Laboratory Assessment of Recycled Tire Reinforcement for Granular Subbase Application

ABSTRACT The current study explores the effectiveness of recycled tires as a pavement reinforcement material and compares their performance with conventional commercial geocell (CGC) reinforcement. Recycled tire cellular grid (RTCG) and recycled tire cell (RTC) are prepared using waste tires for use as reinforcing materials. Laboratory prototype pavements are constructed and tested under repetitive loading. The load-settlement behavior and surface profiles of the pavements are assessed under repeated loading. A 56.51 % decrease in plastic settlement was observed in the RTC-reinforced section when compared to the unreinforced section, surpassing the 37.76 % reduction achieved by the CGC section and 32.18 % by the RTCG section. The load-settlement response of the RTCG-reinforced pavement section is identical to that of the CGC-reinforced pavement section over 5,000 load cycles and is attributed to the higher aspect ratio of RTCG. The introduction of RTC reinforcement significantly enhances the improvement factor, maintaining a factor of greater than 2 throughout 5,000 loading cycles. The reinforced sections showed reduced subgrade settlement contributions to the base course settlement, with RTC performing better than CGC and RTCG. Recycled tire reinforcements showed lower embodied CO2 emissions by about 30 % and reduced construction costs by up to 6.8 % to 12.5 % compared to conventional CGC. The study demonstrated that recycled tire cellular reinforcement significantly improves pavement performance by reducing plastic settlement and enhancing load-bearing capacity, offering a viable solution for recycling and reusing a bulk volume of scrap tires in pavement construction.