An integrated experimental-numerical study of the performance of lime-based mortars in masonry piers under eccentric loading

• Mortars containing metakaolin are stronger than pure-lime or lime-cement ones.
• Mortar strength can be increased by the addition of crushed bricks.
• Hydraulic reactions are promoted by water retained within brick fragments.
• Mortars with metakaolin and crushed bricks produce strong masonry.
• Mortar compressive strength is key parameter influencing the masonry strength.

The paper focuses on the performance of various lime-based materials, alternative to Portland cement mortars, intended for application in repairing historic structures when subjected to mechanical loading. Results of basic material tests indicate that the use of metakaolin as a pozzolanic additive produces mortars with superior strength and sufficiently low shrinkage. Moreover, mortar strength can be further enhanced by the addition of crushed brick fragments, which explains the longevity of Roman concretes rich in pozzolans and aggregates from crushed clay products such as tiles, pottery, or bricks. An integrated experimental-numerical approach was used to identify key mortar parameters influencing the load-bearing capacity of masonry piers subjected to a combination of compression and bending. The simulations indicate increased load-bearing capacities for masonry piers containing metakaolin-rich mortars with crushed brick fragments, as a result of their superior compressive strength.