PROBLEM

Concrete pavement settlement, whether settlement of several panels across all lanes to form a dip or one lane with settled panel(s) causing a faulted longitudinal joint, or multiple panels in succession with faulted transverse joints, is most often caused by weak foundation soils insufficient to support the heavy tractor trailer loads or the increased truck traffic counts.  Once the pavement begins to settle, the pavement system typically is more susceptible to water intrusion, exacerbating the situation.

SOLUTION

Roadway surfaces that have settled can be stabilized and lifted by injecting polymer through tubes at multiple elevations, strengthening the weak sub-grade soils.  This is accomplished by taking DCP tests before the injection process to determine the elevation(s) where the injections will be done; then drilling multiple 3/4″ holes through the concrete and injecting polymer through tubes placed at the level(s) of the weak area(s) into the foundation soils.  This is usually done on a 4′ grid pattern in 4′ elevations.  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.  Injection is continued into the soils to lift the pavement to grade – returning the pavement to original construction, concrete on base on stiffened sub-base/subgrade.  If the faulted joint experiences aggregate lock prior to completing the lift, the joint may require full depth saw cut or if minor can be touched up with diamond grinding.

EXPECTED RESULTS

  • Foundation soils will be sufficiently stiffened to support the load and mitigate future settlement.
  • Deflections will be reduced, and Load Transfer Efficiencies improved.

BENEFITS

  • Zero daytime lane closures.
  • Pavement life extended with proper support of the pavement.
  • Safety hazard eliminated.

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.