About research
Since 2003, when close cooperation was established between the Department of Glass and Ceramics, ICTP, and the Department of Construction Technology, FCE CTU in Prague, research on the exploitation of fly ash emissions from large furnaces has been running based on previous several-year research into alkali activation performed at the Department of Glass and Ceramics. The objective of cooperation is the application of research results obtained in this way in construction practice. The cooperation between CTU and ICTP was and is organized within the framework of research grant projects awarded by the Czech Science Foundation, No. 103/08/1639 ?Microstructure of inorganic alumosilicate polymers? (2008-2010) and No. 103/05/2314 ?Mechanical and engineering properties of geopolymer materials based on alkali-activated fly ashes? (2005-2007).
POPbeton? is a new type of cement-free concrete with a binder consisting exclusively of fly ash. As the existing common term of fly-ash concrete stands for cement-based concrete with fly ash admixtures as a fine inert component complementing the filler, this new type of concrete has been named POPbeton / POPconcrete. POPbeton? has ambitions to become a new construction material reusing some other waste materials such as slag, metakaoline, fine glass waste, as well, or a material for the solidification of some hazardous wastes.
The programme of the exploitation of fly ash emissions from large furnaces is a follow-up to the programme running at the Department of Glass and Ceramics, which has been engaged in research of geopolymer reactions for many years. The objective of cooperation is the application of research results obtained in this way in construction practice. The whole programme is particularly focused on the exploitation of brown coal fly ashes, which are produced in our country in volumes many times exceeding those of black coal fly ashes.
As was confirmed by the tests, activated brown coal fly ash is less reactive, and the resulting mix has worse properties than a mix where only black coal fly ash is used. The verifying tests performed on black coal fly ashes manifested higher fly ash reactivity and thus better resulting properties of POPbeton, comparable or superior to the results achieved abroad. Due to the variety of fly ash types produced in the Czech Republic, however, brown coal fly ash, or potentially a mix of both fly ash types with a composition corresponding to the ratio of both fly ash types produced, remains our priority for POPbeton?.
The principal advantage of this material, therefore, consists in reducing the ecological burden on the environment by reusing waste materials. This is also connected with favourable prices of input materials, more cost-effective in comparison to traditional concrete binders. The persisting disadvantage is the necessity of tempering fly ash together with alkaline activators to set off fly ash activation. For this reason, after the verification of the basic properties of POPbeton activated by tempering, the research was further oriented towards a possibility of activating fly ash without the need for its tempering.
A few facts from the history of collaboration between the Department of Glass and Ceramics, ICTP, and the Department of Construction Technology, FCE CTU in Prague ...
1973 ... first experiments with alkali-activated cement
1974 -1978 ... study into the system of ground Portland cement clinker ? anion-active tenside - alkaline hydrolyzable salt - H2O
1979 ... formulation of principles of gypsum-free Portland cement
1980 - 1984 ... building materials based on special fast-hardening gypsum-free cement
1985 ... discovery of the ability of gypsum-free cement to harden at temperatures of down to -30 °C, the ability of gypsum-free cement to resists temperatures up to 1200 °C
1985 ... reaching compressive strength of 245 MPa in gypsum-free cement (presumed maximum cement strength achievable at that time)
1986 - 1987 ... laboratory and pilot production of gypsum-free cement
1988 ... verification of possibilities of industrial production of gypsum-free cement
1989 ... trial industrial applications of building materials based on special gypsum-free cement, preparation of concrete with a strength of 100 MPa
1992 - 1995 ... experiments with alkaline activation of waste blast furnace slags
1997 ... experiments with alkaline activation of waste fly ashes
1998 ... study into systems of latent hydraulic substances ? alkaline compounds ? H2O
1999 ... reaching compressive strength of 168 MPa in alkali-activated systems of fly ash + slag
2000 ... preparation of materials based on alumosilicate polymers (from fly ash and slag raw materials)
2001 ... preparation of first building materials based on alumosilicate polymers
2002 ... formulation of principles of POPbeton technology (different from PC-based concrete technology), preparation of first POPbeton with a compressive strength exceeding 60 MPa
2001 - present
- research of material properties of alumosilicate polymers based on waste fly ashes, thermally activated kaolinitic substances and waste slags
- optimization of POPbeton technology
- study of material properties of POPbeton
