Expansion joint for concrete structures - is smooth synthetic sheet with trapezoidal projections cast in-situ into concrete

摘要

The expansion joint for concrete structures is made of a hard synthetic laminated material. The joint has a smooth, flat back surface which does not adhere to the concrete. The front surface carries projections of a trapezoidal shape. The projections secure the front surface into the concrete, and increase in size towards the bottom of the joint. The joint forms the shuttering for a concrete pour and is intended to compensate for shrinkage as the concrete sets, and for thermal expansions of the hardened concrete.