Numerous studies have been conducted recently on fibre reinforced concrete (FRC), a material that is frequently utilized in the building sector. The utilization of FRC has grown in relevance recently due to its enhanced mechanical qualities over normal concrete. Due to increased environmental degradation in recent years, natural fibres were developed and research is underway with the goal of implementing them in the construction industry. In this work, several natural and artificial fibres, including glass, carbon, steel, jute, coir, and sisal fibres are used to experimentally investigate the mechanical and durability properties of fibre-reinforced concrete. The fibres were added to the M40 concrete mix with a volumetric ratio of 0%, 0.5%, 1.0%, 1.5%, 2.0% and 2.5%. The compressive strength of the conventional concrete and fibre reinforced concrete with the addition of 1.5% steel, 1.5% carbon, 1.0% glass, 2.0% coir, 1.5% jute and 1.5% sisal fibres were 4.2 N/mm2, 45.7 N/mm2, 41.5 N/mm2, 45.7 N/mm2, 46.6 N/mm2, 45.7 N/mm2 and 45.9 N/mm2, respectively. Comparing steel fibre reinforced concrete to regular concrete results in a 13.69% improvement in compressive strength. Similarly, the compressive strengths were increased by 3.24%, 13.69%, 15.92%, 13.68% and 14.18% for carbon, glass, coir, jute, and sisal fibre reinforced concrete respectively when equated with plain concrete. With the optimum fraction of fibre reinforced concrete, mechanical and durability qualities were experimentally investigated. A variety of durability conditions, including the Rapid Chloride Permeability Test, water absorption, porosity, sorptivity, acid attack, alkali attack, and sulphate attack, were used to study the behaviour of fiber reinforced concrete. When compared to conventional concrete, natural fibre reinforced concrete was found to have higher water absorption and sorptivity. The rate of acid and chloride attacks on concrete reinforced with natural fibres was significantly high. The artificial fibre reinforced concrete was found to be more efficient than the natural fibre reinforced concrete. The load bearing capacity, anchorage and the ductility of the concrete improved with the addition of fibres. According to the experimental findings, artificial fibre reinforced concrete can be employed to increase the structure’s strength and longevity as well as to postpone the propagation of cracks. A microstructural analysis of concrete was conducted to ascertain its morphological characteristics.

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The exceptional structural strength and low cost of steel-concrete composite columns make them a popular choice for civil engineering structures. Numerous forms of composite columns, including steel tubes filled with concrete, have been produced recently in response to various construction situations. Cold-formed steel tubular columns with concrete filling have higher strength and ductility due to their capacity to withstand inner buckling and postpone outward buckling. The objective of this research is to determine the ductile and strength performance of composite columns containing various forms of fibre-reinforced concrete when subjected to axial compression. Several different kinds of fibre-reinforced concrete (FRC) are employed as additives in hollow steel columns, including steel FRC, carbon FRC, glass FRC, coir FRC, jute FRC, and sisal FRC. Axial compression tests were performed on 24 columns, including three hollow steel columns and 21 composite columns. Three distinct slenderness ratios were developed and used. Axial bearing capacity, compressive stress-strain curves, ductility, peak strain, axial shortening, and toughness were among the topics covered by the axial compression test. Experimental findings demonstrated that all conventional composite columns experienced failure through overall buckling, Local buckling and crushing of concrete infill, which was transformed into more ductile failure using fibre-reinforced concrete infills. The test results revealed that fibre-reinforced concrete-infilled steel columns outperformed conventional composite columns in terms of strength, ductility, and energy absorption capacity. The percentage increase in load-carrying capacity was observed as 203.88%, 193.48% and 190.03% when compared to hollow cold-formed steel tubular columns in stub, short and medium columns, respectively. Under assessment of stub, short, and medium columns, the load-strain plots demonstrated that the steel fibre-reinforced concrete in-filled columns performed well in terms of ductility. Localized buckling and crushing of the concrete infill caused the composite columns with low slenderness ratios to fail. In contrast, concrete-filled steel tube columns with higher slenderness ratios showed column failure through the overall buckling of the composite column.

The concept of sustainability in agricultural residue management has gained increasing traction around the world in recent years. After harvesting, large volumes of waste are generated that are often dumped into the environment, causing pollution. In addition to preventing environmental degradation, these wastes can also be used in the concrete industry to reduce mineral resource depletion. With this approach, sustainable development is possible. According to the results of this investigation, the effect of pigeon pea stalk ash (PPSA) as a partial replacement of cement in concrete, a series of experimental tests were performed. It has been found that the compressive strength increases for the mixes from 4 to 8% of cement replacement. In contrast, the strength decreases when the percentage replacement of pigeon pea stalk ash with cement exceeds 8%. Based on the experimental results, concrete infused with 8% pigeon pea stalk ash increased its compressive strength by 6.96%. The compressive strength decreased with a further increase in PPSA content. Although the split tensile strength value of PPSA8 concrete was same value compared to the control concrete, even an 8% PPSA concrete has higher strength than other replacement levels. Concrete with 8% PPSA content was observed to have a higher flexural strength than control concrete. PPSA concrete was prepared with pigeon pea stalk waste up to 8% substitution of cement. PPSA concrete has reduced permeability and higher resistance to acid attack. All the strength and durability test results revealed that PPSA concrete type was superior to the control concrete in terms of mechanical qualities and durability characteristics. The present work discusses concrete's improved economic and environmental aspects with incorporated pigeon pea stalk ash. Hence, this study points toward the highest potential use of more concerned about agricultural wastes like pigeon pea stalk ash in green concrete.