Sustainable use of recycled crumb rubbers in eco-friendly alkali activated slag mortar: Dynamic mechanical properties

Recycled crumb rubber (RCR) can be sustainable used in alkali activated slag mortar (AASM) to economize nature aggregate consumption and reduce environmental pollution. Meanwhile, external dynamic loads (e.g. wind load and earthquake load) can be effectively counteracted by RCR with superior deformation performance. In this study, the workability, static and dynamic mechanical properties, and environmental impact of AASMs mixed with 0% - 60 vol% of RCR substitution for fine aggregates were investigated. A dynamic mechanical analyzer (DMA) was applied in a frequency range of 0.5-2 Hz at a temperature range of -70-70 °C. The experimental results indicate that the workability and mechanical strengths of AASMs decreased with the increase of RCR replacement rate. The storage modulus of AASM generally decreases with the increase in RCR, however, once the RCR replacement rate reaches 60%, the storage modulus is higher than that of the control mortar, presenting typical behavior of thermoplastic materials. The loss factor significantly increases with the increasing content of RCR, indicating that RCR serves competently as an energy dissipating material. Finally, an economic and ecological evaluation demonstrates that AASM with RCR is beneficial to the environment.