Evaluation of Cold In-place Recycling for Rehabilitation of Transverse Cracking on Us 412

Abstract

The objectives of this thesis were to evaluate the dynamic modulus of Cold Inplace Recycling (CIR) mixture made with one reclaimed asphalt pavement (RAP) and four different emulsions and to compare the results with the default values in the Mechanistic-Empirical Pavement Design Guide (M-EPDG). The dynamic modulus (|E*|) of hot-mix asphalt (HMA) is one of the fundamental inputs in the M-EPDG developed in NCHRP Project 1-37A. The M-EPDG provides three levels for |E*| input, which are related nominally to the reliability of pavement performance estimates generated by the Guide. Level 1 |E*| inputs require laboratory measured |E*| values while level 2 and 3 |E*| inputs are estimated using a predictive equation. The study included the determination of input parameters of CIR mixture to be used in the M-EPDG and comparison of the effect of different emulsion types on the dynamic modulus of the mixture. Emulsion type, test temperature and frequency of loading had a significant effect on the dynamic modulus of the mixture. Comparison of the experimental and predicted dynamic modulus data showed that the experimental data was lower than the predicted. Numerous assumptions were required to obtain the predicted dynamic modulus and the experimental data was extrapolated for the missing temperatures. Further study needs to be performed in this area to determine whether the predicted data matches CIR mixtures. Witczak's equation can be used for CIR by assuming that RAP is a "Black Rock" with negligible absorption.