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Owing to enhanced filling ability, self-consolidating concrete offers accelerated casting and superior quality control during construction. However, its high fluidity and high placement rate increase the lateral pressure on the formwork, necessitating an extensive supporting system to retain fresh mixtures in a desired shape. Current recommendations of formwork design for self-consolidating concrete adopt the concept of hydrostatic pressure, even though the measured pressure could be less than the recommended level. This study shows that mineral admixtures such as processed clays can appreciably lessen the formwork lateral pressure. In addition, the correlation between the formwork pressure response and the loss of slump flow is derived, providing an approximate method to estimate the reduction in formwork pressure.

Self-consolidating concrete (SCC) is a recently developed innovative construction material. No additional compacting is needed because of its high filling ability; consequently, the labor cost of compacting is economical. SCC, however, needs a stronger formwork that can resist the higher lateral pressure of cases that use ordinary concrete. This study uses the proposed two-function model to: 1) characterize the pressure response of a fresh SCC mixture; and 2) evaluate the maximum pressure that develops on the formwork. Various SCC compositions were experimented with to show the validity of the evaluation. The experimental results and analytical interpretation suggest that the maximum lateral pressure allowed in the design of the SCC formwork could be determined from 2 parameters that depend on the placement rate and duration of the placement.