Ballasted track systems with rubberized asphalt coatings and related methods

Abstract

An example track system includes: a supporting structure; ballast supported by the supporting structure; a plurality of track ties supported by the ballast; a pair of rails supported by the plurality of track ties; and a layer of rubberized asphalt coating disposed as an interface between the ballast and the supporting structure, the rubberized asphalt coating having bituminous binder, crumb rubber particles, and small gradation hard rock aggregate; wherein resiliency of the layer of rubberized asphalt coating permits particles of the ballast in direct contact with the layer of rubberized asphalt coating to move elastically relative to each other while inhibiting abrasion of adjacent ones of the particles of the ballast against each other and against the supporting structure.

What is claimed is: 
     
         1 . A method for forming a track system having rails, the method comprising:
 providing a supporting structure;   disposing a layer of rubberized asphalt coating on the supporting structure, the rubberized asphalt coating having a bituminous binder, crumb rubber particles, and stone aggregate   disposing ballast on the layer of rubberized asphalt coating, the ballast being configured to support a plurality of track ties; and   disposing a plurality of track ties, configured to support the rails, on the ballast;   wherein resiliency of the layer of rubberized asphalt coating permits particles of the ballast in direct contact with the layer of rubberized asphalt coating to move elastically relative to each other while inhibiting abrasion of adjacent ones of the particles of the ballast against each other and against the supporting structure.   
     
     
         2 . The method of  claim 1 , wherein the rubberized asphalt coating exhibiting 8% to 12% by volume of the bituminous binder, 22% to 40% by volume of the crumb rubber particles, and 48% to 70% by volume of the stone aggregate. 
     
     
         3 . The method of  claim 1 , further comprising disposing a waterproof layer between the layer of rubberized asphalt coating and the supporting structure. 
     
     
         4 . The method of  claim 1 , wherein the layer of rubberized asphalt coating is configured as a waterproofing layer. 
     
     
         5 . The method of  claim 1 , wherein:
 the supporting structure comprises an asphalt underlayment; and   the layer of rubberized asphalt coating is disposed between the asphalt underlayment and the ballast.   
     
     
         6 . The method of  claim 1 , wherein disposing the layer of rubberized asphalt coating on the supporting structure further comprises providing at least a portion of the layer of rubberized asphalt coating in more than one material layer to achieve a desired thickness. 
     
     
         7 . The method of  claim 1 , wherein:
 the supporting structure is a first supporting structure;   the method further comprises providing a second supporting structure adjacent to the first supporting structure; and   disposing the layer of rubberized asphalt coating on the supporting structure further comprises disposing the layer of rubberized asphalt coating on the first supporting structure and the second supporting structure.   
     
     
         8 . The method of  claim 7 , wherein disposing the layer of rubberized asphalt coating on the first supporting structure and the second supporting structure further comprises spanning the layer of rubberized asphalt coating across a transition between the first supporting structure and the second supporting structure. 
     
     
         9 . The method of  claim 1 , further comprising:
 providing constituent components of the rubberized asphalt coating;   mixing the constituent components in a first proportion to form the layer of rubberized asphalt coating;   mixing the constituent components in a second proportion to form rubberized asphalt coating for an under-tie application; and   applying the rubberized asphalt coating of the second proportion to respective undersides of the plurality of track ties.   
     
     
         10 . A track system comprising:
 a supporting structure;   ballast, configured to support a plurality of track ties, supported by the supporting structure;   a plurality of track ties, configured to support a pair of rails, supported by the ballast;   a pair of rails supported by the plurality of track ties; and   a layer of rubberized asphalt coating disposed as an interface between the ballast and the supporting structure, the rubberized asphalt coating having bituminous binder, crumb rubber particles, and stone aggregate;   wherein resiliency of the layer of rubberized asphalt coating permits particles of the ballast in direct contact with the layer of rubberized asphalt coating to move elastically relative to each other while inhibiting abrasion of adjacent ones of the particles of the ballast against each other and the against supporting structure.   
     
     
         11 . The system of  claim 10 , wherein the rubberized asphalt coating exhibiting 8% to 12% by volume of the bituminous binder, 22% to 40% by volume of the crumb rubber particles, and 48% to 70% by volume of the stone aggregate. 
     
     
         12 . The system of  claim 10 , further comprising a waterproof layer disposed between the layer of rubberized asphalt coating and the supporting structure. 
     
     
         13 . The system of  claim 10 , wherein the supporting structure comprises a bridge deck. 
     
     
         14 . The system of  claim 10 , wherein:
 the supporting structure comprises an asphalt underlayment; and   the layer of rubberized asphalt coating is disposed between the asphalt underlayment and the ballast.   
     
     
         15 . The system of  claim 10 , wherein:
 the supporting structure is a first supporting structure;   the system further comprises a second supporting structure positioned adjacent to the first supporting structure; and   the layer of rubberized asphalt coating spans from the first supporting structure to the second supporting structure.   
     
     
         16 . The system of  claim 10 , wherein:
 the system exhibits a discontinuity between the first supporting structure and the second supporting structure; and   the layer of rubberized asphalt coating spans the discontinuity.   
     
     
         17 . The system of  claim 15 , wherein:
 the first supporting structure comprises an asphalt underlayment;   the second supporting structure comprises concrete; and   the layer of rubberized asphalt coating is applied to the asphalt underlayment of the first supporting structure and the concrete of the second supporting structure.   
     
     
         18 . The system of  claim 17 , wherein at least a portion of the asphalt underlayment exhibits a drainage slope, which slopes away from the second supporting structure. 
     
     
         19 . The system of  claim 10 , wherein each of the plurality of track ties has a layer of rubberized asphalt coating disposed on an underside thereof.