Aerated Autoclaved Concrete

Technological Performance

Performance Parameters and Properties

Buyer's Guide

FMEA Analysis for Each System By Component

Third Party Evaluation / Information Sources

Relevant Trade Associations

Performance Parameters and Properties (Back to Top)

Structural Performance

ACC is extremely strong despite its light weight and weighs about 1/5 the amount of regular concrete. ACC can be used in construction for load bearing and non load bearing wall systems.

http://books.google.com/books?hl=en&lr=&id=diiPFbTX-9EC&oi=fnd&pg=PR15&dq=structural+performance+of+aerated+autoclaved+concrete&ots=PpSxlopus1&sig=WW46xM4rur35yhM15BBmCXKfT6E#PPA49,M1

http://findarticles.com/p/articles/mi_qa5310/is_200711/ai_n21297886/pg_6?tag=artBody;col1

Thermal Performance

AAC provides energy savings in both hot and cold climates.  The thermal conductivity increases with density and moisture content.

Permeability Performance

AAC values of air permeability decrease when the density of the specimen increases.  It varies with moisture content.  It is also more permeable around joints, cracks, and other openings.

Durability Performance 

AAC was originally invented specifically for load bearing wall systems and is recommended in areas that are prone to Hurricanes and sever weather.  ACC is will rot, warp, rust, corrode, or otherwise decompose.

http://www.safecrete.com/aac/benefits/lasting.html

Fire Performance

AAC is non-combustible and offers one of the greatest resistances on the market currently.  It also exceeds the requirements of the Standard Building Codes, and critical fire hose tests.  AAC eliminates the need for applying costly fireproofing materials and in addition to no toxins being emitted no dangerous gases are emitted either when the AAC is exposed to extreme heat temperatures.

Indoor Air Quality Performance 

Some of the poorest quality air we breathe is in the building we work in and the homes we live in.  AAC is an inorganic material that contains no toxic substances and does not decompose or let off gas. Since AAC is both a structural and insulation material, it allows the elimination of other materials that may contribute to poor indoor air quality. AAC is an ideal material for homes for the chemically sensitive.

http://www.aacpa.org/aboutaac/index.htm

Buyer's Guide (Back to Top)

The stakeholder group most likely to purchase autoclaved aerated concrete would be the heavy construction industry.  Since this technology is newer and still difficult for the common consumer to get a hold of, it will probably be some time before we see this system used in residential or non-commercial buildings.  AAC can be used in either stacking situations much like CMU's, or can be manufactured on a larger scale to be an entire precast panel.

• AAC performs very well in low rise buildings and with reinforcement, can also be used in larger buildings.
• With a value of R-31, AAC provides great insulation during the winter and prevention from outside heat during the summer.
• As the density of the AAC increases so does the air permeability.  It can reach standards of STC 44.
• AAC performs to high standards under load bearing and extreme weather conditions.
• AAC is non-combustible and above standards in fire resistance.  When exposed to extremes heat it emits no toxins or dangerous gases.
• AAC alone provides the wall structure and the insulation, eliminating the need for materials that might contribute to poor indoor air quality.
  

FMEA Analysis for Each System By Component (Back to Top)

Third Party Evaluation / Information Sources 

1.) Building on Masonry's history; Improved Concrete Blocks are Light, Airy

Summary: The article talks about the different types of masonry and how common it is to find them in most every building. The most common type is concrete because it is cheap and accessible, but it is heavy and therefore drives up transportation costs. A new museum going up in Washington used Autoclaved Aerated Concrete because it weighs 1/3 less than a normal CMU, but provides the same protection. Architect Maria Viteri who is the director of program development says "Seen raw, the final surface is smoother than concrete. While you usually put a finish on a concrete block, you can leave AAC unfurnished and not have porous openings." This article shows that third party observers recommend the product to others for multiple reasons.

CARS Checklist:

• Credibility: The Author's name and position are given. The newspaper title, section, and specific page numer are given.
• Accuracy: The article's date is given showing that the newspaper is five years old. The audience is aimed at anyone interested in the museum or interested in using AAC for future construction.
• Reasonable: The article does not use language that would suggest paid promotion of the product. The facts given are accurate therefore probable. It compares AAC with CMU and does not use contradiction.
• Support: The article is supporting by quoting people's opinions. When quoting, the persons name and job description are given. All necessary citing materials for an outside user are given.

Citation: Geracimos, Ann. "Building on Masonry's History; Improved Concrete Blocks are Light, Airy." The Washington Times B01 26 November 2003 2. 25 Sep 2008 www.washingtonpost.com.

2.) Sensible Home / Concrete House is the Strong, Silent Type

Summary: This document starts with a man (Donald) looking for construction options for his new home. He likes concrete and is wondering in what ways can it be used. The writer replies by informing Donald about shotcrete, panels, and AAC. He writes, "The AAC is made using fine aggregate, cement, and an expansion material. Through the use of heat, the material expands to create tiny air cells as it cures. Almost 80% of the block is air, which is a good insulator." It is a newer material and has many advantages over other forms of concrete building materials.

CARS Checklist:

• Credibility: The author's name is given. The section and page number of the article is at the top of the page. The company's name and web site is listed.
• Accuracy: The documents date is given showing that it is three years old. The audience is specifically aimed at Donald, but applies to everyone interested in new construction.
• Reasonable: The writer responding to Donald informs him of many types of concrete construction not showing any biases. Facts given are a generalization of each product. AAC is comparted to shotcrete, panels, and insulated concrete forms.
• Support: The documants main support comes from its credibility. All citing tools are given at the top of the page and the writers knowledge of the subject is also stated.

Citation: Dulley, James. "Sensible Home / Concrete house is the strong, silent type." The Philadelphia Inquirer Real Estate. J01 10 July 2005 2. 28 Sep 2008 www.philly.com.

3.) Guide for Using Autoclaved Aerated Concrete Panels: I - Structural Design

Summary: Paper that summarizes the recommendations from the AAC products association. It also includes results from research that was conducted at many Universities who studied and tested these recommendations. The research only studied reinforced AAC walls. This paper helps to decide how to use AAC for many different construction needs.

CARS Checklist:

• Credibility: There are multiple author's and all of their names are given. The volume and page numbers are also given. However, there is no contact information.
• Accuracy: The date of the finished paper is given. It is three years old. The audience is anyone interested in learning more about AAC.
• Reasonable: The paper is reasonable because it shows the thoughts and procedures that when into test the AAC materials.
• Support: The facts are supported by detailed representation of what steps were followed during testing of materials. And how the AAC reacted during each senario.

Citation: Barnett, R.E. "Guide for Using Autoclaved Aerated Concrete Panels: I - Structural design." American Concrete Institute 226 1 March 2005 17-28. 29 Sep 2008 www.concrete.org.

The article that stands up best to the CARS checklist is article number 2; then 1, and lastly 3.

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Relevant Trade Associations

-The Aerated Autoclaved Concrete Product Association- This is an association that is dedicated to the success of the AAC, in other words, "Our primary aim is to promote the AAC industry in all aspects. The ultimate goal is the mainstreaming of AAC in North American construction."  http://www.aacpa.org/

 -Portland Cement Association- This association is one that tries to educate the public about concrete in general, and AAC is one of those types that they try and promote.  http://www.cement.org/basics/concreteproducts_acc.asp

- European Autoclaved Aerated Concrete Association- The EAACA's main purpose is to "promote the interests of producers of autoclaved aerated concrete (AAC) and their national associations across all of Europe."  http://www.eaaca.org/

 - National Concrete Masonary Association - The NCMA is one of the top leading associations for concrete products in general, but to be more specific it promotes AAC.  They provide Industry Leadership, Technical Information and Support, Market Information, and even Peer Interaction for those who work with AAC.  http://www.ncma.org/

- American Concrete Institute - The ACI is a nonprofit organization that is there to educate about concrete products.  They are known for being one of the leading authorities on the newest technologies in concrete, which includes AAC. http://www.concrete.org/ 

-Mason Contractors Association of America - The MCAA is one of the few organizations that represents contractor's interests above all else.  They do this in any legislative matter that the contractor may have.  http://www.masoncontractors.org/

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