The Sandston area, just outside of Richmond, Virginia, is at the crossroads of major north/south data transmission lines, and transoceanic data transmission lines. This jack & bore grouting was done to support a road crossing connecting two new data centers.
As part of the construction of a new, multi-billion dollar data center, a utility contractor bored two, 48″ steel casings under a roadway & adjacent wet utilities for a road crossing. Each of the casings had up to 20 different PVC conduits held in place using casing spacers. The contractor needed a grout that could be placed at minimal pressure while ensuring complete fill without damaging the conduits.
To avoid carrier pipe buoyancy, the maximum allowable grout density for the annular space grouting was 45lb/cuft.
CJGeo mobilized a cellular grouting crew to the site and did the jack & bore grouting on both pipes in a single day. The peak grouting pressure was 5psi, and confirmation of fill was achieved when uniform cellular concrete was vented from the 12 o’clock position on the opposite end of each bore. 38PCF CJFill-ST was used to achieve the design strength of 200psi at 28 days.
CJFill-ST is heavier than CJFill-Ultra Lightweight, which is the most common cellular grout that CJGeo uses for annular space grouting. However, in the case, the municipality specified a higher compressive strength due to the proximity of multiple other critical utilities.
CJGeo used wet batch on this project due to the low volume and proximity of a ready mix plant. Wet batch typically has lower peak heat of hydration, which is helpful when grouting around PVC.
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