Autoclaved Aerated Concrete based on Fly Ash in Density 350kg/m3 as an Environmentally Friendly Material for Energy - Efficient Constructions

Abstract

In recent years the evaluation of U-value for buildings materials has been seen. Since 1st January 2014 U-value can’t be higher than 0,25 [W/m2K], but since 2017 this value will be 0,23 and 0,20 from 2021. Therefore, a good solution to fulfill mentioned conditions is using buildings material with better thermos insulation. One of the best construction materials, which have very low λ value [W/mK] is an autoclaved aerated concrete (AAC). It's the reason why AAC is the most popular buildings material from years. AAC could be produced with using various aggregates, like sand or fly ash. Test results of thermal conductivity clearly shown that AAC based on siliceous fly ash have better λ value than sand AAC in the same density. Polish energy policy is based on coal and production AAC based on siliceous fly ash is a great solution to utilization this waste. Autoclaved aerated concrete has better λ value than other available construction materials in polish market. Lower density have good impact on environment, because lower weight caused possibility to transport more products by the same truck and also it means less waste from buildings made from AAC in the future. This waste can be used again in normal production process of AAC. Due to these facts were undertaken studies of possibility of production AAC in 350 [kg/m3] density in PGS process technology. The PGS process technology is a very specific because in a production cement is not used. As a binder are used only: quick lime, gypsum and some part of fly ash. The most important properties of AAC were tested, like: compressive strength, density, λ value or phase composition. Production AAC in lower density could be the next step to improve that it's an environmental friendly material for energy-efficient constructions.