EVALUATION OF RESILIENT MODULUS OF HMA MIXTURES FROM HIGHWAY CONSTRUCTION PROJECTS IN PAKISTAN
ARSHAD HUSSAIN *
Department of Transportation Engineering, National Institute of Transportation, School of Civil and Environmental Engineering, National University of Sciences and Technology, Islamabad, 44000, Pakistan
HASSAN BIN TAHIR
Department of Transportation Engineering, National Institute of Transportation, School of Civil and Environmental Engineering, National University of Sciences and Technology, Islamabad, 44000, Pakistan
M. ZAEEM SHEIKH
Department of Transportation Engineering, National Institute of Transportation, School of Civil and Environmental Engineering, National University of Sciences and Technology, Islamabad, 44000, Pakistan
ABDUL WAHEED
Department of Transportation Engineering, National Institute of Transportation, School of Civil and Environmental Engineering, National University of Sciences and Technology, Islamabad, 44000, Pakistan
MUHAMMAD BILAL KHURSHID
Department of Transportation Engineering, National Institute of Transportation, School of Civil and Environmental Engineering, National University of Sciences and Technology, Islamabad, 44000, Pakistan
*Author to whom correspondence should be addressed.
Abstract
The increase in road traffic on arterials and highways in Pakistan has caused early failure of asphaltic pavements; leading to potholes and cracks in pavements for which a detailed study of determining the relationship between resilient modulus and pavement durability is needed. This study targets upon the determination of resilient modulus of seven plant-produced HMA mixtures from varying highway construction projects of Pakistan and two laboratory prepared HMA mixtures. Resilient modulus (MR) of samples was measured using indirect tensile mode that reflects the effective elastic properties of asphalt mixtures under repeated load. Resilient modulus of various prepared samples of the same mix was then analyzed. Diagnostic checking was performed on the dataset to satisfy the assumptions of the data and delete outliers to proceed further with the analysis. Results of the testing were analyzed using 2n Full Factorial Design of Experiments using Minitab 16. The results of significant factors are presented in this paper, while insignificant factors were omitted from analysis. Loading Duration was found to be the most effective factor on the values of resilient modulus, followed by temperature and air voids. Air voids have been found to be most significant factor among all the mixture properties. This implied that for performance characterization, Hot Mix Asphalt mixtures must be prepared at a little variance in air void contents.
Keywords: Resilient modulus, pavement design, hot mix asphalt, elastic modulus