Effect of waste glass powder addition on properties of alkali-activated silica fume mortars

Abstract

In cement technology, sustainable-based politics demands the use of industrial by-products and waste – based materials. Glass powder (GP) and silica fume (SF) are excellent solid materials to develop a sustainable cement-based material due to a high content of silicon dioxide (SiO2) in their chemical compositions. This study focuses on the properties of alkali-activated silica fume (AASF) mortars containing waste glass powder (WGP). For this purpose, WGP was utilized as partial replacement of sand in AASF mortar mixtures at four levels: 0%, 15%, 30%, and 45% by weight. Displacement -controlled compressive and flexural strength tests were carried out on prismatic 40 × 40 × 160 mm test samples that had been cured for 2,7 and 28 days. The Mercury Intrusion Porosimetry (MIP) test and the thermal conductivity coefficient measurement were carried out following the compressive strength test on 28-day samples. The microstructure morphology and mineralogical properties of the mortar samples were studied by means of Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD), respectively. Experimental studies have shown that at a replacement level of 30%, WGP simultaneously improves the flexural strength of mortars by 12.65% and reduces the thermal conductivity coefficient by 30.88% under stable macro pores and transient capillary–micro pores formation in AASF pore structure. As an alternative to conventional cement mortar, WGP-incorporated AASF mortars attract a great deal of attention.