Influence of temperature and concrete reinforcement on vertical formwork design

Abstract The design of vertical formwork is governed by the lateral pressure exerted by fresh concrete; while maximum lateral pressure is the key parameter for formwork design, the pressure stabilization time is important for determining formwork removal time. This work describes an experimental study of columns made with self-compacting concrete (SCC) to determine the variation in the maximum lateral pressure and the pressure stabilization time with the following variables: concrete temperature and the presence of different reinforcement densities. Maturity functions and their relationship to the resistance acquired by the concrete over time were studied in order to determine the minimum times for formwork removal. The results show that SCC temperatures have an inverse relationship with the lateral pressure of fresh concrete, and the influence of reinforcement on the maximum lateral pressure depends on the number of steel bars and their arrangement; moreover, the lateral pressure of fresh concrete has no influence on the pressure stabilization time. Finally, a formwork removal method based on the maturity index was proposed.