS-based geopolymer mortar helps to reduce the ASR expansion of the mixture containing WGS. The drying shrinkage of the geopolymer mortar decreases with the increase of the WGS content. The increase of WGS decreases the thermal conductivity of geopolymer mortar in the case of mixtures with AAS/b = 0.4, but interestingly thermal conductivity value increases in the case of mixtures with AAS/b = 0.3. The findings of this study suggest that using WGS as partial RS substitution material in geopolymer mortar offers sufficient mechanical and thermal insulation properties without causing durability issues.
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Lindh, Per, and Polina Lemenkova. "Dynamics of Strength Gain in Sandy Soil Stabilised with Mixed Binders Evaluated by Elastic P-Waves during Compressive Loading." Materials 15, no. 21 (November 4, 2022): 7798. http://dx.doi.org/10.3390/ma15217798.
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This paper addresses the problem of stabilisation of poor subgrade soil for improving its engineering properties and stiffness. The study aim is to evaluate the effects from single and mixed binders on the gain of strength in sandy soil over the period of curing. We propose an effective non-destructive approach of using P-waves for identifying soil strength upon stabilisation. The growth of strength and stiffness is strongly dependent on time of curing and type of the stabilising agents which can include both single binders and their blended mixtures. The diverse effects from mixed binders on the properties of soil were evaluated, compared and analysed. We performed the experimental trials of five different binders for stabilisation of sandy soil using cement, lime, Ground Granulated Blast Furnace Slag (GGBFS), energy fly ash and bio fly ash. The methodology included soil stabilisation by binders during a total period of 90 days, strength test for the Unconfined Compressive Strength (UCS) and seismic tests on the stabilised samples. The dynamics of soil behaviour stabilised by different binders for days 7, 14, 28 and 90 was statistically analysed and compared. The optimisation of binder blending has been performed using mixture simplex lattice design with three binders in each case as independent variables. Using P-waves naturally exploited strength characteristics of soil samples and allowed us to compare the effects from the individual and blended binders over the complete period of curing with dominating mixes. The results indicate that strength growth in stabilised soil samples is nonlinear in both time and content of binders with dominating effects from slag which contributed the most to the compressive strength development, followed by cement.
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Ridzuan, Ahmad Ruslan Mohd, Mohd Mustafa Al Bakri Abdullah, Mohd Fadzil Arshad, Muhammad Faheem Mohd Tahir, and A. A. Khairulniza. "The Effect of NaOH Concentration and Curing Condition to the Strength and Shrinkage Performance of Recycled Geopolymer Concrete." Materials Science Forum 803 (August 2014): 194–200. http://dx.doi.org/10.4028/www.scientific.net/msf.803.194.
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Concrete is widely used as a material construction. Globally, the consumption of concrete was estimated to be more than 8 billion tons per year. Nowadays, many problems arise related to concrete manufacturing occur especially on environmental issues. A key concern for environmentalists has always been climate change. One of the ways to mitigate the impact activities on the climate is to reduce carbon footprint. Portland cement are commonly been used in concrete is responsible for about 5% of all CO2emission. It is reported by Davidovit that the production of one ton of Portland cement emits approximately one ton of CO2into the atmosphere. There are several ways to reduce environmental pollution that cause by production and utilization of Portland cement, one of it is Geopolymer concrete. Subsequently Geopolymer concrete incorporating with recycle concrete aggregate (RCA) is one of the alternative to further reduce carbon footprint and as well as can reduce waste. Geopolymer concrete is a concrete that use no cement and produced by the combination of alkaline activator and supplementary cementitious material (SCM) such as fly ash, boiler ash, waste paper sludge ash (WPSA), ground granulated blast-furnace slag (GGBS), and so on in order to reduce carbon emission. In this study the Waste Paper Sludge Ash (WPSA) were used as a SCM and the combination of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) as a binder. Two (2) series of geopolymer concrete specimens comprising two (2) different molar of sodium hydroxide (NaOH) which are 8M and 14M were adopted. The effect variable alkaline molarity on the compressive strength and shrinkage of the geopolymer concrete specimens is tested at the age of 3, 7, 14 and 28 days. The mixture of geopolymer concete with 8M of sodium hydroxide (NaOH) concentration then was categorized into three (3) groups. Each group were been cured at different curing condition which are in ambient condition, oven, and external condition. The size of specimens prepared were 100mm x 100mm x100mm. The result shows that the molarities of sodium hydroxide (NaOH) influenced the strength of Waste Paper Sludge Ash (WPSA) based geopolymer concrete produced incorporating with increasing of recycle concrete aggregate (RCA). The result also show that the geopolymer concrete undergoes very low shrinkage. Curing condition will also effect the strength of geopolymer concrete produced.
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Al Martini, Samer, Ahmad Khartabil, and Reem Sabouni. "Evaluation of Thermal Conductivity of Sustainable Concrete Having Supplementary Cementitious Materials (SCMs) and Recycled Aggregate (RCA) Using Needle Probe Test." Sustainability 15, no. 1 (December 21, 2022): 109. http://dx.doi.org/10.3390/su15010109.
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The evaluation of thermal properties is commonly conducted to characterize non-structural materials, such as lightweight concrete, that are used for thermal insulation. Such materials are designed for thermal resistivity applications. Due to the increased demand to adopt sustainable practices in the construction industry, municipalities in the United Arab Emirates (UAE) emphasize the use of sustainable materials in construction, such as green concrete. The cement in green concrete is partially replaced with supplementary cementitious materials (SCMs); these materials are by-product waste from other industries. The SCMs can contribute to sustainability by reducing the concrete carbon footprint. They can also help in extending concrete durability and service life. However, there is still a lack in the literature regarding the effects of these materials on the thermal properties of concrete. This paper investigates the thermal properties of sustainable concrete mixes incorporating various types of SCMs. The SCMs that are considered in this investigation are fly ash, ground granulated blast-furnace slag (GGBS), and microsilica. Another way to improve the sustainability of the concrete is to partially replace the natural aggregates with recycled aggregates. Thus, a group of the concrete mixes in this investigation were prepared by replacing 40% of natural aggregates with recycled aggregates to investigate the effects of recycled aggregate on the thermal properties of concrete. Further, the thermal properties of three lightweight concrete mixtures commonly used in construction were evaluated. All concrete mixtures were examined for thermal conductivity and resistivity in accordance with ASTM D5334. The results of this investigation showed that SCMs and recycled aggregates have a significant impact on the thermal properties of concrete. The high replacement of ground granulated blast-furnace slag (GGBS) resulted in a remarkable increase in thermal conductivity. This investigation provides significant conclusions and recommendations that are of practical importance to the construction industry in the UAE to promote sustainability. This research aims at formulating recommendations for the effective use of SCMs in the construction industry in the UAE based on their effects on the thermal properties of concrete.
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Khartabil, Ahmad, and Samer Al Martini. "Fresh and Mechanical Properties of Sustainable Concrete Using Recycled Aggregates." Key Engineering Materials 803 (May 2019): 239–45. http://dx.doi.org/10.4028/www.scientific.net/kem.803.239.
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In the last few decades, the United Arab Emirates (UAE) witnessed rapid development in the construction industry. It was recently emphasized to adopt sustainability practice in all aspects related to construction. The recent sustainable practice that was enforced by Dubai Municipality in construction field is “greening the concrete” by solely replacing the Portland Cement with supplementary cementitious materials (SCMs), such as grand granulated blast furnace slag (GGBS) and fly ash. On the other hand, the use of recycled aggregates can also contribute to the greening of concrete and to the reduction of carbon foot print from the construction industry in the UAE. Consequently, it is significant to study the suitability of local available recycled aggregate and their effect on concrete fresh and hardened properties, in order to expand the current practice. The recycled aggregates, used in this investigation, are obtained from a local recycled aggregates plant in Abu Dhabi using concrete from demolished buildings in Abu Dhabi. The natural aggregates in concrete mixtures were replaced by recycled aggregates with the following percentages: 20%, 40%, 60% and 100%. The concrete parameters investigated are mainly the slump retention, rheology and compressive strength. The results are analyzed to arrive to pertinent conclusions for the utilization of concrete with recycled aggregates in different types of construction projects.
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Abd El Fattah, Ahmed Mohsen. "Development of a New Concrete Marine Exposure Site on the Arabian Gulf-East Coast of Saudi Arabia." Key Engineering Materials 711 (September 2016): 45–51. http://dx.doi.org/10.4028/www.scientific.net/kem.711.45.
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A concrete durability site in the Eastern Province of Saudi Arabia that exposes Saudi concrete to harsh marine conditions on the Arabian Gulf and salty air conditions was constructed. The site contains 32 concrete blocks formed from eight different mixtures made with Cement Type I, Cement Type V, Cement Type I with 6% silica Fumes, 25% fly Ash, 70% Ground-granulated blast-furnace slag (GGBFS), Migrate Corrosion Inhibitors (MCI), Calcium Nitrite based inhibitors (CNI) and Caltite. Each mixture formed 4 blocks; 2 were reinforced with black steel and two were plain concrete. The concrete blocks were 1200 mm high, 460 mm wide and 230 mm thick placed vertically. The concrete blocks were placed at three zones to achieve different exposure conditions which are atmospheric, splash or spray zone and tidal zone. Samples will be taken periodically to measure the rate of chloride ingress in each concrete mixture under the different exposure conditions. Embedded steel reinforcement in specimens in atmospheric zone have not recorded corrosion activities at six months of exposure. The steel bars in three zones will be monitored for corrosion activity through linear polarization test. The measured chloride profiles in the exposure site will be compared to the measured concrete transport properties from the companion laboratory specimens. Standard compressive test and bulk diffusion test were conducted for 150x300 mm and 75x150 standard cylinders, respectively. All of the cylinders’ strength exceeded the designed compressive strength of 28 MPa. Whereas for 35 days standard bulk diffusion test, mix contained 100% cement type I had the least chloride concentration, and mix 5 that had 70% GGBFS and 30% cement type I had the highest surface chloride concentration. Overall chloride profiles for all the mixes were within ranges reported in literature. Further tests of chloride binding capacity and bulk diffusion for different intervals will be undertaken.
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Wei, Xiaobin, Feng Ming, Dongqing Li, Lei Chen, and Yuhang Liu. "Influence of Water Content on Mechanical Strength and Microstructure of Alkali-Activated Fly Ash/GGBFS Mortars Cured at Cold and Polar Regions." Materials 13, no. 1 (December 29, 2019): 138. http://dx.doi.org/10.3390/ma13010138.
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Negative temperature curing is a very harmful factor for geopolymer mortar or concrete, which will decrease the strength and durability. The water in the geopolymer mixture may be frozen into ice, and the water content is a crucial factor. The purpose of this paper is to explore the influence of water content on the properties of alkali-activated binders mortar cured at −5 °C. Fly ash (FA) and ground granulated blast furnace slag (GGBFS) were used as binders. Three groups of experiments with different water content were carried out. The prepared samples were investigated through uniaxial compression strength test, Scanning electron microscopy (SEM), and X-ray diffraction (XRD) for the determination of their compressive strength, microstructural features, phase, and composition. The results indicated that, the compressive strength of samples basically maintained 25.78 MPa–27.10 MPa at an age of 28 days; for 90 days, the values reached 33.4 MPa–34.04 MPa. The results showed that lower water content is beneficial to improving the early strength of mortar at −5 °C curing condition, while it has little impact on long-term strength. These results may provide references for the design and construction of geopolymer concrete in cold regions.
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Dheyaaldin, Mahmood Hunar, Mohammad Ali Mosaberpanah, and Radhwan Alzeebaree. "Performance of Fiber-Reinforced Alkali-Activated Mortar with/without Nano Silica and Nano Alumina." Sustainability 14, no. 5 (February 22, 2022): 2527. http://dx.doi.org/10.3390/su14052527.
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The current study is aimed to evaluate the effect of nanomaterials (nano alumina (NA) and nano silica (NS) on the mechanical and durability performance of fiber-reinforced alkali-activated mortars (FRAAM). Polypropylene fiber (PPF) was added to the binders at 0.5% and 1% of the volume of the alkali-activated mortar (AAM). Design-expert software was used to provide the central composite design (CCD) for mix proportions. This method categorizes variables into three stages. The number of mixes was created and evaluated with varied proportions of variables. The primary binders in this experiment were 50% fly ash (FA) and 50% ground granulated blast slag (GGBS). The alkali-activated solution to binder ratio was 0.5, and the sodium hydroxide (NaOH) concentration was 12 molarity. The sodium silicate to sodium hydroxide ratio was 2.5. The cubic specimens and prisms were evaluated in an ambient atmosphere at 23 + 3 °C room temperature at the ages of 7 and 28 days. The mechanical performance of AAM was indicated through evaluation of the compressive and flexural strength, flowability, and unit weight of the alkali activator mortar. In addition, the durability performance and microstructure analysis were also evaluated. The experiments demonstrated that the AAM without fibers and nanomaterials had a higher flow rate than the other mixtures. However, the flowability of all mixtures was acceptable. The highest compressive strength was deducted through the use of 2% NA and higher flexural tensile strength was obtained for mixtures included 1% NS and 0.5% PPF. The lower water absorption was noted through the combination of 2% nano silica and 1% polypropylene fiber. Whereas, the combination of 2% nano silica, 1% nano alumina, and 0.5% polypropylene fiber had the lower sorptivity. In addition, the microstructure analysis indicated that the nanomaterials significantly improved the matrix and the porosity of the matrix was considerably reduced.
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Lee, Jaehyun, Taegyu Lee, Hyeonggil Choi, and Dong-Eun Lee. "Assessment of Optimum CaO Content Range for High Volume FA Based Concrete Considering Durability Properties." Applied Sciences 10, no. 19 (October 4, 2020): 6944. http://dx.doi.org/10.3390/app10196944.
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There have been many studies on the effect of durability and compressive strength on the increase of the mixing rate of admixtures. However, there is no research that can provide a guide on the optimal mixture proportions for maintaining compressive strength and secure durability properties when using local materials. Therefore, the purpose of this article is to assess the durability and engineering performances of concrete based on local fly ash (FA), as well as to derive the optimum CaO content scope for ensuring durability. The results of this study were compared with the results of the previous study of high-volume ground-granulated blast-furnace slag (GGBFS) concrete. To achieve this, tests were carried out by increasing the admixture mixing rate in 10% increments from 0% to 70%. The unit water was set at 175 kg/m3 and the amount of binder was set at 330 kg/m3. It was found that the overall compressive strength of the hardened concrete decreased when the admixture mixing rate increased. In addition, the compressive strength of specimens tended to improve as all the CaO contents of the admixture types increased. When the durability properties were examined, it was found that the relative dynamic elasticity modulus and carbonation depth decreased, and the chloride penetration depth increased as the CaO content increased for both GGBFS and FA. The weight loss rate, however, remained similar. Based on the results of this study, the optimal CaO content that achieved satisfactory engineering and durability properties was found to be between 39% and 48% for FA. The results of this study will be able to offer guidelines for the mixture rates of FA when mixing durable concrete for use in the field. Additionally, these results are expected to be utilized as a basis for determining instructions relating to chemical composition in order to develop binders with improved durability.
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Nguyen, Chinh Van. "Effect of Locally Sourced Fly Ash and GGBS on the Compressive Strength and Chloride Resistance of Concrete." Key Engineering Materials 919 (May 11, 2022): 123–31. http://dx.doi.org/10.4028/p-m72xj5.
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The paper investigated the effect of locally sourced fly ash and ground granulated blast-furnace slag (GGBS) on the compressive strength and chloride resistance of concrete. The mix proportion was cementitious material (total of ordinary Portland cement (OPC), fly ash and GGBS): sand: coarse aggregate: water of 1:2:3:0.6 in which 20% by mass of total cementitious materials was replaced by class F fly ash and GGBS. Compressive strength and rapid chloride penetration tests were conducted at 28, 56 and 120 days. The results shows that fly ash and GGBS reduce slightly the compressive strength but improve significantly the choloride resistance of concrete. Within the range of investigation, 10% of fly ash and 10% of GGBS are recommended to replace OPC as they improve the chloride resistance and maintain the compressive strength of concrete.