The effect of sulfuric acid on steel strength in sanitation structures (Kenya)

The need for sanitation is underscored in the Kenyan 2010 Constitution Article number 43(1)(b). This therefore means that sanitation structures should be taken seriously and their construction should be up to the required standards for better service life. This research involved the evaluation of sulfuric acid effect on steel strength as used in concrete reinforcement in sanitation structures. The study also analyzed the strength of steel as used in the reinforcement of concrete sanitation structures under varying condition including different cement types and concrete covers. Different cement types namely Ordinary Portland Cement (OPC), Portland Pozzolana Cement (PPC) and Limestone Calcined Clay Cement (LC3) were used and concrete covers of 15 mm and 25 mm thickness were applied. Bending, tensile and torsion strengths were determined. The obtained results indicated that the steel metal from reinforced concrete made using LC3 with a concrete cover size of 25 mm showed minimum percentage reduction in strength compared to those from PPC and OPC. Within the conditions under which this research was conducted, it was concluded that LC3 cement with a cover size of not less than 25 mm can be used when constructing reinforced concrete sanitation structures as an attempt to improve service life. The LC3 cement has lower sulfuric acid ingress compared to other types of cements. Sulfuric acid corrodes the reinforcing steel metal hence deteriorating its strength.