Asphalt pavements, sulfur utilization

Utilization of sulfur asphalt pavements in the Middle East appears to have an excellent chance of success. For example, in Saudi Arabia, the production of asphalt in-country has not increased much during the rapid rise of construction activities in recent years. Figure 2 shows the recent and expected production of both asphalt and sulfur in Saudi Arabia. As discussed earlier, demand for asphalt has surpassed the supply. Use of sulfur in pavements may provide the needed binder material and thereby preclude the need for added imports or increased sulfur production(7). 

This chapter discusses current research on the use of sulfur in recycled asphaltic concrete pavements. In addition, it describes the results of laboratory tests and theoretical predictions using the latest linear viscoelastic layered pavement analysis methods (15,16) to compare the performance of various sulfur-asphalt concrete pavements with conventional asphalt concrete pavements in a variety of climates. The relationship between pavement distress and performance used in the computer program was established at the AASHTO road test (17). Finally, the results of domestic field tests of sulfur-asphalt pavements are presented along with a discussion of future trends for the utilization of sulfur in the construction of highway pavement materials. 

Asphalt binder is a thermoplastic material that behaves as an elastic solid at low service temperatures or during rapid loading and as a viscous liquid at high temperatures or slow loading. This double behavior creates a need to improve the performance of the asphalt binder to minimize stress cracking, which occurs at low temperatures, and permanent deformation, which occurs at high service temperatures addition of crumb rubber to sulfur asphalt enhanced the temperature resistance of the binder. Utilization of waste crumb rubber and sulfur in asphalt modification proved to enhance asphalt pavement [129]. 

Elemental sulfur has been modified In an exothermic reaction with commercially available hydrocarbon compounds to produce a pavement binder material that has been successfully utilized to construct several experimental pavement sections on public highways. The engineering properties, the formulation, and the methodology for producing and utilizing this chemically modified sulfur pavement binder, intended as a substitute for asphalt cement, are discussed. 

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