SU1248819A1 - Method of forming tubular articles from concrete mixes - Google Patents

Description

. .

The invention relates to the manufacture of tubular products and molset to be used in the manufacture of vibro-pressurized. Reinforced concrete parquet pipes.

The purpose of the acquisition is to improve the quality of products.

The proposed method of making vibrohydro-pressed reinforced concrete pressure pipes is as follows.

On the vibrating plate, the concrete mixture is laid in the mold with its simultaneous vibroplate. After compaction, the assembled form with concrete is installed on the post of hydraulic pressing and heat treatment. Hydraulic assembly is carried out in stages according to the following mode: Stage I - raising the pressing pressure to 0.2-0.25 MPa with it held for 8- 10 min, II — subsequent pressure rise to 0.5–0.6 MPa with a delay for 15–17 min; I.II — pressure rise to .1.0-1.2 MPa with a pressure of 18–20 min. 20 min, IV - pressure rise up to 1.8-2, O MPa with an exposure of 10-12 min, V - pressure rise up to 3.0-3.2 Sha with an exposure of 16-17 min. By achieving the design pressing pressure 3 , 0-3,2 MPa n Chin which heat treatment is carried out for the entire Diklo effected at a constant test pressure 3.0-3.2 MPa until the transfer of concrete strength. After this, the pressing pressure is gently lowered and the heat treatment is stopped, after which the process proceeds in a known way.

To establish the optimal parameters of hydraulic pressing, the tests were carried out, the results of which are summarized in the table.

Example 1. To form a pipe with a diameter of 1000 mm and a length of 5 meters, a concrete mix is taken with the following composition: portland cement 500-550 kg, crushed stone 5-10 mm crushed stone 980 kg, sand with a modulus of 2.5-670 kg, water 220 l (based on 1 m-concrete). Spiral reinforcement is installed in the outer form and tension of longitudinal reinforcement is applied. Next, the mold is mounted on the core and the concrete is laid with simultaneous vibrating. After completion of the compaction of the concrete mix form pos19i.

blunt on the post of hydraulic pressing and heat treatment. Hydropressing is carried out according to the following regime: Stage I - raising the pressing pressure to 0.2 MPa and holding this pressure for 8 minutes, II - raising the pressure to 0.5 Sh1a and holding it for 15 minutes, III - lifting it. pressure up to 1, 0. MPa and delivery 18 min., IV — pressure rise up to 1.8 MPa and holding time — 10 min, V — pressure rise up to 3.0 MPa and holding time, 16 min. Upon reaching operating pressure, heat treatment is started, which is produced at this pressure until the transfer strength of the concrete is achieved. Then, a continuous crushing pressure of the pressing pressure is carried out and the heat treatment is switched off. Next, the process goes; known by.

The physico-mechanical properties of the pipe are as follows, MPa: tensile strength ka compression 600 ,. water resistance 2.35, crack resistance 3 /, stress in spiral reinforcement 1300.

Example 2. To form a pipe of 1000 mm and a length of 5 m, a concrete mix of the same composition is taken. .After: compaction of the concrete mixture, the hydraulic pressing process is carried out according to the following mode: Stage I - raising the pressing pressure to 0.25 MPa and wiping out this pressure for 10 minutes, II - raising the pressing pressure to 0.6 Mce and holding for 17 minutes, III - raising the pressing pressure to 1.2 MPa and holding for 20 minutes, IV - raising the pressure to 2.0 MPa and holding 12-minute, V - raising the pressure to 352 MPa and holding 17 minutes. Upon reaching a pressure of 3.2 MPa, heat treatment is carried out 5 which is carried out at this pressure to achieve the transfer strength of the concrete. Then the process follows a known path.

The physicomechanical properties of the pipe are as follows: 1, MPa: compressive strength 610, water tightness 2 5 4, crack resistance 3.1, stress in spiral fittings 1350.

The physicomechanical properties of a pipe, f 1000 and 5 m long, manufactured according to the basic object, MPa: compressive strength 420, water resistance 1.4, crack resistance 2, 4, stress in spiral reinforcement 900.

450

1.7

2.2 1000

15.4

600

. 2.35

3.0 1300

26

520

2.0

2.5 1200

18

510

1.9

2.4 1150

17

2.4

3.1 1350

27

Editor, A, Kozoriz

Compiled by L. Karpetkina

Tehred V. Kadar Proof-reader S. Cherni

Order 4174/15 Circulation 555Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

Table continuation

Claims (1)

METHOD FOR FORMING TUBULAR PRODUCTS FROM CONCRETE MIXTURES, including laying the latter in a mold with simultaneous vibration compaction and subsequent hydropressing with heat treatment, characterized in that, in order to improve the quality of the products, a stage hydropressing is performed with the corresponding modes: Stage I - raising the molding pressure to 0.2-0, 25 MPa with a shutter speed of 810 min, II - rise of the pressure test to 0.5-0.6 MPa with a delay 15-17 minutes, III - pressure rise to 1.0-1.2 MPa with a shutter speed of 18-20 minutes, IV - pressure rise to 1.8-2.0 MPa with a shutter speed of 10-12 minutes, V - pressure rise to 3.0-3.2 MPa with shutter speed 16-17 minutes SU „„ 1248819 A1 ί I 2