The use of crumb rubber modified bitumen for crack mitigation-Wet Method.

The present report entitled "The use of crumb rubber modified bitumen for crack
mitigation-Wet method" discusses the usage of waste tyre rubber as a bitumen
modifier. Waste rubber and the environmental impact it causes has been a concern
for the past two decades all over the world, in particular industrialized countries. One
environmental friendly idea to dispose the waste tyres is to add it into bituminous
mixtures for the construction of roads.
The objective of this research is to find a good mix proportion for the rubberised
bitumen. This project attempts to address two components to the problem: the
environmental concern and the engineering properties of the modified mixture. The
addition of rubber to the bitumen can aid on the mitigation of various distresses in
highway pavements. Two main distresses in pavements are deformation (rutting) and
fatigue (cracking).
The interaction between the bitumen and the crumb rubber can be done in the wet or
dry process. The wet process is used for this study due to its added advantages,
which are among others, the formation of a binding gel and the improved thermal
susceptibility of the bituminous mixture. The selection of materials is as well pivotal
in obtaining a good mix, test on the materials used are to meet the necessary
specifications and material characterization. For this project the test methods used
are from the British standards and the local JKR standards.
From the results, it can be concluded that the addition of crumb rubber into the
bituminous mixtures using the wet method, improves the engineering proprieties of
the pavement such as the fatigue resistance and the reduction of permanent
deformation. Moreover, a high proportion of rubber, as high as 19.75%, was added to
the bituminous mixtures, which help address the environmental problem related to
rubber tyres