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

TLDR

Reclaimed asphalt pavement (RAP) aggregates reduce natural resource use, yet their product variability and low resilient moduli often restrict their application in road bases. This study investigates whether cement stabilization can improve the resilient properties of RAP aggregates. Laboratory repeated‑load triaxial tests were performed on RAP samples treated with three cement dosages under varying confining and deviatoric stresses, and the results were fitted with two‑ and three‑parameter regression models. Cement treatment raised resilient modulus from 180–340 MPa to 200–515 MPa, the models captured stress effects, and structural coefficients of 0.16–0.22 suggest enhanced pavement support compared with untreated aggregates.

Abstract

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 (MR) response of treated RAP materials were studied. MR 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 MR 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.