681SLABJACKING

681.1DESCRIPTION—This work is filling voids beneath existing rigid base courses or pavements and

pressure jacking the pavement or base course to grade.

681.2MATERIALS—Use either cement or high density polyurethane grout to jack the slab.

One part cement (by volume) Three parts supplementary cementitious material (by volume) Admixtures—if required and accepted Water—an amount such that the time of efflux is within 16 seconds to 26 seconds (ASTM C939). A more fluid mix with an efflux time of 10 seconds to 15 seconds may be used for the initial injection in each hole. Use a stiffer mix, if the above mix fails to raise the pavement slab.

681.3CONSTRUCTION—

• Provide existing roadway profiles of the areas indicated on the contract documents, showing existing depressions and proposed grade line to be obtained.

profile drawings for the areas that were stabilized. Include the existing profile grade, proposed profile grade and profile grade accomplished by the operation. The Representative may require additional injection based on the results indicated by the profile grade report.

1.a Grout Plant. Section 679.3(b)1.a

1.b Water Tanker. Section 679.3(b)1.b

1.c Drill. Section 679.3(b)1.c

1.d Miscellaneous. Section 679.3(b)1.e

2.a Drilling Holes. Section 679.3(b)2.a, except penetration of the stabilized base may not be necessary.

2.b Mixing. Section 679.3(b)2.b

2.c Jacking. Connect an expanding rubber packer to the discharge hose on the grout pump and lower into the holes. Do not extend the discharge end of the packer below the lower surface of the concrete

pavement. If jacking continuously reinforced concrete pavement, pump in a pattern and in the amount required to raise the pavement to within 0.02 foot, plus or minus, from a string line grade, or as directed. If jacking jointed slabs of concrete pavement and bridge end slabs, pump in a pattern and in the amount required to raise the pavement to within 0.03 foot, plus or minus, from a string line grade, or as directed. Continuous pressures to 200 pounds per square inch will be allowed. Pressure to 300 pounds per square inch will be allowed only for short periods as directed , except if the pavement is bonded to the subgrade, brief pressure rises to 600 pounds per square inch will be allowed.

2.d Overjacking. Bring pavement, raised above the tolerances listed above, to grade by grinding. If the overjacking is greater than 0.10 foot, satisfactorily remove and replace the pavement in as specified in Section 516 at no additional cost to the Department.

2.e Opening to Traffic. Section 679.3(b)2.d

1.a Pump Unit. Section 679.3(d)1.a

1.b Drill. Section 679.3(d)1.b

1.c Pavement Plugs. Section 679.3(d)1.c

1.d Miscellaneous. Section 679.3(d)1.e

2.a Drilling Holes. Section 679.3(d)2.a

2.b Jacking. Inject the high-density polyurethane material under the slab. Control the amount of rise by regulating the rate of injection of the material. When the nozzle is removed from the hole, remove any excess material from the area. If jacking continuously reinforced concrete pavement, pump in a pattern and in the amount required to raise the pavement to within 0.02 foot, plus or minus, from a string line grade, or as directed. If jacking jointed slabs of concrete pavement and bridge end slabs, pump in a pattern and in the amount required to raise the pavement to within 0.03 foot, plus or minus, from a string line grade, or as directed.

2.c Overjacking. Section 681.3(b)2.d

2.d Opening to Traffic. Section 679.3(d)2.d

681.4MEASUREMENT AND PAYMENT—