Description
An update of 16-year review of successful bitumen-rubber asphalt use in China
Alex Visser, Shang Haiyan* and James Ding**
ABSTRACT: The use of the Arizona recipe for producing bitumen-rubber (bitumen and crumb rubber in the wet process) has been used successfully in South Africa for more than 30 years. About 16 years ago, this technology was transferred to China by a South African based company, and a number of projects were constructed. The success of these projects was reported at previous RAR2015 in Las Vegas and RAR2018 in South Africa. The objective of this paper is to give an update of the successful performance of conventional bitumen-rubber as well as novel applications. The successful use is in contrast of the experience of some Chinese clients, as other approaches have not provided the desired performance. The paper first reviews the process employed in China which no longer is applied in other countries, and then provides the performance of a number of projects previously reported, some as old as 16 years, which is phenomenal in China. Some of the novel applications include using bitumen-rubber open-graded friction course to construct a permeable pavement in a large parking area, as well as its use on heavily trafficked freeways to reduce noise. The latter exercise has confirmed the beneficial use as has been reported in other countries. Lastly, a bitumen-rubber SMA wearing course has been used on a heavily trafficked road that carries more than 200 trucks per day with two rear axles with dual wheels each axle carrying 30 tons. The trucks are carrying ore and sand, and despite being significantly overloaded compared with the 10 ton legal axle load, there is no evidence that the overloading is being controlled. Under these circumstances, the road pavement was designed and constructed to carry these loads. The successful use of a specific formulation of bitumen-rubber bodes well for the future, as typical asphalt surfacing only last up to 5 years under Chinese conditions.
KEYWORDS: Long-life, bitumen rubber, asphalt, performance
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