Performance index of natural stone-GFRP hybrid structures

Natural stone is generally used in the buildings decoration and furniture finishes for its aesthetic properties and durability. However, its brittle nature limits its applications, in fact the tensile strength of stone is considerably less than its compression strength; this disparity can limit the use of stone in applications where tensile and flexural strength capacity is required, such as for long spans or thin sections. Reinforcement provides stone elements with flexural strength required for use in long spans, columns and slabs. However, in some cases, reinforced stone may fail to perform its desired capacity because of faulty design, use of inferior quality materials, poor construction practices and insufficient maintenance. If such a problem occurs early in a structure service life, repair and strengthening of the concrete sections may be more favorable than replacement or reconstruction of the failing members. The aim of this work is to investigate the use of sandwich structural laminate in composite materials as external reinforcement both to increase the mechanical resistance and to decrease weight of natural stone. High strength glass/epoxy laminates were bonded to the lower surfaces of marble and granite beams, and 3-point bend and short-beam tests were performed on reinforced and unreinforced specimens. Results indicate that external composite reinforcement can increase the mechanical property of both types of stone up to an order of magnitude as compared to unreinforced control samples.