Retarders of setting concrete are chemical substances added to the body of concrete or its surface and designed to perform a number of tasks to slow the setting process. The cause of solidification of concrete is the interaction of cement and water, in connection with this the mechanism of action of these additives is very simple: the retarder blocks this interaction for a certain period, before the onset of irreversible solidification. In other words, the additives slow down the process of hydration of the composition, which delays the setting and does not allow the composition to harden ahead of time. Usually the setting process can be postponed for several hours.
Self-compacting concrete (SCC) is a mixture of cement, sand, water and various additives that improve the properties of this solution in the area of maximum strength in a short time. The SCC is a material that is compacted under the weight of its weight, and completely fills the formwork even in those places where the reinforcement is densely laid, while the labor costs are reduced by filling the formwork without external influences. The hardened concrete mixture has the same technological properties and strength as the traditional "vibrating" concrete. The main advantages of SCC are: the absence of defects that arise during the compaction of concrete solution; reduction of labor costs due to reduced time for pouring and lack of compaction effects; the possibility of penetration of the mixture into hard-to-reach areas of structures and others.
High-quality concrete is a high-strength concrete consisting of a mixture of cement, sand, water and various high-performance additives that can significantly improve the operational properties. High-quality concrete is multicomponent concrete, which uses composite astringents, chemical modifiers of structure, properties and technologies, active mineral components and expanding additives that add and multiply high properties of individual types of concrete.
The main criteria for this type of concrete are: high strength; high frost resistance (F400 and higher); low water permeability (W12 and above); - high abrasion resistance (not more than 0.4 g / cm2). The theoretical service life of such concrete is about 500 years. With the use of high-quality concrete, such well-known objects as the Tunnel under the English Channel, a 125-story skyscraper in Chicago 610 meters high, a bridge over the Akashi Strait in Japan with a central span of 1990 meters (world record of 1990) are constructed. As well as a bridge across the Nordemberland Strait in Eastern Canada, the length of 12.9 kilometers was built on supports that are submerged in water to a depth of more than 35 meters. Under extremely harsh operating conditions (the concrete is exposed to 100 cycles of freezing and thawing each year), the structures of this bridge are designed for a service life of 100 years.
Decorative fine-grained concrete is a type of concrete intended for the manufacture of thin-walled structures, laying roadway, erection of monolithic buildings, for the creation of paving slabs and other products. This type of concrete is also called sand, and its main difference lies in the fact that the fraction of material particles in the composition should not be more than 2.5 mm. The composition of concrete, which in its structure has a fine aggregate, makes it possible to obtain a more homogeneous structure. Such a structure will contain fewer voids, which negatively affect the strength characteristics of the material. Such properties of concrete make it possible to improve its consistency, thereby improving its viscosity and ease of installation.
The size of the samples with different types of washout depth is 300 mm * 300 mm.
The time of fabric manufacture should be calculated individually, based on the necessary quadrature and the data that the image is deposited at a speed of 15 sq.m. at one o'clock. Also, when making a canvas, it is worth considering the time for creating the image, its additional processing and approval.
Cleaning of finished products is possible with standard surfactants and detergents. When cleaning with the "Körcher" technique, it is necessary to observe the distance to the open surface of the product, depending on the capacity of the equipment. Optimal distances for various types of surfaces are enclosed in a set with a high pressure washer.
Since the image is in the structure of the product itself, the abrasion depends on the grade of concrete and filler used in the manufacture of pavers and outdoor navigation in public buildings with increased traffic.