The new turbulent-mass process for mixing asphaltic concrete paving mixtures has been under study since its recent introduction in 1970. It is increasing in popularity with contractors because of two reasons: the mixing plant requires less equipment; and the process itself appears to result in a significant reduction in polluting emissions. All of this should reduce the cost of production.
Field and laboratory tests and observations indicate that a satisfactory product can be produced by this process, one that is at least equal to conventional plant-mix
This study was initiated to study methods, procedures and/or materials that may reduce premature pavement failures of an asphaltic concrete overlay on an existing bituminous road. The methods included in this study were asphalt additives in the wearing course, full coverage fabric, asphalt rubber interlayer (SAMI) and asphalt rubber seal coat (SAM). .
No material or method was found to totally eliminate reflective cracking. The test sections using softer asphalt (200-300 PEN) in the wearing course provided the best results, with the carbon black and sulfur additives minimizing the flushing that was prevalent in the 200/300 PEN control section.
