Specifically as possible
In Russian practice fillers for concrete production at many factories and quarries that produce crushed stone, a hydraulic stage classification (washing) is excluded from the technological cycle, so they gravel producible unfit for transport and storage. In this regard, the most important condition that determines the quality and durability of structures and facilities that are being built, is technologically reliable supply of permanency grading fillers in the preparation of concrete mix. As the survey showed 86 enterprises of the former societies Mintransstroya, performed by specialists of industrial technology laboratory concrete work prone "Building materials" VAT TSNIYIS in doses from batch to batch coming in extremely inhomogeneous grain structure aggregates. Yes, granite gravel 5-20 mm fraction contains from 0.5 to 37% of particles smaller 5 mm (stone chips and dust), which is almost 4 times higher than the limits sootvet stvuyuschym guests, rubble fractions 5-10 and 10-20 contains the number of smaller particles than the standard limit of 5 times. Used mostly in structures and facilities for compacting concrete mix is vibration sealing concrete and cement thixotropic rozridzhuye body. It helps that the grain-aggregates under gravity fall to dilute cement testing, form a stone skeleton of concrete and replacing (vydavlyuyut) captured in the process of air operations. For each pair of fillers (sand and gravel) there is only a single faction ratio = P / Z, where under the influence of gravity in the process vibration can be generated uniform height uschilnyuvanoho layer defectless stone skeleton with a minimum content of cement and water (cement test) in the concrete mix. Changing from batch to batch of the actual content in the rubble sand fractions (smaller 5 mm) as large, and in less than optimal way of causing a sharp snizh eniye lehkoukladuvanosti concrete mixture. It makes you betonosmesytelnoy operator units (BSU) in both cases increase the amount of water for a given zachynnennya lehkoukladuvanosti. Increasing water zachynnennya requires greater costs of cement (15-20%) in comparison with the flow, the corresponding optimal fillers fractions (= P / Z), established in the selection of the concrete. By setting the properties and composition of the concrete mix can be achieved only when the stability of grain fillers, coming in doses mixing of batch to batch. The analysis of the technology of fillers on schebzavodah and pits showed that the change in practices that prevailed at the industrial level, which would guarantee the preservation constancy of grain fillers, coming in betonosmesyteli mixing of batch to batch, so unreal. The most reliable, technically and economically affordable way to guarantee uniformity and quality fillers served in dozat Ori - the stabilization of grain warehouse (additional dressing) just before serving in the consumables bins mixing (without intermediate storage and transport operations). Stabilization is possible bowl (with circulating water supply) or without washing - dispersion of fillers actual humidity. The process of stabilization can be arranged, firstly, the creation of specialized units (units) that include the supply line of fillers ended disposable mixing silos, and secondly, the re (doobladnannyam) reservoir for heating fillers, thirdly, the creation of integrated units within the existing or projected Mixing. The experts from the industrial technology lab concrete work prone "Building materials" VAT TSNIYIS gained considerable experience in creating sites stabilize grading macadam in different working conditions of factories concrete and concrete structures. Treschynostoykost, durability, serviceability, and other properties of the most important iye bridge structures and facilities depend not only on the quality and uniformity of concrete mixes, ready for mixing, but also from its technology supply and distribution opalubtsi that retains its original composition and that makes it impossible to bundle at vibrouschilnenni. Vibration promotes the influence of gravity in forming the most dense stone skeleton of the possible, but only in an enclosed area for the volume. Vibration of concrete mixture on the open surface of the casing or the distribution layer facilitates its separation from the Department of cement test (solution), which makes it impossible for gravity to form a dense stone skeleton, inevitably causes the formation of cavities and shells in concrete concluded and no longer vibrodiyi restore the original homogeneity of the concrete mixture is impossible. To preserve the original quality of the concrete mixture in the construction of structures (and hence estimated as concrete) to distribute the concrete surface to form successive layers of uniform thickness not exceeding 40 cm with a horizontal surface for the entire area of layer (without the use of vibrators). Uniformity over concrete mixture before vibrouschilnennyam should be such so that in the area of the vibrator is not going bundles uschilnyuvanoyi concrete mix with drain cement and "proliferation" of concrete mix components. In each place vibrouschilnennya be formed closed density (including part of a regular strip of concrete mix, distributed in opalubtsi). Heavy cement concrete - self-sufficient building material that has the potential continuously for decades, to increase its strength, density, durability, zalikovuvaty "emerging defects and from their own resources to ensure implementation of the most favorable for the construction of temperature and humidity conditions curing, which reduces the initial stages of its existence. Potential visa ye whole being provided with material clinker cement and concrete based on it - stocks of cement (one month in the concrete is at least 50% of cement, not responded), heat released during exothermic reaction of hydration of cement, and water introduced to the concrete zachynnenni mix to ensure its necessary lehkoukladuvanosti. The process of formation of concrete in construction does not end when you reach him, given the project quality. This is only half its capacity, and reaching 70% of design strength is realized only one-third capacity, and this time the most dangerous in terms of the environment. Warranty concluded the acquisition of concrete set of properties is achieved: - saving water in the concrete zachynnennya entered in the concrete mix during its preparation by protecting the open surfaces of the volume of air that absorbs moisture from the concrete that zminyalysya - suitability of significant temperature gradients between the poison rum and superficial layers (at samorazohreve concrete), or between concrete surface and the outside air (at one that rozpalubyla, the issuance of the Steam-curing chamber or when removing lids from Steam-curing chamber, the issuance of stock of finished products, etc.)..
Especially dangerous for the surface layer of concrete construction stage of cooling after Steaming. Ventilation internal volume of the camera makes it effectively for drying and removing lids camera leads to intensive drying hot concrete structure that goes with it colder surface air. Intensive drying concrete surface layers occurs when one that early rozpalubyla massive structures, the process increases as normally high temperature inside the concrete.
