Production of Concrete Using Contaminated Water and Its Effects on Compressive Strength of Concrete

Abstract

In saline environment and places where there is no access to clean water for concrete work, contaminated water is often used for mixing and preparation of concrete for different structural members of buildings and this practice is in complete violation of most approved standard codes for concrete production. This study is aimed at determining effects of the use of salt contaminated water on compressive strength of concrete with a view to providing mitigating measures. 150 mm cube samples were cast with these water samples. Compressive strength test was carried out on the cubes. Findings revealed that for potable water, the initial strength was retarded in the first 7 days, uniformly progresses through 14 days, 21 days until the 28 days. In the case of contamination of 1000 mg/litre, concrete strength follows the same trend as the control. As the quantity of contaminated salt increases after this stage, the compressive strength generally decreases. It was further observed that the contamination effects were not pronounced on the strength within the first 7 days. According to the 28 day compressive strength ranged from 23.26 to 15.78 N/mm2 as the concentration of contaminant (NaCl) in concrete mixing water ranged from 0 to 5000 mg/l. The study therefore concludes that the salt contaminated water have adverse effect on the properties of concrete. The use of salt contaminated water for concrete mixing is seen to favorable for strength development only at 4000 and 5000 mg dosages at early ages and reduction in long term strength.