Effect of Air voids in Fresh and Hardening properties of Concrete

Abstract

The introduction of air into concrete mixes has some different effects on the properties of both the fresh and the hardened concrete. In fresh concrete, the tiny air bubbles act as a lubricant in the mix which improves its workability and increases its slump. Also, in a sense, the bubbles function as a third aggregate. Because of their small size, the bubbles act as fines, thereby cutting down the amount of sand needed. Because air entrainment affords increased slump in same time it is possible to decrease the amount of water to get higher strengths without affecting workability. The requested parameters based on the technical specifications of concrete in some of cases are oriented in percent of air voids in concrete and in same time the compression strength of concrete. In this paper using the experiments and requested parameters we can analyze the relationship between the percent of air voids 6% and compression strength of concrete class C 35/45.