Resilient Moduli Response of Moderately Cement-Treated Reclaimed Asphalt Pavement Aggregates

The use of reclaimed asphalt pavement (RAP) aggregate materials in road construction reduces natural resource depletion and promotes the recycling of RAP materials for other applications. However, product variability and low resilient moduli characteristics often limit RAP applications in road bases. Stabilization of RAP materials with cement was hence attempted in a research study to evaluate the effectiveness of cement treatments in enhancing resilient characteristics of RAP aggregates. The present paper describes the results from a series of resilient modulus tests that were conducted in a laboratory environment using a repeated load triaxial test setup. The effects of three different cement dosages and various confining and deviatoric stress levels on the resilient modulus (M-R) response of treated RAP materials were studied. M-R values of untreated and cement-treated RAP aggregates ranged from 180 to 340 MPa and 200 to 515 MPa, respectively, which reveal the enhancements with cement treatment. Regression modeling analyses of M-R test results, by using two- and three-parameter models, are also presented. The analyses show that both models are reasonably capable of capturing the effects of stress levels on treated RAP resilient properties. Test results were also analyzed to determine structural coefficients for pavement design purposes, which ranged from 0.16 to 0.22, suggesting a greater structural support of cement-treated RAP layers when compared with untreated aggregates. DOI: 10.1061/(ASCE)MT.1943-5533.0000268. (C) 2011 American Society of Civil Engineers.