The Impact of the Aggregate Used on the Possibility of Reducing the Carbon Footprint in Pavement Concrete

The aim of this work was to try to reduce the carbon footprint by means of various types of aggregates which are used for concrete intended for road construction. Four types of aggregates were used in the study: local gravel and dolomite, as well as commonly used granite and amphibolite. Aggregates differed not only in their basic properties, but also in the type of minerals, their origin, and, above all, the distance from the construction site. For the experimental tests, a constant amount of CEM III 42.5 HSR-NA cement, 0/2 mm natural sand, and chemical admixtures based on polycarboxylate and air entrainment were used. For each of the four series, the compressive, flexural, and tensile strength were determined. In order to verify the durability of concrete, the frost resistance in salt and the pore structure in hardened concrete were determined after 150 cycles of freezing and thawing. As a result of the research, it was found that the highest compressive strength was obtained for composition based on amphibolite aggregate. The flexural strength for all series exceeded 5.5 MPa, and the highest tensile strength results were obtained for a composition based on dolomite aggregate. An additional element of the work was the determination of the carbon footprint for each recipe and the comparative analysis. As a result of the analysis, it was possible to reduce the carbon footprint by 32% thanks to the use of CEM III cement instead of CEM I. Additionally, the use of local aggregates located 80 km from the construction site allowed the carbon footprint to be reduced by another 19.2%.