Shear behavior of reinforced concrete beams made with recycled concrete aggregates

Abstract

This paper presents a study into the shear behavior of reinforced concrete beams made with Recycled Concrete Aggregates (RCA). Three beams were cast. The first beam was made entirely with natural coarse aggregates to serve as control beam. The second beam was made with 50% replacement ratio of coarse aggregates and the third beam was made with 100% recycled concrete aggregates. The replacement was done by volume method. Replacement of sand was not considered. All beams had 150 x 300 mm cross section and were 3 m long. The reinforcement ratio was constant at ρ=1.04% with constant shear span a/d=3.5. The beams were subjected to four-point loading test. Twelve control specimens were cast with each beam to study the mechanical properties of the three concrete mixes designed. Beams deflection, crack patterns, yielding, ultimate shear capacity, and failure modes are all observed and analyzed. Results suggest no significant changes in the shear behavior as the replacement ratio of coarse aggregates increases. ACI Code provisions for predicting the concrete shear capacity are applicable to reinforced concrete beams made with recycled aggregates. This project is part of an ongoing research on the effect of the all parameters that affect the shear capacity of reinforced concrete beams.