Influence of recycled aggregates on long term mechanical properties and pore size distribution of concrete

This paper presents the results of a study of the long term mechanical properties and pore structures of recycled aggregate concrete. In this study, two different sources of recycled aggregates were used to replace natural aggregate at a level of 100%. The compressive and splitting tensile strength of the concrete were tested, and the pore structures of the concrete were analyzed. The results showed that after 5 years of curing, the recycled aggregate concretes had lower compressive strength and higher splitting tensile strength than the corresponding natural aggregate concrete. However, from 28 days to 5 years, the increase of compressive and splitting tensile strengths was more in the recycled aggregate concretes. After 5 years of curing, the concrete made with 100% of crushed old concrete aggregate had the lowest porosity. Good correlations were found between compressive and tensile strength and porosity.