Most soil under Colorado's concrete driveways has an unusual ability to expand and contract due to moisture absorption. The reason? Bentonite clay.
Bentonite, or Sodium bentonite expands when wet, possibly absorbing several times its dry mass in water. While most soils containing bentonite will not expand more than 35 to 50 percent in volume, it is this expansion in volume that causes the pressure and movement. No concrete is safe, even stamped or decorative concrete can be damaged by swilling soil. Cracking and lifting of concrete is common among most Denver residences.
The Solution? If you are serious about eliminating the maintenance issue surrounding bentonite and its effects on concrete, paving stones are the solution in Colorado.
A correct instillation of paving stones removs bentonite soil down to 12 inches benefit the grade. A geo-tex fabric is then placed in the excavated area. This fabric preserves the load bearing capacity of the base for a greater length of time. High compaction road base is then added between the geo-tex fabric and underneath soil. A high impact plate compactor is then used to compact the road base. This eliminates water expansion and air pockets within the base layer. A small layer of bedding sand is added and smoothed over the road base completing the base layer instillation.
Make sure your paving stone contractor is ICPI Certified, a leading authority on paving stone applications.
A certification is given to contractors who abide by the standards of ICPI. Unlike concrete contractors, paving stone contractors must adhere to the highest standards set by the ICPI ensuring a quality job for your home.