Things You Didn't Know You Needed To Know.
Here at Propump Engineering Ltd we often get asked a multitude of questions about foamed concrete, so we have taken a bit of time to strip back all the jargon and in simple terms tried to answer some of the questions we get asked.?
1.??????What is foamed concrete? Foamed concrete is a highly aerated concrete, typically containing 30 to 80% air bubbles by volume. Foam concrete is an incredibly useful material used to produce large volumes of void filling material and it can easily be pumped long distances and will fill most cavities.
2.??????Why is it called foamed concrete? The name “foam concrete” can be a little misleading, a more apt description would be “foamed mortar” or “foamed grout” other common names are “aerated lightweight concrete” and “cellular lightweight concrete” to name but a few. Air is mechanically entrained using a pre-formed foam that is mixed with the cementitious base material to produce a lighter density, mixed material (foamed concrete).
3.??????How do you make foamed concrete? By mixing cement, sand and water and adding a carefully controlled amount of one of our bespoke foaming agents to the mix to obtain the correct density and strength required. This is all carefully controlled from onboard our calibrated inline pumping and foam generation system.
4.??????Does foamed concrete expand? No, foamed concrete is manufactured using by injecting a “pre-formed” foam, not a chemical or resin based expanding foam (polyurethane foams), as a result, the expansion from base material to the foamed concrete occurs during the production. The volume of material delivered at the end of our hose is the final volume occupying the void.
5.??????What are the different production methods of foamed concrete (Pre-foam V’s Inline)?
Pre-Foam is a method of producing foam concrete can be completed on, or off site. Foam concrete is produced by part filling a standard ready mix concrete truck, the rest of the volume is then made up with foam, using the blades inside the “drum” to mix the material. Pumping would occur as a secondary operation.
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Inline foam concrete production can produce both light weight and heavier density foam concretes. Ready mix trucks carrying full payloads of material will be delivered to site. The inline foam generator and pumping system will pump the neat, base material, whilst injecting the foam, under pressure into the concrete lines, this material is then mixed through a series of in-line mixer plates.
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?6.??????Are there any environmental benefits to foamed concrete? Yes, by using foamed concrete you can reduce vehicle movements by up to a factor of 5! The result is less vehicles on and off site which equals less carbon emissions. For example, manufacturing a lightweight 450 kg/m3 density foamed concrete on site using Propumps’ inline system means that for every 6 m3 of base material delivered to site, we can produce 25 m3 of foamed concrete.
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For more information on this and to see it in action, please visit https://www.youtube.com/watch?v=hNxRUTiHUDY
7.??????What can foamed concrete be used for? Void filling from small pipes to mines! loading reduction, insulating properties and encapsulation to name just a few. For my uses and case studies please visit https://www.foamedconcrete.co.uk/foamed-concrete-applications/
8.??????What are the properties of foamed concrete? Foamed concrete is lightweight, flowable, Insulating and has a low density making it ideal for a multitude of applications. It is also easily machinable and re-excavatable should the need arise. Its high rate of expansion and fluid properties often make it a much more economical filling material than stiff low cement concrete, or hardcore and loose materials that require compaction.
9.??????Why is there no stone or aggregate in foamed concrete??With the addition of high volumes of air and water, stones and other large aggregate would simply fall to the bottom of the mix creating a deviation of mix constituents and an inferior finished product. Having a maximum of 5 mm sand means that all the binder and filler is kept in suspension around the foam as the cement hydrates and cures. This also allows us to keep weight and therefore density low, and aids in the flowing characteristics.
10.??What densities can foamed concrete be produced in? The densities of foamed concrete produced by Propump Engineering range from as low as 150 kg/m3 and up to 1500 kg/m3, but should you have something that you would like us to take a look at please get in touch. Propump Engineering have designed and manufactured bespoke inline foam production systems to allow us to produce and achieve a wide density range on site to meet our clients requirements. For more information on densities please visit https://www.foamedconcrete.co.uk/documentation-and-technical-specifications/
11.??What strengths can foamed concrete achieve??Compressive strengths range from 0.5 N/mm2 to 10 N/mm2 at 28 days. Typically, low strengths are sought for void and trench filling applications and the higher strengths are used for load-bearing applications. For more information, please visit https://www.foamedconcrete.co.uk/foamed-concrete-technical-datasheet/
12.??Why can I only place foamed concrete to certain depths??Because of the structure of air bubbles in the foam. The weight of the top section of the wet concrete crushes the air out of the lower part and the volume is reduced and the density increased.
13.??How long before I can walk on foamed concrete? We advise a minimum of 16 hours; this allows enough time for the material to cure sufficiently.
14.??When can I strip my shuttering? You will be able to strip any form works or shuttering the following morning (around 16 hours) for subsequent pours or layers as required.
15.??Is foamed concrete strong enough to drive over once cured? Typically, yes, but this is obviously dependant on the mix, the depth poured, the site conditions and what you plan on driving over it. We have experiences tracked vehicles driving over 1-day old material that is 0.5 N/mm2 with a designed strength of 1 N/mm2 achieved after 28 days.
16.??How much does foamed concrete cost? All of our work and quotations are tailormade to our clients’ requirements and depending on the overall mix, strength and densities required, foamed concrete can cost anywhere from ￡60.00 to ￡200.00 per m3.
17.??Why chose Propump Engineering Ltd? Established in 1991 as the United Kingdom’s first foamed concrete company, we are well placed to design manufacture and advise on the use of various grades of foamed concrete. Produced using our own patented range of foaming agents our foamed concretes have been used on some of the most prestige and technically demanding construction projects in the world including: - The Channel Tunnel Rail link, Terminal 5 Heathrow airport, London’s Crossrail project, Hong Kong’s airport redevelopment and the world’s biggest ever use of foamed concrete the Combe Down mines stabilisation project, to name a few. For more information, please visit www.foamedconcrete.co.uk or contact a member of the team on 01322 429900 or [email protected]