Rock wool-reinforced concrete: Physico-mechanical properties and predictive modelling

Abstract

Recent developments in lightweight concrete (LWC) have led to a renewed interest in incorporating fibers in concrete. However, research on the specific application of rock wool fiber in LWC is scarce. Hence, the present study aims to investigate the physical and mechanical characteristics of LWC with the inclusion of rock wool fibers (0%–15%) in different water-cement ratios (0.4, 0.5 and 0.6). The relationships between mix proportion and the density, permeable void, water absorption, compressive strength, splitting tensile strength and flexural strength of the composite were investigated. The results showed the density of the rock wool-incorporated specimen was highly reduced (up to 73% reduction) when the incorporation of rock wool fiber reached 15%. The oven-dry densities of the specimens for fiber contents from 2.5% to 10% are 800 kg/m3 to 2000 kg/m3, which can be classified as LWC. Permeable voids of the specimens were increased by 63% by volume with 15% of rock wool inclusion. Only a certain mix proportion fulfilled the requirement to be used as load-bearing internal walls. The correlation between compressive strength and splitting tensile strength was subsequently analyzed. Lastly, the empirical models for all properties were generated using the response surface method with R2 > 0.90. In conclusion, the selection of different mix ratios of rock wool and the water-cement ratio (w/c) for attaining better physical or mechanical properties of LWC will be presented, and hopefully serves as a sound basis for future related studies.