Laboratory Evaluation of the Use of Cement-Treated Construction and Demolition Materials in Pavement Base and Subbase Applications

Construction and demolition (C&D) materials constitute a major proportion of waste materials present in landfills worldwide. With the scarcity of high-quality quarry aggregates, alternative materials, such as C&D materials, are increasingly being considered as a replacement for traditional road-construction materials, particularly as the sustainable usage of these C&D materials has significant environmental benefits. In this research, an extensive laboratory evaluation was carried out to determine the engineering properties of cement-treated C&D materials. The C&D materials investigated were reclaimed asphalt pavement (RAP), recycled concrete aggregate (RCA), and crushed brick (CB). The geotechnical properties of cement-treated C&D materials were evaluated to assess their performance in pavement base/subbase applications. The effect of curing duration on the strength of the C&D materials was analyzed by conducting unconfined compression strength and repeated load triaxial tests. The RAP required 2% cement (by weight) and either 7 or 28days of curing to meet the local road-authority requirements, whereas RCA and CB required 4% cement and 28days of curing. The RAP exhibited the highest strength in all cases, with the same cement content and for the same curing duration, followed by RCA and CB. The resilient moduli of C&D materials increased with an increase in cement content, curing duration, and confining pressure. Humidity curing was found to play an important role in the strength development of cement-treated C&D materials. This study indicates that cement-treated C&D materials are viable construction materials for pavement base/subbase applications.