What is Foam ConcreteFoam concrete is a cement-bonded material made by blending an extremely fluid cement paste (slurry), into which is injected a stable, pre-formed foam, manufactured on site. Fresh foam concrete has the appearance of a light-grey mousse or milk-shake and it is the volume of slurry to foam which dictates the cast density of the foam concrete. The foam is produced using either protein-based foaming agent PROVOTON™, or synthetic additive SYNVOTON™, both of which are manufactured for us exclusively here in the UK. The physical characteristics of foam concrete are determined by the use of one of a number of mix designs: Depending upon the application for which the concrete is required, these mix designs may include the use of Portland Cement (CEM1), either on it's own, or in combination with a percentage of Pulverized Fly Ash, GGBS, or the inclusion of limestone dust or sand. 

Foamed concrete was used for construction of new railway bridge embankments in Colchester to reduce the load imposed on the low strength in-situ ground. The use of ‘rigid’ foamed concrete resulted in small lateral loads, no settlement and allowed a significant reduction in the number of piles and abutment wall thickness.The Transport Research Laboratory has led work on the reinstatment and strengthening of arch bridges with foamed concrete. A number of full-scale projects have been completed including the repair of a 25-year-old bridge deck of the Llandudno junction and Deganwy flyover, in North Wales. The voids between the arches and final road surface of the new Kingston Bridge over the Thames were filled with foamed concrete and two other old bridges have been strengthened in a similar manner. In most cases when filling bridge arches, higher density and strength mix (e.g. 1400kg/m3 and 7N/mm2 respectively) is used in the layers near the road surface while lower density mixes (e.g. 600kg/m3) are usually employed at greater depths.The foundations for two access roads at Canary Wharf were constructed with foamed concrete to reduce the vertical load on the foundations and reduce settlement. Other examples include stabilisation of the tunnel collapse at Heathrow airport, filling voids under roads, filling redundant sewer pipes and inspection chambers, and a large-scale harbour fill in Holland. Probably the largest use by far in the UK is the stabilisation of the Combe Down Stone Mines near Bath, which will eventually require some 400,000m3 of foamed concrete (density 650kg/m3, strength 1N/mm2).

In Holland, foamed concrete reinforced with aramid fibres has been used by the Amsterdam city housing authority (Stadelijkem Woningbouwdienst) as a soil sealant layer. Fibre reinforced foamed concrete has also been used as a shock-absorbing material to trap lead bullets at US military training establishments preventing leaching into groundwater.

http://www.concrete.org.uk/fingertips_nuggets.asp?cmd=display&id=359

Production of Foamed ConcreteThe production of foamed concrete on a small scale is a fairly easy process which does not involve any expensive or heavy machinery  and in most cases uses equipment that is already available for normal concrete/mortar production.Depending on the volume of concrete required (normally limited to less than 20 cubic meters/day) one will only need ;Equipment1. Normal concrete/mortar mixer or special mixers   f or foam concrete.2. Foam Generator3. Formwork (if producing pre- cast components)Materials1. Fine sand 2. Cement

3. Water4. Stable foam

Simple Mix DesignThe first step is of course to decide the wet density and how much foamed concrete you require.

Say  volume of foamed concrete required = 0.5m3 Wet density of  foamed concrete required = 1000 kg/m3

The raw materials required would be ;cement = 200 kgsand = 200 kg (assuming dry sand)water = 100 kg (including water in foam)then from the target volume of  foamed concrete (0.5m3) calculate the air content and final foam volume in the mix.

foam content in mix = 0.25m3 ( 250 liters )If foam output from Portafoam = 1.5 lit/sec then one would need to pump generator for 250/1.5 = 2.77 min. The practical way would be to pump for 166 sec and add the rest of  the foam using a measured container. Mixing proceduresNow that you have worked out the amount of  materials required to make the foam concrete add them dry first starting with the sand and cement. Mix dry constituents for a few minutes and add water in stages and make sure the mixing is thorough. Then add foam to the wet slurry and ensure foam has been completely mixed with the mortar.After mixing is completed check that the wet density of  the foamed concrete  is close to what is required. The dry density (oven dried) of

foamed concrete is normally less than its wet density, depending on w/c ratio, density and also on the cellular structure obtained. So do not forget to target a value of wet density much higher than what we actually require (dry).

Special training and demonstration of Portafoam and  producing foamedconcrete for block / panel production (e.g. mix design, raw materials properties, mixing procedures, quality control, block moulds,  ancillary equipment  etc.) can be provided. We will also provide documentation along with this training and also discuss projects & experience in foamed concrete block production.

ADVANTAGES OF FOAMED PORTAFOAM BLOCKSBACK TO MAIN PAGEFor further enquiries conctact  sarahn5663@gmail.com or dr.norizal@drn.com.my

 

Foam concrete technology was developed in HBP - USM  as early as 1987. We have developed the technology to make foam generators, foaming chemicals, mixers, mix design & methods of producing good quality foamed concrete.Our product range is mainly for small and medium scale production of foamed concrete although we do carry equipment for larger scale production.We have supplied equipment and know-how locally  and also to various other countries around the world. Below are photos and some description on the research and development made on foamed (cellular) lightweight concrete and related areas at the School of Housing , Building and Planning,  Universiti Sains Malaysia.General DescriptionFoamed (or cellular) concrete is made from mixing preformed stable foam to a slurry of cement , sand & water. This action incorporates small enclosed air bubbles within the mortar thereby making the concrete lighter ( of lower density ). Foamed (cellular) concrete may have densities from as low 500 kg/m3 to 1800kg/m3 and strength from less than 1 N/mm2 to 25 N/mm2. It

has a wide range of applications and some of them include wall blocks , wall panels , floor & roof screeds , trench reinstatement ,road foundations, bridge abutments and void filling..

Photo at left shows the stable foam produced at HBP for making cellular concrete. The foam is one of the most important ingredients ("aggregate") in the making of this concrete. It must be stable and last through the initial stages of mixing the concrete. There are many types of foams (some proprietary) but protein foams are now being used more often in the production of foamed

(cellular) concrete.

  Stable foam is the key ingredient in the production of foamed  concrete. This foam is made by a simple foaming generator  where air, water &foaming chemicals are mixed and stable foam is formed. This foam can be derived from either protein or synthetic chemicals. It consists basically of 95 % air and is very stable to enable it to last through the stages of mixing with the mortar slurry. The amount of foam expanded can affect the cost of the concrete being produced.  Generally , it takes about 400-500 liters of preformed foam to make 1m3 of foamed (cellular) concrete ( with a density range of 900 - 1300kg/m3).A Foaming Generator is used to generate stable foam for mixing with the sand & cement slurry to make cellular concrete. There various sizes of foam generators depending on the volume of foam concrete that is needed to be mixed. Foam chemicals also play an important role. Some foam chemicals do not produce the desired expansion of foam and are not stable in the concrete mix.

            

                  Timber forms  used to cast small panels of lightweight foamed (cellular) concrete for a bungalow project in Penang.On the right are blocks cast in steel molds. Although this may be slower, the surfaces are much better than normal bricks

One of the characteristics of foamed (cellular) concrete is its ability to flow and would require forms made of timber or steel to cast the required unit (e.g. block or panel). For void filling or trench reinstatement , the flowing characteristic of cellular concrete is important because no compaction involved (non-compacting concrete) after the concrete is poured.

                           

Picture above is foamed (cellular) concrete being poured to make blocks in steel molds

Larger panels can also be cast out of foamed (cellular) concrete but may need slight mesh reinforcement  to prevent shrinkage cracking and provide some strength during lifting. Although its weight is reduced , the large pre-cast panels still cannot be handled by one person and will require a light lifting device.Foamed concrete can also be used as insulation screed on flat roofs. The insulation provided by this material is much better than normal mortar screeds and you also get a reduction in weight imposed on the roof structure. A density from 900 to 1200 kg/m3 can be used on roof tops for effective insulation.Mixing just cement + water and foam will give you cellular cement. Cellular cement can have lower densities (400 - 700 kg/m3) but their strength is lower than foamed (cellular) concrete and can only be used for insulation (e.g. roof screeds) or void filling applications.

Stable foam can be incorporated easily into concrete masonry to improve its workability and handling. In addition to this one would also get masonry which is more fire resistant and better thermal characteristics.Foamed (cellular) concrete is considered an environment  friendly material since it only uses sand & cement (no large aggregates) and 1m3 of raw materials can give nearly 2 m3 of concrete . This makes it a potential material in housing construction because houses can be built more quickly and cheaply with such lightweight material .   Research on foamed or cellular concrete at HBP has been going on since 1987 and we have mixed various types of foam concrete including those with fibers, fly ash, rice husk ash, accelerators and plasticizers. We also have developed the technology to pour foam concrete into deep forms (e.g. cast-insitu walls) which is a normally difficult procedure.  Part of our research activity also involves testing chemical foaming agents and experimenting on high strength foam concrete. We have developed and tested formulas which will allow the casting of structural beams and columns ( see main page) made of lightweight foam concrete. We are also strongly pioneering in this country, the use of foam concrete in geotechnical applications and utility trenches (Trench Reinstatement).         Most importantly we have managed to develop the technology for producing foam concrete tailored for small & medium scale production. One of our most prominent item is the Portable Foam Generator ( Portafoam TM ) for small to medium scale production of foam concrete which is portable and cost effective . Portafoam will allow  the normal builder to enjoy the benefits of making foam concrete as they wish without any hindrance from requirements such as exorbitant equipment costs or licensing. Producing foamed concrete does not require expensive & complex equipment and is a fairly easy process with a low initial capitaloutlay. More people are discovering the benefits of this innovative material and its many areas of usage within the building industry. PORTAFOAM     makes it to the news !

 PORTAFOAM   Medals and Awards

 

For further inquiries, contact Dr. Norizal at sarahn5663@gmail.com or norizal@usm.my    

http://www.cemex.co.uk/Userfiles/datasheets/concrete-foamed-concrete-ds.pdf