We design and try to build a uniform pavement structure (see above) to cover a site that is not homogeneous.
Our most recent example of land resisting being covered happened after several days of heavy rainfall in south Texas. The photograph presents a five-year-old pavement which appears to have “blown-up” (our technical term) from a localized area of a high-water table. At first, we thought it was cause by a sharply turning garbage truck, but there are no tire tracks or depressions. The upward water pressure pushed to aggregate base and asphalt concrete layer out of the structure.
More typically, pavements will heave and fall with changes in moisture content and freeze-thaw cycles.
Another example for asphalt concrete pavements, there is the constant ultraviolet sunlight to oxidize the asphalt cement. The resulting block cracking combined with vehicle loads will break down the pavement surface. Without ongoing maintenance activity, vegetation will overcome the pavement. Nature eventually takes back the parking lot.
Zimmer Consultants Photographs