Effect of field variables and test procedures on silane weatherproofing performance (FHWA-OK-93-02) 2178

The performance of a generic silane penetrating water repellent material was evaluated using alternate test procedures . Field variables introduced into the laboratory tests included: 1) concrete mix design, 2) concret~ surface finish , and 3) curing and cleaning methods prior to the application of silane. Two basic laboratory tests series were used: 1) Oklahoma Department of Transportation tests, and 2) a series based on NCHRP 244 Series II. Silane performance was evaluated with respect to depth of penetration, absorption, water vapor permeability, and chloride ingress. One mix type examined was similar to standard reference concrete often used in laboratory testing (w/c=0.49) . The other two mixes represented structural deck concrete (w/c=0.44) and high density overlay (w / c = 0.33). Concrete surface finishes studied included smooth/broom and tine. Curing methods examined included use of a linseed oil emulsion compound, use a white pigmented membrane compound, and self-curing. Methods used to clean the concrete surface prior to treatment were dry shot-blasting, high pressure water washing, and no cleaning. Results indicated the need to represent field conditions (particularly mix design) to the extent possible in order to predict better field performance with laboratory tests. Also, relative performance of some mixes was affected by the test procedure performed.Final Report, July 1990-June 1993N