Study of factors affecting the magnetic sensing capability of shape memory alloys for non-destructive evaluation of cracks in concrete: Using response surface methodology (RSM) and artificial neural network (ANN) approaches.

Currently, the field of structural health monitoring (SHM) is focused on investigating non-destructive evaluation techniques for the identification of damages in concrete structures. Magnetic sensing has particularly gained attention among the innovative non-destructive evaluation techniques. Recently, the embedded magnetic shape memory alloy (MSMA) wire has been introduced for the evaluation of cracks in concrete components through magnetic sensing techniques while providing reinforcement as well. However, the available research in this regard is very scarce. This study has focused on the analyses of parameters affecting the magnetic sensing capability of embedded MSMA wire for crack detection in concrete beams. The response surface methodology (RSM) and artificial neural network (ANN) models have been used to analyse the magnetic sensing parameters for the first time. The models were trained using the experimental data obtained through literature. The models aimed to predict the alteration in magnetic flux created by a concrete beam that has a 1 mm wide embedded MSMA wire after experiencing a fracture or crack. The results showed that the change in magnetic flux was affected by the position of the wire and the position of the crack with respect to the position of the magnet in the concrete beam. RSM optimisation results showed that maximum change in magnetic flux was obtained when the wire was placed at a depth of 17.5 mm from the top surface of the concrete beam, and a crack was present at an axial distance of 8.50 mm from the permanent magnet. The change in magnetic flux was 9.50 % considering the aforementioned parameters. However, the ANN prediction results showed that the optimal wire and crack position were 10 mm and 1.1 mm, respectively. The results suggested that a larger beam requires a larger diameter of MSMA wire or multiple sensors and magnets for crack detection in concrete beams.

Effect of seawater salinity, pH, and temperature on external corrosion behavior and microhardness of offshore oil and gas pipeline: RSM modelling and optimization.

This research aims to investigate the effects of seawater parameters like salinity, pH, and temperature on the external corrosion behaviour and microhardness of offshore oil and gas carbon steel pipes. The immersion tests were performed for 28 days following ASTM G-1 standards, simulating controlled artificial marine environments with varying pH levels, salinities, and temperatures. Besides, Field emission scanning electron microscopy (FESEM) analysis is performed to study the corrosion morphology. Additionally, a Vickers microhardness tester was used for microhardness analysis. The results revealed that an increase in salinity from 33.18 to 61.10 ppt can reduce the corrosion rate by 28%. In contrast, variations in seawater pH have a significant effect on corrosion rate, with a pH decrease from 8.50 to 7 causing a 42.54% increase in corrosion rate. However, the temperature of seawater was found to be the most prominent parameter, resulting in a 76.13% increase in corrosion rate and a 10.99% reduction in the microhardness of offshore pipelines. Moreover, the response surface methodology (RSM) modelling is used to determine the optimal seawater parameters for carbon steel pipes. Furthermore, the desirability factor for these parameters was 0.999, and the experimental validation displays a good agreement with predicted model values, with around 4.65% error for corrosion rate and 1.36% error for microhardness.

Effect of graphene oxide on mechanical, deformation and drying shrinkage properties of concrete reinforced with fly ash as cementitious material by using RSM modelling.

The industrial production of cement contributes significantly to greenhouse gas emissions, making it crucial to address and reduce these emissions by using fly ash (FA) as a potential replacement. Besides, Graphene oxide (GO) was utilized as nanoparticle in concrete to augment its mechanical characteristics, deformation resistance, and drying shrinkage behaviours. However, the researchers used Response Surface Methodology (RSM) to evaluate the compressive strength (CS), tensile strength (TS), flexural strength (FS), modulus of elasticity (ME), and drying shrinkage (DS) of concrete that was mixed with 5-15% FA at a 5% increment, along with 0.05%, 0.065%, and 0.08% of GO as potential nanomaterials. The concrete samples were prepared by using mix proportions of design targeted CS of about 45 MPa at 28 days. From investigational outcomes, the concrete with 10% FA and 0.05% GO exhibited the greatest CS, TS, FS, and ME values of 62 MPa, 4.96 MPa, 6.82 MPa, and 39.37 GPa, on 28 days correspondingly. Besides, a reduction in the DS of concrete was found as the amounts of FA and GO increased. Moreover, the development and validation of response prediction models were conducted utilizing analysis of variance (ANOVA) at a significance level of 95%. The coefficient of determination (R2) values for the models varied from 94 to 99.90%. Research study indicated that including 10% fly ash (FA) as a substitute for cement, when combined with 0.05% GO, in concrete yields the best results. Therefore, this approach is an excellent option for the building sector.

A comprehensive study on the impact of human hair fiber and millet husk ash on concrete properties: response surface modeling and optimization.

Revolutionizing construction, the concrete blend seamlessly integrates human hair (HH) fibers and millet husk ash (MHA) as a sustainable alternative. By repurposing human hair for enhanced tensile strength and utilizing millet husk ash to replace sand, these materials not only reduce waste but also create a durable, eco-friendly solution. This groundbreaking methodology not only adheres to established structural criteria but also advances the concepts of the circular economy, representing a significant advancement towards environmentally sustainable and resilient building practices. The main purpose of the research is to investigate the fresh and mechanical characteristics of concrete blended with 10-40% MHA as a sand substitute and 0.5-2% HH fibers by applying response surface methodology modeling and optimization. A comprehensive study involved preparing 225 concrete specimens using a mix ratio of 1:1.5:3 with a water-to-cement ratio of 0.52, followed by a 28 day curing period. It was found that a blend of 30% MHA and 1% HH fibers gave the best compressive and splitting tensile strengths at 28 days, which were 33.88 MPa and 3.47 MPa, respectively. Additionally, the incorporation of increased proportions of MHA and HH fibers led to reductions in both the dry density and workability of the concrete. In addition, utilizing analysis of variance (ANOVA), response prediction models were created and verified with a significance level of 95%. The models' R2 values ranged from 72 to 99%. The study validated multi-objective optimization, showing 1% HH fiber and 30% MHA in concrete enhances strength, reduces waste, and promotes environmental sustainability, making it recommended for construction.

Modeling of success factors of using PU coats in concrete construction projects.

Polyurea coatings are well recognized for their remarkable protective properties, making them highly appropriate for practical use in the field of concrete building. The use of polyurea coatings in the concrete building business is currently constrained, despite its prevalent application in industrialized nations. The limited use may be ascribed to ambiguities about the determinants of effective implementation in this particular setting, as well as the dearth of extensive study in the realm of new building materials. The primary objective of this research is to assess and conceptualize the key determinants linked to the use of polyurea coatings in concrete building endeavors. Utilizing a quantitative research approach, a comprehensive literature analysis was conducted to identify a total of 21 probable success variables. The reliability of the questionnaire was established by the administration of a pilot survey, and afterwards, an exploratory factor analysis (EFA) was performed to enhance the clarity and precision of the underlying components. The researchers used structural modeling (SEM) approaches to develop a robust model using the primary data obtained from the questionnaire survey. The EFA revealed the presence of five unique constructs that have an impact on the effectiveness of polyurea coatings in concrete building projects. These constructions comprise several characteristics, including environmental considerations, functional requirements, protective properties, execution processes, and creative elements. The significance and relevance of this research are shown by the validation of the study's results using SEM. The study makes a valuable contribution towards the progression of polyurea coating use within the concrete building sector.

Effect of wheat straw ash as cementitious material on the mechanical characteristics and embodied carbon of concrete reinforced with coir fiber.

The use of supplementary cementitious materials has been widely accepted due to increasing global carbon emissions resulting from demand and the consequent production of Portland cement. Moreover, researchers are also working on complementing the strength deficiencies of concrete; fiber reinforcement is one of those techniques. This study aims to assess the influence of recycling wheat straw ash (WSA) as cement replacement material and coir/coconut fibers (CF) as reinforcement ingredients together on the mechanical properties, permeability and embodied carbon of concrete. A total of 255 concrete samples were prepared with 1:1.5:3 mix proportions at 0.52 water-cement ratio and these all-concrete specimens were cured for 28 days. It was revealed that the addition of 10 % WSA and 2 % CF in concrete were recorded the compressive, splitting tensile and flexural strengths by 33 MPa, 3.55 MPa and 5.16 MPa which is greater than control mix concrete at 28 days respectively. Moreover, it was also observed that the permeability of concrete incorporating 4 % of coir fiber and 20 % of WSA was reduced by 63.40 % than that of the control mix after 28 days which can prevent the propagation of major and minor cracks. In addition, the embodied carbon of concrete is getting reduced when the replacement level of cement with WSA along with CF increases in concrete. Furthermore, based on the results obtained, the optimum amount of WSA was suggested to be 10 % and that of coir fiber reinforcement was suggested to be 2 % for improved results.

Enhancing performance and sustainability of GGBFS-based self-compacting geopolymer concrete blended with coal bottom ash and metakaolin by using RSM modelling.

This research study is performed on the self-compacting geopolymer concrete (SCGC) combining coal bottom ash (CBA) and metakaolin (MK) as a substitution for GGBFS alone and combined for analysing the fresh properties (slump flow, V-Funnel, and T50 flow), mechanical characteristics (compressive, splitting tensile and flexural strengths) and durability tests (permeability and sulfate attack test). Though, total 195 SCGC samples were made and tested for 28 days. It has been revealed that the consumption of CBA and MK as a substitution for GGBFS alone and combine in the production of SCGC is decreased the workability of SCGC while mechanical characteristics of SCGC are enhanced by utilizing CBA and MK as a substitution for GGBFS alone and combine up to 10%. In addition, the compressive, splitting tensile and flexural strengths were calculated by 59.40 MPa, 5.68 MPa, and 6.12 MPa while using the 5CBA5MK as a substitution for GGBFS in the production of SCGC after 28 days correspondingly. Furthermore, the permeability is decreased by growing the quantity of CBA and MK by the weight of GGBFS alone and jointly in the production of SCGC after 28 days. Besides, the minimum change in length of the SCGC specimen is recorded by 0.062 mm at 7.5MK7.5CBA while the maximum change in length is calculated by 0.11 mm at 10CBA10MK as a substitution for GGBFS at 180 days correspondingly. In addition, the embodied carbon is recorded reduce as the addition of CBA while it is getting higher when the accumulation of MK alone or combined with CBA in SCGC. Besides, response models for prediction were constructed and confirmed using ANOVA at an accuracy rate of 95%. The models' R2 fluctuated from 88 to 99%. It has been observed that the utilization of CBA and MK alone and together up to 10% as substitution for GGBFS in geopolymer concrete provides the best results therefore it is suggested for structural applications.

Effect of banana tree leaves ash as cementitious material on the durability of concrete against sulphate and acid attacks.

The construction industry's rapid growth poses challenges tied to raw material depletion and increased greenhouse gas emissions. To address this, alternative materials like agricultural residues are gaining prominence due to their potential to reduce carbon emissions and waste generation. In this context this research optimizes the use of banana leaves ash as a partial cement substitution, focusing on durability, and identifying the ideal cement-to-ash ratio for sustainable concrete. For this purpose, concrete mixes were prepared with BLA replacing cement partially in different proportions i.e. (0 %, 5 %, 10 %, 15 %, & 20 %) and were analyzed for their physical, mechanical and Durability (Acid and Sulphate resistance) properties. Compressive strength, acid resistance and sulphate resistance testing continued for 90 days with the intervals of 7, 28 and 90 days. The results revealed that up to 10 % incorporation of BLA improved compressive strength by 10 %, while higher BLA proportions (up to 20 %) displayed superior performance in durability tests as compared to the conventional mix. The results reveal the potentials of banana leave ash to refine the concrete matrix by formation of addition C-S-H gel which leads towards a better performance specially in terms of durability aspect. Hence, banana leaf ash (BLA) is an efficient concrete ingredient, particularly up to 10 % of the mix. Beyond this threshold, it's still suitable for applications where extreme strength isn't the primary concern, because there may be a slight reduction in compressive strength.

Effect of used engine oil on the mechanical properties and embodied carbon of concrete blended with wheat straw ash as cementitious material.

Every day, more and more binding materials are being used in the construction industry all over the world. However, Portland cement (PC) is used as a binding material, and its production discharges a high amount of undesirable greenhouse gases into the environment. This research work is done to reduce the amount of greenhouse gases discharged during PC manufacturing and to reduce the cost and energy incurred in the cement manufacturing process by making effective consumption of industrial/agricultural wastes in the construction sector. Therefore, wheat straw ash (WSA) as an agricultural waste is utilized as cement replacement material, while used engine oil as an industrial waste is utilized as an air-entraining admixture in concrete. This study's main goal was to examine the cumulative impact of both waste materials on fresh (slump test) and hardened concrete (compressive strength, split tensile strength, water absorption, and dry density). The cement was replaced by up to 15% and used engine oil incorporated up to 0.75% by weight of cement. Moreover, the cubical samples were cast for determining the compressive strength, dry density, and water absorption, while the cylindrical specimen was cast for evaluating the splitting tensile strength of concrete. The results confirmed that compressive and tensile strengths augmented by 19.40% and 16.67%, at 10% cement replacement by wheat straw ash at 90 days, respectively. Besides, the workability, water absorption, dry density, and embodied carbon were decreased as the quantity of WSA increased with the mass of PC, and all of these properties are increased with the incorporation of used engine oil in concrete after 28 days, respectively.

Effect of calcined clay and marble dust powder as cementitious material on the mechanical properties and embodied carbon of high strength concrete by using RSM-based modelling.

In the last decade, there has been an increase in research on ecologically benign, cost-effective, and socially useful cement alternative materials for concrete. Alternatives involve industrial and agriculture waste, the potential advantages of which may be recognized by recycling, repurposing, and recreating techniques. Important energy reserves and a decrease in Portland cement (PC) consumption may be attained by using these wastes as supplementary and substitute ingredients, contributing to a reduction in carbon dioxide (CO2) production. Consequently, the incorporation of marble dust powder (MDP) and calcined clay (CC) as supplementary cementitious material (SCM) in high strength concrete may lower the environmental effect and reduce the amount of PC in mixes. This study is conducted on concrete containing 0%, 5%, 10%, 15%, and 20% of MDP and CC as cementitious materials alone and in combination. The main objectives of this investigations are to examine the effect of MDP and CC as cementitious materials on the flowability and mechanical characteristics of high strength concrete. In order to examine the ecological effect of CC and MDP, the eco-strength efficiency and embodied carbon were considered. In this context, there are so many trial mixes were performed on cubical specimens for achieving targeted compressive strength about 60 MPa after 28 days. After getting it, a total of 273 concrete specimens (cubes, cylinders, and prisms) were used to test the compressive, splitting tensile, and flexural strength of high strength concrete correspondingly. Moreover, when the amount of MDP and CC as SCM in the mixture grows, the workability of green concrete decreases. In addition, the compressive strength, flexural strength, and splitting tensile strength are increased by 6.38 MPa, 67.66 MPa, and 4.88 MPa, respectively, at 10% SCM (5% MDP and 5% CC) over a period of 28 days. In addition, using ANOVA, response prediction models were generated and confirmed at a 95% level of significance. The R2 values of the models varied from 96 to 99%. Furthermore, increasing the amount of CC and MDP as SCM in concrete also reduces the amount of carbon embedded in the material. It is recommended that the utilization of 10% SCM (5% MDP and 5% CC) in high strength concrete is providing optimum outcomes for construction industry in the field of Civil Engineering.

Synergistic and sustainable utilization of coconut shell ash and groundnut shell ash in ternary blended concrete.

The quest for eco-sustainable binders like agro-wastes in concrete to reduce the carbon footprint caused by cement production has been ongoing among researchers recently. The application of agro-waste-based cementitious materials in binary concrete has been said to improve concrete performance lately. Coconut and groundnut shells are available in abundant quantities and disposed of as waste in many world regions. Therefore, the use of coconut shell ash (CSA) and groundnut shell ash (GSA) in a ternary blend provides synergistic benefits with Portland cement (PC) and may be sustainably utilized in concrete as ternary cementitious material (TCM). Therefore, this study presents concrete performance with CSA and GSA in a grade 30 ternary concrete. Two hundred ten numbers of standard concrete samples were cast for checking the fresh and mechanical properties of concrete at curing ages of 7, 28, and 90 days. After 28-day curing, the experimental results show an increment in compressive, tensile, and flexural strength by 11.62%, 8.39%, and 9.46% at 10% TCM cement replacement, respectively. The concrete density and permeability coefficient reduce as TCM's content increases. The modulus of elasticity after 90 days improved with the addition of TCM. The concrete's sustainability assessment indicated that the emitted carbon for concrete decreased by around 16% using 20% TCM in concrete. However, the workability of fresh concrete declines as TCM content increases.

Use of waste recycling coal bottom ash and sugarcane bagasse ash as cement and sand replacement material to produce sustainable concrete.

Concrete is widely used as a building material all over the world, and its use is increasing the demand of cement and sand in the construction industry. However, the limited resources and environmental degradation are driving scientists to develop alternative materials from vast volumes of agro-industrial wastes as a partial replacement for conventional cement. In the manufacture of concrete, cement is a major binding resource. This study looked into recycling agro-industrial wastes into cement, such as sugarcane bagasse ash (SCBA), coal bottom ash (CBA), and others, to create sustainable and environmentally friendly concrete. This study aims to see how the combined effects of agricultural by-product wastes affected the characteristics of concrete. SCBA is used to replace fine aggregate (FA) ranging from 0 to 40% by weight of FA, while CBA is used to replace cement content ranging from 0 to 20% by weight of the total binder. In this case, a total of 204 concrete samples (cubes and cylinders) are made using a mixed proportion of 1:1.5:3 and a water-cement ratio of 0.54. Workability, density, water absorption, and mechanical characteristics in terms of compressive and splitting tensile strengths were examined in this study. In addition, for each mix percentage, the total embodied carbon was determined. Workability, density, and water absorption were found to be considerably decreased when CBA and SCBA concentration increased. Due to the pozzolanic nature of CBA and SCBA, an increase in compressive and splitting tensile strengths were seen for specific concrete mixtures, and further addition of CBA and SCBA, the decrease in strength. The embodied carbon of SCBA has augmented the total embodied carbon of concrete, though it can be seen that C15S40, which comprises of 15% CBA and 40% SCBA, is the optimum mix that attained tensile and compressive strength by 3.05 MPa and 28.75 MPa correspondingly, with a 4% reduction in total embodied carbon.

Effect of silica fume and fly ash as cementitious material on hardened properties and embodied carbon of roller compacted concrete.

The production of cement releases an enormous amount of CO2 into the environment. Besides, industrial wastes like silica fume and fly ash need effective utilization to reduce their impacts on the environment. This research aims to explore the influence of silica fume (SF) and fly ash (FA) individually and combine them as binary cementitious material (BCM) on the hardened properties and embodied carbon of roller compacted concrete (RCC). A total of ten mixes were prepared with 1:2:4 mix ratio at the different water-cement ratios to keep the zero slump of roller compacted concrete. However, the replacement proportions for SF were 5%-15%, and FA were 5%-15% by the weight of cement individually and combine in roller compacted concrete for determining the hardened properties and embodied carbon. In this regard, several numbers of concrete specimens (cubes and cylinders) were cast and cured for 7 and 28 days correspondingly. It was observed that the compressive strength of RCC is boosted by 33.6 MPa and 30.6 MPa while using 10% of cement replaced with SF and FA individually at 28 days, respectively. Similarly, the splitting tensile strength of RCC is enhanced by 3.5 MPa at 10% cement replaced with SF and FA on 28 days, respectively. The compressive and splitting tensile strength of RCC is increased by 34.2 MPa and 3.8 MPa at SF7.5FA7.5 as BCM after 28 days consistently. In addition, the water absorption of RCC decreased while using SF and FA as cementitious material individually and together at 28 days. Besides, the embodied carbon of RCC decreased with increasing the replacement level of SF and FA by the mass of cement individually and combined.

Assessing the sustainability and cost-effectiveness of concrete incorporating various fineness of eggshell powder as supplementary cementitious material.

The eggshell powder (ESP) has been used as a partial cement replacement to reduce the cement content in concrete production. According to recent estimates, cement production contributes to 7% of global Carbon Dioxide (CO2) gas emissions. However, most of the studies so far have focused on the mechanical strength aspect of the concrete incorporating ESP; however, there is a lack of information on the influence of ESP on the sustainability of concrete in terms of embodied carbon and eco-strength efficiency. Therefore, this study aims at determining the influence of ESP on the sustainability and cost of an M40 grade concrete when different fineness ESP (50 µm and 100 µm) is utilized as partial cement replacement. The sustainability was assessed in terms of embodied carbon and eco-strength efficiency, while the cost-effectiveness was determined in terms of the overall cost of concrete and cost to produce unit compressive strength. It was observed that the control M40 concrete mix achieved a total embodied carbon of 482.88 kgCO2/m3. With 5 to 15% ESP of 100 µm fineness, the total embodied carbon was successfully reduced, ranging from 3.86 to 11.60%. While 5 to 15% of 50 µm fineness, the reduction ranged from 3.69 to 11.10%. The 50 µm fineness ESP exhibited slightly lower eco-strength efficiency compared to 100 µm fineness ESP; however, both achieved relatively higher eco-strength efficiency. In terms of cost, the inclusion of ESP resulted in a significant reduction in overall cost and was cheaper to produce 1 MPa compressive strength.

Sustainability and mechanical property assessment of concrete incorporating eggshell powder and silica fume as binary and ternary cementitious materials.

Cement production emits a significant carbon dioxide (CO2) gas, dramatically influencing the environment. Furthermore, a large amount of energy is consumed during the cement manufacturing process; since Pakistan is already facing an energy crisis, this high energy consumption by the cement industry puts further stress on Pakistan's energy sector. Hence, the price of cement is rising day by day. Furthermore, waste disposals and concrete ingredients' restoration after demolition have adversative effects on the environment. Therefore, using these wastes decreases cement manufacturing, thereby reducing energy consumption, but it also aids in safeguarding the environment. The study aimed to determine the concrete properties by partially replacing cement with only eggshell powder (ESP) and combining ESP and silica fume (SF) in a ternary binder system in the mixture. However, workability, water absorption, compressive strength, split tensile strength, and flexural strength were all investigated in this study. In this experimental study, cement was replaced as 5, 8, 11, 15, and 20% of ESP, along with 5, 10, and 15% of silica by weight of cement in concrete. Approximately 21 mixes were prepared, from which 01 control mix, 05 mixes of ESP alone, and 15 mixes designed with a blend of ESP and SF with a 1:1.25:3 mix ratio and 0.5 water-cement ratios. Study parameters advocate the substitution of 11% ESP and 10% SF as the optimal option for maximum strength. Furthermore, combining ESP and SF diminishes the composite concrete mixture's workability and dry density greatly.

Experimental study on fresh, mechanical properties and embodied carbon of concrete blended with sugarcane bagasse ash, metakaolin, and millet husk ash as ternary cementitious material.

In recent years, the research direction is shifted toward introducing new supplementary cementitious materials (SCM) in lieu of in place of Portland cement (PC) in concrete as its production emits a lot of toxic gases in the atmosphere which causes environmental pollution and greenhouse gases. SCM such as sugarcane bagasse ash (SCBA), metakaolin (MK), and millet husk ash (MHA) are available in abundant quantities and considered as waste products. The primary aim of this experimental study is to investigate the effect of SCBA, MK, and MHA on the fresh and mechanical properties of concrete mixed which contributes to sustainable development. A total of 228 concrete specimens were prepared with targeted strength of 25MPa at 0.52 water-cement ratio and cured at 28 days. It is found that the compressive strength and split tensile strength were enhanced by 17% and 14.28%, respectively, at SCBA4MK4MHA4 (88% PC, 4% SCBA, 4% MK, and 4% MHA) as ternary cementitious material (TCM) in concrete after 28 days. Moreover, the permeability and density of concrete are found to be reduced when SCBA, MK, and MHA are used separately and combined as TCM increases in concrete at 28 days, respectively. The results showed that the workability of the fresh concrete was decreased with the increase of the percentage of SCBA, MK, and MHA separately and together as TCM in concrete.

Combined effect of coconut shell and sugarcane bagasse ashes on the workability, mechanical properties and embodied carbon of concrete.

This experimental research was conducted to study the combined effect of agricultural by-product wastes on the properties of concrete. The coconut shell ash (CSA) was utilized to substitute cement content ranging from 0 to 20% by weight of total binder and sugarcane bagasse ash (SCBA) to substitute fine aggregates (FA) ranging from 0 to 40% by weight of total FA. In this regard, a total of 300 concrete specimens (cylinders and cubes) were prepared using 1:1.5:3 mix proportions with a 0.52 water-binder ratio. The study investigated the workability, density, permeability, and mechanical properties in terms of compressive and splitting tensile strengths. Additionally, the total embodied carbon for all mix proportions was calculated. It was observed that with an increase in CSA and SCBA contents, the workability, density, and permeability reduced significantly. Due to CSA and SCBA being pozzolanic materials, a gain in compressive and splitting tensile strengths was observed for certain concrete mixes, after which the strength decreased. The increase in embodied carbon of SCBA increased the total embodied carbon of concrete; however, it can be said that C15S40 which consists of 15% CSA and 40% SCBA is the optimum mix that achieved 28.75 MPa and 3.05 MPa compressive and tensile strength, respectively, a reduction of 4% total embodied carbon.

Short-term analysis on the combined use of sugarcane bagasse ash and rice husk ash as supplementary cementitious material in concrete production.

Globally, concrete is widely implemented as a construction material and is progressively being utilized because of growth in urbanization. However, limited resources and gradual depravity of the environment are forcing the research community to obtain alternative materials from large amounts of agro-industrial wastes as a partial replacement for ordinary cement. Cement is a main binding resource in concrete production. To reduce environmental problems associated with waste, this study considered the recycling of agro-industrial wastes, such as sugarcane bagasse ash (SCBA), rice husk ash (RHA), and others, into cement, and to finally bring sustainable and environmental-friendly concrete. This study considered 5%, 10%, and 15% of SBCA and RHA individually to replace ordinary Portland cement (OPC) by weight method then combined both ashes as 10%, 20%, and 30% to replace OPC to produce sustainable concrete. It was experimentally declared that the strength performance of concrete was reduced while utilizing SCBA and RHA individually and combined as supplementary cementitious material (SCM) at 7, 28, 56, and 90 days, respectively. Moreover, the initial and final setting time is increased as the quantity of replacement level of OPC with SCBA and RHA separates and together as SCM in the mixture. Based on experimental findings, it was concluded that the use of 5% of SCBA and 5% of RHA as cement replacement material individually or combined in concrete could provide appropriate results for structural applications in concrete.

Influence of coconut shell ash on workability, mechanical properties, and embodied carbon of concrete.

The significant contribution of the carbon dioxide emission from the production of Portland cement which is the main binder used in concrete has called for an imminent need to find environmentally friendly materials as alternatives. The availability of large quantities of agricultural wastes such as coconut shell in most developing countries opens a pathway to explore how these materials can be recycled into concrete as the binder composition. The combustion of most solid agricultural wastes results in the production of ash which can be used to replace Portland cement as a binder in concrete. This paper presents the results from the experimental investigation of the effect of coconut shell ash on the workability, mechanical properties, and embodied carbon of concrete. A total of five mixtures were made with coconut shell ash replacing Portland cement up to 20%. Results from this paper showed that coconut shell ash can be incorporated into concrete mixtures to reduce its embodied carbon. A reduction in embodied carbon of about 15% was achieved when 20% of Portland cement was replaced with coconut shell ash. The incorporation of coconut shell ash into concrete mixtures also resulted in an increase in the mechanical properties up to 10% replacement of Portland cement. The compressive, tensile, and flexural strength of mixtures incorporating 10% coconut shell ash as replacement of Portland cement is 12%, 10%, and 9% higher than that of the control mixture without coconut shell ash.

Effect of local metakaolin developed from natural material soorh and coal bottom ash on fresh, hardened properties and embodied carbon of self-compacting concrete.

The carbon dioxide emissions from Portland cement production have increased significantly, and Portland cement is the main binder used in self-compacting concrete, so there is an urgent need to find environmentally friendly materials as alternative resources. In most developing countries, the availability of huge amounts of agricultural waste has paved the way for studying how these materials can be processed into self-compacting concrete as binders and aggregate compositions. Therefore, this experimental program was carried out to study the properties of self-compacting concrete (SCC) made with local metakaolin and coal bottom ash separately and combined. Total 25 mixes were prepared with four mixes as 5, 10, 15, and 20% replacement of cement with metakaolin; four mixes as 10, 20, 30, and 40% of coal bottom ash as partial replacement of fine aggregates separately; and 16 mixes prepared combined with metakaolin and coal bottom ash. The fresh properties were explored by slump flow, T50 flow, V-funnel, L-box, and J-ring sieve segregation test. Moreover, the hardened properties of concrete were performed for compressive, splitting tensile and flexural strength and permeability of SCC mixtures. Fresh concrete test results show that even if no viscosity modifier is required, satisfactory fresh concrete properties of SCC can be obtained by replacing the fine aggregate with coal bottom ash content. At 15% replacement of cement with local metakaolin is optimum and gave better results as compared to control SCC. At 30% replacement of fine aggregate is optimum and gave better results as compared to control SCC. In the combined mix, 10% replacement of cement with metakaolin combined with 30% replacement of fine aggregate with coal bottom ash is optimum and gave better results as compared to control SCC.