Paving article with improved durability

Abstract

A paving brick with a means for reducing mechanical stress on at least one edge of a top surface, particularly when used in a paving system for roads, streets, sidewalks and like when heavy vehicle load applies a force on the top surface. In one embodiment the means for reducing mechanical stress is a rounded edge. In another embodiment the means for reducing mechanical stress is an angle sidewall having an angle theta between 75 and 85 degrees.

1 . A paving brick for use in the construction of roadways and the like, comprising;
 a bottom surface;   a top surface;   a plurality of vertical sides, wherein at least one of said vertical sides forms a rounded edge with said top surface, and wherein;   said rounded edge comprises not more than one third of the total height of said vertical side of said paving brick.   
     
     
         2 . The paving brick of  claim 1  wherein said rounded edge has a radius of curvature of between 1 mm and 4 mm. 
     
     
         3 . The paving brick of  claim 1  comprising a material with a water vapor transmission rate of at least 1,500 grains per 24 hours per square meter. 
     
     
         4 . The paving brick of  claim 3  comprising a material with a compressive strength of between 40 MPa and 75 MPa. 
     
     
         5 . The paving brick of  claim 3  comprising a material with a tensile strength of between 0.1 MPa and 0.3 MPa. 
     
     
         6 . A paving brick for use in the construction of roadways and the like, comprising;
 a bottom surface;   a top surface;   a plurality of vertical sides, wherein at least one of said vertical sides is sloped such that said top surface has at least one length dimension smaller than at least one length dimension of a parallel bottom surface, and such that an angle formed between the junction of at least one of said vertical sides and said bottom surface is more than 75 degrees and less than 85 degrees.   
     
     
         7 . The paving brick of  claim 6  comprising a material with a tensile strength of between 0.1 MPa and 0.2 MPa. 
     
     
         8 . The paving brick of  claim 6  comprising a material with a compressive strength of 40 mpa to 75 mpa. 
     
     
         9 . The paving brick of  claim 6  comprising a material with a water vapor transmission rate of between 1,500 and 5,000 grains per 24 hours per square meter. 
     
     
         10 . The paving brick of  claim 5  comprising a material wherein the modulus of rupture is between about 10 MPa and about 20 MPa. 
     
     
         11 . A roadway comprising a plurality of paving bricks wherein the distance between said plurality of paving bricks when viewed from the top down is between 5 mm and 15 mm, and wherein said plurality of paving bricks comprise a means for resisting mechanical stress induced spalling of at least one exposed top edge. 
     
     
         12 . The roadway of  claim 11  wherein said means for reducing mechanical stress induced spalling comprises at least one inwardly sloping side wall having an angle theta of between 75 and 85 degrees. 
     
     
         13 . The roadway of  claim 11  wherein said paving bricks are comprised of a material having a water vapor transmission rate of between 1,500 and 5,000 grains per 24 hours per square meter. 
     
     
         14 . The roadway of  claim 11  wherein said paving bricks are comprised of a material with a tensile strength of between 0.1 MPa and 0.2 MPa. 
     
     
         15 . The roadway of  claim 11  wherein said paving bricks are comprised of a material with a compressive strength of 40 mpa to 75 mpa. 
     
     
         16 . The roadway of  claim 11  wherein said paving bricks are comprised of material with a modulus of rupture of between about 10 MPa and about 20 MPa.