Composites with recycled rubber aggregates: Properties and opportunities in construction

Vulcanised rubber is extensively used in many industrial sectors due to its good physical, mechanical and dynamic properties, as well as excellent durability, outstanding abrasive resistance and relatively low cost. Unfortunately, most post-consumer rubber-derived products are still discarded as waste, buried in landfills or incinerated. Such materials require many years to degrade naturally due to i) their complex cross-linked composition, and ii) the additives used during manufacturing to extend the lifespan of rubber. Extensive research has investigated the use of end-of-life rubber as binder (e.g. elastomers, bitumen), or as conglomerates (cement, gypsums) to produce innovative composites in construction. To improve the properties of composites made with recycled rubber, the surface of rubber has been treated with different costly processes to improve the Interfacial Transition Zone (ITZ). However, the results available in the literature are inconsistent and many technical and practical aspects remain unsolved, thus preventing the cost-effective use of rubber in the construction industry. This study provides a comprehensive review on rubber properties and surface treatments of rubber recycled from post-consumer components so as to identify potential applications in composites for construction. It is concluded that an understanding of the chemical, physical and mechanical properties of rubber, as well as a proper characterisation, are necessary to take full advantage of this high quality material. Future research needs in the field are also suggested.