Mortar

Mortar called the material obtained by curing a specially selected blend of an inorganic binder, fine aggregate and, if necessary, special additives. Mortars are divided into heavy - with a density of (dry) 1500 kg / m 3 to the lungs - of up to 1500 kg/m3; by type of binder - on cement, lime, gypsum and mixed (the choice of binder depends on the purpose of the solution, temperature and humidity hardening of the regime and the operating conditions of a building or structure; on purpose - on solutions for the masonry walls and installation of large blocks, finishing and special (heat resistant, acid resistant, injection, etc.). Frost mortar depends on the properties of the materials used, their relations and conditions of their hardening. as placeholders for solutions using heavy and light sands. Permissible amount of clay and dust impurities depends on the type of solution. The largest particle size of sand depends on the application of solutions. Mortar for masonry shall have the greatest size up to 2, 5 mm. In the solutions to rubble, installation of large panels and reinforced concrete structures is permissible maximum particle size of 5 mm. The basic properties of mortars: workability, flexibility, water-retaining capacity. The mobility of the mortar is determined by the depth of immersion of the metallic standard cone weighing 300 g (Fig. 20) . The greater mobility of the mixture, the deeper it sinks into a standard cone. The mobility increases with increasing water content in the mixture, increase the size of sand and lowering of its emptiness. The mobility of the mortar mixture is selected to reflect the designation of the solution (see Table. 4). Fig. 20. The standard cone and the definition of the mobility solution dipping cone (dimensions in cm) water-retaining capacity - the ability to hold the mortar in its composition a sufficient amount of water (water is extracted from the solution with the porous material). Solutions to the lack of retention tend to phase separation (separation of water and subsidence sand). water-retaining capacity of dissolving the mixture is directly dependent on the correct ratio of all components. composition of the solutions is usually determined by using ready-made tables, depending on the brand and destination solutions. Masonry Mortar Type and composition of solutions for masonry and installation depends on the calculated stress and operating conditions of masonry. clutch aboveground structures is usually performed on low-cost binder: lime, lime-slag. for laying the foundations for the presence of aggressive sulphate water use sulfatostoschie cements. For the installation of large-block walls - Portland cement. The mobility of the mortar mixture is selected to reflect the designation of the solution. For aboveground masonry with a humidity of indoor air 60% and laying foundations in wet soil cement consumption in the cement and lime mortar shall be not less than 100 kg per 1 m3 of sand. In winter conditions is not always possible to apply the same compositions of mortar, which in the summer. to solutions for winter works should meet the following requirements: at temperatures below -20 ° C mark solution increases by one step, if the load does not exceed 85% of the calculation, and two notches if the load exceeds 85% of the calculation. In winter brickwork, installation of walls panels and large blocks in the solutions recommended to introduce antifreeze additive (antifreeze and other additives to solutions used in almost the same as for concrete). not allowed to use frozen and then warmed solution. Temperature of masonry mortar at the time of installation must be at least 15 ° C at ambient air temperatures down to -20 ° C and at least 26 ° C at lower temperatures. Finishing Solutions Finishing solutions, there are two types: conventional and decorative plasters. These solutions must possess the necessary degree of mobility, have good adhesion to the base and little change in volume during solidification, so as not to cause cracking of plaster. The largest particle size of sand plaster shall not exceed 2-2,5 mm. decorative solution, used for finishing concrete panels must have a mark not less than the M150, and finishing panels lightweight concrete - not less than M50, plaster facades of buildings - no less than M50. Mark finishing solutions for the frost should not be less than MDE 35. Water absorption solutions with aggregates of quartz sand - no more than 8%, the solutions with aggregates of rock with a tensile strength below 40 MPa - no more than 12%. as placeholders colored decorative solutions using washed sand and sand, obtained by crushing of granite, marble, dolomite, tuff and other white and colored rocks. For exterior plaster stone and concrete walls with relative humidity up to 60% used cement-lime mortar, and for wood and plaster surfaces - lime-plaster solutions. For outdoor plaster caps, belts, rods and other parts of the walls subjected to systematic hydration, used cement and cement-lime mortar for Portland cement. For internal plaster walls when the relative humidity to 60% apply lime, lime-gypsum and cement-lime mortars. decorative solution is used for finishing the visible surfaces of panels and large blocks for color plaster facades of buildings, elements of improvement, etc. grouts Solutions to fill the joints (the joints) precast can only cement. They must meet the following requirements: if the solution is valid design load, then its mark should be at least grade concrete of connected elements, if the solution does not work this load, its brand shall not be less than 100, and if the seam has a fitting or steel fixtures, and the solution should not contain additives which cause corrosion of the metal (in particular, calcium chloride). cement-sand mortar cement-sand mortar used for the floors must be tough and good mobility (11-13 cm). cement-sand mortar used for the floors of the pavers, clinker brick, concrete slabs, mosaic and ceramic tiles, as well as cast-iron perforated plates must have the necessary strength and high viscosity. cement-sand mortar for clean floor (screed) should have a mark on the strength of not less than 50. The same solution for training under the counter should have the brand strength of at least 150 for the floors of clinker from the pavement, concrete or iron. Metallotsementnye solutions M500 and above are made of fat-free steel chips of size 1-3 mm, cement and water. Cement and wood chip mixture to the base unit under the floors consist of Portland cement or angidridovogo binder, sand and sawdust. Screeds are used for leveling the surface of the underlying layer, cover pipe, creating bias in the floor to the ceiling, load distribution. In the construction practice in recent years for floors are increasingly used polymer solutions that get mixing cement aqueous dispersion of polymer (synthetic latex.) Floors in such solutions possess sufficient strength, hygienic and high wear resistance. Waterproofing Solutions Waterproofing solutions are prepared by cements high marks (not less than M400). Solutions for waterproof expanding cement shall be able to (a day after striking seam or joint), the hydrostatic pressure of 5 atm. Indicative of solutions for waterproofing plaster 1:2,5 and 1:3,5 (cement : sand by weight). For the device waterproofing layer, subjected to the action of aggressive waters, as a binder should be applied sulfate pozzolan Portland cement. For sealing cracks in concrete using cement mortars with the addition of sodium aluminate, polymer or bitumen emulsion. Acoustic Solutions Acoustic solutions - it's easy solutions that make sound-absorbing plaster, with a density of 600-1200 kg/m3. placeholders in them are odnofraktsionnye porous sand with particle size of 3-5 mm (sand perlite, pumice, expanded clay). The solution after drawing on the wall across the thickness should be open pores. Produces acoustic solutions on Portland cement, shlakoportlandtsementnoy lime, gypsum binders. They are used as soundproofing, plaster to reduce noise.