Civil Engineering Reference
In-Depth Information
Figure 2 .12
Spray application of liquid membrane-forming curing compound onto the
concrete surface. (Courtesy of Derek Tibbits, Termguard, Perth Head
Office, 84 Welshpool Road, Welshpool, WA 6106, Australia.)
recommended to be overlapped by about 150 mm and sealed with wood
planks, sand, or glue. One of the advantages of using impervious papers is
reusability. Any tears or holes and other such damage can be easily repaired
using curing-paper patches prior to reuse.
Besides the plastic and paper sheets, curing membrane-forming com-
pounds are also commonly used as covering materials for sealing the
exposed surfaces of concrete to prevent moisture loss in the initial stages.
Similar to curing using plastic and impervious paper sheeting, an impor-
tant advantage of this method is that periodic additions of water are not
required. Membrane-making compounds dissolved in a volatile solvent or
water are usually sprayed directly onto the concrete surfaces. An almost-
impermeable layer remains on the concrete surface after evaporation of the
solvent and seals the concrete (Figure 2.12). The properties and applications
of membrane-making materials for the curing of concrete are described in
the Australian Standard (AS) 3799 standard. Membrane sealing is one the
most widely used methods for extending the curing of concrete after an
initial water curing stage. However, curing membranes should be avoided
when the surface of concrete is to be painted or overlaid with a topping.
This is because the membrane will weaken the bond between the finishes
and the concrete surface. Most curing compounds are not compatible with
the adhesives used to lay flooring materials. Membrane-forming com-
pounds can be translucent or white pigmented. A dye is usually added to
the translucent compounds to enable checking for full coverage of the con-
crete surface by the compound. The dye colour usually fades soon after
formation of the membrane.
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