Development of process regulations for production of pipes of reinforced concrete pressure vibro-hydro-compressed

Contents

1. General provisions

2. General view of the article

3. Requirements for applied materials. Warehousing and storage

4. Reinforcement characteristic

5. Concrete Technology

6. Manufacturing technology

7. Intra-plant transportation, warehousing and storage

8. Process Control Map

9. List of equipment and accessories

10. Occupational Safety Instruction

11. List of literature used

Structural drawing of pressure vibro-hydraulic compressed pipe

Formwork sketch of pressure vibro-hydraulic compressed pipe

General provisions

The process regulation for the product is an internal regulatory document of the enterprise, which establishes production methods, technological standards, technical means, conditions and procedure for the process.

This document ensures the production of finished products with quality indicators that meet the requirements of the standards, as well as establishes the safety of work, and the achievement of optimal technical and economic indicators of production .

The process regulation is the main working document used by engineering personnel and workers employed in this production.

Pipes shall be manufactured in accordance with the requirements of GOST 12586.0-83

"Reinforced concrete pressure vibration compressed pipes. Specifications. "

For the production of pipes, heavy concrete of class not lower than C25/30 should be used for pipes of brands TN50-III and TN60-III, C32/40 for pipes of other grades.

The normalized tempering strength of concrete pipes is assumed to be equal to 90% of the concrete class in terms of compressive strength in warm and winter periods of the year.

Pipes shall comply with the established requirements when designing for strength, rigidity and crack resistance.

Pipes are manufactured according to the aggregate flow scheme of production.

Requirements for applied materials. Warehousing and storage

Requirement for materials for concrete mix preparation.

Cement shall comply with GOST 1017885 Portland Cement and Slag Portland Cement. Specification, "grades 400 and above, which is prepared on the basis of clinker of a normalized composition with a content of tricalcium aluminate (C3A) in an amount of not more than 8% by weight.

The grinding fineness shall be such that when the sample is screened through a screen with mesh No. 008 according to GOST 6613, at least 85% of the weight of the sample to be screened passes. Cement setting should begin no earlier than 2 hours 15 minutes, and the end - no later than 10 hours from the beginning of the closing.

Coarse aggregate - crushed stone obtained by crushing of strong rocks or gravel crushed stone satisfying the requirements of GOST 826782, GOST 1026082. The content of lamellar and needle-shaped grains should not exceed 25% by weight, the content of pulverized and clay particles should not exceed 1% by weight. To prepare a concrete mixture, crushed stone should be used: from 5 to 10 mm, from 5 to 15 mm, from 10 to 20 mm .

Fine aggregate - sand shall comply with GOST 873693 "Sand for construction works. Specifications. " Size modulus - 2.5-3.0. Content of pulverized, clay and silty particles in natural sand must be not more than 3% by mass, and in sand from crushing screenings not more than 10%. Sand from crushing screenings and enriched sand from crushing screenings must have a grade of strength of the initial rock or gravel not less than 600. Sand shall be resistant to the chemical effects of cement alkalis and shall not contain organic impurities. Humidity should be within 2.54.0%.

Water shall comply with GOST 2373279 "Water for concrete and mortar. Specifications. " When using service water once a year, tests are carried out for its compliance with technical requirements. The water content of organic surfactants, sugars or phenols, each, shall not exceed 10 mg/l. Water oxidability must not be more than 15 mg/l

Shape and dimensions of reinforcement and embedded items for pipes shall correspond to those given in GOST 12586.183

Reinforcement wire shall meet the following requirements:

- BII and BpII classes as per GOST 7348;

- classes B-I and BpI as per GOST 6727.

Steel cold rolled strip of low carbon steel (for dividing strips) shall meet the requirements of GOST 503

Emulsion lubricant EO2 for lubrication of bell and bushing end template rings in accordance with the Instruction on preparation and use of emulsion lubricant EO2 for molds in the production of reinforced concrete products ;

Marking paint FL59 as per TU 104379 for pipe marking;

Concrete mix shall comply with the requirements of STB 103596 Concrete Mix. Specifications. "

3.2Development and storage of raw materials.

3.2.1 Cement.

Cement is stored and stored in a specialized silo-type rail warehouse.

Cement enters the warehouse in railway cars of all types and in self-unloading car cement trucks with pneumatic loading.

Cement storage shall be sealed and ensure cement protection against atmospheric and soil moisture.

Cement is stored by type, class and brand separately in silos. So that the cement does not merge, it is periodically pumped from the silo to the silo.

Cement is not allowed to be stored in temporary barn warehouses, on sites under canopies and tarpaulin coatings, as well as near ammonia release materials.

Cement, during long-term storage (more than two months) must be checked for a change in its activity before use, to prepare a concrete mixture.

3.2.2. Aggregates - crushed stone, sand.

When entering the warehouse, the aggregates are loaded into special compartments. During unloading, mixing of various types of fillers is not allowed.

At the warehouse, fillers are taken by mass or volume in a state of natural humidity.

Storage and storage of aggregates is carried out separately by fractions. It is not allowed to mix different fractions of aggregate during its storage and storage.

3.2.3. Reinforcement steel and wire.

Reinforcement steel and wire should be stored in closed warehouses. It is also allowed to store reinforcement steel and wire under the canopy, provided that it is protected from moisture ingress.

Reinforcement steel and wire are not allowed to be stored on the ground floor, as well as near aggressive chemicals.

Reinforcement steel bays should be stored in stacks sorted by rolled stock name, grades and diameter. The height of the stack should not exceed 1.5 m, and the width of the passage between them should be at least 1 m.

Bar reinforcement steel should be stored in packages sorted by rolled stock names, grades and diameter, on reinforced concrete or wooden gaskets. The height of the stack shall not exceed 2m. During storage of reinforcement, measures must be taken to prevent curvature of rods.

Cold-drawn wire should be stored in windings and bags weighing at least 80 kg. The coils and bags shall be separated by gaskets.

Each batch of reinforcement steel and wire shall be accompanied by a special document - certificate.

When storing reinforcement steel and wire, check the presence of a label (tag) indicating: manufacturer's trademark; steel brands; smelting numbers, size, reinforcement steel or wire class, weight in kg, order number, additional marking.

Manufacturing technology

Forms of special design are used for preparation of pipes by method of vibration hydro-pressing. The mold is prepared for filling with concrete mixture in the following order. After the next molding, the thrust rings and the centering ring are cleaned from the remains of concrete and grease. Then end surfaces of mold, inner surfaces of thrust and centering rings, as well as longitudinal flanges of segments of outer casing of mold, starting from bell, are lubricated with bitumen mastic for 1.5 m. The inner surface of the halves or segments of the outer casing is lubricated with emulsion grease, leaving 100 mm wide strips of longitudinal joints, on which the adhesive sealing tape is later glued, unmasked. Inner part of mold is prepared for concreting in parallel with preparation of outer casing. Preparation consists in cleaning all rubber surfaces from lubricant and concrete residues, in thorough verification of the integrity of all parts and in gluing with adhesive tape the bushing end of the rubber cover to protect it from damage during concreting. Then rubber surfaces are lubricated with soap emulsion. After the elements are lubricated, the mold begins to be assembled. Mold consists of outer casing and core. Casing may be made of two or four elements bolted to calibrated springs. The mold is assembled in 2 stages. First, outer mold is assembled by means of bolts with calibrated springs. By gluing the longitudinal joints of the mold outer casing with adhesive tape, they are lubricated with emulsion grease. The inner mold is a metal core consisting of two steel cylinders: one solid, and the other (outer) has a perforation. Rubber cover is put on core. An annular gap of 6 mm is provided between the outer and inner cylinders of the core, which is filled with water when pressing the concrete mixture. Spiral reinforcement frame is installed in prepared form. Thrust rings are secured on mold ends (bottom and top of pipe). Longitudinal reinforcement rods are passed through ring holes, which are stressed by means of hydraulic jacks. After that, the outer casing of the mold with the reinforcement frame is placed with the help of a special crossbeam in the vertical position with the bell down. Assembly of two mold parts (outer and core) is performed at the assembly station. Outer casing of mold is installed on core prepared in vertical position by means of crane. It is lowered until the bell ring of preliminary tension of the longitudinal reinforcement stands on the steel bottom ring of the core, which is intended for accurate installation of the casing and the core. The assembled mold is transferred to a concreting station, where a centering ring is installed in the sleeve end of the mold (it is fixed with three clamps), which ensures the correct position of the outer casing relative to the core, and also a loading cone with a vibrator is fixed using rubber bundles. Three to five pneumatic attached vibrators are attached to the mold casing depending on the dimensions of the concreted pipe. At the funnel part, longitudinal joints of the mold are fastened with strubcins to avoid premature expansion of the mold. Concrete mix is fed into mold through loading cone by means of screw concrete dispenser. Vibrators are turned on during feed of mixture and its compaction takes place. After filling the mold with concrete mixture, loading cone and centering ring are removed, and sealing ring with cross is installed in their place. The mold filled with concrete is transferred by a bridge crane to a hydropressure and heat treatment station, where it is fixed in an upright position with four grips (so that when extended by water and steaming, the mold does not break from the post) and is connected to the water pipeline. Pressure in hydraulic system is increased uniformly during half an hour to 2-3 MPa at water temperature up to 6070 ° С.Under the hydraulic pressure of the water that flows through the perforated walls of the core, the rubber cover expands (at the same time the concrete mixture is pressed) and, moving, expands the outer mold bolted to the calibrated springs. It stretches the spiral reinforcement, creating its preliminary tension. Heat treatment with steam is carried out by starting sharp steam into the cavity of the inner part of the mold and under a tarpaulin steaming cap (covering) for 5-7 hours. At the end of the heat treatment, the tarpaulin cover is removed. The shape disconnected from the base is transmitted by the crane to the picking pit, where the ring with a cross (centering ring) is removed. A vacuum system is connected to the interior of the mold, which removes water residues from the interior of the mold. For the convenience of servicing the mold and core, a self-propelled bridge is provided at the top of the pit.

Ends of longitudinal reinforcement are cut off, spring bolts and calibrating ring of bushing part of mold are removed. The casing parts are then removed. The pipe is removed from the casing and transferred to an installation equipped with a rotation drive, where the ends of the longitudinal reinforcement are cut flat and the ends are finished. Then the pipes are transferred to the holding stations, where they are laid on the gaskets in a horizontal position in two, three or four rows. It is maintained for three days during periodic watering with water. After holding, the pipes are transported to the bell grinding machines, and then subjected to a hydraulic test in a special installation.

After hydraulic testing, the pipes are held in the workshop (in winter for 4 hours), and then taken to the finished product warehouse by a self-propelled trolley with a trailer.

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