Composite Fibers for External Reinforcement of Natural Stone

Abstract

Low tensile strength restricts use of natural stone in applications where tensile or flexural capacity is required, such as for long spans or thin sections (e.g., cladding, countertops, desktops). In addition, exposure to agents of chemical and mechanical weathering can decrease the strength of stone over time. The use of composite laminates as external reinforcement to increase the tensile and flexural capacity of natural stone is investigated. High strength (HS) carbon/epoxy laminates were bonded to the lower surfaces of marble and limestone beams, and flexural tests were performed on reinforced and unreinforced specimens. Results indicate that external composite reinforcement can increase the load-carrying capacity of both types of stone by an order of magnitude as compared to unreinforced control samples. Laminate thicknesses of four plies [0.5 mm (0.02) in.] and eight plies [1.0 mm (0.04) in.] produced similar increases in stone strength. However, stone reinforced with four-ply laminates experienced greater deflection before failure than samples reinforced with eight plies.