Comparative Study on the Effect of Curing with Fresh Water and Sewage Water on Structural Strength of Concrete

In this research work, the comparative study of effect of curing with sewage water and fresh water on concrete was investigated. This paper presents the result and findings of an experimental research on the effect of curing with sewage water and fresh water on compressive strength, flexural strength, split tensile strength of concrete. For this concrete cubes, beams, cylinders were cast and curing with fresh water and sewage water for a mix of M-15, M-20 & M-25 for the standard ratio. A total specimen of 18 cubes, 18 beams, and 18 cylinders including specimens for reference concrete were cast for given mixes and exposed to 7 days, 14 days and 28 days period of curing. The reference concrete was prepared with PPC using only fresh water and sewage water curing. Curing of concrete is the operation of maintaining humidity & temperature of freshly placed concrete during some definite period following placing, casting or finishing to assure satisfactory hydration of cement. When water is added to cement, sand & aggregate mix, the reaction between cement & water is exothermic. Hence lot of heat is evolved in reaction. This is known as heat of hydration. The heat of hydration results in evaporation of water from concrete that results in reduction of strength of concrete. Hence external application of water is required. This is ‘curing’. Efficient uninterrupted curing is the key to quality concrete. Proper curing of concrete is crucial to obtain design strength. The curing period depends on the required properties of concrete. Curing is designed primarily to keep the concrete moist by preventing the loss of moisture from the concrete during the period in which it is gaining strength curing may be applied in the number of ways & the most appropriate means of curing may be dictated by the site or the construction method. Various methods of curing are available. The existing study suggests that curing with fresh water is best suited for concrete. Hence the strength of concrete observed in laboratory is illusive & is not the real strength of concrete on site.