Abstract

Different types of binders can significantly affect the strength properties of concrete. The use of cement-containing admixtures is becoming more widespread in the building industry when considering durability and environmental impact. This paper examines how different types of cement containing different admixtures behave. How the compressive strength of concrete changes under elevated temperature, and which concrete mixture has the lowest CO₂ emission. To determine the strength parameters, test specimens of 150x150x150 mm and 70x70x250 mm were prepared from the concrete mixtures. After heating and cooling, they were broken, thereby determining the compressive and flexural-tensile strength values. The ecological footprint was calculated for each mixture, which is substantially influenced by specific parameters for example the type and amount of substitute materials. These materials typically have lower CO₂ emissions than Portland cement. The novelty of this research lies in the combined investigation of the changing compressive strength of concrete at elevated temperatures and its sustainability. The change in the formulation resulted in a saving of the emission of ~10% (43.22 kgCO_2e emissions) compared to the reference value. The importance of reducing the ecological footprint is demonstrated by the authors using a case study of the Gotthard tunnel.