INVESTIGATION OF INTERNAL CURING IN CONCRETE USING PUMICE AGGREGATE

Concrete curing is paramount importance in order for concrete to meet performance requirements. Conventionally curing has been conducted by means of water sparkling on the concrete external surface. For performance and environmental reasons, internal curing has been gaining increased attention. However in a developing country like Ethiopia more data is needed for the effectiveness of this curing technique when used in various concrete mixtures.This experimental investigation addresses potential utilization of internal curing in concretes. For this study internal curing was addressed by means of the most locally available light weight Aggregate in Ethiopia which is pumice aggregate, A total of twelve mixes were designed among which nine mixes with different pre wetted pumice replacement (10%, 20% and 30%) and water to cement ratio (0.4, 0.45 and 0.5), For comparison the remaining three mixes are conventional concrete with water to cement ratio of 0.4, 0.45 and 0.5. For internally cured concretes, different curing conditions were created. In the first method, the internally cured concretes placed inside laboratory with and without polyethylene cover. In the second method, the internally cured concrete was placed outside laboratory with and without polyethylene cover. Fresh concrete and Hardened concrete properties including slump, unit weight and 28 days compressive strength were assessed.