Prediction of lateral form pressure exerted by concrete at low casting rates

In this work, we propose to extend the Ovarlez and Roussel model, for estimating lateral form pressure exerted by fresh concrete, to low casting rates and long duration formwork filling. In this case, the assumption of a linear increase of the concrete yield stress with time at rest is imprecise. This assumption is valid for approximately 1 h at rest after placing and may lead to an overestimation of the lateral pressure for a longer period. Based on chemical arguments and experimental observations, it has been shown that the yield stress increases exponentially over time. The same fundamental physical assumptions made by Ovarlez and Roussel are used to predict the lateral pressure exerted on formwork. Comparison of the proposed model with experimental measurements shows that, pressure can be predicted with an accuracy comparable to the Ovarlez and Roussel model for casting times less than 1 h.