PROBLEM

For composite pavement, the lack of a stable base and foundation soils beneath existing joints and cracks in concrete pavement is one of the causes of premature failure of the asphaltic concrete overlay.  The unstable soils beneath the concrete cause the pavement to deflect as traffic loads are inefficiently transferred from one slab to another beneath the asphalt overly.  In short order, the constant movement causes reflective cracking of the asphaltic concrete overlay.  This reflective cracking then leads to water infiltration at the joints and cracks and even weaker pavement support.  The continual movement of the pavement causes spalling of the asphalt overlay and significantly reduces the life of the overlay.

SOLUTION

Prior to the overlay, apply UDI with URETEK 486 STAR® water resistant expansive polymer to one row of injections on the approach and leave side of each joint and crack.  Inject through tubes, to a depth of approximately 3′ into the foundation soils by drilling 3/4″ holes through the concrete and injecting through tubes into the soils.  This is typically accomplished on a 4′ grid pattern.  URETEK monitors the surface using laser monitors and/or dial indicators and knows that the roadway has become adequately supported when an indication of movement is detected on the monitors.

EXPECTED RESULTS

  • Decreased deflections at the joints and cracks.
  • Increased Load Transfer Efficiencies (LTE’s) at the joints and cracks.
  • Extends the life of the overlay.

BENEFITS

  • Zero daytime lane closures.
  • Multi-lane mile projects are accomplished with up to four production trucks and stay ahead of the prime contractor performing the mill/overlay.
  • Injection can be accomplished in wet soil conditions as URETEK 486 STAR® hydro-insensitive polymer will form a dimensionally stabile polymer even when injecting into saturated soils. The expansion process will also drive the water out of the soil system.