Lightweight material based on the slag
J. Vlčeka,b, V. Tomkováb, F. Ovčačíkb, V. Matějkab,c
aCentre of Environmental Technologies , VŠB -Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava, Czech Republic
bFaculty of Metallurgy and Materials Engineering, VŠB -Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava, Czech Republic
cNanotechnology Centre, VŠB -Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava, Czech Republic
The subject of utility sample is a lightweight material characterized by the fact that its preparation is applied rapidly cooled milled steel slag from ladle metallurgy containing glass phase, where is latent hydraulicity activated by addition of alkaline activator. The main advantage of these products is reduced thermal conductivity, which is achieved by the presence of pores. The use of porous materials effectively helps to reduce of heat losses of buildings. Porosity of these materials is achieved addition by aluminum powder, which will support to preparation lightweight materials. Aluminum powder in mixture, which shows alkaline environment, is participating in chemical reactions, where the main product is hydrogen which the raw material mixture loosens. The basic components of a mixture of raw materials are ladle slag, aluminum powder and binder phase, which is usually lime, may also be applied addition of cement or granulated blast furnace slag. Other components are silica sand or fly ash from coal combustion. The mixture can add other ingredients that control the rheological properties and the process of setting and hardening. The raw material is homogenized in the presence of water and the resulting mixture is cast into forms, where it takes place above the hydrogen evolution reaction and the mixture is loosen. A necessary condition for achieving the porous structure is the synchronization of the development of hydrogen with the process of setting and hardening of the cast product. For acceleration of these processes is product placed into autoclave, which will develop the final strength parameters and aerate concrete product which is ready for export. The advantage is in the replacement of conventional materials by waste materials.
The presented lightweight material based on the slag can be utilized in construction and its advantage is that for its preparation is used waste slag which has insufficient utilization.