Synergistic effect of a small amount of silica aerogel powder and scrap rubber addition on properties of alkali-activated slag mortars

Abstract

The combined use of smart and waste – based materials for energy efficiency in buildings seems as a promising solution. Due to its unmatched insulation properties, silica aerogel is an attractive smart material in cement technology compared to other conventional insulation materials. However, the high manufacturing cost of silica aerogel limits its application in the construction industry. In this study, the combined effect of silica aerogel (0%, 0.3% and 0.6% of binder weight) and scrap rubber (0%, 1.5% and 3.0% of binder weight) addition in alkali-activated slag (AAS) mortars was investigated. A small amount of silica aerogel and scrap rubber addition into mixtures was analyzed with the aim of minimizing reductions in mechanical properties with enhanced thermal insulation. Experimental results demonstrated that in the case of 3.0% scrap rubber loading at 0.3% aerogel content ratio, a remarkable synergistic effect could be observed in terms of thermal insulation up to 33%. Besides, after 2 days of curing, 48.35% and 77.55% increases in compressive toughness and post – peak compressive toughness of samples were detected, respectively. Synergistic effect of a small amount of silica aerogel and scrap rubber in calcium-silicate structure indicates a great potential for energy conservation.