Creep performance evaluation of Cold Mix Asphalt patching mixes

Abstract

Cold Mix Asphalt (CMA) is commonly used in lieu of typical Hot Mix Asphalt (HMA) for localized pavement patching due to the quantities, intermittent locations and times when repairs need to be executed. The objective of this investigation was to evaluate the resistance of CMA to accumulate permanent deformation under cyclic loading, and to present an alternative to assess stability potential from a portable device. Considering CMA is at its weakest state right after placement, and that its resistance to creep improves with curing, the study focused on evaluating the rutting performance of uncured CMA materials at different compaction levels in the laboratory by means of parameters b and FN from a Modified Cyclic Creep Test (MCCT) and by their resistance to penetration with a Light Cone Penetrometer (LCP), defined by the LCP penetration rate (LPR). Based on the experimental results, acceptable laboratory stability can be expected when values below 0.5 με/load and over 1000 load cycles are observed for b and FN, respectively. Considering the potential use of the LCP as a field-friendly quality control tool, models to estimate parameters b and FN from the MCCT as a function of LPR and other CMA characteristics were developed using Multiple Linear Regression Analysis (MLRA). The results suggest that when LPR values are limited to 0.50 mm/blow, CMA materials can be expected to show acceptable stability levels.