Concrete surfaces are usually uneven, rough, and porous. In order to develop a proper substrate for gage bonding, it is necessary to apply a leveling and sealing precoat of epoxy adhesive to the concrete, typically M-Bond AE-10. Before applying the precoat, the concrete surface must be prepared by a procedure which accounts for the porosity of this material.

Contamination from oils, greases, plant growth, and other soils should be removed by vigorous scrubbing with a stiff-bristled brush and a mild detergent solution. The surface is then rinsed with clean distilled water. Surface irregularities can be removed by wire brushing, disc sanding, or grit blasting, after which all loose dust should be blown or brushed from the surface. The next step is to apply Conditioner A generously to the surface in and around the gaging area, and scrub the area with a stiff-bristled brush. Contaminated Conditioner A should be blotted dry with gauze sponges, and then the surface should be rinsed thoroughly with clean distilled water.

Following the water rinse, the surface acidity must be reduced by scrubbing with Neutralizer 5A, blotting dry with gauze sponges, and rinsing with distilled water. A final thorough rinse with distilled water is useful to remove the residual traces of water-soluble cleaning solutions. Before precoating, the cleaned surface must be thoroughly dried. Warming the surface gently with a propane torch or electric heat gun will hasten evaporation.

Micro-Measurements M-Bond AE-10 or GA-2 room-temperature-curing epoxy adhesive are an ideal material for precoating to fill the voids in the concrete. For those cases in which the test temperature may exceed the specified maximum operating temperature of AE10 (+200°F [+95°C]), it will be necessary to fill the surface with a higher temperature resin system such as M-Bond GA-61. In applying the coating to the porous material, the adhesive should be worked into any voids, and leveled to form a smooth surface. When the adhesive is completely cured, it should be abraded until the base material begins to be exposed again.

Surface Cleaning Supplies: http://www.vishaypg.com/docs/11008/surface-cleaning.pdf

AE-10: http://www.vishaypg.com/micro-measurements/list/product-11011/

GA-2: http://www.vishaypg.com/micro-measurements/list/product-11017/

GA-61: http://www.vishaypg.com/micro-measurements/list/product-11016/





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Yuval Hernik

StrainBlog Editor in Chief