Experimental and FEM Analysis for Fracture Performance Evaluation of Concrete Made with Recycled Construction and Demolition Waste Aggregates

Abstract

Paper presents experimental and Finite Element Method (FEM) analysis of fracture behavior of concrete made using Recycled Aggregate (RA). Concrete mixes were prepared using Construction and Demolition Waste (CDW) as replacement of natural coarse aggregates. To study fracture performance, concrete mixes were prepared with water to cementitious content (w/b) ratios between 0.4 and 0.5. Beam specimens of size 100 mm x 100 mm x 500 mm were cast and tested as per method of Three-point bend test on notched beam proposed by RILEM. Fracture parameters like fracture energy, stress intensity factor, energy release rate and characteristic length were evaluated using Load-CMOD (Crack Mouth Opening Displacement) and load deformation curves. Mechanical properties of concrete such as compressive and flexural strength, modulus of elasticity and split tensile strength were also evaluated. The performance of concrete using RA has been compared with concrete using Natural Aggregate (NA) from literature. Results suggest slightly better fracture performance in case of concrete made using RA in comparison to conventional concrete in spite of having similar strength and w/b ratio. Fracture energy parameter in terms of stress intensity factor obtained from FEM analysis were similar to experimental results wherein no significant variation in stress intensity factor for concrete mixes with recycled and natural aggregate were observed. However, it can be stated that values of stress intensity factor of 0.47_NA was lowest and 0.5_RA was highest. There was no significant difference in average fracture energy of mixes and it lies in range of 180 N/m to 300 N/m