Opportunities and barriers of pozzolanic cements

Natural pozzolans have been used as building materials since ancient times. They are used as a supplementary cementitious material in combination with portland clinker to produce cements, characterized by high mechanical strengths and good durability performance. In the past the production of pozzolanic cement was mostly restricted to countries with natural pozzolan availability (Italy, Turkey, Greece, Philippine for example) and considered or even rejected in other countries that had the possibility of using other types of SCMs such as slag or fly‐ash. The market acceptance of natural pozzolanic cement also shows regional dependency. Colour and water demand strongly affect the perception and rheological properties of concrete containing natural pozzolan resulting in poor acceptancy in regions not used to working with this type of cement. Although, this SCM has been studied for very long time, today it makes sense to look closely at new pozzolanic binders. Innovative types of pozzolanic cement with very low clinker content are approaching the traditional cement market, due to the need for clinker factor reduction, and to the availability of separate grinding technology. New applications are being investigated with the aim of exploiting the behaviour of certain pozzolanic material to act as CO₂ adsorbers for the removal of the exhaust gas during the production process. This paper will provide an overview of the most recent research work dealing with natural pozzolanic cement and the possible future opportunities and barriers offered by this very traditional and long‐used building material.