Fracture Behaviour of Recycled Aggregate Concrete Beams - An Experimental Study

The purpose of this research is to assess the effect of recycled aggregates on the fracture energy properties of concrete under various notch depths. In this studyfracture energy of recycled aggregate concrete beams of size 700mmx150mmx150mm with notches of size 7.5mm, 15mm, 45mm and 75mm were provided to study the fracture energy properties like unstable fracture toughness and Crack Mouth Opening Displacement (CMOD). A clip gauge of + 4mm range over a gauge length of 25mm was fixed across the notch at the bottom face of the beam to measure the crack mouth opening displacement (CMOD). Linear varying differential transformer (LVDT) of two numbers was used to determine the deflection of the specimens. Specimens of two water/cement ratios 0.5 and 0.45 were adopted to study the fracture energy and the results were compared. Fracture parameters such as unstable fracture toughness were predicted using empirical relations. Fracture studies elucidates that fracture energy dissipation increases with increase in the notch depth. Also fracture energy dissipation and CMOD of recycled aggregate concrete is more compared to conventional aggregate concrete due to the higher water absorption capacity of recycled aggregates.