Masonry mortars are used to connect elements (bricks, hollow bricks, blocks), which the wall is made of, into a durable structure capable of carrying loads.
Breakdown by method of preparation:
• Mortars prepared on site in a traditional way and from simple ingredients (np. cement, calcium carbonate, sand).
• Ready-made mortars – Factory prepared dry binder mixes, fine aggregate and enriching additives
– for bricklaying with thick joints of average thickness approx 10 mm,
– for bricklaying with thin joints of average thickness approx 3 mm.
Division of mortars for thick joints:
• Traditional – They contain ordinary mineral aggregate and plasticizing agents; they are cold – have a high thermal conductivity coefficient (0,7-1,1 W/mK). We distinguish among them:
– cement mortars with high compressive strength (min 7-8 MPa) and very good adhesion to the substrate; they are laid in layers of thickness from 6 do 40 mm, they are frostproof and waterproof,
– cernent-lime mortars, which are characterized by better workability than cement mortars and better thermal conductivity; however, they have a slightly lower compressive strength.
• Heat-insulating – They are characterized by a low heat transfer coefficient (0,2-0,4 W/mK) thanks to the content of lightweight natural or artificial aggregates, this coefficient is close to that of wall materials – so that there are no thermal bridges and the wall does not freeze in the joints; warm mortars can be both cement and cement-lime mortars, Perlite or expanded clay is most often used as a lightweight aggregate, although mixtures with polystyrene granules are also available.
• Special: to the clinker (reduce the risk of efflorescence on the surface of clinker bricks), winter (for use in winter conditions from -15 do +5°C).
Mortars for thin joints, also called adhesive mortars, are used to join elements produced with high accuracy of dimensions and shape – they cannot compensate for major inaccuracies of the elements. Adhesive mortars make it possible to make joints of a thickness 1 -3 i 2-5 mm – thanks to which it is possible to make high-strength masonry.