A simple novel mix design method and properties assessment of foamed concretes with limestone slurry waste

Abstract

The paper aims to study the effects of LSSW fillers on different properties of foamed concretes (also known as cellular lightweight concretes (CLCs)) with a wide range of concrete densities 650–1200 kg/m3. The LSSW fillers was collected from the western end of the Vindhyan range of India. A unique mix-design methodology with eight design steps was empirically-cum-numerically derived for CLCs, based on specifying targeted green or plastic density as primary criterion, which is an unexplored area till date. Cement to NRS ratio was kept as 1:1.35 for the development of CLCs. NRS was replaced by LSSW fillers, ranging from 25% to 100% with the increment of 25% in NRS fractions. The natural protein based foaming agent used in this study, was in the ratio of 1:20 parts of water. In total, fifteen trials were cast for five phases of each series using cement as main binder. Each phase was based on the variation of water/cement (w/c) ratio, foaming agent/water (fa/w) ratio and NRS/LSSW ratio. Moist curing was adopted for 3, 7 and 28 days.Experimental studies include compressive strength (CS) with performance factor (ratio of CS (in Pa) to oven dry (OD) density (in N/m3)), consistency, achieved density ratio, thermal properties, X-ray diffraction, scanning electron microscopy and image analysis. The results indicated that incorporation of LSSW fillers up to 50% replacement of NRS into CLCs; enhanced CS and corresponding performance factor. It was found that maximum PFc.28d was 382 and 319 at w/c ratio 0.86 for block of density 1002 kg/m3 and 819 kg/m3, respectively. For these two mixes, filler effect as well as nucleation effect was dominant than other mixes. LSSW fillers did not show any pozzolanic, hydraulic or latent hydraulic properties. Thus, use of LSSW is not only beneficial to the concrete industry, but also is friendly to the environment promoting sustainable development.