Flexural behaviour of stone slabs with prefabricated prestressed CFRP-reinforced stone strips

Abstract

A strengthening technique incorporating prefabricated, prestressed, carbon-fibre-reinforced polymer (CFRP)-reinforced stone strips for stone slabs was proposed. To investigate the flexural behaviour of strengthened stone slabs, an experimental campaign consisting of 11 stone-slab specimens was conducted by considering the reinforcement ratio, the prestress level, the length of stone strip and the strengthening method as the main parameters. By installing strain gauges on the CFRP bars and stone slabs, the stress-transfer efficiency between different components of the strengthened stone slab during prestressing and strengthening processes were monitored. The results showed that the temporary device could effectively maintain the prestress imposed in the CFRP bars and transfer it to the stone slabs to be strengthened. Further four-point bending tests indicated that the prefabricated stone strips shifted the failure mode of bare stone slabs from brittle fracture to ductile, with obvious deflection and multiple flexural cracks. The load plotted against deflection responses of the strengthened slabs showed three stages, and a significant increase in the load-carrying and deformation capacities was observed when compared to those of the bare stone slabs. Finally, simplified theoretical models for predicting the flexural strength and initial stiffness of the strengthened stone slabs were proposed and assessed.