Geopolymer concrete with time is gaining recognition as a sustainable alternative to Portland cement concrete, offering lower carbon emissions and utilising industrial by-products. While prior research focussed on its mechanical properties for structural purposes, this study explores its potential for paving applications. A unique geopolymer concrete mixture suitable for paving, referred to as paving quality geopolymer concrete (PQGC), was developed by incorporating slag sand (SS) as a substitute for river sand (RS). The investigation primarily assessed fatigue life PQGC mixes. The findings demonstrate that the inclusion of SS in PQGC has no significant impact on its setting times or workability. However, PQGC formulated with 100% SS, w.r.t PQGC containing RS, exhibited enhanced mechanical strength of 7% in compression, 16.7% in flexure and 8.3% in split tensile tests at 28 days of open-air curing. Following a 14-day period of curing, PQGC achieved a compressive strength of 46 MPa, surpassing the minimum requirement of 40 MPa as per IRC:58 2015 for pavement quality concrete (PQC) by 15%. To evaluate fatigue performance, PQGC beam specimens were subjected to repeated loading at stress levels ranging from 0.9 to 0.6. The resulting fatigue data were employed to develop stress-fatigue life (SN) and Weibull two-parameter fatigue failure models. Comparative analysis with fatigue failure models such as Indian Road Congress (IRC) and Darter revealed that PQGC exhibits superior fatigue resistance and longer life expectancy compared to PQGC. In conclusion, this study confirms that PQGC incorporating SS is an efficient and eco-friendly choice for constructing rigid pavements with advantages such as curing without water, enabling early opening of roadways to traffic, and excellent resilience under cyclic loads.

Since the nineteenth century, reinforced concrete was evolved as a crucial material for construction. This popular composite material is broadly used in different building typologies. However, the decaying of steel rebar due to corrosion is identified as a hindrance that can affect the quality of reinforced concrete structures. In reference to this, the glass fiber-reinforced polymer (GFRP) bar is essential because of corrosion-resistant properties. The researchers performed various tests and numerical analysis to know the response of GFRP-reinforced flexural members in shear and bending. Based on studies over the last decade, this study critically analyzes the response of flexural member reinforced using glass fiber-reinforced polymer (FRP) bars. Understanding the behavior of the FRP bar as the alternating reinforcing material will be aided by this review. Since the GFRP bar has high strength and no yield point, the conventional characterizations of ductility may not be applicable to determine whether GFRP-reinforced concrete components are ductile. Hence, a detailed study is needed to understand the behavior of such structures. This paper explores various properties of GFRP-reinforced beams to appreciate the applications of GFRP reinforcement in flexural members.

Several countries have started using recycled aggregate as a partial replacement to natural aggregate in concrete. Recycled aggregate contains adhered mortar, which distinguishes it from the natural aggregate. In the present study, natural coarse aggregates were entirely replaced by two kinds of recycled coarse aggregates. The recycled aggregates obtained from the jaw crushing method were named recycled coarse aggregate-1 and the aggregates that were further processed by the ball milling method were named recycled coarse aggregate-2. The performance of control concrete and two kinds of recycled coarse aggregate concretes were studied experimentally with respect to mechanical properties. Results indicate that the processing method to obtain recycled coarse aggregates plays an important role in developing the required mechanical properties. The ball mill processed aggregates performed better than the jaw crushed aggregates in concrete. The performance was also assessed with respect to the microhardness of the interfacial transition zone around the surface of the aggregates. The presence of adhered mortar in recycled aggregate weakens it because of the presence of an old interfacial transition zone that affects the strength of concrete. The interfacial transition zone hardness at the aggregate-mortar interface is 53.94, 34.21, and 44.08 % of bulk concrete for control concrete, recycled coarse aggregate-1 concrete, and recycled coarse aggregate-2 concrete, respectively. The addition of silica fume improved the average microhardness, and the same was reflected in the mechanical properties of both the recycled coarse aggregate concretes. It is recommended to use ball mill processed recycled coarse aggregates as a complete replacement to natural coarse aggregates along with a 5 % addition of silica fume for better performance.

The present study concentrates on the performance evaluation of calcined and uncalcined cashew nut-shell ash (UCCNA and CCNA) with treated total recycled concrete aggregate (TRCA) in self-compacting concrete. The achievement of sustainable self-compacting concrete (SCC) is possible by the implication of four stages, which includes TRCA treatment process, gradation selection process through Bailey aggregate grading technique, by considering TRCA replacement percentage with an increment of 25% and up to 100% and by considering UCCNA or CCNA replacement with an increment of 5% and up to 20%. Hardened and fresh properties of SCC have been performed and analyzed based on the compliance requirements of SCC. In addition finding results through microstructure assessment was in line with the findings of the hardened and fresh properties of SCC. In addition, quality and dynamic instability assessments of SCC were analyzed through ultrasonic pulse velocity and drying shrinkage aspects. Besides CO₂, the emission rate and the efficiency rate of SCC, composites were analyzed in detail. Overall findings revealed that CCNA-based SCC mixes performed effectively than UCCNA-based SCC; specifically, incorporation of 75% of TRCA with 15% CCNA was found to be optimal. But with regard to shrinkage performance UCCNA found to be better by imputing less shrinkage compared to CCNA-based SCC mixes. Further with regard to efficiency rate of SCC composites revealed the gain of maximum efficiency of about 0.156 MPa/kg CO₂/m³ and 0.160 MPa/kg CO₂/m³ for 15% and 20% CCNA-based SCC mixes.

The utilization of class F fly ash (F-FA) is limited to 15–30% as a substitution for cement. The study intends to tap into the potential of high-volume F-FA as a pozzolan and micro filler by eliminating aggregates. The article presents the long-term behavior of a novel cement composite called no-aggregate concrete (NAC), incorporating 20% ordinary Portland cement (OPC) and 80% F-FA, with polypropylene (PP) fibers in 0.6, 0.8, and 1.0% volume fractions, in a corrosive environment. The bulk diffusion of preconditioned 100 mm cubes reveals that all mixtures’ chloride-binding capacity increases significantly with prolonged exposure. The total chloride content for mixtures M1, M2, and M3 is within acceptable limits as per EN 206. M4 with 1.0% PP fibers shows a higher total chloride content at 2 cm depth. The average chloride content for all mixtures is within 0.4%. The compressive strength of mixtures cured in water is about 90 MPa at 730 days, and is severely affected in the absence of fibers in a corrosive environment. The microstructure of mixtures at 730 days displays a cohesive, compact, continuous matrix, and the presence of unreacted F-FA.