Dry mortar, in particular cementitious tile adhesive

A dry mortar comprising, in each case relative to the total dry weight of the dry mortar,

• a) 20-50 wt.-% of Portland cement,
• b) 4-8 wt.-% latent hydraulic and/or pozzolanic binder materials,
• c) 35-59 wt.-% of sand,
• d) 1-16 wt.-% of ground calcium carbonate, magnesium carbonate or mixed calcium/magnesium carbonates and/or expanded glass,
• e) 0.1-2 wt.-% of polyethylene and/or polypropylene fibers with a length of 0.2-0.5 mm, wherein the aspect ratio of the fibers is between 2-20, and
• f) 1-15 wt.-% of at least one redispersible polymer powder.

A method for improving the slip resistance and/or the flexibility of a building material comprising the steps of

• a) obtaining a dry mortar by admixing fibers with an average length of 0.2-0.5 mm to a dry cementitious composition comprising 10-50 wt.-% of at least one cementitious binder and 20-75 wt.-% of at least one aggregate, in each case relative to the total dry weight of the dry mortar, and
• b) mixing the dry mortar obtained in step a) with water in a weight ratio of water to the dry mortar of 0.25-0.5,
• wherein the at least one cementitious binder comprises, in each case relative to the total dry weight of the cementitious binder:
• 60-99.5 wt.-%, Portland cement, and
• 0.5-40 wt.-%, latent hydraulic and/or pozzolanic binder materials,
• wherein aggregate is a material that is non-reactive in a hydration reaction of cementitious binders, and
• wherein the aspect ratio of the fibers is between 2-20, and wherein the fibers are polyethylene and/or polypropylene fibers.

A method for achieving a creamy consistency of a building material comprising the steps of

• a) obtaining a dry mortar by admixing fibers with an average length of 0.2-0.5 mm to a dry cementitious composition comprising 10-50 wt.-% of at least one cementitious binder and 20-75 wt.-% of at least one aggregate, in each case relative to the total dry weight of the dry mortar, and
• b) mixing the dry mortar obtained in step a) with water in a weight ratio of water to powder of 0.25-0.5,
• wherein the at least one cementitious binder comprises, in each case relative to the total dry weight of the cementitious binder:
• 60-99.5 wt.-%, Portland cement, and
• 0.5-40 wt.-%, latent hydraulic and/or pozzolanic binder materials,
• wherein aggregate is a material that is non-reactive in a hydration reaction of cementitious binders, and
• wherein the aspect ratio of the fibers is between 2-20, and wherein the fibers are polyethylene and/or polypropylene fibers.

A method for reducing the shrinkage of a building material, the method comprising the steps of

• a) obtaining a dry mortar by admixing fibers with an average length of 0.2-0.5 mm to a dry cementitious composition comprising 10-50 wt.-% of at least one cementitious binder and 20-75 wt.-% of at least one aggregate, in each case relative to the total dry weight of the dry mortar, and
• b) mixing the dry mortar obtained in step a) with water in a weight ratio of water to the dry mortar of 0.25-0.5,
• wherein the at least one cementitious binder comprises, in each case relative to the total dry weight of the cementitious binder:
• 60-99.5 wt.-%, Portland cement, and
• 0.5-40 wt.-%, latent hydraulic and/or pozzolanic binder materials,
• wherein aggregate is a material that is non-reactive in a hydration reaction of cementitious binders, and
• wherein the aspect ratio of the fibers is between 2-20, and wherein the fibers are polyethylene and/or polypropylene fibers.