Natural Weathering of Mineral Stabilized Asphalt Coatings on Organic Felt
U.S. National Bureau of Standards, 1969 - 15 pages
Sixteen years of outdoor weathering of laboratory-prepared smooth-surface and mineral-surfaced, felt-base roofing specimens has provided information on the effects of mineral additives on the durability of coating-grade roofing asphalts. Six finely divided mineral additives (blue black slate, clay, dolomite, fly ash, mica, and silica) were evaluated at concentrations up to 60 percent in California, Mid Continent and Venezuela asphalts. The mineral-surfaced specimens are all performing satisfactorily, and show only minor degrees of degradation. Of the smooth-surfaced specimens, the Mid-Continent asphalt performed the best and the California asphalt the poorest. The mica and blue black slate increased the durabilities of all three asphalts at all concentrations and two coating thicknesses. Fly ash, clay, dolomite, and silica were beneficial in some combinations, but had little effect in others. In general, these early results from outdoor exposure tend to corroborate the results obtained on these coatings exposed in weatherometers. (Author).
60 percent aluminum aluminum-base specimens appearance Applied areas asphalt coatings ASTM base Black Slate 25 blistering Blue Black Slate Building Building Science Series Bureau of Standards California asphalt Cement Center cents Characteristics Clay Column COMMERCE concentrations consists containing corresponding cracking criteria deterioration differences direction divisions doctor bar Dolomite durability early effects exposed exposure failed failure felt-base specimens FIGURE Fly Ash Government granule-surfaced specimens granules grid half heated industry Institute Kraft paper listed longer Loss on ignition losses machine materials measurement method Mica Mid-Continent asphalt mils mineral additives Months Ratio Months National Bureau observed Office Organic panel passed performances period physical prepared procedure produced Properties provides Ratio Months Ratio reference reported Research rolls roofing saturated felt sheets shingle Silica smooth smooth-surface smooth-surface specimens spalling surface TABLE technical Technology temperature tests three asphalts Venezuela asphalt Washington weather weatherometer tests