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Concrete is used as a material in the construction of several types of structures. The structural behavior of concrete is constrained by its lower tensile strength, bending strength, and toughness. Fiber-reinforced concrete is gaining importance in various concrete applications. Research has been carried out to use multiple types of fibers in concrete in different combinations to improve its mechanical characteristics, such as toughness, strength, ductility, and durability. In traditional concrete, microcracks have developed before loading the structure because of volume changes and drying shrinkage. When the load is applied, the microcracks start opening and propagating. Therefore, failure of the concrete member occurs. Hence, the usage of fibers helps arrest the growth of the crack and improves concrete characterization. The goal of this research study is to examine mechanical properties of concrete when used in combination with steel, basalt, and glass fibers. Steel fiber is useful in arresting macrocracks, whereas basalt and glass fibers are effective in preventing microcracks. In this research, the specimens incorporated hybrid (steel, glass, and basalt) fibers in the concrete mix with various percentage proportions at a 0.5% volume fraction. Experiments were carried out to assess the bending strength, compression strength, and splitting tensile strength. Therefore, this research can show comparative analysis for different percentages of fibers to enhance the qualities of concrete and can show the optimum fiber percentage among the proportions selected for this study. [ABSTRACT FROM AUTHOR]

The development of special concrete focussed on sustainability and energy conservation has been approached through the use of recycled materials, novel techniques and processes, and materials that harness natural energy. This paper presents the results of one such study on the development of light-transmitting concrete using a novel polymeric transmitting media, poly-methyl-methacrylate, and a detailed analysis of the results obtained. Four variants based on the diameter and number of rods have been studied, with 5 and 10 mm diameter rods incorporated into 100 mm cube samples. A positive correlation between the area of rods and transmittance has been established; however, a loss in compressive and flexural strength was observed. Seasonal and monthly variation results indicate higher transmittance in summer, with the highest transmittance being observed in the month of May and the monsoon having the lowest transmittance, specifically in the month of July. The results of a case study of the application of the material have also been presented. The cost of construction has been studied, and the prediction of electricity consumption during operations has been carried out. The results have indicated the feasibility of use, even with the high initial cost. Variants have been shown to return the investments in a period of 7–31 years. Additionally, three of the four variants showed a sharp decrease in total CO2 emissions by eliminating the need for energy for daylighting and eliminating the consumption of electricity throughout the service life. Variants have been shown to return the investments in a period of 7–31 years. Additionally, three of the four variants show a sharp decrease in total CO2 emissions by eliminating the need for energy for daylighting and eliminating the consumption of electricity throughout the service life. [ABSTRACT FROM AUTHOR]

This manuscript highlights the mechanical, economical, ecological, and thermal investigations performed on paving quality geopolymer concrete (PQGC) incorporating processed steel slag (PSS) as a substitute for river sand (RSa). The replacement of RSa with PSS ranged from 0 to 100% in the PQGC mix. The mix with 100% PSS content exhibited enhanced geopolymerization, resulting in a denser and more amorphous matrix. This improved the mechanical properties, increasing compressive strength by 10.9%, flexural strength by 23.5%, and splitting tensile strength by 8.3%. The replacement of RSa with PSS in PQGC led to a marginal reduction in (embodied energy) EE and CO2 emissions. However, compared to conventional Pavement Quality Concrete (PQC) and Fly Ash PQC (FPQC), the reduction in EE for PQGC was 44% and 34%, while the CO2 emissions of PQGC were reduced by 1.22 and 1.49 times. Despite these benefits, PQGC with 100% PSS was 19% and 30% more expensive than PQC and FPQC, respectively. The Global Warming Potential (GWP) of PQGC was approximately one-third that of PQC and FPQC at all levels of replacement of RSa in PQGC when compared to PQC and FPQC. Additionally, thermal conductivity decreased from k = 0.67 W/m °C to k = 0.51 W/m °C with 100% replacement of RSa, keeping the concrete cooler. Therefore, PQGC with 100% PSS, when practically implemented, may help reduce surrounding temperatures. This study concludes that PSS is a feasible and reliable alternative to RSa, enhancing the sustainability of PQGC. [ABSTRACT FROM AUTHOR]

The durability of the self compacting concrete is one of the prominent areas of concern in recent years since it has become prevalent due to its ease of handling in the construction industries. However, there is a lack of detailed durability study of M-sand self compacting concrete with polypropylene fibres in the literature. In this paper, self compacting concrete made by Portland pozzolana cement with natural sand and M-sand, different percentages of volume fraction (0%, 0.1%, 0.15% and 0.2%) polypropylene fibres with M-sand is thoroughly investigated for fresh properties, hardened properties, drying shrinkage, water absorption, permeability, acid resistance and corrosion crack initiation time. Further, SEM analysis was carried out to know the effect of polypropylene fibre on the concrete microstructure. The results confirmed that the use of M-sand has improved the fresh, hardened and durability properties of the self compacted concrete than natural sand. Also, it is observed that the addition of polypropylene fibres has reduced the fresh properties of self compacted concrete. However, M-sand with 0.15% polypropylene fibres has slightly improved the strength of self compacting concrete, compression strength by 6.97%, split tensile by 8.68% and flexure strength by 3%. Further, it has reduced the drying shrinkage by 40%, water absorption by 30%, water penetration by 33.33%, and increased the chemical resistance, surface crack initiation period than the natural sand self compacting concrete. Finally, this study concludes that M-sand with 0.15% polypropylene fibres improves the durability of self compacting concrete by reducing effect from aggressive environments and in turn contributes to increased corrosion resistance of reinforcements embedded in concrete. Thus, the study supports the use of self compacting concrete with M-sand and optimum amount of polypropylene fibres to achieve required sustainability in terms of strength and durability. [ABSTRACT FROM AUTHOR]