Indoor Pool Abandonment
Renovation of a medical office building suite required abandoning an indoor swimming pool with lightweight material. The suite was originally used for rehabilitative therapy. The new tenant required a level floor, and not a pool, so pool abandonment was required. The architect had originally specified cellular concrete at a density lower than 60PCF in order avoid overloading the underlying soils. However, the original contractor filled the pool with 120PCF material, which was poorly placed. This resulted in consolidation and settlement, at which time the contractor walked away from the job.
The contractor selected to complete the job had to excavate all of the originally-placed material from the pool.
Material density needed to be less than 60PCF in order for there to be no net increase in loading of the underlying soil compared to loads as designed for the swimming pool. Due to economic reasons, filling the pool in a single lift was important; the so the material had to be able to be placed in a single, 54″ lift.
35PCF cellular concrete was determined to be the most appropriate fill material. Aquaerix pervious cellular concrete was chosen to facilitate the single 54″ lift.
Cellular concrete is comprised of Portland cement, water & preformed foam. The 35PCF material chosen is effectively 70% air entrained concrete. There is no aggregate in the mix, so the bubble structure formed by the preformed foam effectively serves the purpose of aggregate.
Cellular concrete is self-consolidating, and self-levels to within a few inches per 100feet. This helps to ensure that no voids remain in the filled area, to ensure longterm stability.
After the contractor cleaned all of the original backfill material out of the pool, CJGeo placed approximately 60 cubic yards of cellular concrete lightweight fill to complete the pool abandonment. 35PCF cellular concrete was used to ensure 200psi compressive strength at 28 days, and ensure that the underlying soils were not overloaded.