Masonry technology 2. Masonry materials

Artificial stone materials include ceramic and silicate bricks, solid and hollow, hollow ceramic and silicate stones, and concrete and gypsum wall stones.

Full-bodied ceramic brick has dimensions of 250x120x65 mm and modular (thickened) - 250x120x88 mm, brick mass 3.6 ... 5 m. Density 1.6 ... 1.8 t / m3, brand brick 75, 100, 150, 200 , 250 and 300, water absorption up to 8%. Bricks are made by plastic coating with subsequent firing. The main disadvantage is high thermal conductivity.

Hollow, porous and perforated bricks have a height of 65, 88, 103, and 138 mm (1.25, 1.5, and 2 times the height compared to a solid brick) with the same dimensions, and a lower density, 1.35. ..1.45 t / m3. Brands of bricks - 75, 100 and 150. The use of this type of bricks can reduce the weight of wall products up to 30%.

Silicate brick is used for walls with a relative humidity of not more than 75%, brick marks are 75, 100 and 150. The brick is made by pressing the raw mixture of lime and quartz sand and subsequent autoclaving.

Ceramic and silicate hollow stones are: (ordinary - 250x120x138 mm, enlarged - 250x250x138 mm and modular - 288x38x138 mm. The stone thickness corresponds to two bricks laid on the bed, taking into account the thickness of the seam between them. The surface of the stones is smooth and grooved.

Concrete and gypsum wall stones are produced solid hollow. They are made of heavy, lightweight and lightweight concrete and gypsum concrete with dimensions of 400x 200x200 mm, 400x200x90mm and weighing up to 35 kg.

Hollow and silicate bricks cannot be used for laying walls below the waterproofing layer, for laying socles, walls of wet rooms.

Masonry mortar. The solutions used for the device of stone structures, called masonry. Mortar connects individual stones into a single monolith, with their help level the bed of stones, resulting in a uniform transfer of the current effort from one stone to another; the solution fills the gaps between the stones and prevents air and water from entering the masonry. Thus, the solutions provide a uniform transfer of effort, protect the masonry from blowing, water penetration, increase the frost resistance of buildings.

Classification of solutions by type of aggregates:

· Heavy or cold - solutions on quartz or natural sand from dense rocks with a density of more than 1500 kg / m3;

· Light or warm - solutions on slag, pumice or tuff sand, ashes of thermal power plants, blast furnace granulated or fuel slags with a density of less than 1500 kg / m3.

The grain size of sand for all types of mortar should not exceed 5 mm, the mobility of the mortar for masonry is 9 ... 13 cm. Plasticizing agents are widely used: organic - sulphite lye and mylonaph and inorganic - lime and clay.

Classification of solutions according to the type of binder:

· Cement mortars - used for structures below the surface of the earth, in heavily loaded pillars, piers, in reinforced masonry. Composition from 1: 2.5 to 1: 6, grade of the solution from 100 to 300. The minimum cement consumption per 1 m3 of sand is for the underground part of buildings not less than 75 kg, for the above-ground part - 125 kg. Portland cement and slag Portland cement are used only in high grade solutions. for critical structures, in reinforced masonry, in masonry of underground structures, in soils saturated with water, or during winter masonry performed by the method of freezing;

· Lime solutions are used in dry places and with a small load. They have great mobility, plasticity, provide the highest labor productivity. Formulations from 1: 4 to 1: 8 and grades 4, 10 and 25 are used;

· Mixed or complex mortars - cement-lime and cement-clay composition from 1: 0.1: 3 to 1: 2: 15, grade of mortar 10, 25, 50, 75 and 100. Such solutions are used for the laying of most building structures. The second binder removes the beginning of the setting, improves workability and ductility, but significantly reduces the strength of the solution. In the bulk dosage of mixed solutions, the first figure indicates the consumption of cement, the second - lime or clay dough, the third - sand.

The rate of increase in the strength of the solution depends on the properties of binders and hardening conditions. At a temperature of 15 ° C, the strength of a simple solution will increase as follows: after 3 days -25% of the brand strength, after 7 days - 50%, after 14 days - 75% and after 28 days - 100%. With an increase in the temperature of the hardening solution, its strength increases more rapidly, and when it decreases, more slowly.

The workability of the prepared solution depends on the degree of its mobility and water-holding capacity, which protects the solution from stratification - the rapid separation of water and sand sedimentation. The degree of mobility of the solutions is determined depending on the immersion into it of a standard cone weighing 0.3 kg.

Masonry mortars must be not only durable, but also plastic, i.e. they must allow them to be laid in a masonry in a thin, uniform layer. Such a workable solution fills well all the irregularities of the base and evenly adheres to its entire surface. In addition, such an easy-to-use mortar helps to improve the productivity of masons and improve the quality of masonry.

The water- holding capacity of the solution, which prevents the separation of water and sedimentation of the sediment, is especially important when laying the solution on porous bases and to prevent the solution from splitting when it is transported over long distances, when fed to the work site through pipelines. Typically, the water retention capacity of the solution is increased by the introduction of surface-active organic additives or finely dispersed minerals (lime, clay).