Laboratory and Field Investigation of Mechanistic Properties of Foamed Asphalt Recycled Base Course Materials for High Volume Pavements in India

Abstract

The quality of cold in-place recycling (CIR) is strongly dependent on the capability of proper laboratory investigation and design, and quality control during construction. The objective of this study was to evaluate the quality of the first major foamed asphalt CIR recycled layer in India, laid on a national highway in India. A nonnuclear density gauge (NNDG) and a portable seismic properties analyzer (PSPA) were utilized to determine the density and stiffness of the foamed asphalt recycled layer. In addition, cores and material samples from the recycled layer were also tested in the laboratory for density and stiffness using dynamic modulus tests and the seismic method. The results of tests were related to material properties and critical factors influencing the performance-related properties were identified. Comparisons between laboratory and field sample data were made. Foaming temperature and gradation control of crusher dust were identified as parameters requiring tight control to achieve the required quality. The detrimental effects of excess blending of cement were also revealed. The NNDG and the PSPA were found to be capable of identifying poor quality areas both in midsections and at joints, and to be capable of monitoring the quality of recycled layer.