Performance of lower strength LC3 mortars in comparison to conventional cement mortars in modern masonry walls

Masonry is one of the oldest and most widely used construction techniques in history. Even today, unreinforced masonry (URM) remains prevalent in both heritage and modern buildings. Globally, over 70% of buildings incorporate some form of masonry, and in Europe, URM accounts for 15–50% of new housing construction, including in both moderate and high seismic zones.

Masonry structures offer many advantages, such as cost-effectiveness, ease of construction, fire resistance, and good indoor climate performance. However, their key weakness is high seismic vulnerability, especially for URM systems, which are brittle and lack ductility. Additionally, the construction industry significantly contributes to global CO₂ emissions and resource depletion. Therefore, improving both the seismic performance and sustainability of masonry is a crucial research challenge.

Limestone Calcined Clay Cement (LC3) is an emerging low-carbon alternative to traditional Portland cement. By combining calcined clay and limestone, LC3 - 35 achieves strength M5 with up to 60% lower CO₂ emissions. While its material-level performance has been studied, its structural performance, especially in full-scale masonry walls under seismic loading, are yet to be investigated.