Abstract

In foundation of Dong Nai factory contains mineral Pyrite. The process of pyrite oxide will create products sulfuric acid. Physicochemical effects between sulfuric acid and calcium hydroxide in the composition of cement concrete increase calcium sulfoaluminate called Ettringite. This process makes concrete material volume expansion, swelling, causing swelling capacity, making tensile strength of concrete fell from the cracked concrete that make up the cracks separating, forming networks slots cracked surface not rule on the factory floor. Simultaneously with the chemical effects between cement concrete causes swelling, physical effects of sulfate salt crystals forming on the surface of the holes and cracks formed increasing the capacity of the concrete expansion, increased tensile stress in concrete, making the surface more and more intense fracturing.