CO2 Curing for Extruded Textile Reinforced Concrete Components - Requirements and Potentials

The development of new building materials with low CO2 emissions is in a current focus of research worldwide. Additive manufacturing methods such as formwork-free extrusion of textile reinforced concrete, which is partially used to produce lightweight and material-minimized textile reinforced concrete (TRC) components, have great potential in this respect. The fresh concrete is so stiff that it does not change its geometric shape after leaving the extruder. Currently, the concretes used for this purpose have a high binder content resulting in high CO2 emissions. Within a research project at the Institute of Building Materials Research, RWTH Aachen University (ibac), concrete specimens were cured with CO2 up to 48 h immediately after extrusion for the first time. The results show that CO2 curing significantly increases the 1 d and 2 d compressive and flexural strengths compared to reference specimens that were not cured with CO2. The concrete has sequestrated up to 3 wt.% additional CO2 after 48 h. In addition, the CO2 emissions of the concrete can be improved compared to non CO2 cured specimens.