Characterisation of variability in highway pavement materials and construction

Pavement materials and construction (M&C) are inherently variable. Unavoidable inhomogeneous materials, inconsistent construction methods and equipment, and changing weather conditions during construction, among other factors, result in M&C variability. Motivated by the need to provide realistic inputs to pavement quality assurance programs, design procedures and reliability analysis, this paper presents the results of an investigation of variability in key acceptance quality characteristics (AQCs) for both hot-mix asphalt (HMA) and Portland cement concrete (PCC) pavements using empirical data (field and laboratory test results from recently completed construction projects). Variability is measured at three levels: within-lot, within-project and within-state. The variability values found in this study are compared with the variability values reported about 17 years ago. The results showed that major progress had been made over the past two decades in reducing variability in pavement M&C.