Track bed and method of stabilizing a track bed

Abstract

A track bed for a railroad track, includes track ballast made from particulate matter and a multitude of railroad ties supported on the track ballast, wherein at least one region of the track ballast is stabilized by a bonding agent that bonds together particles of the particulate matter, wherein the bonding agent is based on a hydraulic binder, in particular cement, and the bonding agent leaves free voids between the bonded particles so that the track ballast has a water draining capability in the at least one stabilized region.

1 . A track bed for a railroad track, comprising track ballast made from particulate matter and a multitude of railroad ties supported on the track ballast, wherein at least one region of the track ballast is stabilized by means of a bonding agent that bonds together particles of the particulate matter, wherein the bonding agent is based on a hydraulic binder, and the bonding agent leaves free voids between the bonded particles so that the track ballast has a water draining capability in said at least one stabilized region. 
     
     
         2 . The track bed according to  claim 1 , wherein the bonding agent is a hardened cement slurry. 
     
     
         3 . The track bed according to  claim 1 , wherein the hydraulic binder is a Portland cement binder. 
     
     
         4 . The track bed according to  claim 1 , wherein the track ballast comprises a central region located below said railroad ties and side regions arranged on both sides of said central region, wherein only the side regions are stabilized by said bonding agent. 
     
     
         5 . The track bed according to  claim 1 , wherein the stabilized region has a mass ratio of bonding agent to track ballast of 1:10-1:20. 
     
     
         6 . A method of stabilizing a track bed for a railroad track, said track bed comprising track ballast made from particulate matter and a multitude of railroad ties supported on the track ballast, wherein particles of the particulate matter are bonded together by means of a bonding agent that is based on a hydraulic binder, said bonding agent being applied to the particles of the particulate matter so as to leave free voids between the bonded particles so that the track ballast has a water draining capability. 
     
     
         7 . The method according to  claim 6 , wherein the bonding agent comprises or consists of a cement slurry. 
     
     
         8 . The method according to  claim 6 , wherein the hydraulic binder is a Portland cement binder. 
     
     
         9 . The method according to  claim 6 , wherein the bonding agent is poured or sprayed onto the track ballast in at least one region to be stabilized. 
     
     
         10 . The method according to  claim 6 , wherein the bonding agent is mixed with the particles of said particulate matter and the resulting mixture is placed as track ballast on a track formation. 
     
     
         11 . The method according to  claim 6 , wherein the track ballast comprises a central region located below said railroad ties and side regions arranged on both sides of said central region, wherein the bonding agent is only applied to the particles of the side regions. 
     
     
         12 . The method according to  claim 6 , wherein a flowability of the bonding agent, at the time of application, is 2-7 seconds, when measured according to a spread test method inspired from the method described in ASTM D6910/D6910M-09, where the dimensions of the funnel are adapted for slurries (internal top cone diameter: 149 mm, internal bottom cone diameter: 17.3 mm, bottom tube height: 30.3 mm, total height: 190 mm (comprising cone and bottom tube)) and where the time measured to characterize the flowability corresponds to the flow of 0.6 L of the product. 
     
     
         13 . The method according to  claim 6 , wherein the bonding agent has an initial slump of at least 90 mm, measured according to a spread test method inspired from EN 12350-8 referring to the testing of fresh concrete/self-compacting concrete, wherein the dimensions are adjusted for slurries (height 57 mm, internal diameter at top: 21 mm, internal diameter at bottom: 37 mm) 5 min after mixing. 
     
     
         14 . The method according to  claim 6 , wherein the Portland cement has a specific surface of 3000-10000 cm 2 /g. 
     
     
         15 . The method according to  claim 6 , wherein the bonding agent comprises a water reducer. 
     
     
         16 . The method according to  claim 6 , wherein the bonding agent is poured or sprayed onto the track ballast in an amount of 40-70 litres per m 2  of track ballast surface and per m of track ballast thickness. 
     
     
         17 . The method according to  claim 6 , wherein the bonding agent is poured or sprayed onto the track ballast in such an amount that a homogeneous bed of said bonding agent is formed at the bottom of the track ballast. 
     
     
         18 . The track bed according to  claim 1 , wherein the hydraulic binder is cement. 
     
     
         19 . The track bed according to  claim 2 , wherein the bonding agent is a hardened cement paste or cement mortar. 
     
     
         20 . The track bed according to  claim 3 , wherein the Portland cement binder is a cement of the type CEM I, CEM II, CEM III, or aluminate cement. 
     
     
         21 . The method according to  claim 7 , wherein the bonding agent is a cement paste or cement mortar. 
     
     
         22 . The method according to  claim 8 , wherein the Portland cement binder is a cement of the type CEM I, CEM II, CEM III, or aluminate cement. 
     
     
         23 . The method according to  claim 12 , wherein the flowability of the bonding agent, at the time of application, is 2-4 seconds. 
     
     
         24 . The method according to  claim 14 , wherein the specific surface (Blaine) is 3500-6000 cm 2 /g. 
     
     
         25 . The method according to  claim 15 , wherein the water reducer is a plasticiser or a superplasticizer. 
     
     
         26 . The method according to  claim 25 , wherein the water reducer is a polycarboxylate based or a polynaphthalene sulfonate based water reducer. 
     
     
         27 . The method according to  claim 16 , wherein the bonding agent is poured or sprayed onto the track ballast in an amount of 50-70 litres per m 2  of track ballast surface and per m of track ballast thickness. 
     
     
         28 . The method according to  claim 27 , wherein the bonding agent is poured or sprayed onto the track ballast in an amount of 55-65 litres per m 2  of track ballast surface and per m of track ballast thickness. 
     
     
         29 . The method according to  claim 17 , wherein the bed has a height of 5-20 mm.