SU1440730A1 - Method of manufacturing hollow concrete and ferroconcrete articles - Google Patents

Abstract

The invention relates to the field of construction, in particular to the manufacture of hollow concrete and reinforced concrete elements that are resistant in aggressive environments. The purpose of the invention is to intensify the method while reducing labor costs. In the manufacture of concrete and reinforced concrete products in the form set thermoplastic inserts, made hollow of sulfur-containing material, laid concrete mix. The molded articles harden, then the liners are heated to 140-150 0, compressed hot air is fed into the cavity of the liner. When heated, the external surface of the product is cooled to 50-60 ° C for 5-15 minutes, and in the cavity of the liner they create a pressure not exceeding 0.5-0.75 of the tensile strength of the concrete. 1 hp f-ly. ig

Description

(L

e

4 4 О Ч

SLE

Of course, construction refers to the manufacture of hollow concrete and reinforced concrete elements that are resistant to aggressive media. The purpose of the invention is to intensify the process while reducing labor costs.

In the manufacture of concrete and reinforced concrete products in the form set thermoplastic liners made of sulfur-containing material, laid concrete mix. Molded products harden. Then the liners are heated to 140-150 C. They are fed into the cavity of the liner to squeeze hot air.

When the liners are heated, the outer surface of the product is cooled to 50-60 s for 5-15 minutes, and in the cavity of the liner they create a pressure not exceeding 0.5-0.76 of the tensile strength of the concrete.

Example 1. The manufacture of reinforced concrete elements with through voids in monolithic and prefabricated construction. In the form, the reinforcement and hollow cores are fixed in the required position in the form of hollow inserts made of sulfur or sulfur-containing mass. The mold is then filled with concrete. After the concrete has hardened inside the cavity of the liners, the temperature is raised to 140 ° C and molten sulfur. As a result, the element is impregnated with sulfur. At the same time, the pressure inside the cavities is raised, giving hot compressed air. In order to eliminate the breaking of concrete by pressure, the difference in atmospheric pressure inside the cavity and in the external environment is brought to a value that causes tensile stress in concrete to not more than 0.75 of its tensile strength. When a sulfur element appears on the outer surface of the sulfur element, the concrete is completed by relieving the pressure inside the liners and cooling the entire element to.

In order to speed up the process of shedding concrete with sulfur, the outer surface of the element, when it reaches temperature, is cooled to 50 ° C for 5 minutes. In this case, the temperature inside the liners is not reduced, and the pressure is changed to within the range that provides stress in the concrete to 0.5 of the tensile strength, in order to prevent cracking of the outer layers.

five

0

five

0

five

0

five

0

five

Concrete during cooling. In the case of a large thickness of the layer of impregnated concrete, it is advisable to perform the process of surface cooling periodically, to the required degree, make concrete concrete sulfur.

The method allows the formation of local voids and local impregnation of concrete with sulfur — the liner is placed in the concrete of the element only in the place intended for impregnation, and a vacuum is created on the surface of the element in the required place.

When elements are impregnated according to the proposed method, the following physical processes take place: a hot sulfur melt, inside the concrete and concrete, promotes intensive removal of moisture from it through the external surface; when the surface layer of concrete is cooled, a vacuum is created in its pores due to a drop in the water vapor pressure during condensation, and the mass transfer of sulfur to the cooled layers occurs.

Example 2. Thermoplastic inserts made of sulfur are installed in the form, and the concrete mix is placed. After the product hardens, the insert is heated to 150 ° С and compressed hot air is fed into the cavity.

In order to speed up the process, the heated external surface of the product is cooled to 15 minutes. When compressed air is supplied in the cavity, a pressure is created that does not exceed 0.5 of the concrete tensile strength. The process is terminated at the occurrence of sulfur on the surface of the product.

The positive effect of using the proposed method is to intensify the production of hollow elements, reduce energy and labor costs by eliminating technological operations for pre-drying and heating the product, lifting it, dipping it into the melt and removing it from the melt; increasing the temperature of the melt at the final stage, and in products whose concrete hardens under heat treatment conditions, also due to the start of the impregnation process immediately after the end of the isothermal heating; as well as in expanding the field of application in the construction of impregnation with sulfur, since according to the proposed method, the impregnation of gray is carried out from the inside, in the element itself, without using a container with molten sulfur.

In addition, the production of hollow elements according to the proposed method allows to reduce the production cycle, using vibration-free technology when laying concrete. At the same time, the concrete mixture is diluted by increasing the water / cement ratio. This does not reduce the strength and density of the concrete, since the pores in the concrete formed from the excess water are filled with molten sulfur.

Claims (2)

1. Method of manufacturing hollow concrete and reinforced concrete products, 20 including setting in the form of thermoplastic inserts, laying the concrete mixture, hardening and heating up to the melting temperature of the liners, characterized in that, in order to intensify the process while reducing labor costs, after hardening the liners made hollow of sulfur-containing material are heated to 140-150 ° C, are fed to liner cavity compressed hot air. 2. The method according to p. 1, characterized in that when heating the insert, the outer surface of the product is cooled to 50-60 s for 5-15 minutes, and in the cavity of the liner create a pressure not exceeding 0.5-0.75 concrete strength values for stretching.