Durability of green concrete

It is expected that during the next two decades, a large amount of concrete, resulting from the demolition of buildings and structures in Canada, will be available for either disposal or for being recycled for reuse as concrete aggregates. However, only a very small portion of the concrete waste is reused in building construction with most being used as highway base or sent to landfills for disposal. There are several reasons why recycled concrete aggregates (RCA) are not widely used in concrete. Among them are the lack of technical data and specifications, as well as the lack of quality control and quality assurance guidelines in the processing of RCA and in the production of green concrete (GC) mixes prepared with RCA. In orderte ensure the wide use of GC as a structural material in Canada, we need to gain confidence in its short- and long-term mechanical, physical and durability properties. Currently in Canada, there are no established design specifications or guidelines for producing structural-grade GC with satisfactory durability properties. The main objective of this research is to establish these guidelines so that the use of RCA in Canada can be a feasible alternative to conventional concrete. The paper will specifically present the outcome of two durability properties of GC: the vulnerability to freeze/thaw action and chloride permeability. The comprehensive experimental study whose overview is presented in this paper demonstrates that the design and production of durable structural-grade GC is feasible alternative to conventional concrete.