Sementtilime

Sementtilime is a modern binding material used in masonry and plastering that blends cementitious binder with lime to create mortars and plasters that aim to combine early strength with enhanced moisture management. It is designed to be more compatible with historic masonry while offering improved durability and workability compared with pure lime or pure cement mortars.

Composition and variants typically involve a Portland cement–based binder combined with lime putty or hydrated lime, plus optional pozzolanic additives such as fly ash, metakaolin, or natural pozzolans. Proportions vary by application, but common ranges include cement roughly 20–60% by mass, lime 40–80%, and pozzolanic additive 0–20%.

Key properties include increased vapor permeability relative to many cement mortars, which can help regulate moisture in masonry assemblies. The cement portion provides sufficient early strength, while the lime component contributes elasticity and reduced shrinkage cracking. Workability and bonding performance depend on formulation, aggregate choice, and curing conditions.

Applications are primarily in new construction seeking sustainable performance and in restoration or conservation projects where substrate compatibility is important. It can be used for exterior and interior masonry mortars, plaster applications, and repair mortars, with formulation tuned to the substrate, climate, and historical context.

Production and standards considerations involve standard mortar mixing practices with attention to curing and moisture management. Specifications often reference cement–lime–pozzolan mortar guidelines and testing for compressive strength, bond strength, and vapor permeability to ensure suitable performance for the intended use.

Etymology: the name combines elements of cement and lime, reflecting its hybrid formulation. In practice, semettilime formulations vary by region and project requirements.