Specification of eco-efficient concrete for precast components

Part 1: Material Selection and Mix Design

Innovative concrete technology makes it possible to mitigate the environmental impacts – that is to say greenhouse gas emissions (Global Warming Potential, GWP) and the embodied grey energy (Total Primary Energy Requirement, TPER) – of concrete, the construction material most utilised throughout the world. So-called “eco-concretes”, or the binding agents with low Portland cement clinker content employed with such, generally exhibit slow strength development. However, producing precast components requires rapid strength development in order to attain short formwork stripping times. In addition, descriptive standards prescribe a minimum binding agent content and maximum water/binding agent value (w/b value) with the aim, amongst others, of safeguarding concrete durability that cannot be maintained with especially environmentally friendly concretes. The present paper will demonstrate in its first part how eco-efficient concretes can be designed utilising a concept of combined micro and “eco” fillers. These have less impact on the environment, good productionfriendly processability and great early strength when compared with traditional concrete for precast components. Examples of prototypes from Austria will be presented.

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