Zemdrain Liner

The benefits of Zemdrain at a glance
 Reduced surface water/cement ratio
 Virtually blowhole free, smooth surface
 Release agents not used
 High surface durability
 Reduced surface abrasion
 Improved resistance to freeze/thaw action
 Reduced microbiological growth and improved hygiene
 Reduced carbonation
 Reduced depth of ingress of water and chlorides
 Proven cost savings during total useful life (Institute for Domestic Water Supplies Hanover)
Zemdrain controlled permeability formliners (CPF) considerably improve the quality of the concrete surfaces of vertical and inclined walls.

Zemdrain is fixed to the formwork before erection. Once the formwork is erected, concrete is placed and compacted in accordance with normal practice. Zemdrain retains the concrete fines whilst allowing the controlled drainage of excess air and water that is normally trapped at the concrete /formwork interface. Accordingly water retained within the formwork side of the formliner is given back to the concrete during the curing phase (early age curing of green concrete). After removal of the formwork, the very dense, hard, virtually blowhole free surface uncontaminated by release agents produced with zemdrain is immediately visible. Use of zemdrain optimizes the surface water/cement ratio, minimizes blowholes and improves early age curing to give a high quality durable concrete surface with optimum resistance to all forms of environmental attack.
Applications of Zemdrain

Zemdrain of all types consists of a fitter layer consisting of polypropylene fibers with a highly controlled pore structure that ensures retention of cement and fine aggregate but is permeable to water and air. Adhesion of the filter to the concrete is minimal. The rear of the liner is a drainage layer consisting of either polypropylene fibers or a special grid.