SECTION 451 – CONCRETE SLAB STABILIZATION
451.01 Description
This Section describes the requirements for stabilizing concrete slabs by drilling injection holes and pumping a high-density polyurethane under the slab.
451.02 Materials
451.02.01 Materials
Provide materials as specified: Quick-Setting Patch Material, Type 1A ................................ ................................ ................................ ........ 903.07 High-Density Polyurethane Grout ................................ ................................ ................................ ......... 903.08.03.A
451.02.02 Equipment
Provide equipment as specified: Grout Pumping Unit ................................ ................................ ................................ ................................ .... 1006.03 Mixer ................................ ................................ ................................ ................................ .......................... 1006.04 Injection Device ................................ ................................ ................................ ................................ .......... 1006.05 Lift Monitoring Equipment ................................ ................................ ................................ .......................... 1006.06 Deflection Testing Equipment ................................ ................................ ................................ ..................... 1006.07 Grinding Machine ................................ ................................ ................................ ................................ ....... 1006.08
451.03 Construction
451.03.01 Slab Stabilization, High-Density Polyurethane Grout
A.Contractor’s Experience. At the preconstruction meeting, s ubmit the name, experience, and material manufacturer’s certification of a manufacturer’s representative to the RE. Ensure that experience includes a minimum of 5 projects on which slab stabilization operations were successfully completed using high -density polyurethane. Ensure that the manufacturer’s representative is at the work site during all high -density polyurethane slab stabilization. The Contractor may not begin the work until the RE approves the manufacturer’s representative.
B.Weather Limitations. Do not perform slab stabilization if the underlying material is frozen.
C.Drilling Holes. Drill the hole pattern for grout injection as noted in the plans or as determined by the RE in consultation with the Contractor. Drill a minimum of 2 holes per side of transverse joint. Ensure that the minimum horizontal distance between holes is between 2 and 4 feet. Ensu re that holes do not exceed 5/8 inch in diameter, drilled vertically and round, to a depth sufficient to penetrate below the concrete pavement and into the voids, and subbase beneath the slabs. Ensure that base penetration does not exceed 3 inches. Clean holes to remove any obstructions caused during drilling to allow flow of high-density polyurethane.
D.Slab Stabilization. During stabilization operations, ensure the upward movement of the pavement does not exceed 0.10 inch. If the pavement has been lifted in excess of the allowable amount, the RE may require removal and replacement or grinding to the correct grade. After drilling the holes, inject high-density polyurethane under the slabs. As the polyurethane chemically reacts, it will expand and harden to create the necessary lifting forces. Using the pumping equipment, control the amount of rise by regulating the rate of injection of the material. When the nozzle is removed from the hole, remove any excessive material from the area, and seal the holes with high-density polyurethane. Immediately clean up material extruded during the pumping operations as the work progresses.
Referenced in this section
Concrete Slab Stabilization in other states
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Source: Standard Specifications for Road and Bridge Construction, 2019 (rev. 2022-12-21) Edition. Pages 235–235 of 651. View official source ↗