Piers C & D are located on the Hudson River in New Jersey. They are low level relieving platforms supported by timber piles, pile caps and deck boards that were being aggressively attacked by shipworms (Teredo Navalis). The deterioration of the substructure of the piers required immediate stabilization and repair. The project was designed to halt the Teredo attacks on the timber elements of the pier and limit further degradation of the timber. This was accomplished by installing sheeting around the perimeter of the piers and creating an environment not suitable for Teredo, thus preventing any further damage. A lightweight cementitious material was chosen to fill between the bottom of the pier and the existing mud line.

Foam concrete was required to have a wet density between 65 and 72 PCF so that it would not surcharge the existing soil and cause excessive settlement. Other important material characteristics needed for this project included minimal shrinkage after curing, low permeability, and the ability to be placed underwater.

During the placement of the material, segregation and dispersion of the material was minimal and the fill exhibited excellent flow performance and self-leveling characteristics by easily reaching all areas of the enclosure.