Foamed glass granulated-based self-compacting mortars: open-porosity effect on rheological and mechanical properties

Abstract

The foamed glass is currently used in the manufacture of concretes as aggregate to produce lightweight concrete. The lightness of the concrete is assured by the important porosity of foamed glass granulates [GFG], however, they have a closed porosity with a smooth surface. In this respect, this study aims to use foam glass granulates with open-porosity, to produce lightweight self-compacting mortars. GFG were prepared from the glass powder – glass cullet and foaming agent – limestone, according to the current applied process for GFG – heat treatment at 850°C for 20 min. Then from GFG the sand fine aggregate – 0/5 mm was prepared by crushing and sieving. The self-compacting mortars were obtained using natural sand as fine aggregate and other mortars with granulated foam glass substituting sand at volume ratios: 30, 50 and 100 %. Rheological tests of fluidity and physical properties, i.e. density and porosity, by measuring absorption of water and mechanical tests were carried out on studied mortars. The interface of cementitious matrix/GFG granules study shows that open-porosity of GFG sand has favored adhesion to cement matrix, without causing the segregation of the mortar phases. Also, the decrease of the compressive strength for mortars exhibiting a specific lightness, was found. It should be noted that the latter property is very important in construction.