Jan2011_ES&E_D4_ES&E 11-02-02 2:18 AM Page 42
Corrosion
Figure 5. Repairing a clarifier in Slobozia, Romania.
Figure 6. Spraying on Kote Flex ST.
Figure 7. Cracks are treated with Cem-Kote Flex ST and embedded Reinforcing Fabric NW.
and manholes. Chemical resistance of Cem-Kote Flex CR to microbiologically formed sulphuric acid has been extensively tested in the test chamber of the Moscow Vodokanal in Russia, which has a high hydrogen sulphide environment,. Both Flex ST and CR are easy to apply, and tools and equipment can be cleaned simply by washing with water. They are two-component materials, consisting of dry bagged powders and a liq-
uid polymer additive supplied in a plastic container. The two components are mixed on-site using a conventional electric paddle mixer, or mortar mixer, and applied in two coats by brushing or spraying to a total thickness of 1.6 to 2 mm. In new construction, a high pressure wash is sufficient to clean existing concrete. Smaller “bug-holes� are coated over with Flex ST/CR, and larger ones are
pre-filled with the same material mixed with less of the liquid component to obtain a trowel consistency. Any shrinkage cracks are treated with Reinforcing Fabric NW, which provides waterproofing even if the crack bridging capacity of Flex ST/CR is exceeded. Several types of equipment, including peristaltic and positive displacement pumps may be used for the spraying. When there are very rough surfaces,
AnCAT AnC ATLiquid Polymer System • Complete Activation of Polymer Chains • Neat Polymer Flow Rate 0-50 LPH • Max. back pressure up to 150 psig • Modular System • Automation available upon request
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42 | January 2011
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