The Use Of Recycled Aggregates In The Construction Of Portland Cement Concrete Pavement PDF Download

Use of recycled aggregates in portland cement concrete (PCC) can offer benefits associated with both economy and sustainability. Recycled brick masonry aggregate (RBMA) can be used as a 100% replacement for conventional coarse aggregate in concrete that exhibits acceptable mechanical properties for use in structural and pavement elements (Cavalline, 2012). Recycled brick masonry aggregate concrete (RBMAC) is currently not used in any type of construction in the United States. However, use of RBMAC could become a viable construction strategy as the popularity of sustainable building practices increases. Although some researchers have studied RBMAC in the laboratory, minimal research on full-scale installations has been performed to evaluate the constructability concerns associated with its use, the performance of which is highly influenced by the relatively low unit weight and high absorption of the RBMA. A single-source demolition site was used to provide recycled clay bricks which were crushed and graded into RBMA. Material properties of RBMA from this source were compared to material properties of previously developed RBMA and to the concrete paving specifications of the North Carolina Department of Transportation. Preliminary and final RBMAC mixtures were designed for use in a test pavement as part of this study, and laboratory test results were compared to values from previously developed RBMAC mixtures. The RBMAC test pavement, along with a control section of conventional PCC, was constructed within the access roadway of a local industry in order to allow researchers to identify and address concerns related to construction with this material, and to evaluate both early age and long-term performance of RBMAC in a full-scale pavement installation. Due to the novelty of RBMA and the associated risk and expense related to its use in a traditional batch plant, mobile volumetric concrete mixing trucks were used to facilitate construction of the test pavement. Challenges encountered during pre-construction and construction of the test pavement, experience with placing and finishing the RBMAC and control PCC pavement, and the performance of RBMAC in a pavement application are discussed. This study provides the results of both laboratory testing and a full-scale field installation of a new material that stakeholders can consider for use in future sustainable construction applications.