Investigating the Thixotropic Behaviour of Tremie Concrete Using the Slump-flow Test and the Material Point Method

TL;DR

This paper develops a new thixotropic model integrating the Papanastasiou-Bingham framework with thixotropy equations to accurately simulate the flow of Tremie Concrete, revealing how rest-time impacts workability and flow behavior.

Contribution

The study introduces a novel thixotropic model within the Material Point Method that captures concrete flow behavior and workability decline during slump-flow tests, which previous models overlooked.

Findings

The model accurately reproduces field slump-flow measurements.

Thixotropy causes a decline in concrete workability after rest periods.

Rest-time significantly affects the flow behavior of fresh concrete.

Abstract

A new thixotropic model is developed integrating the Papanastasiou-Bingham model with thixotropy equations to simulate the flow behaviour of Tremie Concrete in the Material Point Method framework. The effect of thixotropy on the rheological behaviour of fresh concrete is investigated by comparing field measurements with numerical simulations. The comparison yields new insights into a critical and often overlooked behaviour of concrete. A parametric study is performed to understand the effect of model parameters and rest-time on the shear stress response of fresh concrete. The Material Point Method with the Papanastasiou-Bingham model reproduces slump-flow measurements observed in the field. The novel model revealed a decline in concrete workability during the Slump-flow test after a period of rest due to thixotropy, which the physical version of the test fails to capture. This reduction in workability significantly affects the flow behaviour and the effective use of fresh concrete in construction operation.