Constitutive Relations for Concrete Properties Under Acid Environment

Abstract

The relationships between concrete properties (strength, porosity, and carbonation) and time attacked by acid environment were studied. Current environmental condition with acid rain caused air, soil, and water is acidic. It threats the degradation building with concrete construction. Two groups were organized in this research. One of them which was defined as control specimen was immersed in water curing. The other one was immersed in a solution of 5% sulfuric acid (PH 3) for the purpose of simulating the acidic environment in the laboratory. Different from other reports, the cubes were not previously immersed in water for 28 days but directly immersed in acid solution after being demoulded for one day. Furthermore, the constitutional equations from laboratory experiment were validated by embedding the specimens in acid soil (real acid condition) with similar PH. The results showed that due to immersion in sulphuric acid 5%, concrete had a decreased strength, increased porosity and the occurrence of carbonation at the age of 3-90 days. The result from laboratory experiment for compressive strength was similar with that of a field experiment. Furthermore the relationship between the age of concrete and its porosity considered valid for the age of under 14 days. However, the relationship between the age of concrete and carbonation event judged invalid with that from a field experiment. The results established that the constitutive relations of the properties of concrete in the acid environment were considerably divided by the type of the acid environment.