MODELING OF THE MOTION OF CONCRETE MIXTURE ON THE SURFACES OF MONOLITHIC STRUCTURES

Abstract

This article addresses the problem of uniform distribution of concrete mix during the formation of monolithic structures on inclined and curvilinear surfaces. The relevance of the study is due to the increasing use of shell, dome, and spatial structures in modern construction, where concreting is performed on surfaces with significant inclination and variable curvature. Under such conditions, the behavior of the concrete mix significantly differs from that observed in horizontal structures of monolithic spatial coverings. This leads to potential defects associated with the non-uniform distribution of material over the surface of structures.

At the early stages of hardening, the concrete mix is modeled as a viscoplastic material of the Bingham type, characterized by yield stress and plastic viscosity. Based on the principles of continuum mechanics, the conditions for the onset of flow under the action of gravity on inclined surfaces are analyzed. Analytical expressions are derived that describe the distribution of shear stresses and velocity profiles within the concrete layer, making it possible to determine the critical conditions for the transition from a solid-like to a flowing state.

Special attention is paid to the generalization of the classical flow model for curvilinear shell surfaces. To achieve this, the mathematical apparatus of differential geometry is employed, allowing consideration of local inclination angles, principal curvatures, and variations in the direction of gravity along the surface. It is shown that the stability conditions of the concrete layer are determined by the local geometric characteristics of the shell.

The proposed model provides a theoretical basis for assessing the stability of concrete mixtures on complex surfaces and can be applied to optimize concreting technologies in the construction of monolithic shell structures. The results contribute to improving structural quality and reducing the risk of defects associated with non-uniform material distribution. The obtained results can be used to develop recommendations for mix design selection, placement regimes, and quality control of concreting under real construction site conditions.