Cementmörtel

Cementmörtel is a cement-based binding material used in masonry and plastering. It is a mixture of hydraulic cement, water, and aggregates such as sand, and may include lime or pozzolanic additives. The cement hydrates to form a hard, cohesive bond that transfers loads between masonry units.

There are several variants. A basic cementmörtel consists of cement and sand in various ratios; adding lime can improve workability, adhesion, and vapor permeability. Cement-lime mortars are common in historic or delicate constructions because they are more forgiving and flexible than pure cement mortars. In modern practice, pre-mixed bag mortars meet specific performance classes defined by standards.

Properties and performance depend on the mix and curing conditions. Important factors include bond strength, compressive strength, shrinkage, water absorption, and resistance to freeze–thaw cycles. Workability and open time can be adjusted with lime, plasticizers, or air-entraining agents. Cementmörtel generally achieves higher early strength than lime mortars, but may be less compatible with historic materials if not properly matched.

Applications include bedding and joint mortars for bricks, stones, and blocks, as well as plaster application on walls. Proper substrate preparation, correct mixing ratios, and controlled curing are essential to ensure adhesion and durability. The choice of cementmörtel class or mix should align with the masonry units, environmental exposure, and project requirements.

Standards and labeling follow regional guidelines, with European references such as EN 998 for masonry mortars, which specify classes and performance criteria for cement-based mortars. Safety considerations include handling cement and mixing water to minimize skin and eye irritation.