Petroleum tanks and pipes made of steel or concrete suffer from the interaction between the petroleum products and the materials of the tank or pipe. This work aims to overcome this problem by adding polymer to the cement mortar and post cure it at the proper period to modify its behavior when encountering petroleum products. Unsaturated polyester was selected to prepare polymer cement composites. Four sets of polymer cement composites were prepared. Two sets were cured at room temperature, but one was kept without immersing in any solution. The other sets were post-cured at 50ºC for two and four hours. Six groups of polymer cement composite specimens were immersed in a solution. The solutions were water, 1N and 2N NaCl, kerosene, benzene, and oil engine. The hardness and compressive strength were evaluated after 30 days. The hardness of the specimens was altered according to the solution immersed. The best water absorption and compressive strength results were obtained two hours post-curing specimens, whatever the solution was immersed in. The corrosion rate for all specimens in every solution was low. Again, the lowest corrosion rate was obtained after two hours of post-curing specimens, which indicates that the addition of polymer an