Blower Slab Stabilization

polyurethane grouting for filing voids below blower slab at wastewater treatment plant


During a routine inspection, extensive voids were discovered under the slab supporting a ventilation blower at a wastewater treatment plant.  Staff were concerned that the lack of support under the slab would cause it to settle.  As visible in the pictures, this would easily cause extensive damage to this critical equipment.


The repair had to address the voids under the entire area of the slab, including the areas where the slab surface was unaccessible.

The Solution:

CJGeo proposed polyurethane grouting for filling the voids below the blower slab.  The minimum bearing capacity of the proposed materials was 3700PSF, ensuring adequate bearing capacity and long term stability.


A CJGeo polyurethane grouting crew filled the voids below the blower base and adjacent sidewalk in less than two hours.  Operations were not affected; the equipment stayed in service during the entire repair.