A circular economy is a current tenet that must be implemented in the field of construction.
That would imply the study of the possibilities of the use of waste generated, for obtaining materials
the used in construction as replacements for the raw material used. One of these possibilities is
the substitution of the cement by slag, which contributes to the reduction of cement consumption,
decreasing CO2 emissions, while solving a waste management problem. In the present paper, di erent
types of concrete made by cement substitution with di erent type of slags have been studied in order
to evaluate the properties of these materials. Cement is replaced by slag from di erent steel mills,
both blast furnace and ladle furnace slag. The percentages of slag substitution by cement are 30%,
40% and 50% by weight. Mechanical, physical and environmental properties have been evaluated.
Compressive and flexural strength have been analysed as the main mechanical properties. As far
as physical properties go, density and porosity tests were be reported and analysed, and from an
environmental point of view, a leachate study was performed. It has been found that some kinds
of slag (blast furnace slag) are very suitable as substitutes for cement, providing properties above
those of the reference concrete, while other types (ladle furnace slag) could be valid for non-structural
applications, contributing in both cases to a circular economy.
