Leesburg Annular Space Grouting

Leesburg, Virginia annular space grouting projectChallenge:

A utility contractor installed 200LF of 35″ ID steel casing using jack & bore.  The casing was bored under a four lane boulevard feeding a commercial development and large neighborhood.  A 16″ CPVC waterline was installed as the carrier pipe through the casing.  This annular space grouting project was located in Leesburg, Virginia.

Limits:

Leesburg, Virginia annular space groutingDue to site limitations, only one end of the pipe was accessible for grouting.  The length of the placement was approximately 200LF, so grout had to travel 200LF at low pressure, while ensuring a complete fill.

The Solution:

CJGeo proposed cellular concrete for the annular space grouting.  Cellular concrete is highly flowable.  High flowability ensures low installation pressure, reduces flotation of lightweight carrier pipes, and ensures complete void filling outside of the host pipe.  

Result:

CJGeo successfully performed this Leesburg annular space grouting project in a single day.  The peak pressure at the pump did not exceed 5PSI throughout the project.  Therefore, the project was successfully completed without damaging the CPVC carrier pipe.

CJGeo placed 60PCF wet cast density cellular concrete, with a 950psi compressive strength for this project.  With a 24 hour penetration exceeding 300psi, 60PCF cellular concrete reduces buoyancy with its low unit weight, provides adequate strength, and rapid stability.