Applications Of Light Weight Foam Concrete In Cold Formed Steel Construction

Abstract

Foam concrete by definition is a cementitious material with a minimum of 20% entrained air in the shape of foam (Deijk, 1992). Foam concrete is a lightweight concrete in which coarse aggregate is replaced with air voids. In simple words it can also be considered an aerated mortar. The foam is generated separately before mixing with the help of a foam generator machine and then added to the cement slurry in order make the foam concrete. The foam is produced with a liquid chemical called the foaming agent that is added with water to make foam in the foam generator. This foaming agent makes a foam with tiny bubbles that are not easily broken during the mixing process and retain their shape. The amount of foam and water cement ratio (w/c ratio) plays an important part in the strength and density of the foam. An increase in the amount of foam used means lower density and lower strength and an increase in the w/c ratio has the same effect on foam concrete samples. Typically the density of the foam concrete ranges from 300 kg/m3 to 1850 kg/m3 and the w/c ratio used ranges from 0.4 to 1.25. (Thakrele, 2014) In this investigation a foam concrete with the density of around 1500 kg/m3 is produced with a trial an error method using different w/c ratios and amount of foam in the mix. 18 cube specimens are prepared with different mixes, then their density is recorded and they are air cured to replicate the conditions at site. Then their compressive properties are investigated to select an option that is easy to make in the field. Then the selected formulation was used to make a cuboid of the size 4”x4”x1” to check its thermal conductivity against a cuboid made of mortar. The results showed that the foam concrete has exceptionally better thermal properties compared to mortar. Foam concrete is known for its excellent thermal and acoustic properties (R. Ramamurthy, 2009). VI Finally windows of cold formed steel were made in order to check the structural value, if any, that is added by the foam concrete formulation. The formulation selected was then used to fill the windows and compressive tests were done on them with and without the foam concrete infill. The results showed that the windows with foam concrete showed an increased compressive strength compared to the windows without the foam concrete. Thus confirming that the foam concrete also gives a structural value to the system and can be used to compliment the structural strength of the cold formed steel structures.