Promoting the Use of Fe-Rich Slag in Construction (2023-02)¶

The construction sector is responsible for significant CO2 emissions, especially due to the production of ordinary Portland cement (OPC). One option to decrease CO2 emissions is to print mortar made from an alternative binder. A precursor was used consisting of mainly non-ferrous metallurgy Fe-rich slag and a minor amount of OPC (<16 wt%), which forms upon alkali-activation a hybrid binder. A 3D-printable hybrid mortar was developed in a stepby-step performance-based approach, with a focus on the fulfilment of criteria relevant for 3D printing: shearthinning, high yield stress, and stiffness development. The criteria to be met were determined using a commercially available 3D-printable OPC-mortar. Several raw materials were introduced to develop a hybrid mortar with a particle packing that positively influenced the pumpability and buildability. The effect of the precursors and superplasticizer on reactivity was investigated. The final mortar reached the printing criteria, offering a suitable alternative to 3D-printable OPC-mortars.