This study examines the effect of elevated temperature on various properties of reactive powder concrete (RPC) containing varying percentages of recycled fine aggregates as sand replacement. Recycled fine aggregates were collected from two sources, i.e., demolished normal strength concrete and demolished RPC. The specimens were prepared using 25%, 50%, and 75% replacement of natural sand with recycled fine aggregates, exposed to two different curing conditions and were subjected to four temperatures, i.e., 25, 200, 400, and 600 °C. Later, the specimens were tested for mass loss, compressive strength test, split-tensile strength test, flexural strength test, and water absorption test at all temperature ranges. Results determined that although the mechanical properties degraded with the temperature rise, the recycled aggregates can be employed as a partial replacement of natural sand in RPC without causing a significant decrease in the performance of RPC, and can help to produce more sustainable RPC by using recycled aggregates.

This paper presents the effect of using Carbon Fiber Reinforced Polymers (CFRP) as retrofitting material on seismic behavior of Plain Cement Concrete (PCC) and Glass Fiber Reinforced Concrete (GFRC). The experimental work was carried out in two steps. In first step, cylindrical specimens of size 150 mm × 300 mm were cast by using both PCC and GFRC. In second step, the specimens were wrapped by CFRP in three different patterns. All the specimens were tested under monotonic compressive loading. The test results were later used in the non-linear static cyclic analysis of reinforced concrete frame modeled in a finite element based analytical tool. Seismic vulnerability assessment was then carried out using a modified capacity spectrum method to develop analytical curves for the frames. The results showed significant improvement in seismic performance of frames strengthened by CFRP. Collapse hazard level for unconfined GFRC structure was increased by 20.73% as compared to unconfined PCC structure. There was 21 to 28% improvement observed in collapse hazard level in confined PCC structures as compared to their unconfined counterparts. However, confinement of GFRC structures resulted in only 8% increase in collapse hazard level as compared to unconfined GFRC structures.