Laboratory Comparative Study on the Performance of Plain Bitumen and Crumb Rubber Modified Bitumen on DBM Grade 2

In the present study, the physical properties of aggregates and bitumen were determined. Rothfuchs method is carried out to obtain the proportion of aggregate mixing and Marshall Stability method is adopted for bituminous mix design. Then for the neat bitumen, Marshall Tests were conducted to obtain the OBC for DBM Grade II. The OBC of 5.2 % is obtained for the mix. The present study aims in investigating the Mashall properties of the bitumen modified with 15 % and 18 % of crumb rubber mixed with 500g of bitumen i. e. (75g and 90g crumb rubber) is used for the preparation of CRMB. Two categories of the size of crumb rubber were used, having sieve size (3.35mm2.36mm) and (2.36mm 1.18mm). Penetration tests and Softening point tests were performed on the modified bitumen using various sizes of crumb rubber modified bitumen. For the molds prepared with CRMB and with neat bitumen, a comparative study is made among the modified bitumen samples using the various sizes of Crumb Rubber particles and the best size is suggested for the modification to obtain best results