The pavement distresses including stripping, rutting, and low temperature cracking have been known to greatly decrease the service life of pavement. The simple laboratory tests are used to measure HMA's (Hot Mix Asphalt) fundamental engineering properties that can be linked back to the pavement distress-prediction models. It is envisioned that these simple laboratory tests would play a key role in the quality control of HMA mixtures. To minimize premature pavement distresses, it is imperative to investigate the relationship between the simple laboratory tests and pavement distresses.
Moisture induced damage in asphalt concrete pavement, better known as stripping, is a primary cause of distresses in the Hot Mix Asphalt layer. AASHTO T 283 has historically been used to detect moisture damage of asphalt mixes. This method is established for the Marshall mix design process. However, the current hot mix asphalt design calls for the use of Superpave mix design procedure using the Superpave Gyratory Compactor. The differences in the mix design methods will most likely introduce significant differences in stripping test results. Therefore, there is a need to improve the AASHTO T 283 test procedure and to develop the new criterion for the Superpave HMA specimens. A structured laboratory program test is conducted in this research to study the effects of the various factors on the HMA specimen's susceptibility to moisture damage. The experimental test program is divided into two parts: one part is a complete factorial
experimental program for two aggregate sources with virgin asphalt binder, the second part is a partial factorial experimental program for the other two aggregate sources with polymer modified asphalt binders. The complete factorial experiment is used to identify and evaluate the contributions of the individual factors, along with all the possible interactions among the various factors. The partial factorial experiment, on the other hand, is used for validating findings from complete factorial experimental results. In the data analysis, the effects of different factors on dry tensile strength, freeze-thaw conditioned tensile strength, and tensile strength ratio (TSR) are investigated in this research. The effects of all the factors investigated in this research are summarized in this research. The recommendations for the proposed stripping test procedure for Superpave HMA are given finally.
Rutting and low temperature cracking are also primary failure modes of Hot Mix Asphalt pavements. In the mid-1980s, polymer-modified asphalt concrete mixture has been widely used to minimize rutting and low temperature cracking failures of flexible pavement. In this research, three polymer modifiers are used in the laboratory test. The influences of the modifiers to rutting resistance and low temperature cracking resistance are investigated and regression procedures are performed in an attempt to develop mathematical relationships between pavement distresses properties and HMA's physical properties and strength properties obtained from the simple laboratory tests.