Lightweight Concrete Incorporating Volcanic Ash-Based Blended Cement and Pumice Aggregate

Abstract

This paper presents the workability, mechanical, durability, and microstructural properties of lightweight concrete (LWC) incorporating pumice aggregate, normal-weight gravel aggregate, ASTM type I portland cement, and volcanic ash (VA)–based ASTM Type I blended cement (PVAC). Workability and mechanical properties of LWC mixtures such as slump, air content, compressive strength, tensile strength, density, and modulus of elasticity are described. The durability and microstructural characteristics are investigated by drying shrinkage (DS), water permeability, mercury intrusion porosimetry (MIP), differential scanning calorimetry (DSC), and microhardness tests. The variables in the study include percent replacement (0, 50, 75, and 100% by volume) of coarse gravel aggregate (GA) by coarse volcanic pumice aggregate (VPA), water-to-binder ratio (W/B) by mass, aggregate-to-binder ratio (A/B) by mass, total binder content, and cement types (ASTM type I cement and PVAC). The investigation suggests the production of blended PVAC-based LWCs for structural applications having satisfactory strength and durability characteristics. The use of PVAC induces the beneficial effect of reducing drying shrinkage and water permeability as well as refinement of pore structures and better interfacial transition zone (ITZ).