SU1066810A1 - Method of compacting construction mortars - Google Patents

Abstract

A METHOD FOR CONSTRUCTION MIXTURES in a mold by periodically acting alternately applied pressing load and vibration, characterized in that 9 to increase the strength and frost resistance of the material, the pressing load in each subsequent period is increased according to the law Pi P - n, where Pi is the pressing pressure in i-om period; - the order number of the period, and the number of periods is 2-9 ;, p - pressing pressure in the first period, equal to 1-10 kgf / cm; X is the intensity increase indicator equal to il-3, and the vibration frequency is according to the law f + f-p where f; f is the vibration frequency in the i-OM period; the vibration frequency in the first period is 4-10 Hz; the intensity of the increase is 1-2.

Description

The invention relates to methods for the manufacture of building products.

The known method includes laying in the form of a concrete mixture and the impact on it of a constant vibration of a given frequency and periodic pressing load, which is applied with a frequency of 0.1-10 Hz (5-600 impacts per minute) and a duration of ± 0.2-0 8 from the time period. In this case, the ratio of the specific pressing load and the specific vibration load is 1-50 G1.

The disadvantage of this method is the relatively low degree of compaction due to the low ratio between the values of the pressing and vibration loads. In addition, the mixture is vibrated at the moment when it is in a pinched state, which reduces the effectiveness of vibration.

The closest to the invention is a method involving alternately applying vibration and pressing loads, while the frequency of vibration and the pressure of the pressing load do not change during the whole time of compaction of the concrete mix 2,

This method does not provide a high-quality compaction of the material, since, due to the short-term effect (1-2 periods), the particles of the concrete mix do not get out of equilibrium, which excludes the possibility of their better mutual arrangement.

The aim of the invention is to increase the strength and frost resistance of the material obtained.

This goal is achieved by the fact that, according to the method of compaction of building mixtures in a mold, by periodically acting alternately applied to a pressing load and vibration, the pressing load in each subsequent period is increased according to the law Pi P. nf, where Pi is the pressing pressure in the i-th period; ri, is the sequence number of the period, with the number of periods being 2-9; Р - pressing pressure in the first period, equal to .1-10 kgf / cm

X is the rate of increase in intensity, equal to 1-3, and the frequency of vibration according to the law f ;. f. – n, where is the vibration frequency in the i-OM period; f is the frequency of vibrations in the first period, equal to 4-10 Hz; Z the intensity of the increase in frequency is 1-2,

FIG. Figure 1 shows a graph of the load P and the vibration f during the compaction of the prototype; in fig. 2 - the same, according to the proposed method; nA fig. 3 - a device for implementing the proposed method

Compaction, carried out in the initial period, with lower loads, followed by an increase in them according to the proposed regularity, is more efficient, since it allows the particles of compacted material to leave the pinch state and create an ordered mutual arrangement.

The best packing of particles of material is promoted by the vibration acting between the load and the load. When this occurs, the thixotropic softening of the mixture and, consequently, its structural resistance to compaction.

The use of compressive loads in increasing steps is caused by the need to overcome the gradually increasing structural resistance of the mixture to compaction during its formation.

The gradual increase in the frequency of vibration is due to the fact that as the density of the mixture is increased, the so-called vibration compaction threshold increases, in order to overcome which it is necessary to apply the vibration of the increasing vibration frequency.

A device for carrying out the method consists of a vibration impact load 1, a mold from material 2, a pressing pressure load 3, a valve-distributor. 4, a throttle from the regulator 5, an energy accumulator 6, an electric discharge drive 7, an energy carrier drive 8, a power carrier rechargeable device 9, a pressure actuator 10 of the outlet power supply 11.

In order to create a periodic pressing load, conventional actuating cylinders equipped with pressure and velocity controllers of the energy carrier can be used.

The tests are carried out with a load increasing from 5 to 50 kgf / cm (P 5 kgf / cm, X 1, p 10), a load increasing from 5 to 135 kgf / s (P - 5 kgf / cm X 3, p 3) load increasing from 5 to 80 kgf / cm (P 5 kgf / cm X 4, p 2). Time period T is 12 s. The frequency of vibration during the test is gradually increased from 5 to 50, from 4 to VO and from 4 to 108 Hz,

To compare the known and proposed sealing methods, a mixture of the following composition is used:

Medium sand 92

Portland cement M400 8

Water (over 100%) 8

Cylindrical specimens with a height and a diameter of 50 mm are prepared from the mixture. KOTojaie is tested for strength and frost resistance. Frost resistance tests were carried out at 100 freeze-thaw cycles to detect the difference in frost resistance of a material compacted in various ways;

The results of the comparison of the strength and frost resistance of the material are shown in the table.

As can be seen from the table, the tensile strength and frost resistance of the material compacted by the method in accordance with the invention is higher than by a known method.

The positive effect of compaction by this method can be obtained by compaction of rigid cement-concrete, asphalt-concrete mixtures, primers, fortified with portland cement, carbide resins, bitumen, bitumen emulsions and local in treadmill (lime, ashes of coal, slag).

Constant

Known 50

Proposed

Gradually improved

Gradually increasing from 5 to 125 kgf / cm

Famous

Constant 125

Gradually increase the offerable from 5. to 125 kgf / cm

50

Increases according to the formula f 5 where P is the order

in accordance with the formula f 5pu, where. period sequence number

ten

50

80

3

0.63

72

47

0.80

91

70

80 80 Increased in accordance with the formula f 4пf, where the period sequence number is 108

0.73

86

64

0.80

90

65

Those

"".

....

.: e .l.; v.

;:.;. g ".".

/

; /

b

AN

v

Cd

-) (

// 7 1

0

one

four...

I

fiez

Claims (1)

METHOD FOR SEALING CONSTRUCTION MIXTURES in the form by periodic exposure to alternately applied pressing load and vibration, characterized in that, in order to increase the strength and frost resistance of the material, the pressing load in each subsequent period is increased according to the law Pi = P '· η? , where is pi 1 pressing pressure in the i-th period; ^η ί serial number of the period, and the number of periods is 2-9; R! pressing pressure in the first period, equal to 1-10 kgf / cm ² ; X rate of increase in intensity equal to 11-3, and frequency vibration - by law f + = f ‘J 1 Where vibration frequency in the i-th period; f ' the vibration frequency in the first period, equal to 4-10 Hz; Z - intensity increased frequency, equal to 1-2. sa s