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