Crack Pattern Evolution in Textile-Reinforced Mortars: A Durability-Based Study Under Acidic Aging

Textile-Reinforced Mortar (TRM) externally bonded composites are increasingly adopted as a sustainable and effective technique for reinforcing masonry structures. However, their long-term performance in aggressive environments remains insufficiently explored, particularly under acidic conditions where durability concerns are critical. This study investigates the influence of acidity level and exposure duration on the cracking behavior of TRM systems subjected to direct tensile testing. A ternary lime-cement-pozzolan mortar combined with a glass fiber textile was used to fabricate TRM tensile coupons, which were then conditioned in sulfuric acid solutions at pH 1.5 and 3.0 for periods of 1000 and 3000 h. Reference groups were stored in water and a dry climatic chamber. Following the aging phase, direct tensile tests were performed to examine the evolution of surface cracking, focusing specifically on quantifying the number and width of cracks at peak load. The results demonstrate a clear correlation between increased environmental aggressiveness and crack development, with lower pH values and longer exposures resulting in a greater number of wider cracks. These findings offer critical insights into the degradation mechanisms governing TRM systems in acidic environments and support the development of durability-oriented design strategies for their application in conservation and structural retrofitting.