This article is about a buiding material called foamed concrete. It describes what foamed concrete is, how foamed concrete is made, how it used and what its advantageous properties are.

Key Takeaways

  • Foamed Concrete is a lightweight, versatile building material with wide a variety of uses.
  • It is made from cement, sand, water and foam. Changing the relative amounts of these ingredients change its physical properties.
  • It does not need vibration or compaction and is free-flowing, making it easy to cast.
  • Other advantages include good thermal insulation, excellent load spreading and it does not settle.
  • Applications include void filling, roof insulation, pre-cast blocks & panels, and trench reinstatment.

What is foamed concrete?

EABASSOC Foamed Concrete (also known as cellular lightweight concrete, CLC or Aircrete) is a lightweight, free flowing, cementitious material which is ideal for a wide range of applications in the building and construction industry.

In fact, Foamed concrete is not a single product but a vast range of products which vary according to their precise make up and their strength and density properties. It can, therefore, be tailored for optimum performance and minimum cost by choice of a suitable mix design for each end use. By choosing a suitable mix design, foamed concrete can be made with a range of dry densities, from 400 kg/m3 to 1600 kg/m3 and a range of compressive strengths, 1 N/mm2 to 15 N/mm2.

Foam used to make foamed concrete has a consistency like shaving foam
Foam for making foamed concrete.
The bubble structure of cured foamed concrete
Cured foamed concrete has a bubble structure.

How is foamed concrete made?

It is made by adding a special pre-formed foam to a cement mortar slurry. The foam is made from EABASSOC Foaming Agent, a highly concentrated, highly efficient, low dosage liquid which is fed with water into an EABASSOC Foam Generator. Inside the foam generator, the concrete foaming agent is diluted with water to make a pre-foaming solution which is then forced at high pressure through the foaming lance. This produces a uniform, stable foam which has a volume of about 20 to 25 times that of the pre-foaming solution.

The terms cellular concrete and aircrete are used to describe foamed concrete but they can also refer to similar materials made by different methods, such as aerated autoclaved concrete.

Foamed concrete is often made in a ready mix truck or, for small quantities, in a cement mixer. Just like normal concrete, it sets (becomes solid) over 6 - 12 hours after it has been cast. After setting it gains strength over the course of the following days and weeks. Compressive strength testing is normally carried out after 7 and/or 28 days.

Whilst they are similar materials, there are differences between foamed concrete and normal concrete. The main difference being that there is not any foam in normal concrete.

Casting foamed concrete

Due to its free-flowing nature, foamed concrete is quick and easy to cast. It can be poured into place directly from a ready mix truck, or by gravity via a series of channels. It can also be pumped into place using a concrete pump. The most suitable pump is a peristaltic pump.

On a construction site, foamed concrete is being cast into formwork from a ready mix truck.
Casting of EABASSOC Foamed Concrete by pouring from a readymix truck
Formwork into which foamed concrete has been cast.
EABASSOC Foamed Concrete in place after casting

What is foamed concrete used for?

EABASSOC Foamed Concrete can be used for a wide variety of applications within the building and construction industry. By varying the mix design used to make it, its properties can be adjusted specifically for each job or contract. Applications include:

  • Panels and Blocks for Walls
  • Planned and Emergency Void Filling
  • Roofing Insulation
  • Levelling Floors
  • Road Sub-Bases and maintenance
  • Bridge Abutments and Repairs
  • Trench Reinstatement
  • Insulating Underground Hot Water Pipes
  • Land Reclamation
  • Ground Stabilisation
  • and many Other Uses

What are the advantages of foamed concrete?

It can be placed easily, by pumping if necessary and does not require compaction or levelling. It has excellent water and frost resistance and provides a high level of both sound and thermal insulation. Foamed concrete is very stable and lightweight, and will not sink into soft ground or impose undue loading on roofs and other structures.

It is very versatile and since it has a huge range of dry densities and strengths, it can be tailored for optimum performance and minimum cost by choice of a suitable mix design. Different mix designs have different quantities of sand, cement, water and foam. Optimisation can be further refined by using different types of cement, sand or other ingredients such as fly ash.

The advantages of foamed concrete are:

  • Does not settle
  • No compaction or vibration needed
  • Free flowing, spreads to fill all voids
  • Non-hazardous
  • Reliable quality control
  • Properties can be varied to suit needs
  • Highly cost effective
  • Can be pumped
  • Lightweight, reduces direct loading
  • Excellent load spreading characteristics
  • No maintenance required
  • Excellent sound and thermal insulation
  • Excellent resistance to freeze-thaw
  • Does not impose lateral loads
  • Low water absorption over time
  • Excellent fire resistant property
Foamed Concrete being poured into place from a ready mix truck on a construction site.

EABASSOC Foamed Concrete is very stable and will not collapse or reduce its volume whilst it is setting. Foamed concrete has excellent longevity and will last in excess of 100 years.

How can EAB Associates help me with foamed concrete?

Our primary means is through the sale of EABASSOC Foaming Agent and by providing excellent customer service: we have over 30 years experience in the field of foamed concrete and we are pleased to offer detailed advice to EABASSOC Foaming Agent users, including suggestions for mix designs for various applications and teaching customers how to calculate foam quantities for the mix designs. We can give practical advice about making and placing foamed concrete. We are also available for conducting trials, site work supervision and full scale contracting work. Contact Us for more information.