Effects of glass fiber-reinforcement on the mechanical properties of coarse grained building stone

A great number of coarse-grained natural stones have very high added-value when used as building materials. However, problems using these materials arise from its brittleness behavior, which are related to its very heterogeneous texture, showing high volume of pre-existing cracks. Glass fiber-reinforced epoxy composite (GFRC) is being used to improve mechanical performance of such stones when employed as building materials. To our best knowledge, there are no studies to evaluate how the reinforcement affects the mechanical behavior of finished products that employ this technique. In present experimental investigation one proposes a slope-based criterion to evaluate the useful service loads of pegmatitic materials when glass fiber-reinforcement is applied. To validate the proposed criterion, a digital image correlation (DIC) system was employed to observe and measure strain and fracture behavior during the realization of 4-point bending tests. Both proposed criterion and DIC show that crack propagation occurs long before the material reaches maximum load. GFRC acts as a crack inhibitor, raising the breaking load up to 6× in comparison with the specimens where no reinforcement was applied. The results from this study enhance the capability to apply such materials as building materials and provide an important tool to perform prior mechanical understanding of stone products using GFRC.