Projects / Programmes
Synthesis and characterization of alkali activated foams based on different waste
| Code |
Science |
Field |
Subfield |
| 2.01.00 |
Engineering sciences and technologies |
Civil engineering |
|
| Code |
Science |
Field |
| T150 |
Technological sciences |
Material technology |
| Code |
Science |
Field |
| 2.01 |
Engineering and Technology |
Civil engineering |
waste glass, slags, fly ash, alkali activation, alkali activated foams
Researchers (12)
Organisations (2)
Abstract
Alkali-activated materials, also called geopolymers, are an environmentally friendly and technically acceptable alternative to cement, concrete, and ceramics. In order to produce AAM, precursors containing (i) SiO2 and Al2O3 in sufficient quantities and in a reactive form-glassy state (e.g. ash, activated clay), and (ii) alkaline activators in a solution (mostly NaOH, KOH, Na-water glass, K-water glass) are needed. When these two components are mixed, firstly, the dissolution and transport of the components (Al, Si) in the alkaline activators takes place, and then, through poly-condensation of the Al and Si, an aluminosilicate network is formed, which can be amorphous or partially crystallized.
Suitable precursors for AAM are thermally activated clay, natural pozzolan (e.g. volcanic ash), as well as different kinds of industrial waste, such as ashes (fly ash, bottom ash, bio-based ashes) and various slags. Many products can be obtained by the alkaline activation process which could replace traditional construction products. They range from blocks, slabs, paving-stones, curbs, and partitions, to refractory materials and materials for specific industrial applications (e.g. insulation plates).
Foams, which are produced when appropriate foaming agents are added to an alkaline activated sludge, are one of the most promising types of alkali-activated materials due to potentially higher added value. Such foams are non-combustible and dimensionally stable, and have high strength and good insulation properties.
The main objective of this project is to develop new lightweight alkali-activated foams based on the mixture of various secondary raw materials (fly ash, slag and waste glass). Different foaming agents and stabilising agents (in varying proportions) will then be investigated in order to achieve the highest possible porosity (Al powder, H2O2, NaOCl, SDS). In addition to the use of waste materials, the additional advantage of such foams (in comparison to commercially available inorganic foams) will be that they will be produced at temperatures lower than 100 °C, and they will be stable also at elevated temperatures (expected up to 1000 °C).
To achieve these goals, focus of project will be on:
- identification of local waste flows to be used in alkali activated production,
- selection of proper combinations of solid waste precursors and alkaline activators by DOE (Design Of Experiment) approach to obtain optimal characteristics,
- finding of optimal foaming agents and foam stabilizing agents in order to obtain highly porous structure,
- characterization of foams at room temperature and at elevated temperature (up to 1000 °C),
- quantification of the environmental footprint of the new technology and products by life cycle assessment (LCA).
Project is divided into six work packages related to the specific goals of the project, and it will be performed by ZAG –Department of Materials and IJS - Department of Advanced Materials. Both groups are already highly experienced in the preparation and quantification of foamed materials of different origins.
The acquired knowledge will provide the basis for the development of various new products by using precursors that are currently landfilled and potentially harmful to the environment. Furthermore, new interdisciplinary knowledge, combining technical properties with environmental aspects will be obtained for the designing of alkali activated materials from different precursors (fly ash, slag, glass).
Significance for science
Over the last few years research into alkali geopolymers has intensified. In fact, this specialized field is of high topical importance, proven by the publishing of numerous papers and citations, projects and industry transfers…
Within our project the scientific contribution will be related to the determination of the influential parameters of waste glass and waste slag for the process of alkali activation.
For the foaming process itself, however, an important understanding of the stabilization process of the foams and implementation of this knowledge will result in a stable uniformly porous structure, together with the various foaming agents. For design of optimal performance, the most important factors are starting materials (precursors, based on waste), alkaline activators, stabilizers, foaming agents and curing regime, which is usually performed at a slightly elevated temperature (up to 80 oC).
Our published articles related to the topic of foaming in fly ashes have already achieved noticable citation within a period of one year from the publication, and we estimate that by deepening the understanding of processes and applications on other starting materials (in our case, slag and waste glass), we can prepare scientific publications of high quality. Articles on the phenomenon of foamed alkali-activated materials have only been appearing in recent years; therefore, this is still a niche area for an in-depth research. Activities in this field can further improve impact trough citations, and offer the possibility of joining to the international projects.
Since an environmental analysis will also be part of the project through i.e. life cycle assessment (LCA) of such products, where it is estimated that due to the use of waste materials and low temperature synthesis, alkali activated foams will be an environmentally acceptable alternative to similar products, such as foamed glass or porous ceramics. Such analyzes will also provide bench mark comparisons to the existing products, and provide the information on the impacts on greenhouse gases and other parameters within the LCA. This interdisciplinary approach will also contribute to environmental sciences.
In addition, we will contribute to the development of science and profession through international activities in this field, primarily through the activities of the Rilem Association, an association of top experts in the field of construction (https://www.rilem.net/) and its technical committees (TC DTA Durability testing of alkali activated materials and TC CCC Carbonation of concrete with additional cementitious materials); project leader V.Ducman is a member of these committees. Based on the results of the tests and inter-laboratory comparisons obtained within these committees, as well as additional research and analysis, we will be able to evaluate the long-term behavior of such materials under different conditions and also contribute to Rilem's guidelines for testing such materials and products.
Significance for the country
Over the last few years research into alkali geopolymers has intensified. In fact, this specialized field is of high topical importance, proven by the publishing of numerous papers and citations, projects and industry transfers…
Within our project the scientific contribution will be related to the determination of the influential parameters of waste glass and waste slag for the process of alkali activation.
For the foaming process itself, however, an important understanding of the stabilization process of the foams and implementation of this knowledge will result in a stable uniformly porous structure, together with the various foaming agents. For design of optimal performance, the most important factors are starting materials (precursors, based on waste), alkaline activators, stabilizers, foaming agents and curing regime, which is usually performed at a slightly elevated temperature (up to 80 oC).
Our published articles related to the topic of foaming in fly ashes have already achieved noticable citation within a period of one year from the publication, and we estimate that by deepening the understanding of processes and applications on other starting materials (in our case, slag and waste glass), we can prepare scientific publications of high quality. Articles on the phenomenon of foamed alkali-activated materials have only been appearing in recent years; therefore, this is still a niche area for an in-depth research. Activities in this field can further improve impact trough citations, and offer the possibility of joining to the international projects.
Since an environmental analysis will also be part of the project through i.e. life cycle assessment (LCA) of such products, where it is estimated that due to the use of waste materials and low temperature synthesis, alkali activated foams will be an environmentally acceptable alternative to similar products, such as foamed glass or porous ceramics. Such analyzes will also provide bench mark comparisons to the existing products, and provide the information on the impacts on greenhouse gases and other parameters within the LCA. This interdisciplinary approach will also contribute to environmental sciences.
In addition, we will contribute to the development of science and profession through international activities in this field, primarily through the activities of the Rilem Association, an association of top experts in the field of construction (https://www.rilem.net/) and its technical committees (TC DTA Durability testing of alkali activated materials and TC CCC Carbonation of concrete with additional cementitious materials); project leader V.Ducman is a member of these committees. Based on the results of the tests and inter-laboratory comparisons obtained within these committees, as well as additional research and analysis, we will be able to evaluate the long-term behavior of such materials under different conditions and also contribute to Rilem's guidelines for testing such materials and products.
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Most important socioeconomically and culturally relevant results
Interim report
