Flexural Behavior of sustainable High-Performance Hollow Core Slabs Reinforced with Hybrid Fibers Rehabilitated by CFRP Sheets

Abstract

This study investigates the behavior of High-Performance Hollow Core Slabs (HCS) reinforced with hybrid fibers containing sustainable lightweight coarse aggregate (LWA) rehabilitated by injection, and carbon fiber polymer (CFRP) sheets together. Five hollow core slab specimens with dimensions of (800×400×100) mm with two types of sustainable LWA; The first conventional HCS specimens (HCSB) contains crushed clay brick as coarse LWA, and the other conventional HCS specimens (HCSA) contains artificial LWA. Three types of fiber used in this study were: Macro-hooked steel fibers (type S1), straight steel fibers (type S), and Micro polypropylene fiber (PP), with different volume fractions. Five tested HCS specimens were repaired by injection and rehabilitated using two layers of CFRP sheets and tested to determine their ultimate load-carrying capacity. A comparison between the behavior of HCS specimens before and after rehabilitation was carried out. The test result showed that the use of CFRP sheets to strengthen the HCS specimens leads to a significant increase in the load capacity for all types of HCS specimens. The percentage recovered of load capacity after rehabilitation was 5.6%, 5.8%, and 6.7% for HCS specimens (HCSB, HCSB1, HCSB3), respectively. The load capacity for HCS specimen containing artificial LWA had been increased by about 7.03% and 8.5%  for HCSA and HCSA3 compared to high-performance HCS before rehabilitation. Moreover, The deflection of the rehabilitated HSC specimens was significantly increased in comparison with HSC specimens before rehabilitation.