Flexural performance of novel ECC-RC composite sandwich panels

Abstract

To address the shortcomings of precast concrete sandwich panels (PCSPs) such as insufficient load-bearing capacity, poor ductility behavior, and susceptibility to cracking under temperature stress, this study reinforced the face layer of PCSP with engineered cementitious composite (ECC), resulting in the development of novel ECC-RC composite sandwich panels (ECSPs). The flexural performance of ECSP was revealed by way of a four-point bending test and finite element analysis. Test results showed that incorporating ECC into the wythes substantially improved the flexural performance of PCSP, and the maximum crack width of ECSP was well below the corresponding limit requirement when the mid-span deformation reached the serviceability limit state of the panel. ECSP presented a long load-hardening phase owing to the excellent tensile toughness of ECC, and the properties of the reinforcement could be fully utilized in ECSP without causing “over reinforced” damage as seen in PCSP. Finite element analysis demonstrated that the initial cracks of ECSP did not occur at the tensile edge of the panel, indicating excellent durability of ECSP. Based on the test results and finite element analysis, a formula for the flexural carrying capacity of ECSP was proposed, and the corresponding calculation model demonstrated better applicability. It is recommended to use 20 mm thick ECC to reinforce the face layer of ECSP for optimal economic benefits in practical engineering, while paying attention to the interface problem between ECC and concrete.