Field Investigation of Formwork Pressures Using Self-Consolidating Concrete

There is no widely accepted method for predicting formwork pressures developed by self-consolidating concrete (SCC). The common practice is to assume full liquid head when designing wall forms. This practice helps to avoid malformed elements of formwork blowouts but it can also lead to overly conservative designs and higher costs. In order to optimize formwork designs, it is necessary to identify and characterize the flow/stiffening properties of SCC relevant to the magnitude of the lateral pressure envelope are required. Form pressures are determined by the rate of concrete placement relative to the rate of the development of concrete stiffness. Reducing the rate of concrete placement allows the concrete to gain shear strength and reduces the maximum form pressures. Mixture design should be done prior to the start of construction. Concrete control parameters have to be established to ensure compliance. Changes in the water content of the aggregates can significantly affect the stability of the mixture. This article investigated various approaches for characterizing concrete rheology and found that flow parameters are sensitive to the conditioning of the concrete prior to measurement.