Bond Splitting Strength of High–quality Recycled Coarse Aggregate Concrete Beams

Abstract

This study concerns high–quality recycled coarse aggregate concrete which was recently specified in Japanese Industrial Standards (JIS). The objective of this study is to determine the basic properties of recycled aggregate concrete when used for the beams of reinforced concrete structures. During a period of one year after the placement of concrete, regular observations were made to identify the magnitude of drying shrinkage cracks generated in the beams. Furthermore, for the beams in which drying shrinkage cracks were generated, the bond splitting strength was investigated. The study found that the drying shrinkage cracks at the material age of one year were slight, showing that the generation of drying shrinkage cracks was suppressed compared with when using an intermediate–quality recycled coarse aggregate. The observed bond splitting strength was equivalent to that of normal concrete, unaffected by the formation of slight drying shrinkage cracks. When the high–quality recycled coarse aggregate of the study was used for reinforced concrete beams, the bond splitting strength was equivalent to that of normal concrete even when recycled coarse aggregate was substituted entirely for normal coarse aggregate. These findings suggest that reinforced concrete beams made using high–quality recycled coarse aggregate can be used as members of architectural structures.