Experimental study on the material model of the stress - strain relationship of lightweight concrete using lightweight aggregates from construction and demolition wastes

Abstract

Advanced technologies have been developed to produce lightweight aggregates from construction and demolition waste, helping to reduce the use of limited natural resources. In this paper, the author presents an experimental study on the material model of the stress-strain relationship of lightweight concrete beams using recycled lightweight aggregates. Based on the study, a material model is proposed for the stress-strain relationship diagram applied in the analysis of concrete beams. The stress-strain relationship of recycled lightweight concrete is proposed as a linear stress-strain relation with an ultimate strain value of εcu2 ≈ 0.0031. The experimental and simulation software results on the flexural behavior of beams using recycled lightweight aggregates under short-term loading show that the load-deflection relationship develops through four stages: uncracked elastic, postcracking, and approaching the failure state. The load-deflection curves obtained from experimental tests and simulation software are relatively close and similar. The deflection analyzed in simulation software compared to experimental results shows a deviation of 4%. This demonstrates that the proposed stress-strain relationship model for recycled lightweight aggregate concrete is appropriate.

Keywords: Lightweight concrete; recycled lightweight aggregate; reinforced concrete beams under flexure; stress-strain; loaddeflection.