Durability assessment of concrete with natural and Linz Donawitz slag as coarse aggregates

Abstract

Rapid growth of infrastructure has resulted in incessant consumption of natural aggregates in cement concrete leading to its depletion. Efforts have been made to utilize industrial by-products such as steel slag aggregates in concrete as partial replacement for natural aggregates. However, the utilization of Linz Donawitz (LD) slag aggregates in concrete is very limited compared to other slag aggregates. The limited utilization could be attributed to the expansive nature of LD slag aggregates, which may result in durability issues. In this study, the compressive strength and durability characteristics of concrete with 100% LD slag coarse aggregate are investigated considering three different cement types, including Ordinary Portland Cement (OPC), Portland Pozzolana Cement (PPC) and Portland Slag Cement (PSC) for all the mixtures. LD slag and control concrete were examined for durability by conducting water permeability, electrical resistivity, drying shrinkage, rapid chloride penetration (RCPT) and water absorption tests. X-Ray Diffraction (XRD) analysis along with the microstructural investigations using SEM-EDS was carried out to supplement durability results. The compressive strength results indicated that LD slag concrete depicted higher strength than control concrete and there was a steady increase in strength with curing duration. Interestingly, PSC concrete depicted higher rate of strength gain compared to other cements. Further, LD slag concrete depicted low permeability and water absorption compared to control concrete, where it can be anticipated lower freeze–thaw damage. RCPT results indicated lower penetration of chloride ions representing delayed corrosion of steel in LD slag concrete. Overall, LD slag concrete depicted enhanced durability than control concrete.