An experimental study on mechanical behaviour of concrete by partial replacement of sand with brick fines

Heat is one of the primary factors that causes concrete structures to deteriorate over time and enhance concrete's structural properties. In an experimental investigation, brick fines were substituted for sand at different percentages of 5%, 10%, 15%, and 20% to test the mechanical behaviour of concrete exposed to high temperatures. At 15% replacement of brick powder, the maximal strength at standard temperatures had attained. An optimal concrete and ordinary concrete had then been exposed for 2 h at temperatures ranging from 100 degrees C to 600 degrees C at 100 degrees C intervals. The quality check and strength characteristics of replacement and conventional concrete were evaluated, including weight loss, Ultrasonic Pulse Velocity (UPV), rebound hammer, and compressive, tensile, and flexural strengths at ambient and high temperatures. The quality of concrete decreased with temperature increase because of crack development and incompatible deformation between aggregate and cement paste. The strength decreased with increased temperature because of calcium silicate hydrate (CSH) breakdown and capillary water evaporation. Furthermore, a particular temperature at which cracks appear in concrete specimens exposed to high temperatures had determined using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) analyses. The brick powder performed better in enhancing the concrete's strength characteristics after being heated.