Movement and embedding characteristics of interlayer aggregates during roller-compacted concrete compaction process using discrete element simulation. (20th July 2020)

• Record Type: Journal Article
• Authors: Liu, Donghai; Xia, Xietian; Sun, Longfei
• Is Part Of: Construction & building materials. Volume 249(2020)
• Publication Date: 2020-07-20
• Subjects: Roller-compacted concrete -- Compaction quality assurance -- Interlayer bonding quality -- Discrete element simulation -- Aggregate movement -- Interlayer aggregate embedding -- Rheological properties -- Mortar; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2020.118765
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Movement and embedding of interlayer aggregates in RCC were monitored by discrete element simulation. The mortar of RCC was found only slump flow under vibration condition. Typical shapes of coarse aggregates were selected according to the sphericity by 3D scanning. Embedding of interlayer aggregates was found mainly happen during the vibration liquefaction of RCC. Abstract: During the vibrating compaction process of roller-compacted concrete (RCC), interlayer aggregates embed into the lower layer and the meshing force is formed, which is critical for the interlayer bonding quality. This paper employs the discrete element method to simulate the vibrating compaction process of two-layer RCC specimens. By studying the embedding process of interlayer aggregates with different sizes under different compaction forces, suggestions about construction quality control are offered. For more accurate assessment of aggregates movement, the typical real shapes of aggregates were obtained by 3D scanning, and the rheological properties of RCC mortar were experimentally investigated. Additionally, the compaction properties of RCC were examined with two-layer specimen molding experiment using a shaking table. On this basis, the discrete element model of RCC, as well as its contact model and meso-structural parameters, was built with Particle Flow Code. Finally, the embedding and movement of the interlayer aggregates were analyzed in the discrete element model of two-layer specimens under different compaction forces. The obtained results demonstrate that lager aggregate size and compaction force tend to improve the compaction effectiveness and lead to larger and quicker embedding of interlayer aggregates. Furthermore, it is found that the aggregates embedding mainly happens during the vibration liquefaction of RCC. Based on the results, proposals were advanced for optimal overall embedding values, in order to guarantee the interlayer strength of RCC. In addition, this paper also provides guidance for the development of monitoring devices of aggregate movement for further research about tracking the real interlayer aggregates under practical construction.