Performance of concrete containing crushed waste concrete exposed to different fire temperatures

Recycled aggregate obtained from the construction and demolition waste has currently received increasing attention, due to its potential to be used in environmentally friendly concrete structures. Further, the deficiency of natural aggregates, shortage of dumping sites, increase in transport cost and environmental pollution lead to use of recycled aggregate as a substitute material in the production of concrete in many countries. This experimental study demonstrates the properties of concrete containing crushed waste concrete exposed to different fire temperatures. In the experimental work, the fresh concrete properties (slump test) and the hardened concrete properties, (compressive strength, splitting tensile strength, flexural strength and modulus of elasticity) were carried out. A total of thirty concrete mixes with different cement contents (300, 350, and 400 Kg/m³) at w/c ratio (0.5) were made and the percentage of replacement of natural coarse aggregate by fired recycled coarse aggregate at fire temperatures (300,600 and 800°C) for fire duration (2) hours was (0, 25, 50 and 100%). In the process of mixing, equal consistence among all concrete mixes was achieved. The obtained results indicate that the recycled coarse aggregate subjected to fire can successfully be used for making structural concrete.