Wal-Mart Parking Lot

The project was in Shreveport, Louisiana in the Shreve City Shopping Center at the new Wal-Mart Super Center.  An Asphaltic Surface Treatment was applied to the existing concrete parking lot prior to paving with hot-mixed asphaltic concrete.  This "under-sealing" is an economical method often employed to assist new asphaltic concrete overlays in preventing water from seeping through the joints between existing concrete panels should they move and "reflect" up through the new surface.


The thumbnail to the right shows the application of hot liquid asphalt to the existing concrete surface with one of our asphalt distributors (click picture for larger view).


The thumbnails to either side show aggregate being applied onto the hot asphalt.  Aggregate is hauled from a nearby stockpile to the chip spreader in tandem dump trucks (click picture for larger view).


This thumbnail shows the aggregate being rolled to insure proper seating in the liquid asphalt (click picture for larger view).


This parking lot has been around we are told since the early 1960's and the base was still in relatively good condition.  As long as water is not allowed to infiltrate into the base and sub-grade soils below, a good base could theoretically last forever.  However, once the surface of a pavement structure ages to the extent that any small cracks develop, inevitably water will seep in, then the very expensive pavement structure begins to deteriorate.  The loss of a pavement structure starts out slowly with a few potholes here and there, then alligator cracking in increasingly larger areas usually begins to develop and grow, and then finally base and sub-grade matter are squeezed to the surface.  Then all is lost.









SURFACE      The SURFACE may consist of Asphaltic Concrete (Hot-mix), Portland Cement Concrete, or Asphaltic Surface Treatment
BASE          The BASE my be constructed with compacted crushed stone, crushed shells, or other crushed aggregate.  The aggregate may be further stabilized by mixing in an agent such as cement, lime, or fly ash.  Sometimes cement can be mixed with local sand to provide an adequate and inexpensive base.
SUB-GRADE   The SUB-GRADE usually consists of compacted natural local soils.  Sometimes it may be treated with a stabilizing agent such as cement, fly ash, or lime.