EFFECT OF SIZE OF LIGHTWEIGHT AGRREGATE PARTICLES ON VOLUME CHANGES OF LIGHTWEIGHT AGGREGATE CONCRETE AT EARLY AGES

摘要

This paper deals with early age volume changes and moisture transport in Lightweight Aggregate Concrete (LWAC). On three LWAC with a water/cement (w/c) ratio of 0.37 autogenous deformations in the first two weeks after casting and compressive strength were measured. The LWAC mixtures differed in the grading of the lightweight aggregates (LWA). The quantity of water absorbed in the LWA was kept constant. It was found that the concrete with fine particles swelled more than the one with coarse particles. In order to proceed towards the modeling of water transport from the LWA to the cement paste, absorption-desorption properties of the LWA and their moisture loss towards the matrix were studied. It was found that only a part of the entrained water was available for the internal curing and that the LWA showed moderate shrinkage as a consequence of moisture loss.