Properties of lightweight concrete made with crushed natural pozzolana as coarse aggregate

Abstract

This paper describes a laboratory-based study examinig the use of natural pozzolana as an aggregate component in lightweight concrete (LWC). A range of conditioning variables, including cement and moisture content, storage period up to one year, was investigated. In order to explore these effects, a series of five concrete mixes using the same Portland cement was prepared. Three mixes (LWC1, LWC2, LWC3) were designed with cement content of 400 kg/m3 and three different W/C ratios leading to three different workability expressed with of a measured slumps of (3±1, 5±1 and 7±1) cm. Further two mixes (LWC4, LWC5) were also made with cement dosage of 300 and 350 kg/m3 and a constant workability with a slump of 3±1cm. The investigated properties included density, compressive strength, tensile strength and elastic modulus. The results were obtained for ages up to 365 days under different curing conditions (wet and dry). It is concluded that LWC with pozzolana, as coarse aggregate, has sufficient strength and adequate density to be accepted as structural lightweight concrete.