lightweight concrete 3

[goldmandm]

I've heard about some lightweight concretes used in Europe for years (air injected?) that are now being used in the USA. Does anyone have the background story on this material, what its limits and assets are, and who is working with it or selling it in the US?<br>

 

[Ron]

There are numerous &quot;lightweight&quot; concretes available, with three distinct separations: <br>1.&nbsp;&nbsp;Lightweight structural concrete - just a lighter weight version of conventional portland cement concrete, utilizing sintered clay or expanded shale coarse aggregate to reduce the conventional unit weight by about 20 percent.<br><br>2. Lightweight insulating concrete - used primarily for roof deck applications, coming in two primary forms; one with aggregate (perlite or vermiculite) and having a compressive strength from about 125 psi to 350 psi depending on need and formulation, and the other being a &quot;cellular&quot; concrete consisting of portland cement, water, and a foaming agent (usually with no aggregate) and having a compressive strength of about 250 psi to 400 psi, again depending upon need and formulation.&nbsp;&nbsp;Dry unit weights of these materials range from about 25 pcf to 40 pcf.<br><br>3. Lightweight concrete for geotechnical applications - this is a variation in use of the cellular lightweight insulating concrete for roofing and may be used with or without aggregate, most often without.&nbsp;&nbsp;It is used as a convenient lightweight volumetric fill to reduce the weight and corresponding stresses in soil structures, both above and below surrounding grade.&nbsp;&nbsp;Several manufacturers and suppliers provide these materials, but as with roofing application, uses specialized equipment and placement (pumping) so the contractors are usually dedicated to this process and usually dedicated to one supplier.&nbsp;&nbsp;Brand name of one such material is &quot;Cellcore&quot;.&nbsp;&nbsp;<br><br>I have some experience with all of these, most notably 2 and 3.&nbsp;&nbsp;Have used, tested, evaluated, and consulted on many applications of &quot;2&quot;, and have specified &quot;3&quot; in specialty design applications of fill (where overburden unit weight was critical to settlement considerations) and in industrial pavement over poor soil conditions where high modulus material was needed for pavement support, but unit weight had to be kept down for long-term settlement of roadway on marsh land.

 

[Rjakiel]

The air injected lightweight concrete you are referring to might otherwise be referred to as lightweight foam concrete. This product has been installed in Europe by a company named VOTON International. In the United States the installer is AJ VOTON LLC (ph#708-681-1300). It is a very useful product. It is primarily used as a lightweight fill on many highway and building foundation projects that cannot support the weight of normal weight fills. Because is very flowable it can be pumped long distances and is commonly used as an annular backfill on tunnel projects. It has many other uses such as backfill behind MSE walls, architectural terracing, landslide fills, culvert fills, void filling and weight reducing fills. Its primary structural properties are: unit weights 25 to 100 pcf, compressive strength 40 to 1,700 psi. It also has a low shrinkage and permeability.

 

[pricklyPete]

Ron,

Regarding your item #2, I am checking some roof joists for a new mechanical unit. The existing roof deck has what is referred to on the existing drawings as "insulating concrete". It is on top of a 26 gage metal form deck. The project is a mall in MN that was built in 1965. Would this be the same thing?

I did my best job to weigh it and determine its volume in order to calculate its density. I come up with about 19 pcf. The material is not very strong and can easily be broken or crushed with one's hands.

 

[unclesyd]

Ron,
What PricklyPete may have is your insulating concrete. Back in the early 60's I helped an acquaintance spray lightweight concrete roofs on beach houses. The roof at the time was called a Bermuda Roof. The roof was a series of steps with a minimum thickness of 3". I didn't work with material on commercial buildings but know he worked on a considerable number of commercial roofs in this area. I also help spray the holes of a number fishing boats, where we used 3" plus a 3/4" coat of stucco.

The material use was a bag mix especially for roofs and had the necessary in ingredients + a whitening agent. It was mixed at the site and Ivory Liquid Soap was added and then the mix was pumped with MOYNO Pumps and at the nozzle 120 PSI air was added.
There was another nozzle where both the soap and air were added at the nozzle. This worked OK but you didn’t have the control of the other system.