EFFECTS OF FORMWORK SURFACE MATERIALS ON CONCRETE LATERAL PRESSURE

Abstract In this study, the effect of formwork surface materials on the concrete lateral pressure was investigated. Seven wall formworks were constructed. Populus nigra timber, pinus silvestris timber, plywood and steel sheet were used as surface materials for these formworks. One of two formwork, which had the same surface material, was watered except for the steel formwork before placing the concrete. Concrete was placed into the formworks and the lateral pressures of concrete on formworks surface were measured by a strain measurement system. As comparison the limiting value of concrete lateral pressure was calculated by ACI-347 equation. It was concluded that, watering the surface of wood formworks increased lateral pressure of concrete on the formworks. Lateral pressure of steel formwork was equal to limiting value of ACI-347 and larger than lateral pressure of populus nigra, pinus silvestris, and plywood formworks. The lateral pressure of pinus silvestris formwork was some less than 3.3%, 7.2%, 21%, respectively, lateral pressure of populus nigra, plywood, and steel formwork”.