Types of Lightweight Fill
There are a few different types of lightweight fill: Cellular (foamed) concrete, geotechnical polyurethanes, expanded lightweight aggregate concrete, and expanded polystyrene (EPS).
Cellular concrete, also called foamed concrete, is a mixture of Portland cement and water that’s treated with a foaming agent. The foaming agent effectively acts as a very high air entraining admixture. Typical cellular concrete mixes for lightweight fill applications are greater than 60% air content. Cellular concrete can be either pervious or impervious. Pervious cellular concrete is excellent for lightweight fill applications where buoyancy is a concern.
Concrete Jack installs cellular concrete for lightweight fill applications. We have the capacity to produce both pervious and impervious mixes. Our equipment allows for truck-batched production or steady-stream production on job sites.
Because cellular concrete is a neat mix of Portland cement and water, there are no components that will degrade with time, so cellular concrete is very dimensionally stable for long periods of time. Cellular concrete is not susceptible to solvent attack.
Cellular concrete is nearly self-leveling, and will find and follow very small leaks. This is a great characteristic when you want it, and a terrible characteristic when you don’t want it. Therefore, special attention must be paid to ensuring a closed, water-tight vessel or space being filled to reduce leakage and spills during placement.
We install cellular concrete.
Geotechnical polyurethane is a very versatile lightweight fill material. Geotechnical polyurethanes are mixed and place on site. In addition to their very light weights–2 pounds per cubic foot is easily achieved, and yields bearing capacities of approximately 5,000PSF–geotechnical polyurethanes react and cure within a few seconds to minutes. This allows for easy placement and shaping of embankments and even sprayed vertical applications.
Unlike cellular concrete, geotechnical polyurethane lightweight fills can not be made pervious. Polyurethane lightweight fills are rigid cellular plastics, so they are susceptible to some solvent attacks. However, when protected from UV light, geotechnical high density polyurethanes have exceptional life expectancies, and incredible bearing capacity to weight ratios.
We install geotechnical polyurethanes for lightweight fill.
Expanded Lightweight Aggregate Concrete
Expanded lightweight aggregate concrete is just like regular concrete, except in place of standard aggregate, the concrete is mixed with special lightweight aggregate. Lightweight aggregate concrete is generally used for applications where it is the actual traffic surface, such as bridge decks. Lightweight aggregate concrete is generally more expensive, and heavier than cellular concrete, high density polyurethane, or expanded polystyrene, but is the only lightweight fill material which will tolerate direct traffic. Therefore, lightweight aggregate concrete isn’t used as a fill material. We do not install lightweight aggregate concrete.
Expanded polystyrene (EPS) is manufactured offsite from jobs, and transported in its expanded state to jobs. Therefore, there are relatively high transportation costs of EPS. However, it’s extremely lightweight, and the blocks can be stacked and trimmed on site to conform the required profile. Unlike cellular concrete, EPS does not require forms to install above grade. However, a primary weakness of EPS is its susceptibility to solvent attack. We do not install EPS lightweight fill.