Abstract
The friction at the steel-concrete interface on the boundary layer that occurs during the flow of a fluid concrete in a drain plays an important part in its pumpability. These frictions are directly related to the composition of the formed boundary layer which depends on the concrete composition parameters. In order to highlight the relationship between concrete composition and friction interface, the authors initially developed and validated an apparatus called tribometer allowing them to make steel-concrete interface friction measurements and deduce interface parameters. Its' simple use at building sites enabled the authors to study the influence of the concrete composition on the resulting interface friction and its parameters, namely, viscous constant and interface yield stress. The results show that the increase in the cement paste volume, the water per cement ratio and the proportioning in superplasticizer support the concrete pumpability. The increase of the fine sand quantity in concrete induces negative effects on the interface frictions and on pumpability.
