The research of mortars shrinkage made with reclaimed aggregate

Abstract

The researches of mortars shrinkage tested by shrinkage gutters method will be presented in the article. This method allows automatic measurement any volume changes (expansion and shrinkage) from the moment the mortar is laid in the gutter. Reclaimed aggregate was made from the fresh unused mortar subjected to granulation and accelerated binding. This effect was obtained by the use of chemical admixture package consisting of two components: a superabsorbent and a setting accelerator. The control mortar and three types of mortars containing reclaimed aggregate (granulate) in variable amounts: 15%, 25% and 50% were tested. The age of the applied granulate was 1 and 14 days. Reclaimed aggregate (granulate) was dosed by mass conversion of natural aggregate into granules. The conducted research allowed estimating the influence of the age and quantity of reclaimed aggregate on the micro structure of tested mortars and on shrinkage of the tested composites. The shrinkage of mortars containing 1 day granulate is larger than mortars containing 14 day granules. The shrinkage of the mortar with 50% content of 1 day granulate is greater by about 20% than the mortar with 50% content of 14 day granulate after 40 days of measurements in automatic gutters.