The laboratory results are also compared with analogous asphalt rubber mixes produced elsewhere by the wet process (ARwet).
Previously made with natural rubber, it is now produced with synthetic rubber mixed with pigments, fillers, resins and curing materials, and when sheeted is heat cured.
Binder in asphalt rubber mixes is generally stiffer than the binder in conventional mixes and requires higher compaction temperatures.
Car tyres consist of natural and/or synthetic rubber mixed with a multitude of chemical additives (such as plasticisers, fillers, anti-degradants, vulcanisation substances and reinforcing agents) to give tyres the desired characteristics [3, 4].
This paper presents the results of the second phase which analyzed the mechanical performance of dry-process crumb rubber mixes, more specifically, their response to moisture sensitivity and plastic deformations.
Push-out tests conducted by Han et al. (2015) to investigate the static behavior of a steel and rubber-filled concrete composite beam with different ratios of rubber mixed with concrete and studs.
The review finds that the low temperature properties of crumb rubber modified binder (CRMB) are govern by the factors such as asphalt properties, crumb rubber properties, mixing temperature, mixing time, mixing type and admixture.
Still, it must be emphasized that the formulation of rubber mixes for tires is more an art than a science.
The softness of a racing tyre and hence the grip it offers depends on the amount of carbon, sulphur and oil added to the rubber mix.
(Vulcanization is the interlinking of rubber molecules in order to create a usable elastic solid. It is conducted by heating the rubber mix along with sulfur and various additives in a tire mold for about 20 minutes at a temperature of approximately 300° F, or 150° C).
