Analysis of the influence of water qualities on the strength of concrete

Abstract

Concrete is commonly employed in construction for its tremendous compressive strength, despite its low tensile strength. This study aimed at analyzing the strength of concrete when mixed with water of varying qualities. Before concrete is formulated, tests are done on the aggregates to ascertain the right proportions but not on water used. Dreux-Gorrise concrete formulation method was employed. CAMWATER (tap water), rain water and water from a free-flowing river was used to cast concrete samples after which it was crushed to obtain 7 and 28 day resistances. The water qualities varied were pH and hardness. Hydrochloric acid and sodium hydroxide were used to vary the pH of water. Results showed an increase in concrete strength as a function of increase in water pH. Water with a high pH resulted in concrete with an appreciable strength value while acidic water resulted in very low strength values. The usage of hard water for mixing concrete resulted in a strength value lower than with soft water. Conclusively, water quality has an effect on the strength of concrete. Therefore, it is advisable to use water with a high pH value for mixing concrete, preferring rainwater over tap water when mixing concrete due to hardness of water.