Comparative Study on the Effects of Recycled Glass-Fiber on Drying Shrinkage Rate and Mechanical Properties of the Self-Compacting Mortar and Fly Ash-Slag Geopolymer Mortar

In this comprehensive experimental study, the effects of recycled glass fiber on the drying shrinkage and mechanical properties of the self-compacting mortar and fly ash-slag geopolymer mortar were investigated. An experimental/analytical approach was adopted to characterize the mechanical properties (compressive and flexural strength) and the drying shrinkage rate of the reinforced self-compacting mortars and fly ash-slag geopolymer mortars with inclusion of different recycled glass fiber volume fractions and lengths. To this end, a total of 207 specimens were experimentally tested. Scanning electron microscope (SEM) images were used to detect the failure mechanism of recycled glass fibers. Moreover, based on the collected data, some empirical equations were developed to correlate recycled glass fiber volume fractions to the mechanical properties of the reinforced fly ash-slag geopolymer mortars and self-compacting mortars, considering high values of coefficient of determination. The experimental results showed that adding recycled glass fiber has much greater effects on increasing the flexural strength and decreasing the drying shrinkage rate in fly ash-slag geopolymer mortars when compared to self-compacting mortars.