Improved Mechanical Properties and Early-Age Shrinkage Resistance of Recycled Aggregate Concrete with Atomic Polymer Technology

Abstract

To overcome some inferior physical and mechanical properties of recycled aggregate concrete (RAC), an enhancing technique is presented in this paper to improve the performance of RAC by adding a promising chemical admixture, an atomic polymer technology (APT) in the form of a mesoporous inorganic polymer (MIP). The RAC samples with different added amounts of MIP were prepared, and their mechanical and physical properties were measured. Various basic material and durability properties, such as stiffness, strength, and early-age shrinkage, were evaluated. The smart piezoelectric cement modules as either sensors or actuators were fabricated, and they were embedded in concrete beams to monitor the early-age stiffness-gaining process of the RAC samples during its curing stage. The corresponding monitoring techniques based on wave propagation were developed and implemented, through which the gradually improved performance of RAC with increasingly added amounts of MIP was evaluated and the early-age condition of RAC during its curing period were monitored in situ. The findings on the improved mechanical properties of RAC with atomic polymer technology and condition assessment from an early age with smart piezoelectric cement modules will potentially promote widespread application of recycled concrete in engineering, improve the sustainability of RAC structures, and provide viable health-monitoring techniques for RAC structures.