A Study of Chunk Rubber from Recycled Tires as a Road Construction Material

The feasibility of using large rubber chunks from shredded tires as aggregates in coldmixes for road construction was investigated in this study. The research was directed toward development of a chunk rubber asphalt concrete mix design for low volume road construction using local aggregate, shredded tire rubber chunks and a cationic emulsion. A set of mixes using different combinations of chunk rubber content, emulsion content and fly ash content were tested. Marshall stability results of mixes with 10% Type C fly ash showed optimum emulsion contents of 6.8, 7.3 and 7.8% for 2, 4 and 6% rubber, respectively. The Marshall stability values decreased for increasing rubber contents. The target Marshall stability value of a suitable cold mix at 43oC was required to be 2225 N. A mix with 10% Type C fly ash, 2% rubber and 7% emulsion showed an average Marshall stability value of 1600 N. Based on the Marshall stability results, some of these mixes appeared to be suitable as binder courses or stabilized drainable bases for low volume roads. If 9 kg of chunk rubber equivalent is produced per tire, then a one km long and 7.3 m wide low-volume road with a 100 mm thick base built with this mix can incorporate approximately 3350 tires. This application can minimize the scrap-tire waste problems of rural communities.