Potential for using recycled glass sand in engineered cementitious composites

Abstract

This paper outlines attempts to characterise a green engineered cementitious composite (ECC) with a matrix containing waste recycled glass sand (GS) as a replacement for the silica sand (SS) commonly used in ECCs. To assess self-healing rate in GS-ECCs, specimens were pre-cracked up to 60% of their original flexure deformations and left to heal under moist curing. Alkali–silica reaction expansion, compressive and flexural strength, mid-span beam deflection capacity, crack development, rapid chloride penetration and resistivity were tested to assess the performance of different sound and preloaded ECC specimens. In addition, results of scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy of healed cracks were evaluated. Mechanical and physical results of GS-ECCs showed performances that were better than or comparable to the corresponding SS-ECC. This study also reveals an acceleration and improvement in self-healing rate with GS replacement level. A C–(N,A)–S–H (calcium-(sodium, aluminium)-silicate-hydrate) with low calcium/silicon ratio was confirmed to be the main outcome in the self-healing products of GS-ECCs.