Cements with a high limestone content – Mechanical properties, durability and ecological characteristics of the concrete

• Cements with limestone content up to 50 wt.-% can be used by an adopted concrete technology and reduction of w/c ratio to about 0.35.
• Limestone seems not to be totally inert component. The contribution of limestone to the compressive strength is also remarkable when higher amount of Portland cement clinker is replaced with limestone.
• The production of concretes made of limestone-rich cements exhibited roughly 25% less CO2 emission, but needs approximately the same energy demand.

This paper deals with the performance of concretes made of cements containing high levels of limestone between 35 and 65 wt.-%. The Article mainly focuses on cements with 50 wt.-% limestone. Several experiments regarding the fresh and hardened concrete properties were carried out. Chloride penetration, freeze-thaw resistance, carbonation resistance and long-term deformation behavior were analyzed.The results show that concretes with cements containing up to 50 wt.-% limestone and a water/cement-ratio of 0.35 may have sufficient properties for practical application if a stringent supervision is ensured. Furthermore, these concretes can exhibit mechanical and durability properties comparable to concretes according to EN 206-1 and the German national application document DIN 1045-2 made of EN 197-1 cements. Besides, the results revealed that these properties depend highly on the limestone characteristics. Life cycle assessment analysis revealed that a cut-off up to 25% in global warming potential of concretes made with such cements is achievable in comparison with German average cement with the same performance.