Abstract
Recycled construction and demolition (C&D) waste can reduce the rebuild cost, and is environmentally friendly when recycled asphalt pavement (RAP) aggregate constitutes the main part. This paper investigated the mechanical performance of RAP concrete, and the applicability of RAP in road base layers also was discussed. Several mechanical laboratory tests were selected, including the unconfined compressive-strength, splitting-strength, and compressive-resilience modulus tests. The RAP concrete had a good road performance in a cold region, which was proved by the temperature-shrinkage test, dry-shrinkage test, freeze–thaw-cycle test, and water-stability test. Based on various cement dosages from 3.5% to 5.5% in RAP concrete mix design, three RAP aggregate replacement ratios (30%, 40%, and 50%) were selected to study the variation of mechanical properties with increasing curing time, and the optimal aggregate substitute ratio was determined. A scanning electron microscope (SEM) was used to observe the inner-structure interface between the asphalt binder and cement stone. A numerical model is presented to simulate the RAP compressive strength with respect to the effect of multiple parameters. The research results can provide a technical reference for RAP use in the reconstruction and expansion of low-grade highway projects.
Highlights
Recycled construction and demolition (C&D) waste can reduce the rebuild cost, and is environmentally friendly when recycled asphalt pavement (RAP) aggregate constitutes the main part
C&D waste-recycling research began near the end of the 20th century in the United States, when the Texas Department of Transportation initially investigated the feasibility of using a waste–asphalt mixture in highway construction and maintenance application in 1994
Giulia et al [32] summarized the development of reclaimed asphalt pavement (RAP) material used in new asphalt construction, and the effect of RAP content was discussed
Summary
Construction and demolition (C&D) waste management has become a worldwide concern, as up to 600 million tons of waste construction materials are produced each year. Saeed and Reza [23] evaluated the performance of recycled asphalt mixtures in C&D waste materials, and the optimal binder content was determined. Papakonstantinou [28] investigated the performance of recycled asphalt pavement (RAP) aggregate use in Portland cement concrete (PCC). Other studies investigated RAP concrete applications, including new asphalt pavement, base layers, structural members, and so on [30,31]. Giulia et al [32] summarized the development of reclaimed asphalt pavement (RAP) material used in new asphalt construction, and the effect of RAP content was discussed. To 5.5% in the RAP concrete mix design, three recycled aggregate mixture contents (30%, 40%, and 50%) were selected to study the variation of mechanical behavior concerning different curing times, and the optimal RAP aggregate-substitute ratio was determined.
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