Percentage Of Ground Granulated Blast Furnace Slag Research Articles

Comprehensive evaluation of microstructure and mechanical performance of sustainable ambient-cured alkali-activated composites

Cement is one of the building materials that is most frequently utilized in the construction field. However, the cement industry contributes significantly to the production of greenhouse gases. Therefore, many works have focused on improving sustainable construction materials that could contribute to decreasing greenhouse gas emissions. This study aimed to design a sustainable geopolymer mortar (GPM) made of fly ash (FA) and ground-granulated blast furnace slag (GGBS), which would be suitable for repairing damaged concrete structures. The work focused on investigating the effect of GGBS percentage, alkaline activator ratio, and superplasticizer dosage on the compressive strength, setting time, and workability of an ambient-cured GPM. The results of this research indicated that the compressive strength of GPM improved with the increase in GGBS percentage until a certain limit. However, the workability and setting time deteriorated with the increase in GGBS percentage. Increasing the alkaline activator ratio contributed to improving the compressive strength, workability, and setting time of GPM up to specific levels, but then they started to reduce. Superplasticizer dosage contributed to enhancing the compressive strength, workability, and setting time of GPM. This study found that the optimum FA/GGBS-based GPM that may be used in repair applications contains 50% GGBS, 50% FA, and 5% superplasticizer. The silica sand/binder ratio and alkaline activator ratio were 2.75 and 1.0, respectively. The compressive strength at 1 day, setting time, and workability of the optimum mix were about 12.70 MPa, 20 min, and 138.75 mm, respectively. The XRF, XRD, TGA, and SEM analyses were useful tools used to interpret the effects of the alkaline activator ratio on the fresh and mechanical properties of GPM.

Effect of waste glass powder on the durability and microstructural properties of fly ash-GGBS based alkali activated concrete containing 100 % recycled concrete aggregate

This research investigates the effective utilization of waste glass powder (WGP) in fly ash (FA)-ground granulated blast furnace slag (GGBS) based alkali-activated concrete (AAC) containing 100 % recycled concrete aggregate (RCA) cured at ambient temperature. FA substituted with WGP in the range of 0–25 %, and the percentage of GGBS was kept unaltered at 50 %. The influence of WGP on the strength, durability, and microstructural properties of FA-GGBS based AAC was evaluated. The experimental results showed that the strength and durability were enhanced with the increases of WGP of up to 20 %, and then started to decrease. The highest compressive strength (51.4 MPa) and ultrasonic pulse velosity (UPV) (4.35 km/s) were obtained for F30W20 (FA:GGBS:WGP - 30:50:20). In addition, sorptivity, chloride, and water permeability were reduced by 39.92 %, 56 %, and 64.13 %, respectively for optimized specimens as compared to a control sample (without WGP). Furthermore, the microstructural analysis was carried out to investigate the alteration in the mineralogical and morphology. On the basis of microstructural investigations, WGP notably enhanced the microstructure of FA-GGBS-based AAC by enhancing the formation of reaction products, including C-S-H and C-(N)-A-S-H gel. At last, this study found that CO2 emissions, energy consumption, and cost analysis were lowered by approximately 60 %, 28 %, and 41 % compared to conventional concrete of the same quality.

Durability of Slag Based Geopolymer Stabilized Clay with High Moisture Condition

Clay soils, characterized by their cohesiveness and water retention capacity, exhibit low aeration and tend to swell when water is absorbed, leading to subsequent contraction. The moisture content significantly affects the properties of marine clay, resulting in low strength and high compressibility. Traditional stabilizers such as lime and cement have been extensively studied for their ability to enhance the compressive strength, reduce swelling potential, and improve the overall durability of the soil. These stabilizers offer numerous benefits in terms of soil properties and have been extensively researched. However,due to environmental concerned, geopolymer has been explored as an alternative replacement to the traditional stabilizer. In this research, stabilized clay soil using ground granulated blast furnace slag(GGBS) based geopolymer were prepared and tested for the compressive strength and durability characteristic. Different percentages of GGBS (10%, 20% and 30%) were used to stabilize the clay soil with different activator/binder ratio (0.5, 0.75 and 1.0) and initial moisture content (0.75wL, 1.0wL, and 1.25wL). Cement stabilized specimen were also prepared for comparison. Unconfined compression test and wet-dry cycle were performed to evaluate the compressive strength and durability of treated soil. It was found that the strength of treated sample decreased with increment of initial moisture content. Increasing the binder dose was necessary to achieve the strength requirements for high water content soils. Thus, it shows that the use of a GGBS based geopolymer binder for the purpose of stabilizing soft soil is an alternative that is both effective and environmentally friendly.

Analysing the influence of ground granulated blast furnace slag and steel fibre on RC beams flexural behaviour

This study examines the effect of Ground Granulated Blast Furnace Slag (GGBS) and steel fibers on the flexural behaviour of RC beams under monotonic loading. Various percentages of GGBS were used to substitute cement, namely 0%, 20%, 40%, 60%, and 80% and fibers were added to the concrete mix as 0%, 0.5%, 1%, and 1.5% of the volume of concrete. The load–deflection behaviour of GGBS-incorporated RC beams with fibers was compared with the control RC beam. Beams were tested under load control for 28 days and 180 days. The ultimate load of the GGBS-incorporated RC beam up to 40% cement replacement was found to higher than that of the control beam. The strength of concrete is reduced by 28% and 19% when cement was partially replaced by 80% of GGBS at 28 and 180 days, respectively, compared to control concrete without fibres. Further, the analytical load–deflection response of GGBS-incorporated RC beams was determined by using several codes of practice, namely, ACI 318-11(2011), CSA A23.3-04 (2004), EC-04 (2004), and IS 456 (2000). The Codal provisions were primarily based on the effective moment of inertia, Young’s modulus, and modulus of rupture, stiffness, and cracking. Average load–deflection plots obtained from experiments were compared with the computed load–deflection of analytical studies. It was found that the analytically predicted load–deflection behaviour is comparable with the corresponding average experimental load–deflection response. Moment curvature relations were also developed for RC beams.

Experimental Study by Use of GGBS as Partial Replacement of Cement on Compressive Strength of Concrete

Abstract: Compressive strength may be increased by using mineral admixtures by replacing some amount of the cement in concrete. Several widely used mineral admixtures include silica fume (SF), ground granulated blast furnace slag (GGBS), and fly ash (FA). In this paper, GGBS admixture is employed to replace cement at percentages of 10%, 20%, 30%, and 35%. Concrete comes in two varieties, M-30 and M-35, which are both utilized. The Different percentage of GGBS are tested in order to see how they affect the concrete's strength. According to the findings, GGBS does have a role in raising concrete's compressive strength. At 20% cement substitution, GGBS improves the compressive strength of both concrete mixes. Then, they lowered the concrete's compressive strength.

XGBoost Prediction Model Optimized with Bayesian for the Compressive Strength of Eco-Friendly Concrete Containing Ground Granulated Blast Furnace Slag and Recycled Coarse Aggregate

The construction industry has witnessed a substantial increase in the demand for eco-friendly and sustainable materials. Eco-friendly concrete containing Ground Granulated Blast Furnace Slag (GGBFS) and Recycled Coarse Aggregate (RCA) is such a material, which can contribute to a reduction in waste and promote environmental sustainability. Compressive strength is a crucial parameter in evaluating the performance of concrete. However, predicting the compressive strength of concrete containing GGBFS and RCA can be challenging. This study presents a novel XGBoost (eXtreme Gradient Boosting) prediction model for the compressive strength of eco-friendly concrete containing GGBFS and RCA, optimized using Bayesian optimization (BO). The model was trained on a comprehensive dataset consisting of several mix design parameters. The performance of the optimized XGBoost model was assessed using multiple evaluation metrics, including Root Mean Squared Error (RMSE), Mean Absolute Error (MAE), and coefficient of determination (R2). These metrics were calculated for both training and testing datasets to evaluate the model’s accuracy and generalization capabilities. The results demonstrated that the optimized XGBoost model outperformed other state-of-the-art machine learning models, such as Support Vector Regression (SVR), and K-nearest neighbors algorithm (KNN), in predicting the compressive strength of eco-friendly concrete containing GGBFS and RCA. An analysis using Partial Dependence Plots (PDP) was carried out to discern the influence of distinct input features on the compressive strength prediction. This PDP analysis highlighted the water-to-binder ratio, the age of the concrete, and the percentage of GGBFS used, as significant factors impacting the compressive strength of the eco-friendly concrete.

Assessing the effect of corrosion on optimised low carbon concrete

Global warming is a serious issue that threatens the world and future life of human. The sectors of construction are a major source of carbon emissions, with cement manufacturing making up a major contribution. Low carbon concrete (LCC) is a solution for reducing the emission of net from whole process of manufacturing.Lowering the buildings embodied carbon dioxide equivalent (eCO2) is a critical response to global and national carbon reduction targets. Globally, the construction industry is developing databases, procedures and tools for assessing and reducing embodied eCO2 in buildings. The construction industry consumes 40% of world energy and contributes 30% of human greenhouse gas (GHG) emissions. Partially replacing clinker, the major element of typical Portland cement, with pozzolanic or latent hydraulic industrial by-products like ground granulated blast furnace slag (GGBS), significantly decreases cement costs by conserving energy in the manufacturing process. It also minimizes CO2 emissions from cement mill and provides low-cost solution to the environmental challenge of industrial waste disposal. In this study, three percentages of GGBS were used (0%, 25%, and 50%).Corrosion in steel reinforcements is one of the industry's most serious and costly problems. In this study, an accelerated corrosion test was used to determine the correlation between corrosion resistance and optimal strength concrete mixtures. For this study, nine mixed patterns were created and casted into 100 mm cubes and 100 × 100 × 400-mm prism moulds, and 10-mm-diameter rebar was embedded into the concrete prisms for the accelerated corrosion test. The findings of this experiment reveal that resistance typically rises with the strength and percentage of GGBS. This was not the case for all samples, like the 35 MPa samples with 25% GGBS were shown to be more impervious, i.e. to sustain resistance greater than the 40 MPa samples with the same GGBS percentage. This research suggests that the widely held belief that higher-strength concrete always results in greater durability may not always be correct, as the concrete durability is dependent on the cement and the GGBS efficiency.

Assessment of engineering properties of slag mixtures as a bottom liner in landfills

This work examines the engineering properties and leachate characteristics of ground granulated blast-furnace slag (GGBS) blended with laterite soil–bentonite mixtures as a bottom landfill liner. In this study, laterite soil is considered a non-expansive and non-plastic clay; in contrast, bentonite is a highly expansive and highly plastic clay. Laboratory experiments were performed to quantify the effect of GGBS–laterite soil–bentonite mixtures on the liquid limit (LL), free swell index (FSI), compaction characteristics, unconfined compressive strength (UCS), hydraulic conductivity (k) and leachate characteristics tests. As the GGBS percentage in the mix blend increased, the LL, FSI, optimum moisture content, k determined with deionised water/diesel oil contaminants and leachate concentration decreased, whereas the maximum dry densities and UCS value increased. Furthermore, X-ray diffraction analysis and energy-dispersive X-ray spectroscopy were performed on UCS samples to determine the occurrence of a hydration reaction in mix blends at 0, 14 and 28 days of curing. The test results revealed that an increase in the calcium (Ca)/silicon (Si) ratio and a decrease in the aluminium (Al)/calcium ratio enhanced the UCS during the curing period. Consequently, 20% GGBS combined with laterite soil–bentonite mixes proved to be the ideal material for landfill bottom liners in waste containment systems.

Enabling sustainable rapid construction with high volume GGBS concrete through elevated temperature curing and maturity testing

Nowadays, low carbon footprint concrete for construction relies heavily on ground granulated blast-furnace slag (GGBS) as a partial cement replacement material (CRM) in places where other CRMs are in short supply. However, it is relatively well-known that the low early-age strengths of GGBS concretes discourage the maximisation of cement replacement in most applications; a constraint which can be potentially overcome through exploitation of hydration acceleration under elevated temperature curing. Concrete and mortar mixes of 47 MPa 28-day target mean cube strength were developed and investigated in this study with various percentages of GGBS (0, 20, 35, 50 and 70%) and cured under isothermal and non-isothermal regimes (20, 30, 40 and 50 °C and adiabatic). Higher temperatures appeared to significantly accelerate the strength gain of GGBS concretes, particularly those containing high GGBS percentages. In-situ strength development may be estimated through maturity functions which were initially developed for neat Portland cement concretes. The accuracy of several maturity functions, such as the Nurse-Saul, Arrhenius, Weighted Maturity, Weaver-Sadgrove and Rastrup ones, were examined together with two strength-maturity/time correlations. It was found that although maturity methods can be used to optimise a concrete mix in terms of GGBS content and depending on the application, it is not possible to obtain consistently reliable estimates for GGBS concretes from the current functions. Nonetheless, from the current models considered, the Arrhenius, Weighted Maturity and Rastrup functions appear as more appropriate for higher replacement levels of cement with GGBS. Overall, the present study highlighted a need for further improving maturity functions to account for the strength development of GGBS concrete.

Development of GGBS-Based Geopolymer Concrete Incorporated with Polypropylene Fibers as Sustainable Materials

Geopolymer concrete, because of its less embodied energy as compared to conventional cement concrete, has paved the way for achieving sustainable development goals. In this study, an effort was made to optimize its quality characteristics or responses, namely, workability, and the compressive and flexural strengths of Ground Granulated Blast-furnace Slag (GGBS)-based geopolymer concrete incorporated with polypropylene (PP) fibers by Taguchi’s method. A three-factor and three-level design of experiments was adopted with the three factors and their corresponding levels as alkali ratio (NaOH:Na2SiO3) (1:1.5 (8 M NaOH); 1:2 (10 M NaOH); 1:2.5 (12 M NaOH)), percentage of GGBS (80%, 90%, and 100%) and PP fibers (1.5%, 2%, and 2.5%). M25 was taken as the control mix for gauging and comparing the results. Nine mixes were obtained using an L9 orthogonal array, and an analysis was performed. The analysis revealed the optimum levels as 1:2 (10 molar) alkali ratio, 80% GGBS, and 2% PP fibers for workability; 1:2 (10 molar) alkali ratio, 80% GGBS, and 2.5% PP fibers for compressive strength; and 1:2 (10 molar) alkali ratio, 80% GGBS, and 1.5% PP fibers for flexural strength. The percentage of GGBS was found to be the most effective parameter for all three responses. The analysis also revealed the ranks of all the factors in terms of significance in determining the three responses. ANOVA conducted on the results validated the reliability of the results obtained by Taguchi’s method. The optimized results were further verified by confirmation tests. The confirmation tests revealed the compressive and flexural strengths to be quite close to the strengths of the control mix. Thus, optimum mixes with comparable strengths were successfully achieved by replacing cement with GGBS and thereby providing a better path for sustainable development.

An overview of mechanical properties of engineered cementitious composite (ECC) with different percentages of GGBS

This paper reviews the mechanical properties of engineered cementitious composites (ECCs) studied in recent years with a focus on cement replacement by Ground Granulated Blast-furnace Slag (GGBS) leading to a more sustainable material. The main objective is to study the effect of GGBS substitution amounts (from zero up to 90%) on the mechanical properties of ECCs made with polyethylene (PE) as well as polyvinyl alcohol (PVA) fibers. Furthermore, an experimental study was conducted to investigate the compressive and tensile properties of high strength, high ductility PE-ECC with 60% cement replacement by GGBS. The average compressive strength of cube specimens was 59.1 MPa, while tensile specimens (dogbones) showed a tensile strength of up to 6.6 MPa and tensile strain capacity of 6.4% when using the proposed PE-ECC. It can be concluded that by increasing the GGBS substitution amount up to a certain level, the tensile strain can be increased.

Effect of GGBFS on Workability and Strength of Alkali-activated Geopolymer Concrete

This paper focuses on the development of a concrete material by utilizing fly ash and blast furnace slag in conjunction with coarse and fine aggregates with an aim to reduce pollution and eliminate the use of energy extensive binding material like cement. Alternative binding materials have been tried with an aim to get rather an improved concrete material. Alkali-Activated Solution (AAS) made of the hydroxide and silicate solutions of sodium was adopted as the liquid binder whereas, Class F” fly ash and Ground Granulated Blast Furnace Slag (GGBFS) mixed in dry state were used as the Geopolymer Solid Binder (GSB). The liquid binder was used to synthesize the solid binder by thermal curing. The paper investigates the use, influence and relative quantities of the liquid and solid binders in the development of the alkali-activated GGBFS based Geopolymer Concrete (GPC). Varying ratios of AAS to GSB were taken to assess their optimum content. Further, different percentages of GGBFS were used as a partial replacement of Class F fly ash to determine the optimum replacement of GGBFS in the GPC. In order to assess their effects on various properties test samples of cubes, cylinders and beams were cast and tested at 3, 7, and 28 days. Thermal curing of GPC has also resorted for favorable results. It was found that AAS to GSB ratio of 0.5 and GGBFS content of 80% yielded the maximum strength with a little unfavorable effect on workability. The overall results indicated that AAS and GGBFS offer good geopolymer concrete which will find its applicability in water scarce areas. Doi: 10.28991/cej-2021-03091708 Full Text: PDF

Performance of GGBS Cement Concrete under Natural Carbonation and Accelerated Carbonation Exposure

One of the primary problems related to reinforced concrete structures is carbonation of concrete. In many cases, depth of carbonation on reinforced concrete structures is used to evaluate concrete service life. Factors that can substantially affect carbonation resistance of concrete are temperature, relative humidity, cement composition, concentration of external aggressive agents, quality of concrete, and depth of concrete cover. This paper investigates the effect of varying the proportions of blended Portland cement (ordinary Portland cement (OPC) and ground granulated blast-furnace slag (GGBS)) on mechanical and microstructural properties of concrete exposed to two different CO2 exposure conditions. Concrete cubes cast with OPC, and various percentages of GGBS (0%, 30%, 50%, and 70%) were subjected to natural (indoor) and accelerated carbonation exposure. The aim of this paper is to present the research findings and authenticate the literature results of carbonation by using GGBS cement in partial replacement of OPC. The concretes with OPC are compared to concretes with various percentages of GGBS, to assess the carbonation depth as well as rate of carbonation of GGBS-based concretes, under both accelerated carbonation and natural carbonation exposure conditions. Even though GGBS cement increases the carbonation depth, the results are not the same with different GGBS replacement percentages. A correlation is made between concrete samples exposed to 15 ± 2% carbon dioxide (CO2) concentration and those exposed to natural CO2 concentration. The results reveal that the products formed by carbonation are similar under both exposure conditions. The experimental tests also revealed that GGBS cement concrete has a lower carbonation resistance than OPC concrete, due to the consumption of portlandite by the pozzolanic reaction. The combination of 70% OPC and 30% GGBS behaved well enough with respect to accelerated carbonation exposure, the depth of carbonation being roughly equivalent to that of control group (100% OPC). The results also show that rate of carbonation becomes more sensitive as the percentage of GGBS replacement increases (binder ratio), rather than duration of curing. Concretes exposed to natural carbonation (indoor) achieved lower carbonation rates than those exposed to accelerated carbonation.

The Impact of Using Different Ratios of Latex Rubber on the Characteristics of Mortars Made with GGBS and Portland Cement

Preserving natural resources and implementing the concepts of sustainable engineering to approach the zero waste concept helped in reducing the detrimental environmental effects in the last two-decade. Proposed re-using of Ground Granulated Blast Furnace Slag (GGBS) as an alternate solution is to get rid of them and profit from them concurrently. In this process, GGBS is used as cement substitute material to enhance mortar characteristics. On the other hand, the required water for concrete mixture should be characterized by several characters, which similar to drinkable water, therefore, using of Latex Rubber as a water substitution reduces the demand for such water in the construction industry. In this project, percentages of GGBS that have been used were 0%, 10%, 30%, and 50% which compatible with (0, 10, 20 and 30) % of Latex Rubber. Suitable tests were performed to measure properties of mortar by GGBS and Latex Rubber such as setting time, compressive strength and Permeability test (Electrical resistivity). The results obtained indicate that the setting time reduced with increasing Rubber Latex in spite of increasing the proportion of water to binder. Additionally, increasing the Latex Rubber amount leads to decrease the compressive strength and electrical resistivity of mortars.

Study of dissolution parameter of ground granulated blast furnace slag as cement replacement on mechanical properties of mortar

Abstract The current study was focused to find the impact of the dissolution of Ground Granulated Blast Furnace Slag (GGBS) in water before combining it with the other proportions of mortar. Two mixing types were used in the study. First, the conventional mixing method, wherein the GGBS was added with the cement and sand. Second, the new mixing method, wherein the GGBS was dissolved in water before adding to cement and sand. Five dissolution times (0, 1, 3, 6, 12 h) were studied with various percentages of GGBS as cement replacement (0%, 2.5%, 5%, 10%, 20%).The new mixing method has given higher compressive strength as compared to the conventional mixing method. The maximum compressive strength was obtained at 2.5% and 5.0% GGBS for a standing duration of 1 hr immersion in water. The higher compressive strength of mortar cubes was due to the hydrolysis of GGBS in water and was determined by the mobility of Ca and Si ions. As the ratio of Ca/Si decreased, the compressive strength was increased and was more prominent as long as the portlandite Ca(OH)2 was in active state. The compressive strength at earlier stage was developed because of the pozzolanic activity and mobility of ions.

Alkali activation of clayey soil using GGBS and NaOH

Construction of buildings and other engineering structures on the expansive soil is risky due to its high compressibility, low shear strength and unequal settlement. Expansive soils like clayey soil always create a problem in foundation. The problems involved during foundation are swelling, shrinkage characteristics of soil. An experimental study is carried out to improve the stability of the clayey soil using Ground Granulated Blast Furnace Slag (GGBS) and 12 M Sodium Hydroxide (NaOH). The Alkali to Binder ratio (A/B) maintained is 0.40 and 0.60. The amount of GGBS percentage added to the soil is 6%, 12%, 18% and 24%. The strength of the soil is tested at the 7th, 14th and the 28th day using the Unconfined Compressive Strength Test. The strength achieved at the 28th day for the Alkali to Binder ratio (A/B) of 0.60 for different percentages of GGBS is 580 KPa, 1880 KPa, 2803 KPa, 4062 KPa.

Mechanical and gamma-ray shielding properties and environmental benefits of concrete incorporating GGBFS and copper slag

Ground granulated blast furnace slag (GGBFS) and copper slag (CS) are industrial waste by-products, which are mostly discarded in landfills. Alternatively, they can be used in concrete production to reduce the consumption of cement and natural aggregates. One of the applications that can benefit from heavy-weight aggregates such as CS, is concrete tailored for radiation shielding purposes. However, there was no prior study on effect of combined use of CS and GGBFS on radiation shielding capability of concrete. This study is aimed to address the effect of GGBFS and CS content on gamma-ray shielding and mechanical performance of high-density concrete. For this purpose, concrete mixes were prepared with different percentages of GGBFS (0–60%) and CS (0–100%) as a partial replacement of cement and natural fine aggregate, respectively. The workability, compressive strength, splitting tensile strength, and radiation shielding capability of concrete mixes subjected to 137Cs and 60Co point sources were evaluated. Based on the test results, the workability of fresh concrete was enhanced (up to 63%) with increasing replacement ratios of GGBFS and CS. The optimum compressive and splitting tensile strengths were obtained by incorporating 30% GGBFS and 50% CS, which were about 20% higher than that of the control mix. The linear attenuation coefficient increased slightly with GGBFS content. On the other hand, the use of heavyweight CS aggregates increased the linear attenuation coefficient by up to 31%. Results showed that concrete made with 60% GGBFS and 100% CS exhibit superior radiation shielding capability and satisfies the strength requirements for structural applications. Therefore, it is suitable for radiation shielding of structures such as healthcare centers. Finally, the ecological analysis revealed that the concrete made with recycled materials is Eco-friendlier and contributes to sustainable development of construction industry.

Effect of Alkali Activator on the Standard Consistency and Setting Times of Fly Ash and GGBS‐Based Sustainable Geopolymer Pastes

In this study, an attempt has been made to study the effect of alkali activator on the standard consistency and setting times of low calcium fly ash (FA) and ground granulated blast furnace slag (GGBS)‐ based sustainable geopolymer pastes. Different proportions of FA and GGBS were blended into mixes of geopolymer paste using sodium hydroxide (SH) and sodium silicate (SS) as alkaline activator solution (AAS). Tests on geopolymer pastes for consistency and initial and final setting times were carried out for three different SH : SS ratios of 1 : 1, 1 : 2, and 1 : 3 for both 2.5 M (molarity) and 5.0 M of SH concentration. While increasing the molarity of SH, both consistency and setting time decreased. For all the blended binder mix, the setting time decreases with an increase in the quantity of SS in the alkali activator solution. An increase in the amount of GGBS content in the geopolymer blended binder mix increases the consistency and decreases the setting time. For both 2.5 M and 5 M blended geopolymer mixes, a decrease in the percentage of GGBS and an increase in the percentage of FA increased the setting time. Microstructural studies such as X‐ray fluorescence analysis (XRF), X‐ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FT‐IR) analyses were carried out, and the results are presented. The FT‐IR spectra for the blended binder mixes demonstrated the formation of geopolymerization and the presence of the functional groups.

Effect of Ground Granulated Blast Furnace Slag as Partial Replacement in Fly Ash-Based Geopolymer Concrete

Replacement of Ordinary Portland cement (OPC) with geopolymer concrete (GPC) using fly ash is currently utilized in the construction industry to reduce the excessive carbon footprint. However, fly ash has lower strength development compared to OPC. Due to that reason, ground granulated blast furnace slag (GGBFS) is chosen to be blended with fly ash to produce GPC with improved mechanical strength. The analysis of the mechanical properties includes workability, compressive strength and splitting tensile strength of hardened GPC specimens have been carried out. The specimens were prepared with different percentages of GGBFS, from 0 % up to 20 %, partially replacing the fly ash-based GPC. Experimental results showed that the slump, compressive strength and splitting tensile strength of the GPC increase as the GGBFS percentage increases and found to be suitable for structural application.

Influence of Aluminosilicate for the Prediction of Mechanical Properties of Geopolymer Concrete – Artificial Neural Network

In this paper, details and results of experimental and predictive studies carried out to determine the mechanical properties of Aluminosilicate materials like Ground Granulated Blast furnace Slag (GGBS) and Fly Ash (FA) based geopolymer concrete specimens are presented and discussed. The major parameters considered in the experimental study are the percentages of GGBS and Fly ash and the percentage of manufactured sand (m-sand) used to replace conventional river sand used in the production of geopolymer concrete. Sodium hydroxide and sodium silicate solutions were used as the activator in the production of geopolymer concrete. The mechanical properties of the geopolymer concrete determined were the compressive strength, split-tensile strength and flexural strength. The test results showed that the mechanical properties of geopolymer concrete improved with increase in the percentage use of GGBS. Also, it was observed from the test results that increase in the percentage use of m-sand increased the mechanical properties of the geopolymer concrete up to an optimum dosage beyond which reduction in the mechanical properties was observed. The predicted mechanical properties of the geopolymer concrete using Artificial Neural Network (ANN) was found to be in good agreement with the test results.