Determination of life expectancy of concrete septic tanks under biogenic sulphuric acid corrosion

Deterioration of concrete in sulfate environment has been studied for a long time and there is still no universal agreement on precise process of deterioration. In determining the life expectancy of concrete structures exposed to sulphuric acid attack, developing laboratory investigations simulating the deterioration process can be quite challenging. First, the determination of the level of sulphuric acid concentration requires careful analysis since the process is affected by the presence of anaerobic bacteria. Secondly, the development and calibration of an accelerated testing method is required to measure deterioration in the laboratory within a reasonable time period. The research work presented here covers the development of a method for accelerated testing of concrete exposed to sulphuric acid corrosion to predict the remaining life of reinforced concrete septic tanks used in rural Victoria. The concrete specimens were prepared in the laboratory using the similar mix design and ingredients used in septic tank production for the country Victoria prior to 1990. Early results of the accelerated testing developed are presented with comparisons from other published work. © 2009 Taylor & Francis Group, London.