Ecological aspect of waste concrete fines application as cement replacement in fine-grained composites

Cement production is a very energy-intensive process which is responsible for around 5-8% of global carbon dioxide emission caused by human activity. Thus, replacing it with other materials is very beneficial for the environment. The paper presents the research on the use of a waste concrete fines which partially replaced cement in concretes. The fines was obtained in the thermal and mechanical treatment of concrete rubble. Then the research experiment considered the impact of two factors on selected physical and mechanical properties of the fi ne-grained concretes. These factors included: contents of the recycled fines (10, 20, 30% of cement’s mass) and its grinding time (0, 30, 60min). The results confirmed that the right technology enables the recycled fines to substitute 20% of the cement’s weight. Such activity allows energy saving compared to clinker and will also cover part of the ever-increasing cement demand – while protecting raw material.