A critical review on the performance of portland cement concrete with recycled organic components

The quick accumulation of recycled organic components with the modern society development has caused serious environment issues, and the utilization of these recycled organic components in concrete production can effectively mitigate recycling pressure. Portland cement concrete mixes containing recycled organic components behave differently in both fresh and hardened stages compared to conventional concrete, which need to be thoroughly studied before a large-scale field application. This paper aims to critically review the currently-reported performance of concrete with recycled organic components and to identify the knowledge gap for future sudies. This paper first conducted the characteristic investigation of recycled organic components, which provided the needed information for the classification of recycled organic components. Then the property performance, including workability, mechanical properties, and durability of concrete containing recycled organic component was evaluated. It has been concluded that both the workability and concrete strength will decrease with the added recycled organic components. However the durability performance, including freeze-thaw, impact resistance, and the resistance to alkali-silica reaction can be enhanced with the added recycled organic components. Aiming at the decreased strength, surface treatment methods have been reviewed. The current finding demonstrated the NaOH surface treatment for rubber particles and oxidation method for reclaimed asphalt mixture aggregates can enhance the concrete performance, respectively. Finally, the practice of applying recycled organic components in high strength and self-consolidating concrete was summarized, which demonstrated the potential of high performance concrete production with recycled organic component. Current knowledge gaps were identified to point out the challenges for the further study, including the difficulties to produce high strength and self-consolidating concrete with replacement ratio of recycled organic components higher than 50%. This study will provide the firm base for the application and future study on concrete containing recycled organic components, including reclaimed asphalt pavement (RAP), recycled asphalt shingles (RAS) and recycled crumb rubber (RCR).