PROCHON Piotr PhD

The 76% of total greenhouse gas emissions in European Union comes from fossil fuels combustion and industrial processes. Ordinary Portland Cement (OPC) production has a significant effect on global environment, emitting over 5% of total CO2 emissions. Therefore researchers try to develop an alternative binding material with low carbon footprint. One of the possible solutions are alkali-activated binders – geopolymers.

The geopolymers are new, sustainable, amorphous, non-organic alumino-silicate polymers. Their properties, binding reactions and possible methods of product introduction into the market are examined starting from the late 70-s of the XX century. Obtaining a geopolymer composite requires the use of pozzolanic material (e.g. fly ash) mixed with activator, most commonly alkaline activator, and adequate curing. Received alkali-activated, environmentally friendly binder presents mechanical properties similar to OPC including thermal and chemical resistance.

Fly ash (FA) is a pozzolanic, industrial by-product defined in EN 450-1 widely used as cement and concrete additive. FA can be obtained through combustion of coal, co-firing of coal and biomass or from biomass. Due to fact that the main chemical compound of coal FA are silica, alumina and iron oxides it can be used as a raw material in geopolymerization process.

In Fly ash based geopolymers the geopolymerization mechanism analysis is complicated by presence of crystalline phases: mullite, hematite or quartz. In accordance with Fernandez- Jimenez et al. researches the fly ash composition  is a major factor for proper geopolymers binding process. The minimum level of reactive silica and alumina must be obtained in FA compound to guarantee a set off of binding reaction. Geopolymers composites received from low - calcium FA present good compressive strength, excellent chemical resistance and minor drying shrinkage. Biomass Fly Ash  and co-combustion fly ash have different chemical compound and needs to be examined for possible utilization as geopolymer binder. High level of calcium affects the polymerization process and can deteriorate the microstructure. On the other hand adding close to 5% of quicklime or calcium hydrate quicken hardening of geopolymers and increases its strength.

The objective of this research is to determine the influence of calcium additive on geopolymerization process and to define functional relationship between the amount of this additive and mechanical properties of geopolymer mortars based on co-combustion fly ash. The research scope includes the analysis of chemical and physical properties of FA, preparation of geopolymer mortars using FA obtained from polish energy plant, a different calcium additives, an alkaline activator and a reference sand. Tests will be conducted on fresh and hardened mortars in accordance with European standards.

Used methodology bases on European standards for fly ashes and mortars. Basic analysis of raw material will be done in accordance with EN 450-1 Fly ash for concrete. Definition, specifications and conformity criteria. Mortar samples will be prepared similar to procedure presented in EN 196-1 Methods of testing cement. Determination of strength. The same standard will be used for measurement of mechanical properties. Obtained results will be evaluated and will form the basis for correlation function of relationship between calcium compound and mechanical properties.

Publications :

1. Prochoń, P., Zhao, Z., Courard, L., Piotrowski, T., Michel, F., Garbacz, A. (2020). Influence of Activators on Mechanical Properties of Modified Fly Ash Based Geopolymer Mortars, Materials, 13 (5) 1033, 1-24. https://doi.org/10.3390/ma13051033
2. Piotrowski, T., Glinicka, J., Glinicki, M. A., Prochoń, P. (2019). Influence of gadolinium oxide and ulexite on cement hydration and technical properties of mortars for neutron radiation shielding purposes. Construction and Building Materials, 195, 583–589. https://doi.org/10.1016/j.conbuildmat.2018.11.076
3. Piotrowski, T., Prochoń, P. (2018). Influence of water to solid ratio on mechanical properties of GBFS-based geopolymer foam concrete. MATEC Web of Conferences, 163, 1–8. https://doi.org/10.1051/matecconf/201816306003
4. Piotrowski, T., Prochoń, P., Capuana, A. (2018). Mechanical Properties of Polymer Cement-Fiber-Reinforced Concrete (PC-FRC): Comparison Based on Experimental Studies. in M. M. Reda Taha, U. Girum, & G. Moneeb, M. M. Reda Taha, U. Girum, & G. Moneeb (Eds.), International Congress on Polymers in Concrete (ICPIC 2018) : Polymers for Resilient and Sustainable Concrete Infrastructure (pp. 227–234). https://doi.org/10.1007/978-3-319-78175-4_27