Extension of Asphalt Pavement Life by Reduction of Temperature

Abstract

High temperatures, particularly during the summer months can lead to a number of problems for asphalt pavements---such as rutting and accelerated aging of asphalt binders, which can cause premature cracking. This paper presents the concept of using geosynthetic reinforced chip seal (GRCS) with high albedo aggregates to reduce pavement temperatures. The concept of the use of GRCS depends on two factors---the higher reflectivity of the chips or aggregates and the insulation provided by the asphalt binder saturated geosynthetic layer. Both of these factors reduce the amount of heat that is transmitted through the top part of the pavement to the deeper areas. The results of field-testing show that the benefit of reduction in temperature at the maximum temperature depth is enhanced at higher solar radiation/higher ambient temperature periods. Temperature reductions in the range of 6-12C can be expected in pavements in many parts of India. The utility of the approach has been investigated with the use of mechanistic empirical pavement design analysis (MEPDS). The reduction in temperature leads to a significant increase in rutting life as well as fatigue damage life, by decreasing the aging potential. Furthermore, the GRCS layer also helps in reducing the ingress of moisture from rainfall, and hence prevents the onset of moisture-induced damage. The lowering of temperature also helps us avoid the need for the use of higher grade of asphalt binders. This application will be useful for both higher volume pavements (such as busy intersections with slow traffic and high temperature related rutting problems) and low volume pavements (with relatively thin sections and fatigue cracking problems).