High Cement Replacement Research Articles

Green engineered cementitious composites with enhanced tensile and flexural properties at elevated temperatures

This study provides new insights in the design of green hybrid polyethylene (PE)-steel fibre reinforced high strength engineered cementitious composite (HSECC) with superior tensile and flexural strength at both ambient and elevated temperatures. Blends of high volume of ground granulated blast furnace slag (GGBFS), dolomite powder and fly ash were utilized to achieve a 60 % cement replacement for the HSECC mixes. These mixes were then exposed to 20–600 °C and a total of 210 specimens were tested to assess their residual tensile stress–strain behaviour, flexural load–displacement response, and toughness. Results indicate that high volume of GGBFS can be very effective in limiting the surface damage and retaining high strength at elevated temperatures. A combination of 1.5 % PE-0.75 % steel with quaternary blend of GGBFS, dolomite and fly ash demonstrated at least 60 % and 40 % retention in tensile and flexural strength at 600 °C, respectively. This was significantly better than the strength of the traditional control silica fume mix considered in this study as well as results reported in many previous literatures on HSECC. Microstructural examination was further conducted to understand the mechanism of fibre deterioration and justify the resulting change in pseudo-hardening behaviour with temperature rise. Findings obtained in this study clearly demonstrated the effectiveness of PE-steel fibre hybridisation at elevated temperature and confirmed that with right binder selection, superior tensile and flexural performance can be achieved even with a very high cement replacement level.

1:1 or 2:1 ‐ Does it matter for calcined clay as supplementary cementitious material?

AbstractCalcined clays are the most promising future supplementary cementitious material which are capable of replacing fly ashes and blast furnace slag on the long run due to their potential to achieve high cement replacement levels and their global availability. In the last decade most research has focused on calcined clays rich in the 1:1 kaolinite. Clay with less than 20 to 25 % kaolinite were seen as worthless. Even the content of 2:1 phyllosilicates in the kaolinitic clays was neglected and not even mentioned although especially these clays are dominant in areas like central and northern Europe. Here, highly kaolinitic clays are rare or used by other industries leading to high prices. This paper is based on published works and highlights whether information obtained for calcined 1:1 dominated clays can be applied for calcined 2:1 dominated clays or not and where further research is needed.

Comparative environmental assessment of low and high CaO fly ash in mass concrete mixtures for enhanced sustainability: Impact of fly ash type and transportation

The effect of fly ash type on the sustainability of concrete mixtures has yet to be quantified. This study aims to assess the environmental impacts of low calcium oxide (CaO) and high CaO fly ash in mass concrete mixtures from Thailand. The study analyzed 27 concrete mixtures with varying percentages of fly ash as a cement replacement (0%, 25%, and 50%) for 30 MPa, 35 MPa, and 40 MPa compressive strengths at specified design ages of 28 and 56 days. Sources of fly ash have been located between 190 km and 600 km away from batching plants. The environmental impacts were assessed using SimaPro 9.3 software. The global warming potential of concrete is reduced by 22–30.6% and 44–51.4% when fly ash, regardless of type, is used at 25% and 50%, respectively, in comparison with pure cement concrete. High CaO fly ash has more environmental benefits than low CaO fly ash when utilized as a cement substitute. The reduction in environmental burden was most significant for the midpoint categories of mineral resource scarcity (10.2%), global warming potential (8.8%), and water consumption (8.2%) for the 40 MPa, 56-day design with 50% fly ash replacement. The longer design age (56 days) for fly ash concrete showed better environmental performance. However, long-distance transport significantly affects ionizing radiation and ecotoxicity indicators for terrestrial, marine, and freshwater environments. Furthermore, the results show that a high cement replacement level (50%) may not always have a reduced environmental impact on mass concrete when considering long-distance transportation. The critical distance calculated based on ecotoxicity indicators was shorter than those calculated using global warming potential. The results of this study can provide insights for developing policies to increase concrete sustainability using different types of fly ash.

Interpretable machine learning model for autogenous shrinkage prediction of low-carbon cementitious materials

Supplementary cementitious materials (SCM) are key components of low-carbon cementitious materials. However, their effects, especially for the emerging high cement replacement ratio formulations, are sometimes very challenging to predict, leading to restrictions in most standards. Through advanced Machine Learning techniques, this study provides novel insights into the autogenous shrinkage properties of concrete containing various kinds of supplementary cementitious materials such as slag, fly ash, silica fume, calcined clay, and filler. Four machine learning models are optimized and their predictions are compared on a dedicated database, including ternary and quaternary cement blends. The Extreme Gradient Boosting (XGBoost) model exhibited the highest accuracy among these models. Interpretative tools such as SHAP analysis are then used to obtain novel information about the relative influence of the SCM on the autogenous shrinkage depending on their dosage. The model is finally compared to the recently modified versions of the B4 and the CEB analytical models to predict the autogenous shrinkage of unknown concrete formulations. The model showed significantly better predictions than the analytical models, and a web application is proposed, paving the way for precise and interpretable autogenous shrinkage predictions of cementitious materials incorporating SCM.

リサイクルセメントを用いた高強度モルタルの圧縮強度に関する基礎的研究

In this study, compressive strength of high strength mortar using cement-based powder extracted from sludge separated from ready-mixed concrete was examined for the purpose of assisting effective treatment of returned concrete. As far as the mortar with a W/B of 30% was compared, the mortar with a high recycled cement replacement rate of over 75% took a longer time to flow down and tended to have a higher viscosity than the other mortars. And, it was found that the compressive strength of mortar using 100% recycled cement was about 0.7 to 0.8 that of mortar using ordinary Portland cement.

Fresh and Mechanical Properties of High-Performance Self-Compacting Concrete Containing Ground Granulated Blast Furnace Slag and Polypropylene Fibres

The purpose of this study was to evaluate the appropriateness of polypropylene fibres (PP) to decrease the brittleness of high-performance self-compacting concrete (HPSCC). The influence of PP fibre content on the fresh and mechanical assets of PP-fibre-reinforced HPSCC was investigated. PP fibres were applied with 0, 0.025, 0.05, 0.075, 0.125, 0.25% contents to the HPC blends with high cement replacement by ground granulated blast furnace slag (GGBS). The impact of PP fibre fraction on fresh properties of HPSCC, counting passing capability as well as filling parameters is discussed. In addition, the mechanical properties, i.e., compressive, splitting tensile, and flexural strengths, were evaluated after 7 and 28 days of specimens’ maturation in water. The higher content of PP fibres gradually reduced the HPSCC workability and improved the mechanical properties. The high performance of fresh and hardened ecological HPSCCs containing 46% GGBS instead of cement with 0.025–0.25% PP fibre content proves the great potential of using these composites in various applications in the construction industry. The advantages of the potential recycling of GGBS include, among others, the reduced use of cement in a durable material, reduced amount of waste in landfill and lower emission levels of greenhouse gases.

Utilizing of Magnetized Water in Enhancing of Volcanic Concrete Characteristics

Volcanic concrete is an eco-friendly concrete type in that it contains coarse and fine aggregates that all extracted from the igneous volcanic rock. However, utilizing of volcanic ash (VA) as partial/full replacement of concrete cement significantly affects the concrete workability, especially at high cement replacement ratios. This has also some adverse effects on concrete strength. Utilizing magnetized water (MW) in concrete as a partial/full replacement of ordinary tap water (TW) has a notable effect on enhancing the fresh and hardened concrete properties. This research aims to study the effect of using MW prepared in a magnetic field of 1.4 Tesla on the workability and hardened properties (compressive, tensile, and flexural strengths) of volcanic concrete. In this study, VA partially replaced volcanic concrete cement with ratios of 5%, 10%, 15%, and 20%. Ten volcanic concrete mixes were prepared in two groups. The first one was prepared with VA (0–20%) and mixed with TW. The other group was prepared with the same VA contents like group one, but mixed with MW. Microstructure imaging for volcanic concrete was also conducted in this study. Results of water tests showed 17% and 15% increase in total dissolved solids (TDS) and pH, respectively, of MW compared with those of TW. In addition, the water magnetization decreased the water surface tension by 7% compared with that of TW. Results of hardened concrete tests showed that the best ratio of VA in volcanic concrete was 5% with and without using magnetized water. The volcanic concrete slump decreased when using TW; however, using MW enhanced the volcanic concrete slump by up to 8%. The compressive strength was improved by 35%, 23%, and 20% at 7 days, 28 days, and 120 days, respectively, with no VA and with the presence of MW. The compressive strength was improved by 11%, 12%, and 11% after 7 days, 28 days, and 120 days, respectively, with using 5% VA and with the presence of MW. Both splitting tensile strength and flexural strength of volcanic concrete with and without VA or MW behaved similar to that of the corresponding compressive strength.

Early Age Monitoring of High Cement Replacement Mixtures for Pavement

Decarbonization of concrete will require a combination of alternative binding materials and higher cement replacement rate with supplementary cementitious materials. Developing tools and methods that help engineers evaluate the properties of early age concrete pavement, such as setting time and strength gain, will be necessary to adopt new concrete mixes. Two concrete pavement test sections were constructed, a high early strength concrete mix with 25% (control) and 40% replacement of cement with fly ash (HVFAC), along with monitoring of the concrete’s setting time, saw-cut timing, and strength gain. A non-contact ultrasonic device was used to estimate setting time through measuring leaky Rayleigh wave energy transmission. The laboratory setting time of the control and HVFAC mix measured with the non-contact device was 5.5 h and 15 h, respectively, and agreed with measured isothermal calorimetry results. Further calorimeter tests showed that adding an accelerating admixture or replacing part of the cement with nano-limestone decreased the HVFAC setting time up to 4.4 h. The field setting time of the control mixture with the non-contact device measured 4.2 h, which was shorter than the laboratory estimate. Based only on the experience of construction personnel, saw-cutting for these mixtures was initiated too early and caused significant joint raveling, reinforcing the importance of in situ setting time measurement. The maturity method was successfully implemented with embedded wireless temperature sensors that rapidly and easily estimated the in-place compressive strength and improved opening time determination for concrete with high cement replacement levels, which are sensitive to the volume of supplementary cementitious materials, admixtures, and ambient conditions.

RETRACTED: Effect of rice straw ash and palm leaf ash on the properties of ultrahigh-performance concrete

The global expansion of agricultural production has increased the amount of agricultural waste (AW). Accordingly, AW should be disposed of properly to preserve the environment. This study focuses on using rice straw ash (RSA) and palm leaf ash (PLA) as partial replacement for cement in the production of ultrahigh-performance concrete (UHPC). In particular, this research investigates the effect of using RSA and PLA as pozzolanic materials on the microstructure and the fresh, mechanical and physical properties of UHPC. Eleven UHPC mixtures are prepared as control mixtures without RSA and PLA. Five mixtures are used with 10%, 20%, 30%, 40% and 50% RSA, whilst five residual mixtures contain 10%, 20%, 30%, 40% and 50% PLA. Results indicate the efficiency of RSA or PLA as a partial substitute (i.e. 20% of cement weight), with mechanical properties and durability better than those of the reference mixture. The microstructure analysis shows that 20% RSA or PLA yields denser concrete than the control mixture. The UHPC samples with 20% RSA and 20% PLA achieve the best results of 188.5 MPa and 185 MPa by increasing compressive strength by about 13.2% and 11.1%, respectively, compared with the control mixture at a test age of 28 days. Important mechanical properties, such as splitting tensile strength, flexural strength and modulus of elasticity, exhibit a trend similar to that of the compressive strength results for all the UHPC mixtures. The average values of splitting tensile strength and flexural strength at 28 days are about 11% and 14% of the compressive strength of the same UHPC mixtures, respectively. The significance of the current study is the relatively high cement replacement percentages of up to 50% by weight and the use of AW as replacement materials.

Evaluation of the Prediction and Durability on the Chloride Penetration in Cementitious Materials with Blast Furnace Slag as Cement Addition

Blast furnace slag (BFS) is a mortar additive in which the utilization of varied curing conditions and the basicity of BFS determine the fineness of the resulting mortar and, thereby, its salt prevention properties. This study evaluates and compares the salt-prevention properties of mortar prepared by either steam curing or water curing. The physical properties, for example, the BFS fineness, revealed the factors significantly affected by basicity that influence the salt-preventive properties of mortar in the specimens examined, such as the lead time and diffusion coefficient. Furthermore, these factors were also significantly affected by differences in curing conditions and other physical properties. However, few studies have examined its use in reducing chloride ion permeability as the main factor of corrosion reactions. Thus, this study evaluates specific surface, water/binder ratio (W/B), and curing conditions on the chloride penetration in cementitious materials with blast furnace slag as cement addition in terms of delaying chloride ion penetration, which affects corrosion reactions. Results of the study are intended to guide development of products for use in the precast concrete industry, toward extending the life of concrete structures, especially reinforced concrete structures in marine environments. In addition, the resulting durability measurements from the experiment conducted are illustrated. This study indicates that differences in Blaine size properties significantly influence water curing. Furthermore, results reveal the effects of combining BFS with various Blaine values and ratio-affecting properties on mortar. In conclusion, concrete materials that decrease durability against chloride attack and improve mechanical properties for precast manufacturer industrial applications are successfully developed in this study. In addition, the use of water-curing conditions, high Blaine value, high cement replacement ratio, and W/B tend to improve the general mechanical property performance and durability against chloride ion attack.

Performance of sustainable mortar using calcined clay, fly ash, limestone powder and reinforced with hybrid fibers

Green mortar (GM) is a mortar that at least one of its components uses waste materials or materials that do not cause environmental destruction throughout their production. This research aims to design a mortar with the highest possible cement and sand substitutions with acceptable fresh and hardened properties. The experimental work was conduct in three phases. In phase one, calcined clay replaced cement by 20%, 25%, 30%, 35%, and 40% in mortar mixes. Then, the cement replacement raises to 50% by substituting cement with a combination of calcined clay (CC) and fly ash (FA) in different percentages in other mortar mixes. In phase two, limestone powder (LP) partially replaced sand by 20% and 30% (by weight) in two of the chosen mixes from phase one that contained high cement replacement and fairly good fresh and hardened properties. Then environmental impacts of GM mixes have been evaluated by estimating the reductions of CO2 emissions from producing such mixes. Phase three involved the effects of incorporating 0.5% fibers (by volume) on the properties of GM using two types of steel fibers with different aspect ratios. Ultra steel fibers (USF) with an aspect ratio of 65 and steel nail fibers (SNF) with an aspect ratio of 20. The inclusion of hybrid fibers was by combining USF and SNF in different percentages while maintaining the same volumetric fraction of 0.5%. The fresh and hardened properties have been determined in phase three also. The results show that replacing OPC with 25% CC provides the best increment on compressive strength by increasing the compressive strength by about 21% at 28 days. The use of 20% LD as sand replacement increases the flow and 28 days-compressive strength by about 55% and 13%, respectively, for the mortar that contains 35% CC+ 15% FA. The test results of reinforced mixes show that the hybridization of 0.175% USF and 0.325% SNF affords the best enhancements on the mechanical properties. The results obtained from the estimated reduction of CO2 emissions study reveal that incorporating 30% CC + 20% FA as cement replacements and 30% LP as a sand replacement reduces the CO2 emissions by approximately 41%. Therefore, adopting the concept of green mortar is a promising approach for mitigating CO2 emissions and preserving natural resources.

Mitigation of autogenous shrinkage of high-strength concrete using rice husk ashes with distinct pore structures

The effect of particle size (50% passing size (D50) of 20 μm, 14 μm and 7 μm) and content (8%, 10% and 12% by mass) of rice husk ash (RHA) on the autogenous shrinkage evolution of high-strength concrete was investigated. RHA samples were selected based on differences in their pore structures, which were investigated by means of nitrogen adsorption isotherms, scanning electron microscopy and absorbency tests. Cement–pozzolan hydration development was studied using isothermal calorimetry. The concretes were subjected to mercury intrusion porosimetry and compressive strength tests. Considering a statistical 22 factorial analysis with a central point, the results showed that D50 and the interaction between D50 and RHA content influenced the autogenous shrinkage at 28 and 100 days. The water absorbed internally by the preserved RHA pore structure (D50 ≈ 20 μm) in the high cement replacement (12% RHA) mixes reduced the final autogenous shrinkage of concrete without a decrease in compressive strength. In addition, the RHA with a more preserved pore structure accelerated the hydration kinetics by heterogeneous nucleation. However, this behaviour did not influence the early autogenous shrinkage results.

Interaction between high performance fiber reinforced cement-based composites and steel reinforcement

This paper presents results on the interaction between a mild steel reinforcing bar and two High Performance Fiber Reinforced Cement-based Composite (HPFRCC) matrices, a Hybrid Fiber Reinforced Concrete (HyFRC) composite with and without high cement replacement by fly ash and an Engineered Cementitious Composite (ECC). The experimental program consists of rebar pull-out tests conducted under both monotonic and cyclic loading with and without transverse steel spiral reinforcement. In addition, fiber pull-out tests to investigate the synergy between micro- and macrofibers in HyFRC on rebar pull-out resistance were also conducted. The multiscale crack control in HyFRC avoids matrix splitting and instead guarantees the more ductile frictional rebar pull-out behavior. The HyFRC matrix without fly ash exhibits the best rebar bond performance among all HPFRCCs under investigation.

Durability and microstructure of eco-efficient ultra-high-performance concrete

The sustainability of ultra-high-performance concrete (UHPC) could be enhanced by using by-product materials with high replacement percentages. This research aims to study the effect of using blast furnace cement (CEM III), fly ash (FA), and granulated blast furnace slag (GBFS) as partial replacements to cement in UHPC. CEM III with percentages of 30%, 50%, and 100%; FA and GBFS with percentages of 30% and 50% were used as replacements from ordinary Portland cement (OPC) weight. Compressive strength and modulus of elasticity tests were conducted to evaluate the results of UHPC specimens. The effect of sulfate attack was studied at concentrations of 5, 50, and 75 g/l, at 28, 90, and 180 days, for each concentration individually. Chloride penetration was also studied through the colorimetric method using the AgNO3 solution. The development of UHPC microstructural properties was studied via SEM and EDX analysis. Results showed that concrete with high cement replacement of FA up to 50% percentage had better results in compressive strength and modulus of elasticity reached to 160.9 MPa, and 51.64 GPa respectively. Concrete can still achieve ultra-high-performance of 157.4 MPa with FA replacement of up to 50% for a long period and a high concentration of sulfate attack. However, for CEM III or GBFS, attack period, sulfate concentration, or replacement percentage must be lowered to preserve the concrete still achieving ultra-high-performance. SEM images and EDX analysis for the enhanced UHPC structure show the high dense microstructure and so small ITZ thickness, and strengthened the results obtained from the conducted permeability and compressive strength tests.

3D printing of calcined clay-limestone-based cementitious materials

This paper aims to investigate the influences of high Portland cement substitutions (>60 wt%) by low-grade calcined clay (CC) and limestone (LF) on 3D concrete printability, stiffness evolution and early-age hydration. Results show that, with the same dosage of admixtures (superplasticizer and viscosity modifier), increasing LF and CC content reduced the slump, flowability and initial material flow rate, and significantly improved the buildability of fresh mixtures, which can be attributed to the reduced water film thickness (WFT). Furthermore, the stiffness evolution and SSAtotal development up to the first 3 h were accelerated by increasing CC content, which can also be linked to the change of WFT, and consumption of superplasticizer for the dispersion induced by hydration products. Additionally, the dilution effect on compressive strength and hydration caused by the high cement replacement was observed.

Improvement of Bond Strength and Durability of Recycled Aggregate Concrete Incorporating High Volume Blast Furnace Slag.

This paper aims to experimentally investigate the effects of high volume cement replacement of blast furnace slag (BFS) on the bond, strength and durability of recycled aggregate concrete (RAC). Concrete mixtures were prepared containing 0%, 15%, 30%, 45%, 60% and 75% BFS with each of recycled aggregate and natural aggregate. Measurements of the compressive and bond strength, the resistance to chloride-ion penetration and the water permeability of concrete are reported. In addition, a microhardness test was also performed to evaluate the quality of interfacial transition zone (ITZ) in concrete. Test results of the bond strength and the compressive strength of RAC mixtures, in spite of the cement replacement amount with BFS, show that the concretes result in reduced strength when compared to natural aggregate concrete (NAC) mixtures, while the strength gains for the BFS-based concrete are higher than that of the reference mixtures without BFS at long-term ages. Incorporating BFS in concrete can inherently improve the durability properties by increasing higher resistance to chloride-ion penetration and lower water permeability. This improvement in the mechanical and durability properties of the BFS-based RAC mixture may be due to the additional pozzolanic reaction of BFS, which enhances the properties of ITZ in concrete, resulting in an improvement of the strength of concrete.

Study on the use of lightweight expanded perlite and vermiculite aggregates in blended cement mortars

This paper presents an experimental investigation on lightweight aggregate mortars containing high volume cement replacement materials. For this purpose, expanded perlite (EP) and expanded vermiculite (EV) are used as the lightweight aggregate (at sand replacements of 50% and 100%), while ground granulated blast furnace slag (GGBS) (35% and 70% replacement level) and fly ash (25% and 50% replacement level) are adopted as the supplementary cementitious materials (SCMs). The results showed that EP is beneficial for improving the flow of fresh mortar, and soft mortar (flow diameter > 200 mm) can be produced by using EP in SCM-cement blends. Both EP and EV can be utilised to produce lightweight mortar in the density range of 1400–1700 kg/m3 and 900–1100 kg/m3 at 50% and 100% sand replacements, respectively. Although the lightweight aggregates resulted in compressive strength decrease, the developed lightweight mortar using 50% EP (with or without SCMs) can be classified as type N mortar (compressive strength exceeding 5.17 MPa) while those prepared with 100% EP as well as 50% EV can be categorised as type O mortar. Response surface methodology carried out in this study also demonstrated that the mathematical equations can suitably estimate the studied performances of the lightweight mortars.

The Effect of Sugarcane Bagasse Ash on the Properties of Portland Limestone Cement

This paper tries to investigate sugarcane bagasse ash (SCBA) as a cement replacement material and its effect on the water consistency, setting times, soundness, specific gravity, water absorption and mortar compressive strength of SCBA-Portland limestone cement (PLC) blend at cement replacement from 0 -15 wt.% at interval of 2.5 wt.%. Calcination of sugarcane bagasse was conducted and the optimum condition was obtained ash at 650°C at 90 mins with a higher Si + Al + Fe content from nine compositional analysis of ashes obtained via X-ray fluorescence spectrometer and then employed as cement replacement material for this research work. The consistency and setting times of the blended cement samples were carried on paste using Vicat apparatus while the soundness, specific gravity and compressive strength using Le Chatelier apparatus, density bottle and strength testing machine respectively according to ASTM standards respectively. Results showed an increase in the water consistency and setting times of SCBA cement pastes as SCBA content was increased from 2.5 – 15wt.% which was attributed to unburnt carbon present in the ash due to its high LOI. The elongated setting times could also due to clinker diminution by cement replacement with SCBA and high-water demand. The SCBA cement blends produced accelerated setting time results compared to PLC owing to lime present in SCBA which enhances early hydration. The specific gravity diminished while the volume expansion of the SCBA cement pastes experienced an increase as SCBA was increased due to lower density of SCBA compared to PLC and increased lime content due to increased SCBA content respectively. An increase in the mortar compressive strengths of SCBA cement blends was experienced as the curing days progressed from 3 to 60 days. PLC blended with SCBA produced an enhanced early strength due to the presence of lime which tends to accelerate the rate of formation of hydration assembly. Whereas, at a high cement replacement of 12.5 wt.% SCBA produced exceptional mortar compressive strength especially at 60 days despite clinker diminution indicating pozzolanic activity due to SCBA inclusion. The optimal cement replacement with SCBA was observed at 5 wt.% in comparison with control especially at 28 days and did not adversely affect its strength owing to pozzolanic activity.

Strength, Carbon Footprint and Cost Considerations of Mortar Blends with High Volume Ground Granulated Blast Furnace Slag

Ground granulated blast furnace slag (GGBFS) is a by-product obtained from the iron making process and has suitable properties to be utilized as high volume cement replacement to produce sustainable concrete. This study focuses on investigating the influence of GGBFS replacement level (0%–70%) and water/binder ratio (0.45 and 0.65) on the performance of cement mortar blends. In order to characterize the engineering performance, the compressive strength of the mortar blends was evaluated. Whereas to ascertain the carbon footprint, environmental life cycle assessment was conducted. Besides the compressive strength and carbon footprint, the materials cost for each mortar blends was computed. Based on the compressive strength/carbon footprint ratio analysis, it was found that increased replacement level of GGBFS gave better performance while the cost efficiency analysis shows that suggested GGBFS replacement level of up to 50%. Overall, in considering the strength performance, carbon footprint and materials cost, the recommended GGBFS replacement level for cement blends is 50%. In addition, when the binder content is kept constant, mortar blends with lower water/binder ratio is preferable when considering the same parameters.

The engineering performance of concrete containing high volume of ground granulated blast furnace slag and pulverized fly ash with polycarboxylate-based superplasticizer

This experimental investigation was conducted to study the development of ternary blended concrete that containing high cement replacement level of ground granulated blast furnace slag (GGBS) and pulverised fly ash (PFA) with the polycarboxylate-based superplasticizer (PCE). In order to make this GGBS-PFA ternary blended cement system at high cement replacement level suitable for practical production, measures need to be developed to enable acceptable early strength development for concrete produced using the materials to be achieved. An optimum combination ratio of GGBS and PFA in ternary blended cement system was prior determined in this study for consistent production control. Besides, an optimum dosage of M-PEG type PCE was determined by using marsh funnel test as well for the compatible use in this GGBS-PFA ternary blended cement system. Experimental results indicated that the optimum ratio for GGBS and PFA was 4:1 at 50% cement replacement level by total binder’s weight while the optimum dosage of PCE was 1.0% by total binder’s weight in this ternary blended cement system. Mechanical properties such as flexural and compressive strengths and UPV were then examined on hardened concretes at 7, 28, 56 and 90 days. In addition, Scanning Electron Microscopy (SEM) techniques combined with Energy Dispersive X-ray (EDX) had been performed for better understanding the phase changes and microstructures development of maturing GGBS-PFA ternary blended cement system. In this study, the GGBS-PFA ternary blended concrete with 60% cement replacement achieved the optimum performance with the inclusion of 1.0% of PCE superplasticizer by total binder’s weight.