Cost Comparisons of Lightweight Concrete

Fernando Martinez Lewels has a M.S.C.E degree from the University of Texas at El Paso. He is now working with the Agartif company in Chihuahua, Mexico (about 170 miles from El Paso Texas). This Company has developed a type of lightweight aggregate that provides material for all types of construction needs, at reasonable cost and with good thermal insulation values. They manufacture the equipment required to do this according to the needs of their customers; the feed stock are common construction materials that should be available in most locations. Their philosophy in developing this type of aggregate is to be able to use this everywhere, without depending on a lightweight aggregate quarry, so you can have access to this material in any part of the world. In Mexico we have a saying that "we build our homes so we have to go outside in the summer to be fresh, and in the winter we go outside to catch the rays of sun to be warm". Lightweight concrete can help this situation by making available materials for more comfortable homes.

Questions and Answers

Q: Can the production cost of a slab, beams and walls be reduced by the use of lightweight concrete in comparison to conversional concrete

A: (Kelly) I doubt that the use of lightweight concrete will actually reduce the cost of a project. It is lighter and more insulating, but is also less strong in compression. The aggregate might actually cost more, depending the the resources available in your locality.

Q: I know that building costs will depend on area and type of construction. Are you able to give me a rough ball park comparison between typical "stick built" or prefab and concrete construction - such as pumicecrete? We are wanting to build such buildings for our art school and I am putting a fundraising letter together. Want to give some cost comparisons to our supporters.

A: (Kelly) Much of the cost of construction with either approach is the same. A stick-built wall might be a bit less expensive, because it is so standard that the trades people are all set up for this approach. The difference might be about 5% at the most. But a lightweight concrete building would be much more substantial, probably last longer, and be somewhat more earth-friendly.

Q: I was in Kashgar China to look at magnesia cement, perlite panels, light weight concrete. The product is good .6m x 3m x .15m . The cost however including shipping and taxes comes to $14 sq meter. The cost of technology, astronomical. I want the product for the earth quake areas, the idea is not to make a lot of money but to support and develop a sustainable system. Have experimented with mgo mgcl and perlite, got no where. Please suggest a line of action.

A: According to the e-mail the problems that this gentleman has are: cost of technology and physical behavior of material at site, therefore what I recommend is for him to produce my aggregate so he can have a sustainable source of lightweight aggregate for him to produce the elements of concrete that he needs. In order to quote this gentlemen what will be his cost in producing this aggregate I will need the following data:
1.-Capacity required per year
2.-Cost of following local materials: a.- Cement cost/lb or per kg; b- Gypsum cost/lb or per kg; c- Natural sand cost/lb or per kg.
With this data I can tell him what will be his cost per ton of aggregate (Material Only); from here he can calculate his indirect costs + time of amortization of equipment, etc. And if he needs to have a total cost in manufacturing lightweight concrete we can help him if required. In other words he will have the flexibility to produce as much lightweight concrete as needed.

Q: They tell me cement delivery to our site will be expensive and I understand with Lavacrete they can bring the "plant" out to our site to eliminate cement truck delivery. We have well water at the site. I have not found a site for comparing Lava concrete to other materials as you mention below.

A: (Kelly) You should be able to mix your own pumicecrete on-site. I think that this would be a good choice for your area, since the scoria is available, and is a good insulating material. It could be used below grade as well, if properly moisture-proofed.