51. Economical Recycled Concrete Aggregates to Attenuate Successive Rockfall Impacts: Large-Scale Field Modeling.
- Author
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Su, Yuchen, Zhong, Heng, Wang, Yuan, and Lv, Yaru
- Subjects
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RECYCLED concrete aggregates , *CONSTRUCTION & demolition debris , *ROCKFALL , *WASTE products , *IMPACT testing - Abstract
An enormous amount of construction and demolition waste is generated globally every year, and it increases disposal costs in landfills. The advantage of adopting crushed concrete aggregate as an alternative cushioning material provides a novel approach for reusing and recycling waste materials. However, a lack of understanding of the dynamic responses of recycled concrete aggregate (RCA) inhibits their potential use. In this study, large-scale field tests are carried out to replicate dynamic impact loading on an instrumented concrete shed that is shielded by a 1 m-thick RCA cushioning layer. Six successive large-scale field boulder impact tests with energy levels reaching 70 kJ are conducted. Two different RCA particle sizes—RS (100–150 mm) and RL (200–250 mm)—are investigated. The results show that up to 82% maximum transmitted load can be reduced if the RL cushioning layer is replaced with RS cushioning layer. This phenomenon is attributed to the force chains composed of small particles that are more susceptible to collapse than large particles. To optimize the load-reduction performance of the RCA cushioning layer, practitioners should adopt a small particle size when considering a single boulder impact. In contrast, after six impacts, the maximum transmitted load for Rs is approximately 4.2 times larger than that for RL. This increased load is caused by the relative particle breakage index (Br) for RL being at least 1.3 times larger than that for Rs. This finding indicates that the amount of crushing RCA particles increases with increasing particle size. This phenomenon induces force chains to collapse more easily, and the transmitted load decreases. An RCA cushioning layer with a large particle size can effectively reduce the transmitted load under the consideration of successive impacts. This implies that the combined effects of particle size and number of successive impacts strongly influence the load distributions exerted on structures shielded by an RCA cushioning layer. Highlights: Six successive large-scale field boulder impact tests with energy levels reaching 70 kJ are conducted. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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