Evaluation of commercial and scrap tyre cellular reinforcement infilled with demolition waste for granular sub-base of flexible pavements: A sustainable approach

Abstract

Nowadays, the use of geocell is gaining more importance in pavement industry as it offers improved performance through confinement and tensioned membrane actions. In recent years, solid waste management seeks greater attention as it poses serious issues related to their disposal, health, and environmental hazards. Effective recycling and reuse of these wastes could be a viable and economical approach towards sustainable construction. In this regard, two such wastes (scrap tyres and construction and demolition (C&D) waste) are investigate. The recycled concrete aggregates (RCAs) obtained from the C&D waste are used as granular sub-base (GSB) material, and its performance is compared with conventional crushed aggregates (CCAs). Scrap tyre is used as cellular reinforcement (recycled tyre cell (RTC)), and its effectiveness as a reinforcing material is compared with the commercial cellular reinforcement (commercially available geocell (CGC)). The study involves construction of laboratory pavement sections under unreinforced and reinforced conditions and testing under repeated loading. The pavement sections supplemented with CGC and RTC reinforcement shows reduced permanent deformation by 27%, 33% and 30%, 35%, respectively, for CCA and RCA infill materials. The comparable performance of RCA with CCA is attributed to the self-cementation effect offered by the adhered residual cement mortar. With CGC and RTC reinforcement, the residual pressure at the subgrade level reduces by 30% and 37%, respectively. The provision of cellular reinforcement improves the stress distribution angle, and the highest improvement is observed in case of RTC. The improved behaviour with RTC is due to the larger strip thickness and tensile strength of recycled tyre strip than those used in the preparation of CGC. Irrespective of the infill material, higher strains are experienced under the loading zone than the neighbouring cells. Overall, the study promotes the use of scrap tyres and RCAs in bulk volume for pavement construction, offering an eco-friendly, cost-effective, sustainable, and long-lasting pavements.