Although gypsum is one of the most environmentally friendly building binders, its use in the buildings is relatively limited and therefore the broadening of the gypsum product portfolio is desirable. One possibility is the development of the lightweight gypsum materials with better thermal insulation properties, attractive acoustic properties and also lower transportation costs. The lightweight gypsum materials can be used in a similar way as an aerated autoclaved concrete (AAC), whose energy consumption at production is several times higher.
The main methods of the preparation of gypsum-based lightweight materials are described and compared. Gypsum can be lightened indirectly by the lightweight filler or directly. In the directly lightened materials, the pores are introduced into the gypsum material either by some chemical reaction producing gas or by the help of surface active substances. For the chemical lightening a large scale of waste products can be used. Lightening by the help of waste stone powder is described in detail. The materials with the properties comparable with the properties of AAC were prepared. Their bulk density was under 600 kg/m3, compressive strength was about 2 MPa and coefficient of thermal conductivity was under 0.2 W/m.K.
Lightweight gypsum materials can be used as a thermal insulating blocks, for the lightweight gypsum boards, partitions blocks, lightweight fire-resistant plasters or thermal-insulating plasters.
AAC, chemical lightening, direct lightening, gypsum, indirect lightening, inorganic filler, lightening methods, organic filler, SAS, waste products
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