Performance Evaluation of Asphaltic Airfield Pavements using Elvaloy as a Fuel Resistant Polymer

Abstract

Fuel is considered as one of the primary factor for distresses at airfield pavements, filling stations, parking lots and industrial plants. Accidental fuel spillage on asphaltic pavement can lead to its deterioration due to asphalt’s solubility in fuel, which in turn may cause stripping and raveling phenomenon - a potential for Foreign Object Debris damage (FOD) to aircrafts. Development of bituminous binder with an intrinsic fuel resistance property is essential to arrest pavement damage and maintenance operations in areas with high risk of fuel spilling. This research is focused on investigating the effect of various proportions of fuel resistant polymer on the performance based properties of binder and hot mix asphalt (HMA) mixes. Laboratory investigations were conducted using gradation for asphalt wearing course as specified in Manual Series 4 of Asphalt Institute (MS-4) of Asphalt Institute with nominal maximum size of 19 mm - a commonly adopted gradation by Military Engineering Services of Pakistan. The material used included Margalla crush, Attock oil Refinery Limited (ARL) binder 60/70 and Elvaloy RET 4170 as a fuel resistant polymer. In first phase of research study, control 60/70 and polymer modified binder (PMB) are characterized with consistency and Superpave performance tests. Second phase included HMA characterization of unmodified and modified mixes using: Marshall test for determining strength and volumetric parameters; Indirect Tensile Strength test and Resilient Modulus test for evaluating cracking potential and strength parameters, Hamburg Wheel Tracker test for quantifying the Rut propensity; and Solubility test to determine the fuel resistance of sample mixes. The analysis of performance based tests on binders and HMA mixes were carried out using two-way factorial design of experiment. The elastic recovery and complex modulus values revealed that 1% PMB is least susceptible to high temperature variations and it also performed better at low temperature compared to control 60/70 and higher percentages of PMB. Also, mixes prepared with 1% PMB showed maximum resilient modulus both before and after conditioning in fuel, least rut susceptibility and high fuel resistance. This research study recommends 1% PMB to be used as a fuel resistant polymer in airfield pavements. This research can help public aviation/ highway agencies and other private contractors to incorporate jet fuel resistant polymer in flexible pavements to arrest pavement deterioration due to fuel spillage and control FOD damage to aircrafts.