RU218808U1 - MOUTH PLUG FOR METAL MOLD FOR FORMING CONCRETE ELEMENTS - Google Patents

Abstract

The utility model relates to the field of construction, is intended primarily for the manufacture of products of small architectural forms and can be used to obtain monolithic thin-walled concrete elements of natural hardening. The plug of the mouth of a metal mold for vibrocasting provides stable humidity and temperature during hydration at the stage of setting and hardening of the concrete mixture throughout the product due to the fact that it is made of a soft elastic sleeve made of polyvinyl chloride filled with heavy, loose filler, and overlapped at the edges of the sleeve. It improves the quality of concrete products. 3 w.p. f-ly, 3 ill.

Description

The utility model relates to the field of construction, is intended primarily for the manufacture of products of small architectural forms and can be used to obtain monolithic thin-walled concrete elements of natural hardening.

A monolithic thin-walled concrete element is made by pouring into an almost vertical mold cavity during vibration compaction of the concrete mixture. After molding, the samples are kept in the mold until the concrete gains stripping strength, usually 10-36 hours. The concrete element is then removed from the mold and is ready for use.

Concrete hardening is carried out due to hydration - a special chemical reaction that occurs between the binder components and water. At the end of the hardening period, a monolithic base with increased strength properties is created. The best indicators of hydration are observed at air humidity of 75-100% and at a temperature of +15...25°C.

The hardening of concrete looks like drying out, but in fact, it is a reaction that occurs with the obligatory participation of water. When concrete hardens in air, its surface dries quickly and the hydration reaction stops. A pressure difference is formed in the thickness of the concrete and on its surface, which leads to the appearance of defects in the form of cracks.

To protect against drying out, the surface of the concrete is covered with waterproof materials, such as film, tarpaulin, in some cases, with a layer of sawdust or sand, which is constantly moistened.

In vertical casting, collapsible molds are usually hermetic and have only open mouths for pouring concrete mixture into the cavity. Mouths with a small width can reach a length of several meters, which contributes to the rapid drying of the exposed surface of the manufactured concrete element.

There is a known method for the manufacture of combined decorative facade products, in which, after filling and compaction, the mold is covered with a covering material and kept under conditions of maximum moisture and heat saving in a warm room for at least 12 hours until stripping strength is gained (RU 2701010, publ. 08/09/2018).

The disadvantage of this method is the loose fit of the bedspread, due to the larger covered surface, which contributes to uneven hydration of the upper part of the figured product, respectively, the impossibility of obtaining high concrete strength in one of the parts of the formed product.

The task to be solved by this technical solution is to ensure stable humidity and temperature during hydration at the stage of setting and hardening of the concrete mixture throughout the product.

This problem is solved due to the fact that in the plug of the mouth of a metal mold for vibrocasting, consisting of a covering material, the covering material is made of a soft elastic sleeve made of polyvinyl chloride, filled with heavy, loose filler and overlapped at the edges of the sleeve. Sand or metal shot was used as a filler. To cover the product, plastic ties or metal clips are used.

The technical result provided by the given combination of features is to improve the quality of concrete products by ensuring the uniformity of the hydration process during drying of the concrete element.

The essence of the utility model is illustrated by graphic materials and photographs:

figure 1 shows a General view of the plug mouth of the prefabricated form in working condition, where 1 is a soft elastic sleeve with a filler; 2 - the place of overlap of the sleeve;

figure 2 shows plugs made of soft elastic sleeves, filled with sand, covered at the edges with plastic ties;

in fig. 3 shows a plug placed at the mouth of the prefabricated mold.

Curing in water is the best conditions for curing concrete. Hardening and hydration are impossible without water. Continuous curing in a humid environment improves the strength characteristics of concrete and reduces the number of shrinkage cracks than curing in air. When concrete is kept in air, on its surface, as a result of drying, the hydration reaction decreases as a result, the hydration process is uneven in the volume of the concrete product, micro or macro cracks are formed; air-cured cement stone has more shrinkage structural defects, and a higher susceptibility to corrosion. Hence warpage, loss of strength of the entire product and many cracks due to internal stress. Concrete should harden, not dry. If the moisture has evaporated in the solution, then the curing process stops.

If the mouth of a vertical, practically hermetic form is not hermetically closed, representing, for example, a gap 3 cm wide and 120 long, in contact with the outside world, then the end of the concrete element dries out and, as a result, uneven hydration of the concrete product with the appearance of cracks, a decrease in the strength of the entire products. When installing a loose plug or in the absence of a plug, stress occurs in the concrete and microcracks appear, the product becomes of poor quality.

To obtain high-quality figured products from a concrete mix during vertical casting, it is necessary to create such hardening conditions, under which the concrete will gain the desired strength at the desired rate, and its structure will be of the highest quality.

The plug of the mouth of a metal mold for vibrocasting includes a shell in the form of a soft elastic sleeve 1, a filler in the form of a heavy mixture, such as shot, sand or wet sand; overlaps along the edges of the sleeve, for example, in the form of plastic ties 2.

The shell in the form of a soft elastic sleeve, made of PVC and filled with sand, has sufficient weight to press against the mouth, which makes it possible to exclude air from penetrating through the mouth into the mold. The ends tightened with plastic couplers guarantee not scattering of sand and prevent its hit in a form. The ends of the sleeve, as an option, can be glued or soldered, pulled together with metal clips or metal twists.

As a filler, sand or other heavy bulk material can be used, for example, metal shot, small spherical stones, rounded sand or heavy rounded slag materials, which, under their own weight, press the shell of the soft sleeve to the inner sides of the mouth of the mold, sealing it.

After pouring the concrete mixture into the cavity of the collapsible mold, a plug is placed on the mouth, thereby sealing the metal mold. The hydration process takes place in a warm room for at least 10 hours, after which the plug is removed, the mold is dismantled and the finished concrete product is removed.

Under the weight of the filler, the mouth (loading gap) is reliably blocked and water does not evaporate through this gap. As a result, since the concrete mixture does not lose water as a result of evaporation and has the same moisture conditions of maturation, the maturation of the concrete mixture occurs with less shrinkage and the strength of the finished product is higher both in the local area where the plug is laid and in the whole product.

If concrete matures without moisture evaporation, its strength is always higher than that of concrete, which matures under conditions that moisture can evaporate from its surface. The use of an orifice plug makes it possible to achieve moisture stabilization during hydration in the entire product.

Thus, the proposed cap of the mouth of a metal mold for vibrocasting has a number of advantages compared to various covering materials and can significantly improve the quality of concrete products of complex shapes, simplify the process of drying products.

The utility model is used for the manufacture of figured concrete profiles such as curved plates (with dimensions: length 1200, 1600 mm, thickness 20 mm, 25 mm, width 600 mm, 800 mm) and confirms the possibility of improving the quality of production of concrete products with a figured profile.

Claims (4)

1. The plug of the mouth of a metal mold for vibrocasting, consisting of a covering material, characterized in that the covering material is made of a soft elastic sleeve, filled with heavy, loose filler and overlapped at the edges of the sleeve. 2. The plug of the mouth of a metal mold for vibrocasting according to claim 1, characterized in that the soft elastic sleeve is made of polyvinyl chloride. 3. The plug of the mouth of a metal mold for vibrocasting according to claim 1, characterized in that sand or metal shot is used as a filler. 4. The plug of the mouth of a metal mold for vibrocasting according to claim 1, characterized in that plastic ties or metal clips are used to cover the product.

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