Effect of Formwork Characteristics on SCC Lateral Pressure

摘要

Lateral pressure exerted on vertical formwork by fresh self-consolidating concrete (SCC) controls its design. Several factors, including material properties, placement conditions, and formwork characteristics, can affect formwork pressure. This paper presents the influence of formwork width (0.20-1.0 m), shape (circular versus square), and surface material (PVC, plywood, steel, and polyester filter membrane) of formwork on lateral pressure characteristics. The diameter of the pressure sensor used to evaluate lateral pressure characteristics is also investigated. The results showed that the increase in formwork width can increase the initial lateral pressure and delay the time needed for the formwork removal. Correction factors accounting for the changes in the formwork width on the initial pressure and pressure decay were developed. The formwork surface materials did show significant effect on initial formwork pressure, and different pressure decay responses were observed for each formwork material. The longest time for pressure cancellation was obtained for the steel formwork, and the shortest one for the polyester filter membrane.