The Impact of Cement Aggregates on the Fire Resistance Properties of Concrete and its Ecological Footprint

Abstract

The strength properties of concrete are significantly influenced by the type of binder used. In the case of cement, the use of cement-containing admixtures (CEM II) is becoming increasingly popular from a durability and environmental point of view. The first question was how cements containing different admixtures behave and how their compressive strength changes under high temperatures (fire). First, the experiments were carried out with the cement tests, and then the concrete specimens were checked for the extent to which the addition of admixtures modifies the favourable effect measured for cement. Under thermal loading, the value of the residual compressive strength of the cement paste increased with the addition of the admixture content. The results of the compressive strength test and the developed crack patterns were consistent with each other. The most severe cracking was observed in the Portland cement specimens, and the decrease in strength was also the most significant. Based on the results of the cement tests, several types of cement were used for the concrete tests. The second research question was: Which concrete recipe has the lowest specific ecological footprint? Therefore, for each formulation, the specific ecological footprint is crucially influenced by the type and amount of substitute used, as their specific CO2 emissions are typically lower than those of Portland cement. Based on our previous studies, a reduction in the specific ecological footprint of up to 10 % can be achieved by using substitutes. The novelty of our research lies in the combined use of fire resistance and ecological aspects, which helps to select a formulation with better technical properties and, at the same time, more sustainable.