Enhancement the properties of lightweight concrete mortars by some additive materials

Abstract

The interfacial transition zone is the most important zone which can be controlled in the physical and mechanical properties of the lightweight concrete aggregates. So, this work aims to study this zone, and enhance the properties of the lightweight concrete aggregates using some additive materials such as perlite and tuff. Three clay samples were collected from Hungary. The fired aggregates were mixed with cement mortar and characterized using X-ray diffraction (XRD) with Rietveld method and scanning electron microscopy (SEM) combined with energy dispersive spectroscopy (EDAX). The physical and mechanical properties of the samples were measured according to ASTM methods. The results showed that the density of the concrete mortars after adding the additive materials was decreased by 12-20% at 28 days. The interfacial transition zone was affected by the reaction between the surface of the aggregates and the cementitious materials. The calcium silicate hydrate (C-S-H) phase was decreased the bulk density and compressive strength of the concrete mortars.