Experimental assessment on mechanical performance of precast concrete sandwich panels manufactured with mixed recycled aggregate

Abstract

Mixed recycled coarse aggregate (MRA), derived from construction and demolition waste of masonry-concrete composite frame structures, primarily consists of recycled concrete aggregate (RCA) and recycled brick aggregate (RBA). Due to the high porosity of MRA, its application to precast concrete sandwich wall panels (PCSPs) is beneficial for improving their thermal performance. However, the influence of MRA on the mechanical properties of such sandwich panels remains inadequately characterized. This study presents experimental findings on the axial and flexural behavior of PCSPs incorporating MRA (MRA-PCSPs). Results show that with a 50 % MRA replacement rate, the axial and flexural bearing capacities of the panels decreased by 15.7 % and 6.7 %, respectively. Compared with bending performance, MRA has a more significant adverse effect on axial compression performance. When the RBA content in MRA increased from 10 % to 30 %, the cracking loads under axial compression and bending tests decreased by 24.7 % and 15.1 %, respectively, but the ultimate load was not adversely affected. While the inclusion of MRA did not compromise the composite action of PCSPs, using a thicker insulation board led to reductions in both the load-bearing capacity and composite performance. The addition of edge frames significantly enhanced the mechanical performance of MRA-PCSPs, increasing their axial and flexural bearing capacities by 23.6 % and 204.5 %, respectively. The composite action of the wall panels is significantly enhanced after adding edge frames, which is basically equivalent to solid wall panels.