ضحى نزار محمد علي محمد علي

Considerable amounts of reclaimed asphalt pavement (RAP) are left in stockpiles due to the increased maintenance and rehabilitation actions. In addition to helping to eliminate extra RAP stockpiles, using RAP as a substitute for aggregate in Portland cement concrete (PCC) might also reduce the amount of natural aggregate used in PCC. This study tested the effect of replacing 15%, 30%, and 45% RAP by weight of coarse aggregate in RCC on the compressive, tensile, and flexural strengths, modulus of elasticity, and drying shrinkage. It was found that the replacement of 45% RAP had a negative effect on the properties of RCC, the percentage of decrease in the compressive, tensile, and flexural strengths, and the modulus of elasticity was (28%,32.5%,18.5%, and 31.5%), respectively. As for the drying shrinkage increases much more with the replacement of coarse aggregate with RAP. The increase rate reaches 30% when replacing 45% coarse aggregate with RAP

Due to increased maintenance and rehabilitation actions, significant volumes of Reclaimed Asphalt Pavement (RAP) are left in stockpiles. Replacing aggregate in Portland Cement Concrete (PCC) with additional RAP could help eliminate surplus RAP stockpiles and reduce PCC's natural aggregate consumption, positively impacting the environment and the economy. This paper is a state-of-the-art review of the literature on using RAP to Roller-compacted Concrete pavement (RCCP). The potential of RAP aggregates has been assessed based on their characteristics and the optimum moisture content (OMC), maximum dry density (MDD), compressive strength, splitting tensile strength, flexural strength, modulus of elasticity, abrasion resistance, shrinkage, porosity, water absorption, and freeze-thaw of RCCP. The literature study illustrated how a low-density, smooth-textured hydrophobic asphalt covering surrounds RAP aggregates. potentially reducing the maximum dry density (MDD) and optimum moisture content (OMC) of RCCP mixtures. This asphalt layer could reduce RAP's ability to bind with cement paste, reducing its strength properties. In addition, the hydrophobic nature of RAP may reduce porosity and water absorption. On the other hand, agglomerates and dust can have the reverse impact. Pavement application might be done with a lower replacement of RAP (less than 50%) without affecting the pavement's strength, porosity, or water absorption. However, Increasing the replacement of RAP aggregate may not be conducive to mechanical performance, but it has the potential to enhance the toughness and energy absorption capacity of pavements.