A sewer trunkline expansion in Richmond, Virginia required five bored road crossings ranging from 60″ to 72″.
Tunnel lengths ranged from 200LF to nearly 600LF, and were mined through rock using slurry microtunneling.
The design engineer required cellular concrete for annular space grouting due to run length, and buoyancy control of the carrier during grouting.
Not many; the longest run on this project, 600LF is a relatively short distance to push cellular concrete.
CJGeo proposed 38lb/cuft non-permeable cellular concrete to meet the designer’s 200psi 28 day compressive strength requirement.
Over four different mobilizations, CJGeo successfully placed approximately 900CY of annular space grout.
Cellular concrete generation was performed using wet batch continuous generation. Wet batch generation was chosen due to the relatively small daily volume of material placement and very constrained sites.