AE behavior of concrete with low-treated recycled aggregate in compression test: Fid-Bau Portal

AE behavior of concrete with low-treated recycled aggregate in compression test

Watanabe, T. / Nishibata, S. / Hashimoto, C. / Ohtsu, M.

For recycling concrete, it is studied to use recycled aggregate for new concrete in Japan. We study utilizing of low-treated recycled aggregate. Physical properties of the low-treated recycled aggregate are lower than normal aggregate. It is widely recognized that compressive strength of concrete with low-treated recycled aggregate is weaker than normal concrete in equal of water-cement ratio. It is expected that cracking due to fracture process of concrete with low-treated recycled aggregate is not similar to normal concrete. 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 by applying Acoustic Emission (AE) measurement. As the results, compressive strength of recycled aggregate concrete with the oscillation could be increased more than 10 % with comparing to the concrete mixed by non-oscillation of mixture. As a result, it is clarified that trend of cracking in concrete with low-treated recycled aggregate differ from normal concrete by acoustic emission. In addition, Kaiser Effect is not clearly observed in concrete with low-treated recycled aggregate. However, cracking of recycled aggregate concrete with the oscillation is similar as normal concrete. By applying 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.