The effect of cement and reclaimed asphalt pavement on the mechanical properties of stabilized base via full-depth reclamation

One method for improvement of distressed pavements is full-depth reclamation (FDR). In this technology, the present asphalt layer is pulverized and mixed with the aggregate layer beneath it and then the mixture is stabilized using a stabilizer agents such as Portland cement in order to increase the strength parameters of the mixture. The aim of this study is to evaluate the laboratory results of stabilizing the blend of reclaimed asphalt pavement (RAP) and aggregates with cement in order to be used as a treated base coarse in full-depth reclamation (FDR) method. The present study was conducted using two different types of aggregate soils. Compaction and unconfined compressive strength (UCS) tests were carried out on different ratios of RAP to aggregates of 0/100, 20/80, 40/60, and 60/40. Four cement contents of 3, 4, 5, and 6 percent were added and the samples were cured for 7 and 28 days after compaction. Results show that by assuming a constant percentage of RAP, by increasing one percent of the Portland cement, the UCS value for the stabilized layer including SP-SC and GW-GC increased by an average of 376 and 410 kPa, respectively. According to this research, the elastic modulus of FDR layers can be assumed between 9000 and 40,000 kPa with respect to soil type and dosage of RAP in FDR layers. Results also show that the optimum content of Portland cement for construction of FDR layers is between 3 and 4% for SP-SC soil and between 3 and 5% for GW-GC, respectively.