FP-96 English Version - Eastern Federal Lands Highway Division

Section 502502.08 Undersealing and Slab Stabilization. This work consists ofpumping a hydraulic cement grout mixture through holes drilled in the pavementinto voids underneath the slabs to stabilize and underseal concretepavement.(a) Preliminary testing. Perform all testing at night or when there is no evidenceof slab lock-up due to thermal expansion. Testing may be allowed tocontinue if the slabs are not interlocked or under compression. Furnish testingequipment as provided in Subsection 502.04(i).Test each designated slab using a static method as follows:(1) Position one set of gauges with one gauge referenced to the corner ofeach slab on both sides of the joint near the pavement edge.(2) Set the gauges to zero with no load on the slab on either side of thejoint.(3) Move the test truck into position and stop with the center of the testaxle 12 inches behind the joint and the outside test wheel 12 inches fromthe pavement edge. Read the back gauge.(4) Move the test truck across the joint to a similar position 12 inchesforward from the joint and stop. Read the forward gauge.(5) Repeat for each joint to be tested. Underseal all slabs with a deflectionof more than 0.03 inches.(b) Drilling Holes. Drill holes using the required hole pattern. An alteredhole pattern may be approved based on slab testing and field conditions.Size drilled holes to provide a positive seal for the pumping nozzle. For thefirst undersealing, drill holes to a depth of 3 inches beneath the bottom of theconcrete.Submit the number, depth, and location of holes for the second undersealingfor review and approval.346