Freeze-Thaw Durability of Air-Entrained Concrete Incorporating Natural and Recycled Concrete Aggregate Mixtures

The present study investigates the effect of natural aggregate (NA) and recycled concrete aggregate (RCA) in concrete mixture on Freeze-Thaw (F-T) durability. Freeze-thaw action is considered to be one of the most destructive actions that can cause significant damage to concrete pavement structures. To check the F-T durability; various physical, chemical, mechanical properties test has been conducted on the virgin or natural aggregate (NA) and recycled concrete aggregate (RCA) collected from Illinois. The aggregate resistance for degradation has been measured by using micro-deval and sulphate resistance test. The F-T durability of standard concrete mix using various percentages of NA and RCA has been investigated with or without air-entraining admixtures (AEA). The internal damage of the concrete due to rapid freeze-thaw (F-T) has been evaluated by comparing the relative dynamic modulus (RDM) of elasticity of a specimen at the lab, after a specific amount of F-T exposure, to the dynamic modulus test prior to the start of F-T exposure. The results show that concrete sample prepared with air-entrains agent survived more number of F-T cycles and also concrete prepared using RCA samples shows better durability than NA.