Search

This work studied the compressive behavior and microstructure of cement-based recycled concrete (CE-RC), low-volume fly ash (FA) recycled concrete (LFA-RC), and high-volume FA recycled concrete (HFA-RC) under different curing ages. The compressive properties, energy absorption properties, and microstructure of CE-RC, LFA-RC, and HFA-RC were measured and compared with cement-based normal concrete (CE-NC). The addition of coarse recycled concrete aggregate (CRCA) leads to more macropores and micro cracks in the concrete. As the result, the mechanical property of RC is worse than normal concrete. FA improved the energy absorption performance of recycled concrete in the early stage. With the continuous curing, pozzolanic reaction occurred between FA and the cement hydration product. The internal microstructure of LFA-RC and HFA-RC was improved. However, part of the FA in HFA-RC can only act as a filler and cannot fully participate in the secondary hydration reaction. Therefore, in the mature age, the internal pore distribution of LFA-RC was the most uniform. And the improvement of strength is more obvious. [ABSTRACT FROM AUTHOR]

AbstractConcrete face rockfill dams, preferred for their adaptability in unloading and soft rock foundations, encounter significant deformation control challenges at increased heights. This study analyses the stress and strain of five Chinese dams, ranging from 179.5 m to 233.5 m, demonstrating improved structural responses by implementing high-modulus zones in the rockfill and concrete embedment. The findings reveal a direct relationship between rockfill settlement, concrete face slab deflection, and dam height. Incorporating a high-modulus zone and concrete embedment resulted in reduced rockfill settlement by 15% and 5.8%, concrete face slab deflection by 17% and 41.9%, and joint deformation by 10%–20% and 21.2%, respectively. This study is expected to support the deformation control of high-concrete-face rockfill dams. [ABSTRACT FROM AUTHOR]