Effect of Alkaline Environment on the Bond Behavior of TRM Composites Through Single-lap Shear Tests

Textile Reinforced Mortars (TRM) are increasingly used for strengthening existing masonry structures, offering a sustainable solution. This system consists of textile fibers embedded in an inorganic matrix, typically cement or lime-based mortars, applied to the substrate’s surface. Although the mechanical properties of these composite systems have been extensively studied, there is still limited understanding of their long-term performance and durability. This study aims to enhance knowledge in this area by examining the bond behavior of TRM composites exposed to an alkaline environment using single-lap shear tests. For this purpose, single-lap shear specimens were constructed using clay brick as the substrate, a lime-based mortar, and two different fabrics—basalt and glass. These specimens were subjected to an alkaline solution to simulate accelerated aging conditions, with constant temperature and pH. The specimens were tested after 1000, 3000, and 5000 hours of exposure to evaluate their bond behavior compared to control specimens of the same age. Additionally, the effect of the alkaline environment on the material properties of the composite constituents was investigated. Elastic modulus tests were conducted on cylindrical mortar samples and compared to reference samples, displaying satisfactory resistance to alkaline conditions. The study identified and compared the strength, stiffness, and failure mode of each specimen to the reference stage, providing valuable design parameters for various field applications.