Abstract

The paper presents results of the study performed within the European Thematic Network ECOserve (www.eco-serve.net). The production of blended cements in Europe and its applications in construction are analyzed in respect to environmental impact and technical properties. The efficiency of reduction of CO2 emissions into the air and the use of energy for blended cement production is discussed using data e.g. from the German industry. The influence exerted by different main constituents of blended cement on concrete properties has been discussed on the basis of a comparison between concrete made from Portland cement and concretes made from cements containing, for example, limestone or blast furnace slag. The comparison shows that the advantages and disadvantages of the different main constituents for the properties of concrete, which extend from workability via strength development to durability characteristics, are distributed fairly evenly. The option of combining several main constituents makes blended cements particularly well suited for developing these cements into even more robust systems. A user of blended cements gets one optimized and quality controlled product from one source. The use of blended cements offers numerous benefits for the cement producer, the ready-mix-concrete producer and the end-user. The overall environmental benefit results from the reduction of the specific CO2 emissions of cement and concrete. The topic of environmental impact from cement-based materials to soil and groundwater is also addressed. Leaching of major, minor and trace elements from all cement-based materials – CEM I, CEM II, CEM III, CEM IV – is found quite systematic. Blended cements e.g. based on blast furnace slag feature low Cr VI leachability.