SU1423392A1 - Method of compacting concrete mix - Google Patents

Abstract

The invention relates to the construction industry and is intended for the molding of products from concrete mixtures. The purpose of the invention is to improve the quality of compaction, improve working conditions and increase the service life of equipment. The concrete mixture is compacted by pressing with a force of 0.05–15 MPa with simultaneous application of a pulley load with an amplitude of 5–40% of the pressing force and a frequency of 0.05–0.99 Hz. Pulsated load is applied with a step change in the pressing force in accordance with the dependence ((T) 0.5 (PMaKc + P..nH) -fO, 5.4,, sin2, n / ,, T (n I; 2 ... K), where I (t) is the pressing force at the moment of time t, MPa, t is the time of pressing, s; And „- the amplitude of the pulsating load,%; / „- frequency of pulsating load, Hz; I-. | ..-, P-- and - maximum and minimum pressing force, MPa; n is the number of steps. Moreover, the rise time of the pressing force in each period is 0.6-0.8G, where T is the period duration, and the duration of the impact of the pulsating load in each stage is 2-7 times higher than or equal to. 2 h. item f-crystals, 2 tablets., 2 ill. S (L с 4 4 SLE CO WITH YO

Description

 X

 ; “-. ..--with ., . .-xJ ..-,. - s.- L ..:

   . ..: about . . . about - -. °: L. . FI.2

i The invention relates to construction HfUycTpHH and is intended to form concrete products.

A: The purpose of the invention is to improve the quality of coal, improve working conditions and reduce the service life of equipment.

FIG. Figure 1 shows a graph of pulsation variation in steps in frequency, amplitude, and duration; in fig. 2 is a schematic diagram of a hydraulic (pneumatic) installation for carrying out the proposed method.

The installation of hydraulic (pneumatic oro) action for drying the proposed method contains a pressure source 1 and a device 2, which is pulsed by pressing in stages, consisting of a sensor limiting the upper limit of pressure, shut-off valves, a software device, step mode, sensors that limit the pressure to the pressure limit in stages, the 3-node assembly and the pressure hoses 4. I The method is carried out as follows.

A maximum pressing load with a force equal to 0.05–15 MPa and a pulsating load with a frequency of 0.05–0.99 Hz and an amplitude equal to 5–40% max. . In the process of compaction, the amplitude is stepwise reduced, and the frequency is increased accordingly (Fig. 1). In this case, the duration of each stnjeHH is equal to or exceeds the previous one in | 2-7 times. The rise time of the pressing Y | force in each period is 0.6–0.87, rjae T is the duration of the period. The magnitude | of the pressure load is determined f

P (t). 51p2 / „t; (, 2, ..., and),

 P (t) - pressing pressure at the moment

time t;

t is the pressing time; Mouth - maximum pressing pressure;

Rmin is the minimum pressing pressure in the rt-th stage;

A, 1 is the amplitude of the pulsation in the lth stage;

/ n - the frequency of pulsation in the n-th stage, p - the number of stages. The specimens are molded - cylinders with a diameter of - f) OM 100 mm, height 100 mm from a concrete mixture of the composition by weight: n: n: u: B 1 .I, 16: i2,43: 0,335.

Compacted with a two-stage equal to the duration of the mode of pressing

and the total duration of compaction.

Baseline: pressing time

each step with; amplitude L, from Mouths, maximum pressing pressure P „ad.2.5 MPa; minimum pressing pressure 1.5 MPa,, 0 MPa; ripple frequency, 5 Hz, 75 Hz.

Examples

 with; 1- stage;

P (c) .4XO, 5x5

2.0 MPa;

5 s; 1- stage;

Р (, 5 с) - - - + у ° З1п2 ХО, 5 X

X7, 5 MPa; with; 1- stage;

P (c) S sin2jiXO, 5 X

, 0 MPa; 5 s; 1- stage;

Р (, 5 c) - - + - ° sin2.nXO, 5X

X 12, 5 MPa; with; 2 step

P (c) .XO, 75X

, 25 MPa; with; 2 step;

P (c) - - ° -f | sin2 xo 75 x

, 0 MPa; with; 2 step

R (, 21 с) - Ч ° 15-5 п2лХО, 75Х 22

, 5 MPa; m; 2 step;

9 44-9 P 04 P (c) .XO, 75X

, 25 MPa.

The test results are summarized in table. 1 and tab. 2

Claims (2)

1. A method of compacting a concrete mixture by pressing with a force of 0.05–15 MPa while simultaneously applying a pulsating load with an amplitude of 5–40% of the pressing force, characterized in that, in order to improve the quality of compaction, improve working conditions and increase equipment service life , a pulsating load is applied with a frequency of 0.05- 0.99 Hz with a step change in the pressing force according to / - max- | / min Lee I (t) fh .4 / .T; , 2, ..., k); where / (t) is the pressing force at time t; t is the pressing time; AH, is the amplitude of the pulsating load; / n - the frequency of the pulsating load: Riaks - the maximum pressing success; - minimum pressing force; n is the number of steps. 2. The method according to claim 1, characterized in that the duration of the impact of the pulsating load in each step is 2–7 times longer than the previous one, and the time for lifting the pressing force in each / oh period is 0, b - 0.8 times the maximum. T a b. P and c a 1 40; thirty; 20; 0.05; 0.3; ten; 50.55; 0.8; 0.99 thirty; ten 0.5; 0.99 40; thirty; 20; 0.05; 0.3; ten; 50.55; 0.8 0.99 thirty; 100.5; 0.99 40; 50.55; 0.99 40; 50.05; 0.99 T a o l and c a 0.8 0.8 0.6 0.6 0.8 0.6 89,8 88.7 51.1 50.8 72, L 70.7 .lii . Cvi