The role of expanding admixture in the development of strength of prepacked concrete

Abstract

Prepacked concrete is a special type of concrete which is different from the normal concrete in a number of ways. In this concrete, the coarse aggregates are first placed into the formwork and subsequently cement-based grout, usually with admixtures, is injected to fill the spaces between the coarse aggregates. This paper highlights the influence of chemical admixture, particularly the effectiveness of expanding agent in the development of strength of prepacked concrete at different ages of 7, 28 and 90 days. Along with prepacked concrete, normal concrete specimens having same water-cement and aggregate-cement ratios were made and tested under the same condition to evaluate the comparative behavior of strength development. It has been found that the overall compressive strength of both types of concrete with superplasticiser were higher than in concrete without any admixture. Expanding admixture, however, had been shown to have excellent performance in developing both compressive and tensile strength, as it provided better contact through expansion as well as through reduction in water-cement ratio in the grout.