Effect of aggregate gradation and mortar rheology on static segregation of self-compacting concrete. (30th October 2020)

• Record Type: Journal Article
• Authors: Yan, Weishuo; Cui, Wei; Qi, Lan
• Is Part Of: Construction & building materials. Volume 259(2020)
• Publication Date: 2020-10-30
• Subjects: Self-compacting concrete -- Static segregation -- Aggregate gradation -- Mortar rheology -- Aggregate generation algorithm -- Immersed boundary method; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2020.119816
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: A fluid-particle coupling method based on IBM is proposed to simulate SCC. A random irregular aggregate algorithm is used to model the aggregate. A validation experiment is carried out to verify the accuracy of the simulation method. The effect of aggregate gradation and mortar rheology on SCC segregation is assessed. Abstract: Due to the high flowability of self-compacting concrete (SCC), compared with ordinary concrete, it is more prone to have stability problems and segregation. In order to study the segregation of SCC, a random irregular aggregate generation algorithm is developed to simulate the actual aggregate gradation, and a fluid-particle coupling method based on immersed boundary method (IBM) is proposed to simulate the rheological behavior of SCC. To verify the accuracy of the simulation method, a validation experiment is carried out, by comparing the results of the experiment and the simulation, it can be found that the numerical simulation method is reasonable and feasible. The influences of aggregates and mortar on the SCC static segregation are systematically studied by comparing the simulation results of different aggregate gradation and mortar rheological properties. The stress generated by gravity and buoyancy of large aggregates can easily overcome the mortar yield stress and settle in the mortar when the large aggregate content is higher and the mortar yield stress is lower. Then SCC is more prone to segregation while mortar viscosity only affects the time required to achieve stability and does not affect the static segregation results. Therefore, by adjusting aggregate gradation and mortar rheology, SCC can reach a relatively stable state, which has a guiding significance for the practical preparation of SCC in preventing its segregation.