Experimental Investigation on the Partial Replacement of Fine Aggregate with Recycled Concrete Aggregate in Concrete with Shape Memory Alloy Fibers under Different Exposure Temperature
Research in the field of recycled aggregate concrete (RAC) and their efficient and optimum use in concrete structures has been an area of interest since many years. One of the main concerns for using such concrete in buildings is its spalling in fire and post-fire residual mechanical properties. To alleviate this concern, shape memory alloy (SMA) fibers were added to RAC to form fiber reinforced recycled aggregate concrete (FRRAC). The effect of elevated temperature on the strength and durability properties of concrete with partial replacement of natural fine aggregate by recycled fine aggregate was studied under this research work. SMA fibers were added by 0.5% and 1% of the volume of concrete to enhance the strength and reentering ability to reduce crack development in the concrete. Here, natural fine aggregate is replaced by recycled fine aggregate concrete with 0%, 50% and 65% respectively. Total 162 cubes and 81 cylinders were cast and tested to evaluate the strength as well as durability property viz. water permeability of FRRAC. Concrete specimens were subjected to different exposure temperature viz. ambient temperature (25°-30°C), 400°C and 800°C. The test results show that the replacement fine aggregate with recycled aggregate does not affect the mechanical properties of concrete up to 50% replacement, where as the addition of SMA fibers increases the compressive as well as tensile strength of concrete. Up to exposure temperature of 400°C the mechanical as well as durability properties of concrete did not undergo severe deterioration. Keywords - Recycled fine aggregates, Shape memory alloy fibers, Elevated temperature, Compressive strength, Split tensile strength, Flexural strength, Water permeability, Crack closing ability, Mass loss.