Estimation of resilient modulus of cement-treated construction and demolition waste with performance-related properties

Abstract

Construction and demolition (C&D) waste is generated for 100 billion tonnes per annum globally, which has caused underground water contamination and farmland occupation when disposing the C&D waste by landfilling. The C&D waste materials have been recycled and used as an alternative to virgin mineral aggregates in pavement construction. This study aims at proposing a convenient method to estimate resilient modulus of cement-treated C&D waste materials when used in pavement base layer based on material performance-related properties and using discrete element simulation tests. Two kinds of materials are investigated, they're blends of two C&D waste materials, crushed bricks (CB) and recycled concrete aggregate (RCA). Fundamental property experiments were carried out on the aggregates to evaluate the engineering performance. Unconfined compress strength (UCS) tests were conducted on cement-treated materials to analyze the effect of curing duration and cement content on UCS. The numerical resilient modulus (Mr) tests by the discrete element method (DEM) were conducted to evaluate the resilient performance of C&D waste. The simulation results were verified with the lab measurements. Test results showed that the test materials have a high water absorption and a low durability. The minimum cement content was determined as 5% to satisfy the strength requirement of 4 MPa according to the national standards. Mr increases with confining pressure. Performance-related properties (UCS, γd, E50) were proposed to build their correlations with k values of the resilient modulus model, which are formulated to predict the k values. The values of Mr predicted by the performance-relatedproperties were consistent to the DEM modeled ones.