Abstract
Ceramic-added air lime mortars have been used since ancient times owing to the pozzolanic effect provided by crushed ceramic particles that impart hydraulic properties. This work reviews the historical use, composition, reaction mechanisms, characterization techniques, and performance properties of ceramic-added air lime mortars. The fine ceramic powder composed of silica and alumina phases reacts with calcium hydroxide released during lime hydration to form calcium silicate hydrates (CSH) and calcium aluminate hydrates (CAH) via pozzolanic reaction. This provides hydraulicity and reduces setting time compared to pure air lime mortars. The coarser ceramic particles also serve as aggregate and refine the microstructure as filler. The reactivity depends on the ceramic composition, amorphous phase content, particle size distribution, and firing temperature. Optimal proportioning of the fine ceramic powder and coarse ceramic aggregate is necessary to achieve desired properties. Ceramic addition enhances the durability of air lime mortars against weathering while maintaining compatibility with lime-based masonry structures. Key novelties of this review include: (i) in-depth analysis of the influence of ceramic characteristics (mineralogy, particle size, pozzolanicity) and processing on reaction kinetics and phase evolution; (ii) systematic assessment of mechanical, physical and durability properties in comparison to conventional air lime mortars and cement-based grouts; (iii) elucidation of microstructural mechanisms governing performance using advanced characterization techniques; (iv) critical appraisal of test methods and standards for evaluation; and (v) rigorous discussion on potential applications in construction, conservation and repair, with case studies.