Utilization of Construction and Demolition Debris Under Traffic-Type Loading in Base and Subbase Applications

As construction and remediation take place throughout New Jersey, the amount of construction and demolition debris increases, while the availability of landfill space decreases. A viable solution for disposing of these materials is to incorporate them into base and subbase applications. An extensive laboratory program was conducted on two types of construction and demolition debris: recycled concrete aggregate (RCA) and recycled asphalt pavement aggregate (RAP). These two materials were compared with dense-graded aggregate base coarse (DGABC), which currently is being used in roadway base applications in New Jersey. Both RCA and RAP were mixed at various percentages with the DGABC to evaluate whether an optimum mix blend could be formulated. The materials were evaluated under a traffic-type loading scheme that included resilient modulus and permanent deformation via cyclic triaxial testing. Laboratory tests indicated that the RAP, RCA, and DGABC blended materials all obtained higher resilient modulus values than the currently used DGABC. The permanent deformation results indicated that the RCA mixed samples obtained the lowest amount of permanent deformation when the material was cyclically loaded to 100,000 cycles. In contrast, the permanent deformation testing on RAP mixed samples resulted in the highest amount of permanent deformation at the same number of cycles. Existing models currently used for quarried base and subbase materials were used to predict the permanent deformation in the recycled materials. Laboratory test results indicated that these models could be used for predicting permanent deformation in unbound recycled materials.