Fresh state properties of lime mortars with foam glass dust

Abstract

Fine glass waste has been found to be a suitable addition to lime mortars because of the high amorphous content. The behavior of fresh air lime mortars and natural hydraulic lime mortars modified by foam glass dust is assessed with the purpose of exploring a new application of this waste dust as lime mortar admixture. The rheological parameters were correlated with relative density measurements, water retention abilities of mortars and air content in mortars. The effect of foam glass dust was found to be dosage-dependent. The fresh mortars behave generally as Hershel-Bulkley fluids with an evolution of the rheological parameters with admixture content. The replacement of lime by foam glass dust caused a reduction in mixing water reducing the yield stress simultaneously; however, the viscosity of the resulting mortars slightly increased. A change in behavior of mortars from shear-thickening to shear-thinning was observed. The natural hydraulic lime based mortars showed a gradual change from thixotropic to rheopectic behavior with increasing glass dust addition. The foam glass dust appears to be well suited to air lime plaster mixtures used in machine thin-layer rendering due to its plasticizing properties, and ability to increase water retention and reduce air content in the mortars.