General Questions FAQs

Q: What is cellular concrete?

“concrete, cellular -- a lightweight product consisting of portland cement, cement-silica, cement-pozzolan, lime-pozzolan, lime-silica pastes, or pastes containing blends of these ingredients and having a homogeneous void or cell structure, attained with gas-forming chemicals or foaming agents.” The American Concrete Institute International (ACI-116R-90).

In common terms cellular concrete is generally defined as a lightweight cementitious material that contains stable air or gas cells uniformly distributed throughout the mixture at a volume greater than 20%. Cellular concrete can be thought of as a concrete, which utilizes a stable air cell structure rather than traditional aggregate.

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Q: What are the advantages of pre-formed foam?

The pre-formed foam process offers excellent quality control and assurance of specified density. Preformed foam, unlike gas-forming chemicals, assures a consistent three-dimensional distribution of the engineered air cell system. Pre-formed foam produces a consistent matrix of relatively small air cells which are more desirable than a disorganized matrix of different size bubbles often created with the gas off method of reactive admixtures.

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Q: Are there different manufacturers of cellular concrete?

Yes! The Mearlcrete® division of Cellular Concrete LLC has several good competitor companies. ACI Committee 523 is supported by a group of dedicated individuals from several vending companies who represent the cellular concrete industry and work diligently toward the advancement of cellular concrete usage worldwide.

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Q: What are the disadvantages of cellular concrete, compared to typical concrete?

In the lower density ranges cellular concrete does not develop the compressive strength of plain concrete. While this may be a disadvantage in plain concrete applications, it is an advantage in a cellular concrete application. It should be considered that cellular concrete and plain concrete are typically used for different types of applications. Each form of concrete exhibits a unique family of performance characteristics. Each should be utilized in the appropriate type of project.

To produce consistent high quality cellular concrete you must have access to a foam-generating device.

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Q: Is there a difference in the pre-formed foam for Geotechnical applications and roof, floor or other layment applications?

Yes! Special formulations of foam concentrate are offered for each type of application. There are also various blends and mix designs within each category of Mearlcrete® and GeofoamTM concentrate. Your Cellular Concrete LLC representative can advise you on product selection. As an example, a sloped roof deck might require a product with a relatively slow flow rate and low density to maintain a slope with low unit weight. Conversely, a Geotechnical bulk fill application might require a very fluid and fast flowing product with a heavier density to fill all the small fissures in the project with a higher strength and density concrete.

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Q: Is cellular concrete the same as CLSM “flowable” fill?

No! "Flowable" fill is typically a very wet cement and fly ash slurry mix. Although cellular concrete and CLSM flowable fill are fluid products, and are often both acceptable for the same application or project, cellular concrete exhibits less unit weight as well as enhanced sound and heat insulating properties. Often flowable fill reaches compressive strengths that make removal of the material problematic. Low density cellular concrete is very easy to remove with hand tools only.

Technically, cellular concrete is a controlled low strength material, but “CLSM” by definition, commonly refers to cement- fly ash slurries, while “cellular concrete” refers to the addition of an engineered air cell system to cement or cement/fly ash slurry.

CELLFLOW™ from Cellular Concrete LLC is the answer to the demand for an air enhanced CLSM flowable fill product that can be produced at the Ready-Mix concrete plant. CELLFLOW™ is an additive that may be added directly to the 1.5 – 2.0 inch slump flowable fill mix without the use of a foam generator. CELLFlOW™ CLSM exhibits a high flowablity characteristics and 20-25% air content. CLSM flowable fill no longer needs high water contents and high ultimate compressive strengths. See the product section on CELLFlOWT™ for further details.

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Q: Is cellular concrete the same as lightweight concrete?

“concrete, lightweight – concrete of substantially lower density than that made using aggregates of normal density” The American Concrete Institute International (ACI-116R-90)

Cellular concrete weighs considerably less than typical “lightweight” concrete. By definition “lightweight” concrete is a concrete made with aggregates that are substantially lighter than typical stone aggregates. Typically, lightweight concrete has a density + 120 lb. / cu.ft. Typical cellular concrete, utilizing the internal air cell structure instead of an aggregate, exhibits <20 - >60 lb. / cu. ft.

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Q: Is segregation a problem?

A: Unlike plain concrete there is little to segregate in cellular concrete rendering segregation a moot point. The cellular concrete equivalent to segregation would be a collapse of the air cell system and a volume reduction in material. To prevent this one should use the most stable liquid foam concentrates and treat the mixed cellular concrete with some care in placing. Fresh cellular concrete is not fragile and can be pumped for long distances but conversely neither is it indestructible.