Deterioration of concrete sewers

The corrosion and maintenance of concrete sewers have always been an area of social as well as financial priority. The corrosion of the concrete sewer system is related to biodegradation of concrete which led to formation of sulphuric acid. The sulphuric acid so produced affects the life span of structure by causing expansion which eventually led to collapse of structure as a whole. The damage is further amplified in case of splashing of waste waters in the sewer network as compared to stagnant waters. In order to access the degree of damage an experimental program was carried out. This paper presents the results of degradation depth of concrete subjected to stagnant and flowing condition of sulphuric acid solution (H2SO4) made with different the water-cement ratio and concentration of sulphuric acid. For this purpose, concrete cubes with various water-cement ratios were made. These cubes were exposed to sulphuric acid solution of pH 1,2,3 and 4. The results revealed that surrounding conditions play one the important role in deciding the erosion depth in addition to water cement ratio. From the experiment it was also affirmed that erosion depth depends on the concentration of the acidic solution.