Evaluation of Compressive Failure in Recycled Aggregate Concrete with Oscillation of Mixture Inserting Vibrators by Acoustic Emission
Takeshi WATANABE, Sayaka NISHIBATA, Chikanori HASHIMOTO and Masayasu OHTSU
Abstract:It was obtained that compressive strength of concrete with low-quality recycled aggregate could be improved by oscillation of mixture inserting vibrators. Therefore, to evaluate properties of cracking in recycled aggregate concrete with the oscillation, compression test in concrete of recycled aggregate is conducted, applying AE measurement. As the results, compressive strength of recycled aggregate concrete with the oscillation is increased more than 10% with comparing to the concrete mixed by non-oscillation of mixture. From relationship between ratio of cumulative AE hits and load level, it is clarified that increasing of micro-cracking in recycled aggregate concrete is observed at lower stress level than normal concrete, but cracking of recycled aggregate concrete with the oscillation is similar as normal concrete. By applying the b value and Ib-value, it is recognized that scale of macro-cracking and failure in recycled aggregate concrete is larger than normal concrete, and recycled aggregate concrete is recovered by the oscillation. Key Words:Recycled aggregate concrete, Oscillation of mixture, Acoustic emission, compressive failure, Ib value