Behavior of alkali-activated slag pastes blended with waste rubber powder under the effect of freeze/thaw cycles and severe sulfate attack

At present, the need to include waste materials such as waste rubber as a part of building materials is getting more attention rather than any other time. The incorporation of waste rubber as a part of building materials decreases the landfills and reduces the consumption of virgin raw materials. Most of the pre-vious studies incorporated waste rubber as a part of aggregate(s). Thus, this work is the first attempt to study the opportunity of including waste rubber powder (W-R-P) as a part of precursor of alkali-activated slag (AAS) pastes aiming to increase their resistivity against the deterioration resulting from freeze/thaw cycles and severe sulfate attack. For this reason, the slag was partially replaced with W-R-P at ratios from 1% up to 15%, by weight. All the pastes were activated by sodium silicate. After curing, pastes were exposed to 5-20 cycles of freeze/thaw as well as 5-20 cycles of immersion in 5% NaSO4 for 15 h followed by drying at 80 degrees C for 6 h. The compressive strength before and after exposure was measured. Thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) were conducted to analyze the results. The results showed that despite the incorporation of W-R-P particles have a negative effect on the compressive strength, their particles have a positive effect on mitigating the deterioration resulting from freeze/thaw cycles and severe sulfate attack. (C) 2020 Elsevier Ltd. All rights reserved.