Mechanical properties of alkali-activated concrete containing crumb rubber particles

Substituting fine aggregate in alkali-activated concrete (AAC) with recycled rubber particles from waste tires helps reduce the excessive consumption of natural resources and the adverse environmental impacts of solid waste. This study investigates the feasibility of developing rubberized fly ash-slag-based AAC in the construction industry. Recycled rubber particles were used to partially replace fine aggregate in five volume ratios, ranging from 0% to 20%, to prepare AAC at ambient temperature, and their mechanical properties were measured through a set of experimental tests. The results show that the addition of rubber particles reduced the compressive strength, splitting tensile strength, and flexural strength of AAC by 5.2–34.5%, 7.2–46.1%, and 12.8–63.7%, respectively, while substantially improving its energy absorption capability by 31.5–53.3%. To balance the reduction in the strength of AAC with the improvement in its ductility, the recommended optimal volume ratio of rubber particles in it is 10–15%. A constitutive model of AAC containing crumb rubber is also proposed based on the experimental data. The findings of this study provide a reference for the use of crumb rubber in AAC, and can contribute to a circular economy in the construction industry.