Application of a highly modified asphalt binder for protection from water intrusion into wooden railroad ties

Abstract

Methods for applying a weather-proofing asphalt membrane composition to wooden railroad ties is disclosed. The asphalt membrane composition generally comprises an asphaltic binder, an elastomeric polymer, a wax modifier, a thickener, fumed silica and/or fumed alumina, and/or a saponified fatty acid and resin acid gelling compound. In one embodiment, the asphalt membrane composition is sprayed as a hot liquid onto the surface of the railroad tie. In other embodiments, preformed pads comprising asphalt membrane composition are applied, using to heat, to the surface of the railroad tie. Optionally, an aggregate cover is applied with or to the asphalt membrane composition. The asphalt membrane composition is formulated to reduce the water permeability of the tie, and protect the tie from degradation due to moisture, UV radiation, and extreme temperatures, thus prolonging the usable lifespan of the wooden railroad tie.

1 . A method of applying a weather-proofing asphalt membrane composition to a wooden railroad tie having cracks and/or air voids on its surface, the method comprising:
 applying the composition onto the surface of the wooden railroad tie, wherein application of the composition penetrates at least some of the cracks and/or air voids that exist on the surface, and   allowing the composition to cool;   wherein the composition comprises an asphalt binder and at least one additive.   
     
     
         2 . The method of  claim 1 , further comprising mixing and heating the composition prior to applying it to the surface of the wooden railroad tie. 
     
     
         3 . The method of  claim 1 , wherein the at least one additive is selected from an elastomeric polymer, a wax modifier, or a filler. 
     
     
         4 . The method of  claim 2 , wherein the filler comprises fumed silica or fumed alumina. 
     
     
         5 . The method of  claim 1 , wherein the composition comprises an asphalt binder, an elastomeric polymer, and a filler. 
     
     
         6 . The method of  claim 1 , wherein the composition further comprises at least one wax modifier. 
     
     
         7 . The method of  claim 1 , wherein the asphalt binder comprises 85 to 97 wt. % of the composition. 
     
     
         8 . The method of  claim 2 , wherein the elastomeric polymer comprises 1 to 6 wt. % of the composition. 
     
     
         9 . The method of  claim 2 , wherein the wax modifier comprises 1 to 5 wt. % of the composition. 
     
     
         10 . The method of  claim 2 , wherein the filler comprises 1 to 10 total wt. % of the composition. 
     
     
         11 . The method of  claim 1 , wherein application of the composition to the wooden tie reduces the water permeability of the wooden tie. 
     
     
         12 . The method of  claim 1 , wherein the composition is formulated to become substantially tack-free about 30 minutes after being applied to the surface of the wooden tie. 
     
     
         13 . The method of  claim 9 , wherein the wax modifier comprises an amide wax. 
     
     
         14 . The method of  claim 2 , wherein the elastomeric polymer comprises a styrene-butadiene-styrene compound. 
     
     
         15 . The method of  claim 1 , wherein the composition is applied by spraying. 
     
     
         16 . The method of  claim 15 , wherein the composition is sprayed onto the surface of the wooden tie using a spraying system mounted to mechanically driven mobile equipment. 
     
     
         17 . The method of  claim 15 , wherein the composition is sprayed onto the surface of the wooden tie using a spraying system mounted to a manually driven mobile equipment. 
     
     
         18 . The method of  claim 15 , wherein the composition is applied using a rail-mounted vehicle or device from a position above the surface of the railroad tie. 
     
     
         19 . The method of  claim 1 , wherein the composition is applied onto the surface of the wooden tie at a thickness of approximately ⅛ of an inch. 
     
     
         20 . The method of  claim 1 , wherein the composition is applied to the wooden tie at a temperature between 300° F. and 350° F. 
     
     
         21 . The method  claim 1 , further comprising applying aggregate to the composition.