Cracking Susceptibility of Concrete Made with Recycled Concrete Aggregates

O. Burkan Isgor, Oregon State University


As high-quality, local, natural aggregate resources continue to become less available, and the cost of landfilling waste material rises, the need for alternative aggregates and recycling of waste material will increase. Using recycled concrete aggregates (RCA) in new concrete is one way to address both of these issues. However, there has long been a concern that RCA may negatively affect the properties of new concrete in which it is included. In particular, since concrete produced with RCA typically contains a larger volume of mortar than conventional concrete, drying shrinkage has been considered to be a potential source of cracking in concrete. Excessive cracking in concrete can cause premature structural deterioration because it will lead to increased permeation of hazardous external contaminants (e.g., deicing salts), accelerated freeze-thaw damage, and corrosion of steel reinforcement. The present study seeks to address the identified gap in research by investigating how RCA as a replacement for natural aggregate in new concrete may affect the material’s long-term cracking susceptibility. In this research it was hypothesized that unique properties of concrete produced with RCA due to the presence of adhered mortar may provide a buffer against cracking, even though the concrete may go through higher amounts of shrinkage. If RCA can better endure these deformations, less stress will build internally, and subsequently, the cracking susceptibility may be reduced. The present research tests this hypothesis.

Project Details

Project Type:
Project Status:
End Date:
December 31,2013
UTC Grant Cycle:
OTREC Small Starts
UTC Funding: