Case studies - Foam

FOAM BLOCK

Problem: When Shorewood Road was in need of replacement there was a section that was constructed on top of a peat deposit.  If the peat is loaded with conventional road building materials it will consolidate down. 

Solution: The designer chose light weight foam blocks to help bridge the peat and build a stable road base.  During construction we had to keep the excavation dry

because the water table was up into the subgrade.  To keep the area dry the contractor set up well points.  The well points had to stay working until the stone base, curb and asphalt was placed on top of the foam blocks.  The weight of these materials will provide the long term ballast for the foam so it will not float.  The designed weight above the foam is 64 LB/CF. 

Installation: When installing the blocks these general guidelines should be followed:

1.    Have a good level subgrade to avoid gaps between blocks

2.    Stager the joints of the blocks

3.    Stager the layers of the blocks

4.    Use 2 cleats pen block between layers

In some cases you may need to install a utility line in the foam fill. This can easily be done by cutting a notch into the foam blocks.  The light weight foam blocks are a cost effective solution to removing and replacement of a peat subgrade with compacted clay or stone.