RESUMEN
The article discusses the effect of additives of waste mineral wool fibers on geopolymer binder. This is an important study in terms of the possibility of recycling mineral wool waste. The paper describes an effective method for pulverizing the wool and the methodology for forming geopolymer samples, labeled G1 for glass-wool-based geopolymer and G2 for stone-wool-based geopolymer. The compressive and flexural strengths and thermal conductivity coefficient of the geopolymer with the addition of mineral fibers were determined. The key element of the article is to verify whether the addition of mineral wool fibers positively affects the properties of the geopolymer. The results obtained prove that the addition of fibers significantly improves the flexural strength. For the G1 formulation, the ratio of compressive strength to flexural strength is 18.7%. However, for G2 samples, an even better ratio of compressive strength to flexural strength values of 26.3% was obtained. The average thermal conductivity coefficient obtained was 1.053 W/(m·K) for the G1 series samples and 0.953 W/(m·K) for the G2 series samples. The conclusions obtained show a correlation between the porosity and compressive strength and thermal conductivity coefficient. The higher the porosity, the better the thermal insulation of the material and the weaker the compressive strength.
RESUMEN
Waste generated in fine wool production is homogeneous and without contamination, which increases its chances of reuse. Waste mineral wool from demolition sites belongs to the specific group of waste. However, the storage and collection require implementing restrictive conditions, such as improper storage of mineral wool, which is highly hazardous for the environment. The study focuses on the leachability of selected pollutants (pH, Cl-, SO42-) and heavy metals (Ba, Co, Cr, Cu, Ni, Pb, Zn) from the waste mineral wool. As a solution to the problem of storing mineral wool waste, it was proposed to process it into wool-based geopolymer. The geopolymer, based on mineral wool, was also assessed regarding the leaching of selected impurities. Rock mineral wool is very good for geopolymerisation, but the glass wool needs to be completed with additional components rich in Al2O3. The research involved geopolymer prepared from mineral glass wool with bauxite and Al2O3. So far, glass wool with the mentioned additives has not been tested. An essential aspect of the article is checking the influence of wool-based geopolymer on the environment. To investigate the environmental effects of the wool-based monolith and crushed wool geopolymers were compared. Such research has not been conducted so far. For this purpose, water extracts from fragmented geopolymers were made, and tests were carried out following EN 12457-4. There is no information in the literature on the influence of geopolymer on the environment, which is an essential aspect of its possible use. The research results proved that the geopolymer made on the base of mineral wool meets the environmental requirements, except for the pH value. As mentioned in the article, the geopolymerisation process requires the dissolution of the starting material in a high pH (alkaline) solution. On the other hand, the pH minimum 11.2 value of fresh geopolymer binder is required to start geopolymerisation. Moreover, research results analysed in the literature showed that the optimum NaOH concentration is 8 M. for the highest compressive strength of geopolymer. Therefore, the geopolymer strength decreases with NaO concentration in the NaOH solution. Geopolymers glass wool-based mortars with Al2O3 obtained an average compressive strength of 59, the geopolymer with bauxite achieved about 51 MPa. Thus, Al2O3 is a better additional glass wool-based geopolymer than bauxite. The average compressive strength of rock wool-based geopolymer mortar was about 62 MPa. The average compressive strength of wool-based geopolymer binder was about 20-25 MPa. It was observed that samples of geopolymers grout without aggregate participation are characterised by cracking and deformation.