Application Procedures


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5. INSTALLATION

Preparatory Work

Surface Preparation - Concrete surfaces to be treated must be clean and free of laitance, dirt, films, paint, coatings or other foreign matter. The surfaces must also have an open capillary system so as to provide tooth and suction for the Xypex treatment. If surfaces are too smooth, the concrete should be acid etched, lightly sandblasted or waterblasted. Structural defects such as cracks, faulty construction joints and honeycombing should be routed out to sound concrete and repaired in accordance with Xypex Specification Manual Repair Procedures. It should be noted, however, that Xypex is not designed for use in expansion joints or chronic moving cracks.

Horizontal surfaces should have a rough wood float or broom finish. On fresh horizontal concrete, Xypex Concentrate DS-1 or DS-2 powder can be power troweled into the surface while it is still in its plastic state.

Wetting Concrete

Prior to the application of Xypex, concrete surfaces must be thoroughly wetted with clean water to control surface suction, aid the proper curing of the treatment and ensure the growth of the crystalline formation deep within the pores of the concrete. Excess surface water should be removed before the application.

Methods

To mix Xypex for slurry coat application, the Xypex powder is mixed with clean water to a creamy consistency in the following proportions by volume:
Mixing for Brush Application
1.5 lb./sq. yd. (0.8 kg/m2) - Mix 5 parts powder to 2 parts water. 
2.0 lb./sq. yd. (1.0 kg/m2) - Mix 3 parts powder to 1 part water.

Mixing for Spray Application
For 1.5 lb./sq. yd. (0.8 kg/m2) formulation, mix 5 parts powder to 3 parts water.
The mix may vary with equipment type.

Mixing for Dry-Pac
Mix 6 parts Xypex Concentrate powder with 1 part clean water by volume.
Do not mix too wet, otherwise, mix may crack and spall as it dries.

Application

The Xypex treatment should be applied with a semi-stiff bristle brush, a janitor's broom for large horizontal applications, or with specialized spray equipment. For recommended equipment, contact Xypex Chemical Corporation or the nearest distributor. The Xypex treatment must be uniformly applied under the conditions and quantities specified. One coat should have a thickness of 1/16 in. (1.25 mm). When a second coat is required, it should be applied after the first coat has reached an initial set but is still green, (less than 48 hours). Light pre-watering between coats may be required due to drying. The Xypex treatment cannot be applied in rain or during freezing conditions.

Coverage

For normal surface applications, the coverage rate per coat is 1.5 lb./sq. yd. (0.8 kg/m2). For construction joint surfaces, the coverage rate is 2.0 lb./sq. yd. (1.0 kg/m2). See mixing instructions.

Curing

A misty fog spray of water must be used for curing the Xypex treatment. Curing must begin as soon as the Xypex coating has hardened sufficiently so that it is not damaged by a fine spray. Under most conditions it is sufficient to spray Xypex-treated surfaces three times a day for 2 - 3 days. In hot, dry weather spraying may be required more frequently. During the curing period, the Xypex treatment must be protected from rainfall, frost and puddling of water.

For concrete structures that hold liquids e.g. reservoirs and tanks, the Xypex treatment should be cured for three days and then allowed to set for 12 days before filling with liquid.


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