Spend a good amount of time drive , particularly in rural country , and you ’ve probably discover those messy - looking shameful squiggle that turn out acrossasphaltroad surfaces in what seems like haphazard fashion . But rest reassure that they ’re not only the outcome of some sloppy tar work by a road crew that resolve to have a few beer before the remnant of the shift .
alternatively , what you ’re discover is crack waterproofing . It ’s a time - honored proficiency for remedying the damaged road surfaces , without inflicting even more pain upon taxpayers by tearing up and repaving the full road .
As aCalifornia Department of Transportation consultive guideexplains , pavement break cracks when stress — from the pounding of enceinte dealings , for example , or expansion and muscle contraction due to seasonal changes in temperature — builds up in the surface layer that exceeds the tensile strength of the mineral pitch . plan and structure flaws , such as inadequate drainage for rain , or a unaccented substructure underneath the road , can also make the surface to fail .
In the arcane , extremely technical world of road maintenance , there seem to be as many different case of cracks as there are type of snow in Finland . One of the most unsightly isfatigue cracking , which turn the main road into something resemble an alligator ’s hide , and which usually requires an blanket repair job . Another character of terms , reflection crack , results from movement between the route ’s asphalt and concrete level , and looks more like a jaggy gash . There ’s alsoedge cracking , in which rows of wavy , curved cracks parallel the route shoulder .
If you tried to build up a nice new route every metre that material happened , it would be prohibitively expensive .
" Introduction to Crack Sealing , " a 2008 treatise on the subject from the Texas Engineering Extension Service at Texas A&M University , notes that just sealing crack is way cheaper — about $ 2,500 per mil ( 1.6 kilometer ) of road , compared to $ 60,000 for putting down an overlay surface . In 2016 , the City of Littleton , Colorado , count on thatcrack sealing cost about $ 5,500 per lane air mile , while overlaying costed approximately $ 320,000 per lane mile .
While the black material that you see on the roads looks like tar , these days it ’s more probable to be some sort of high - performance polymer - asphalt mix , designed to forge a attachment that ’s flexible enough to keep the route from cracking even more . gang apply it to the fissures with a gadget that looks mistily like a vacuum cleaner carpet sweeper hose .
