Rubberised bitumen

When the wet process is employed, the homogeneity of mixture is ensured and the positive effect of the crumb rubber to the permanent deformation performance of the asphalts is more distinct. It has been reported that the permanent deformation characteristics, rut depth and the rut rate, of an asphalt concrete (AC 8 mm) with rubberised bitumen decreased in comparison to the AC 8 mm with Venezuela 50/70 grade bitumen, when the wet process was used (Neutag and Beckedahl 2011). The stiffness modulus determined by the indirect tensile test was found to increase. 

In March 2008 WRAP published the results of a review carried out to investigate the worldwide use of crumb-modified asphalt over the previous 25 years [2]. The work was conducted for WRAP by Scott Wilson and involved a desk study of published information from 1983 to 2008 on the use of rubberised asphalt (RA) worldwide and the results of communications with relevant industrial experts on the practical issues associated with the use of RA in their countries. There are two main processes for using rubber in asphalt (Le., the dry and wet processes) and this review concentrated on the use of the wet process, as this is the method to produce rubberised bitumen. Rubberised bitumen can be used in four different areas of application ... 

Unvulcanised rubber in the form of granules. It is used for dissolving in hot bitumen for making the surfaces of so-called rubberised roads Power Factor... 

In another study using crumb rubber (size 0/0.7 mm and quantity 15% and 18%), it was also found that the characteristic and rheological properties of the bitumen improved. However, the storage stability requirement of the rubberised modified bitumen (RmB) was not satisfied. When wet and dry processes were compared on extracted RmB from an asphalt concrete mixture (AC 8 mm), it was found that the effect of crumb rubber was more profound when the wet process was used (Lukac and Valant 2011). 

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