Shuttering for prismatic concrete components

摘要

The shuttering is esp. for columns and supports, its tube being expanded by heating to allow removal after the concrete has set. In a first stage the temperature is slightly raised to speed up drying of the concrete, while in a second stage and after setting more heat the tube diameter expands. The difference in expansion between the heated tube and the unheated insulating and protecting one causes visible relative movement between the two and thus indicates the degree of expansion. In the case of climbing shuttering, a sealing ring is used, of metal, plastics or other hard material on the inside, inverted over the reinforcing steel. The outside is of soft sealing material such as foam rubber. This is a press-fit in the tube, preventing liquid concrete flowing downwards during subsequent pouring. Wall anchors pressed into the fresh concrete prevent lifting with the shuttering.