Retempering of Concrete Made by Using Artificial Sand

Abstract

Adding water to a plastic mix to increase slump is an extremely common practice, even though it is not recommended because it increases the porosity of concrete. Concrete often arrives on site more than half an hour after initial mixing. Placement operations can take anywhere from 10 to 60 minutes, depending on the field conditions and the size of the load. When the slump decreases to an unacceptable level during the operations, water is added to the mix. Objective of this paper to study the strength characteristics of retempered concrete made by using artificial sand. Usually the retempering process is used with normal concrete or with ready mixed concrete; an attempt is made to check the compressive and flexural strength of normal retempered concrete with an addition of retarder in three different percentages as 0.2%, 0.4% and 0.6% at retempering time of 15 minutes to 90 minutes. Presently there is scarcity of the natural sand. Hence it is being replaced by artificial sand. This is replaced by manufactured sand. The artificial sand is manufactured by breaking stone into smaller and smaller particles in such way that the gradation of particle will match with Zone-II of I.S. 2386- part-II.