effect of water infiltration rate on mechanical properties of heat-treated crumb rubber containing cementitious mortar

The modification of cementitious mortar by replacing 5 wt.% of its fine aggregates by 50 minutes heat-treated waste crumb rubber in air at 320˚c induced about 50 and 40% compressive strength and toughness increase, respectively. it was assigned to enhanced modified rubber/cementitious matrix interfacial strength via surface localized oxidized sulfur groups in the former implementing the microstructural evolution of the latter during the hydration process. the modified hybrid composite showed water infiltration rate of 1.42 lit/min much lower than the crumb rubber containing mortar, 2.62 lit/min and the control sample, 1.63 lit/min. accordingly, the crumb rubber and its heat-treated version containing mortars were classified as the most porous and compact solidified samples. consequently, the crumb rubber containing cementitious mortar showed the lowest compressive strength; while the control sample and heat-treated crumb rubber modified cementitious mortar represented higher compressive strengths. the hybrid cementitious mortar, however, showed minute density decrease due to the enhanced matrix compactness through hydrated cement formation against polar inter crumb rubber.