The phenomenon of physical sulfate attack (PSA) is scarcely studied, especially in lightweight concretes (LWC) with thermally expanded clay aggregate (TEC). What has been reported is that PSA it is mainly influenced by the pore distribution and size and its interconnectedness. It is of interest to analyze how the hydraulic conductivity is related to the PSA, due to TEC alveolar structure that have voids to reduce its density. In this work, lightweight concretes with water/cement ratios of 0.49 and 0.45 were tested to PSA resistance according to the modified ZH90 method, which consisted of exposing the specimens to 90 thermal cycles, between 5 ¿ and 30 ¿, in a 30 % sodium sulfate solution. This accelerated method is intended to give information on PSA resistance due to the rapid crystallization and recrystallization cycles of sodium sulfate. In this work, the evaluation also includes the evaluation of mass change and visual appearance of samples in contrast with other properties