Conventional concrete pavement traditionally has a lower life-cycle cost, but is directly responsible for increased carbon dioxide emissions and urban heat islands, and is inefficient in managing stormwater runoff. Pervious concrete pavement with permeable layers is a greener and cleaner option.
A new paper, “Reclaimed Asphalt Pavement as a Substitution to Natural Coarse Aggregate for the Production of Sustainable Pervious Concrete Pavement Mixes,” by Surya Kant Sahdeo; Gondaimei Ransinchung, Ph.D.; K. L. Rahul; and Solomon Debbarma, S.M.ASCE, in the Journal of Materials in Civil Engineering explores using reclaimed asphalt pavement as a substitute to natural coarse aggregate in the production of sustainable pervious concrete pavement mixes.
This study discusses the effect of utilizing coarse reclaimed asphalt pavement (RAP) aggregates as a replacement to natural coarse aggregates (NCAs) for the production of pervious concrete pavement (PCP) mixes. Coarse RAP (RC) aggregates were utilized in proportions of 0%, 25%, 50%, 75%, and 100%, respectively. It was observed that the porosity and permeability coefficient of the PCP mixes increases considerably as the RAP replacement level increases. Meanwhile, the incorporation of RC was also found to negatively affect the mechanical properties of the PCP mixes. However, the compressive and flexural strength values were noted to be well within the prescribed limits (5–25 MPa and 1–3.2 MPa) required for a PCP mixture. On the other hand, the incorporation of RC was observed to reduce the hardened density, resistance to abrasion, and resistance against aggressive environment of chlorides and sulfates. Therefore, in order to prepare a PCP mixture such that there exists a fine balance in various properties, it is recommended that RC up to 50% may be utilized as a replacement to NCA. In view of achieving maximum sustainability, RC up to 100% may be completely utilized for the production of PCP mixes provided a binary gradation is adopted. Utilization of RAP in preparation of pervious concrete pavement mix will not only resolve the issues related to clearance of an enormous amount of RAP dumps, but would go a long way in dealing with various other environmental and ecological impacts.
Read the recommendations in the ASCE Library: https://doi.org/10.1061/(ASCE)MT.1943-5533.0003555