Investigation on Failure Mechanism of Nanomodified Recycled Aggregate Concrete
- Publication Type:
- Journal Article
- Jianzhu Cailiao Xuebao/Journal of Building Materials, 2017, 20 (5)
- Issue Date:
© 2017, Editorial Department of Journal of Building Materials. All right reserved. The crack evolution of recycled aggregate concrete (RAC) and the performance of RAC after incorporation of different amount of nanoparticles (nanosilica sol and nanolimestone) were studied. Under uniaxial compression, the crack development of RAC specimens with different water-cement ratios (0.4, 0.5 and 0.6) and aggregate replacement ratios were observed by high speed camera. Scanning electron microscopy (SEM) observation and mercury injection test were conducted for studying the microscopic morphology and pore structure of the interfacial transition zone (ITZ) of nanomodified RAC and the influences of different mass fraction of nanoparticles and different treatment processes on it were analyzed. The results indicate that the crack of RAC is usually derived from new ITZ or old ITZ (determined by the weaker one) and then it gradually extends to the surrounding area. The evolution of crack eventually leads to the longitudinal splitting failure of the RAC. Nanosilica sol could improve the microstructure of ITZ. Therefore, the strength of nanosilica sol modified RAC was enhanced. But the improvement by nanolimestone is not very significant for it can't enter the interface transition zone to fill the pore in it.
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