Recycled Concrete-Highway Systems
Suitability of Using Recycled Concrete Aggregate with Filter Geotextiles in Road Construction
Use of the recycled unbound material has become more widespread in the United States and all over the world as the production of demolished material and construction waste has been increasing in a gradual pace and the land for disposal is becoming limited and more expensive. It is a known fact that natural aggregate is a finite source and over time will diminish. While the supply of natural aggregate decreases, due to continuing construction worldwide, the amount of demolished concrete increases. The demands to use of recycled concrete aggregate instead of the virgin aggregate as the course base in new roads and highways is also increasing in this manner.
One of the main concerns about the use of recycled concrete aggregate (RCA) in road applications is the potential for precipitating calcium-based compounds. This phenomenon especially becomes important if the road profile where RCA will be used contains a filter fabric around the underdrain systems. Several studies have shown that recycled concrete aggregate has suitable physical and geotechnical properties for road construction; however, the studies related to leaching behavior and potential clogging have not been investigated in depth.
This research program focuses on investigating the clogging probability of filter fabrics that are placed in vicinity of the RCA used as the base/subbase layers, to determine the RCA/Geotextile interactions both in terms of physical migration of fine particles and precipitation of new calcium-based compounds. A wide range of geotechnical and chemical property tests are being conducted along with the monitoring the variations within the leached materials. The research program also includes the geochemical modeling and the numerical analysis. It is expected that the results of this research to have noticeable effect on the current understanding of the clogging phenomena of geotextile because of calcium carbonate precipitation and to cause some revisions on the applied regulations nationwide.
