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.

Freeze-thaw cycle and abrasion resistance of alkali-activated FA and POFA-based mortars: Role of high volume GBFS incorporation.

Alkali-activated binders made from various waste products can appreciably reduce the emission of CO2 and enhance the waste recycling efficiency, thus making them viable substitutes to ordinary Portland cement (OPC)-based binders. Waste materials including fly ash (FA), palm oil fuel ash (POFA), and granulated blast furnace slag (GBFS) reveal favorable effects when applied to alkali-activated mortars (AAMs) that are mainly related to the high contents of silica, alumina, and calcium. Therefore, fifteen AAM mixes enclosing FA, POFA with high volume of GBFS were designed. The obtained GBFS/FA/POFA-based AAMs were subjected wet/dry and freeze/thaw cycles. The impact of various GBFS contents on the microstructures, freeze-thaw cycle, abrasion resistance, mechanical and durability features of the proposed AAMs were evaluated. The results showed that presence of Ca can significantly affect the AAMs durability features and long-term performance. The abrasion resistance of the AAMs was decreased with the decrease of CaO contents. Furthermore, the abrasion depth of 70% AAMs (0.8 mm) was lower in comparison to the mix made by replacing 50 wt% of FA with GBFS (1.4 mm). Generally, increase in the GBFS contents from 50 to 70% could largely impact the AAMs properties under aggressive environmental exposure. The expansion and physical impacts during the freezing-thawing cycles was argued to destroy the bonds in C-S-H and paste-aggregates, causing the formation of large cracks. It is asserted that the AAM mixes made from FA, POFA and high volume of GBFS may offer definitive mechanical, durable, and environmental benefits with their enhanced performance under aggressive environments.

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.

Mechanical Properties of Fly Ash-Based Geopolymer Concrete Incorporation Nylon66 Fiber.

This study was carried out to investigate the effect of the diamond-shaped Interlocking Chain Plastic Bead (ICPB) on fiber-reinforced fly ash-based geopolymer concrete. In this study, geopolymer concrete was produced using fly ash, NaOH, silicate, aggregate, and nylon66 fibers. Characterization of fly ash-based geopolymers (FGP) and fly ash-based geopolymer concrete (FRGPC) included chemical composition via XRF, functional group analysis via FTIR, compressive strength determination, flexural strength, density, slump test, and water absorption. The percentage of fiber volume added to FRGPC and FGP varied from 0% to 0.5%, and 1.5% to 2.0%. From the results obtained, it was found that ICBP fiber led to a negative result for FGP at 28 days but showed a better performance in FRGPC reinforced fiber at 28 and 90 days compared to plain geopolymer concrete. Meanwhile, NFRPGC showed that the optimum result was obtained with 0.5% of fiber addition due to the compressive strength performance at 28 days and 90 days, which were 67.7 MPa and 970.13 MPa, respectively. Similar results were observed for flexural strength, where 0.5% fiber addition resulted in the highest strength at 28 and 90 days (4.43 MPa and 4.99 MPa, respectively), and the strength performance began to decline after 0.5% fiber addition. According to the results of the slump test, an increase in fiber addition decreases the workability of geopolymer concrete. Density and water absorption, however, increase proportionally with the amount of fiber added. Therefore, diamond-shaped ICPB fiber in geopolymer concrete exhibits superior compressive and flexural strength.

Chemical Distributions of Different Sodium Hydroxide Molarities on Fly Ash/Dolomite-Based Geopolymer.

Geopolymers are an inorganic material in an alkaline environment that is synthesized with alumina-silica gel. The structure of geopolymers consists of an inorganic chain of material and a covalent-bound molecular system. Currently, Ordinary Portland Cement (OPC) has caused carbon dioxide (CO2) emissions which causes greenhouse effects. This analysis investigates the impact on fly ash/dolomite-based-geopolymer with various molarities of sodium hydroxide solutions which are 6 M, 8 M, 10 M, 12 M and 14 M. The samples of fly ash/dolomite-based-geopolymer were prepared with the usage of solid to liquid of 2.0, by mass and alkaline activator ratio of 2.5, by mass. After that, the geopolymer was cast in 50 × 50 × 50 mm molds before testing after 7 days of curing. The samples were tested on compressive strength, density, water absorption, morphology, elemental distributions and phase analysis. From the results, the usage of 8 M of NaOH gave the optimum properties for the fly ash/dolomite-based geopolymer. The elemental distribution analysis exposes the Al, Si, Ca, Fe and Mg chemical distribution of the samples from the selected area. The distribution of the elements is related to the compressive strength and compared with the chemical composition of the fly ash and dolomite.

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.