The Paving Blog

Addressing a question I received via email today, so here goes -

Pavement cracks come from a small variety of sources.  Typically, both in asphalt paving and concrete paving, the sub grade below the roadway itself determines pretty much everything dealing with the heaving and contraction issues which severe weather induces.  Asphalt is nowhere as rigid as cement, but it can also crack under stress.  Naturally, no crack ever improves, after that point.  It is a matter of widening and becoming yer more glaring and severe, separated more so by continuing the same stresses and now even factoring in the presence of pockets of trapped water which will further erode the integrity by freezing itself and causing flaking or absolute separation.

Concrete, as a rigid monolithic piece, will always crack.  Even the best professionals understand this.  What typical highway construction specifications insist on is the presence of re bar, or rods of connecting metal, imbedded inside the cement itself, which will take the cracking and do not allow it to separate in any gross manner. Naturally, severe cracking will need repairing, but re bar gives the surface a chance to last longer as a viable road or driveway surface.

Typically, expansion joints are placed in concrete literally “inviting” it to crack along predetermined lines.  Once this is done, if it happens, then the preset position has been accounted for and dealt with.  Further damage would necessitate replacement of the concrete however, if the cracks appear elsewhere.

It is not a comfortable or productive feeling seeing a crack form in concrete.  As I stated above, cracks don’t “get better”. But they can be filled, reducing if caught on time, further damage.  Once weather and water are allowed inside the cracks, a surface is not long for this productive world.  Improper placement of the expansion joints is a very common reason for cracking.