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Projects / Programmes source: ARIS

Recycling of waste titanogypsun in cement composites

Research activity

Code Science Field Subfield
1.06.01  Natural sciences and mathematics  Geology  Mineralogy and petrology 

Code Science Field
P420  Natural sciences and mathematics  Petrology, mineralogy, geochemistry 

Code Science Field
1.05  Natural Sciences  Earth and related Environmental sciences 
Keywords
waste red titanogypsum, phase composition, mcrostructure, ettringite, recycling, cement composites, leaching, mechano-physical properties
Evaluation (rules)
source: COBISS
Researchers (1)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  32263  PhD Vesna Zalar Serjun  Geology  Head  2019 - 2021 
Organisations (1)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  1502  Slovenian National Building and Civil Engineering Institute  Ljubljana  5866324000 
Abstract
The large quantities of different synthetic gypsums represent a global economic and environmental problem. Numerous different types of industrial residues have been routinely recycled in the construction sector, but in the case of waste industrial gypsum this practice has not been widely implemented, since it has a low recycling potential due to its specific chemical and physical properties. The recycling of red titanogypsum in cementitious composites requires knowledge of its properties, in particular about the hydration mechanism, the development of phase composition, and the microstructure. Gypsum is on one hand an essential ingredient in the production of cement composites, but on the other hand the increased amount of gypsum used in the preparation of cement composites can be reflected in the in the lower mechanical properties. Two theories have been presented to link ettringite formation in systems containing a high quantity of gypsum (so-called over-sulphated systems) with expansion. However, there is a lack of experimental evidence which could directly link the observed expansion to the formation of ettringite. The results of some analyses have also shown that the amount of ettringite and expansion varies widely between systems with different alumina containing compounds. Since in-depth knowledge of the mechanisms and kinetics of the hydration process, the sequence of formation and identification of the mineral phases formed, together with time dependent chemical and mechanical properties of the composites, is crucial in order to develop cement composites containing high quantities of red titanogypsum (in combination with some additional industrial waste), realization of this project would contribute significantly towards the characterization of described systems. The realization of proposed research work would enable to define the fundamentals based on which the behaviour of the proposed two- and three-component cement systems, as well as similar systems, could be predicted. Further, the effects of increased amounts of formed ettringite on the potential destructive mechanisms would be explained on the phenomenological level. The methodology will be based on a broad range of complementary methods. Cement composites described in the project proposal would promote the development of a low­carbon and circular economy, based on the usage of lower amounts of cement and local renewable materials. The proposed program consists of a central node for various topics and fields, which will make it possible to assess the new knowledge particularly in the field of geology (mineralogy, petrography) and also in the fields of chemistry, materials and construction.
Significance for science
Realization of this project would contribute significantly towards the characterization of described systems of cement composites containing high quantities of sulphate (red titanogypsum also in combination with some additional industrial waste). The results of proposed research work would enable to define the fundamentals based on which the behaviour of the proposed two- and three-component cement systems, as well as similar systems, could be predicted. Further, the effects of increased amounts of formed ettringite on the potential destructive mechano-physical mechanisms would be explained on the phenomenological level for the first time. Proper implementation of the results of mineralogical and chemical investigations would enable precise quantification and characterization of the mobilization processes in the investigated cement composites. The parallel results of mechanical and physical analyses would be used to predict the durability of the investigated composites. The proposed program consists of a central node for various topics and fields, which will make it possible to assess the new knowledge particularly in the field of geology (mineralogy, petrography) and at the same time in the fields of chemistry, materials and construction. From two different aspects, the project represents an innovative approach: firstly, more precise knowledge about the hydration and structural processes of cement-based systems with a high amount of sulphate will ensure the development of cement composites with the maximum possible content of red titanogypsum, corresponding to the required properties, and secondly, by using of waste materials of local origin the final composites will represent a sustainable products, i.e. green concrete. The newly gained findings and composites formulation will represent a transition to a low­carbon circular economy, which directly replaces natural raw materials and cement. Worldwide, few such cement composites are produced, since their microstructure development is not known in detail. In this way a direct transfer of technology and of new knowledge around the world will be possible. In the production and formulation of new cement composites, knowledge about the detailed mechanisms of hydration, microstructure evolution, and durability and inertness, are crucial.
Significance for the country
Realization of this project would contribute significantly towards the characterization of described systems of cement composites containing high quantities of sulphate (red titanogypsum also in combination with some additional industrial waste). The results of proposed research work would enable to define the fundamentals based on which the behaviour of the proposed two- and three-component cement systems, as well as similar systems, could be predicted. Further, the effects of increased amounts of formed ettringite on the potential destructive mechano-physical mechanisms would be explained on the phenomenological level for the first time. Proper implementation of the results of mineralogical and chemical investigations would enable precise quantification and characterization of the mobilization processes in the investigated cement composites. The parallel results of mechanical and physical analyses would be used to predict the durability of the investigated composites. The proposed program consists of a central node for various topics and fields, which will make it possible to assess the new knowledge particularly in the field of geology (mineralogy, petrography) and at the same time in the fields of chemistry, materials and construction. From two different aspects, the project represents an innovative approach: firstly, more precise knowledge about the hydration and structural processes of cement-based systems with a high amount of sulphate will ensure the development of cement composites with the maximum possible content of red titanogypsum, corresponding to the required properties, and secondly, by using of waste materials of local origin the final composites will represent a sustainable products, i.e. green concrete. The newly gained findings and composites formulation will represent a transition to a low­carbon circular economy, which directly replaces natural raw materials and cement. Worldwide, few such cement composites are produced, since their microstructure development is not known in detail. In this way a direct transfer of technology and of new knowledge around the world will be possible. In the production and formulation of new cement composites, knowledge about the detailed mechanisms of hydration, microstructure evolution, and durability and inertness, are crucial.
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