A hard-core soft-shell model for vibration condition of fresh concrete based on low water-cement ratio concrete

Abstract

The newly developed vibration-compacting modular production technology of concrete with low water-cement ratio puts forward new requirements for the study of rheological mechanical model of concrete. The existing contact model of discrete element method cannot effectively express the complex dynamic relationship between concrete aggregate and mortar under vibration. In this article, an improved hard-core soft-shell contact model, which is suitable for the simulation of concrete with low water-cement ratio under vibration state, is proposed according to the vibration and compactness characteristics of the concrete. According to the rheological properties of the concrete mortar, the calculation method of soft-shell force is improved. The relationship between the shear stress and its displacement in the process of trying to solve the tangential soft-shell is clarified. In order to characterize the adsorption effect of mortar on aggregate, the gravitation is added in the normal soft-shell force calculation. Slump test under non-vibration state and L-box test under vibration state are carried out to verify the correctness of the improved hard-core soft-shell contact model. The improved hard-core soft-shell contact model can effectively simulate the dynamic response of the complex multiphase concrete fluids with low water-cement ratio, and accurately characterize the change in its rheological properties.

Keywords

• hard-core soft-shell model
• hi theory
• shear-vibration equivalent theory
• pfi parameters