JPH1024410A - Production of highly flowable concrete and production equipment therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently produce highly flowable concrete by shortening a kneading time at a time of the production of the highly flowable concrete. SOLUTION: Cement 5, sand 8, gravel 11, water 14 and an admixture 21 are charged in a mixer 1 to start kneading and, when the engine torque at the time of the driving of the mixer 1 falls from the max. value to become almost constant stable predetermined shaft torque, a predetermined amt. of correction water 17 and a corrected admixture 24 are almost simultaneously supplied to the mixer 1 and, further, kneading is performed so as to obtain a predetermined engine torque.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for adding a corrective water and a corrective admixture when adding a corrective water and a corrective admixture so that the slump flow value and the rote time value of the high fluidity concrete become predetermined values. The present invention relates to a method and a facility for producing high-fluidity concrete which can be simultaneously charged into a mixer.

[0002]

2. Description of the Related Art Ready-mixed concrete used for construction work and the like has been conventionally used in ready-mixed concrete production facilities such as batcher plants and the like to prepare ready-mixed concrete such as cement, water, sand (fine aggregate) and gravel (coarse aggregate). Although it is manufactured by kneading materials, there are two means for manufacturing this ready-mixed concrete: mortar advance kneading and two-stage kneading.

[0003] Fig. 8 shows the relationship between the shaft torque of the mixer and the time when the mortar advance kneading is performed.

That is, when the mixer is driven, first, cement, fine aggregate, and primary water are charged into the mixer to start kneading the mortar.

[0005] The shaft torque T of the mixer is determined by kneading the mortar.
Rises to a certain value, the shaft torque T
Has a substantially stable constant value, but falls slightly with the passage of time.

When the shaft torque in the stable state slightly decreases to a predetermined shaft torque T1 in the mortar kneading stage, then coarse aggregate, admixture, and secondary water are charged into the mixer. The correction water amount is calculated by the calculator based on the torque T1, and the obtained correction water amount is put into the mortar in the mixer together with the coarse aggregate, the admixture, and the secondary water.

When the coarse aggregate, admixture, secondary water, and correction water are charged into the mixer and the kneading is continued, the shaft torque T temporarily increases, and the peak shaft torque T appears. But,
Thereafter, the shaft torque T gradually decreases with the passage of time.

When the shaft torque T gradually decreases to a predetermined shaft torque T2.1, the amount of the correction admixture obtained by the calculator based on the shaft torque T2.1 is added to the ready-mixed concrete in the mixer. And the shaft torque T is set to a predetermined value.
Is carried out until the shaft torque T2.
When the number reaches 2, stop the mixer.

By performing the mortar advance kneading in this way, it is possible to knead ready-mixed concrete having a predetermined slump flow value and a predetermined roto-time value.

FIG. 9 shows the relationship between the shaft torque of the mixer and the time when performing the two-stage kneading.

That is, when the mixer is driven, first, cement, fine aggregate, coarse aggregate, and primary water are charged into the mixer to start the first-stage kneading.

The shaft torque T of the mixer rapidly increases due to the first-stage kneading. When the shaft torque T rises to a certain value, the shaft torque T increases.
Has a substantially stable constant value, but falls slightly with the passage of time.

When the shaft torque T drops slightly to reach the predetermined shaft torque T1 in the first kneading stage, the admixture and the secondary water are introduced into the mixer. At this time, the correction water amount is calculated by a calculator. The calculated amount of corrected water is put into the mixer together with the admixture and the secondary water.

Further, when the admixture, secondary water, and correction water are charged into the mixer and the second-stage kneading is continued, the shaft torque T once decreases rapidly, and thereafter, the shaft torque T becomes substantially stable. , And gradually descends over time.

When the shaft torque T gradually decreases to a predetermined shaft torque T2.1, the amount of the correction admixture obtained by the calculator is introduced into the ready-mixed concrete in the mixer, and the shaft torque T is reduced to a predetermined value. Kneading is performed until the value decreases to the value of the shaft torque T2.2, and the mixer is stopped when the value of the shaft torque reaches the predetermined value T2.2.

By performing the two-stage kneading as described above, it is possible to knead a ready-mixed concrete having a predetermined slump flow value and a predetermined roto-time value.

The reason why the correction water and the correction admixture are added during the mortar advance kneading and the two-stage kneading is to bring the slump flow value and the funnel time value of the ready-mixed concrete close to the specified values.

[0018]

However, in the above-mentioned conventional means, in any of the means, the correction water is added and kneading is performed, and then the correction admixture is added and further kneading is performed. However, there is a problem that the raw concrete production capacity decreases.

It is an object of the present invention to shorten the kneading time and improve the production capacity of high-fluidity concrete out of ready-mixed concrete by enabling the correction water and the correction admixture to be added simultaneously. It was done.

[0020]

SUMMARY OF THE INVENTION The present invention relates to a method for feeding kneaded cement, fine aggregate, coarse aggregate, water and an admixture into a mixer, starting kneading, and driving a shaft when the mixer is driven. When the torque decreases from the maximum value to a substantially constant required shaft torque, a predetermined amount of the correction water and the correction admixture are supplied to the mixer substantially simultaneously, and kneading is further performed until the predetermined shaft torque is reached. It is.

[0021] The present invention also relates to a mixer for mixing cement, fine aggregate, coarse aggregate, water and an admixture which are metered and charged, and a correction water supplied via a first flow control valve. A corrective admixture measuring hopper configured to weigh and supply the corrective admixture supplied via the second flow control valve to the mixer, A shaft torque calculator that calculates the shaft torque when driving the mixer, and a shaft torque stable state that determines whether the shaft torque is stable based on the shaft torque signal obtained by the shaft torque calculator. A determiner, a calculator for calculating the amounts of the correction water and the correction admixture to be input to the mixer based on the data signal from the data storage when the shaft torque has reached a required stable value; The first flow control valve based on the corrected water flow signal A corrected water metering controller that outputs a valve opening and closing command signal, and a corrected admixture metering controller that outputs a valve opening and closing command signal to the second flow control valve based on the corrected admixture amount signal obtained by the arithmetic unit. And the correction water and the correction admixture can be supplied to the mixer almost simultaneously from the correction water measurement hopper and the correction admixture measurement hopper.

According to the present invention, in both the method invention and the apparatus invention, the correction water and the correction admixture can be introduced into the mixer almost simultaneously, so that the kneading time per batch is shortened and the high fluidity concrete is reduced. Production efficiency is improved.

[0023]

[Calculation Procedure of Corrected Water Amount and Corrected Admixture Amount] In the present invention, the procedure of calculating the corrected water amount and the corrected admixture amount when the corrected water and the corrected admixture are simultaneously supplied to the mixer will be described with reference to FIGS. .

First, the change in the shaft torque of the mixer when producing high-fluidity concrete in the present invention will be described. The change in the shaft torque is different from that in the mortar advance kneading shown in FIG. 8 and the two-stage kneading shown in FIG. , As shown in FIG.

That is, when the mixer is driven, cement, fine aggregate, coarse aggregate, water, and an admixture are almost simultaneously introduced into the mixer, and kneading is started.

The shaft torque T of the mixer is increased by the start of kneading, and after a predetermined time has elapsed, the shaft torque T reaches a peak state. Thereafter, the shaft torque T rapidly decreases until the shaft torque T reaches a predetermined value. It becomes stable and slightly descends over time.

Thus, the shaft torque T is equal to the predetermined shaft torque T.
If the torque is higher than 2.1, a predetermined amount of the correction water and the correction admixture calculated in advance by the calculator are simultaneously charged into the mixer, and the concrete is kneaded, and the shaft torque T becomes the predetermined shaft torque T2.2. When it becomes, stop kneading.

By kneading in this manner, high-fluidity concrete can be manufactured in a short time.

Thus, the shaft torque T2.1 and the slump flow value S at the start of the correction addition for adding the correction water or the correction admixture are
The relationship between F (cm) and the funnel time value RT (sec.) Is as shown in the SF torque curve and the RT torque curve in FIG. These relationships can be determined from kneading data of a plurality of batches.

Next, in the graph of FIG. 3, a target value range (SF target range) 2a and a target value range (RT target range) 2b of the slump flow of the high-fluid concrete kneaded are determined and the SF target is set. An intermediate width a of the range and an intermediate width b of the RT target range are determined.

Thus, the intermediate point between the SF target range 2a and RT
If the width 2c of the intermediate point of the target range 2b is determined, the intermediate width c of the intermediate point of the SF target range and the intermediate point of the RT target range is determined, and the torque at the intermediate point of the width 2c is determined, the intermediate point of the SF target range and the RT target An average value T2.1AV of the shaft torque at the start of the correction addition at the midpoint of the range is obtained.

At the end of kneading, the shaft torque T2.2, the slump flow value SF (cm), and the rotation time value RT (se
c. 4) are as shown in the SF torque curve and the RT torque curve in FIG. These relationships are also obtained from kneading data of a plurality of batches.

In FIG. 4, the average value T2.2AV of the shaft torque at the end of kneading at the midpoint of the SF target range and the midpoint of the RT target range is obtained by performing the same processing as in FIG.

The average value T of the shaft torque at the start of the correction addition
2. Average value of shaft torque T2.2A at the end of kneading with AV
By taking the difference in V, a torque drop amount TMIX due to kneading for a certain period of time when no correction water or correction admixture is added is obtained.

[0035]

TMIX = T2.1AV−T2.2AV (i)

Next, a target shaft torque T2.2a for the slump flow value SF and the funnel time value RT to become the target values at the time of completion of the kneading is calculated.

The target shaft torque T2.2a is obtained from the relationship between the shaft torque T2.2 at the end of kneading used for calculating the average shaft torque T2.2AV at the end of kneading, the slump flow value SF, and the rotation time value RT. .

That is, as shown in FIG. 5, the intermediate point of the torque range 2d where the SF target range torque and the RT target range torque determined based on the SF target range and the RT target range overlaps the target shaft at the end of kneading. It is assumed that the torque is T2.2a.

Next, in the actually kneaded batch, the shaft torque drop amount ΔT2 to be reduced from the actual shaft torque to obtain the target shaft torque T2.2a at the end of kneading is determined. In this case, assuming that the shaft torque actually measured in the actually kneaded batch is T2.1r,

ΔT2 = T2.1r−T2.2a−TMIX (ii) That is, the shaft torque drop amount ΔT2 is an adjustment amount for obtaining the target shaft torque T2.2a at the time of completion of the kneading when the shaft torque is T2.1 (see FIG. 2).

In order to determine the correction water addition amount and the correction admixture amount from the shaft torque reduction amount ΔT2, the shaft torque reduction amount ΔT due to the addition of only the correction water is shown in FIG. FIG. 7 shows the drop amount ΔT. The relationships shown in FIGS. 6 and 7 are obtained in advance by kneading a plurality of batches.

Shaft torque drop ΔT at the time of addition
Is

ΔT = T2.1−T2.2−TMIX (iii) Therefore, the correction data of the correction water is obtained from the relationship of the equation (iii). Then, the torque curve is

ΔT = αXW (iv) Here, α is a proportional constant, and W is a correction water addition amount.

From the equation (iv), the corrected water addition amount W for obtaining the shaft torque drop amount ΔT2 only by the addition of the correction water is obtained.
ΔT2 is

## EQU5 ## It is obtained as WΔT2 = ΔT2 / α (v).

Similarly, from FIG. 7, the relationship between the corrected admixture addition amount Ad and the shaft torque drop amount ΔT is obtained.

ΔT = β × Ad (vi) Here, β is a proportionality constant. Therefore, the correction admixture addition amount AdΔT2 for obtaining the shaft torque drop amount ΔT2 only by adding the correction admixture is:

## EQU7 ## It is obtained as AdΔT2 = ΔT2 / β (vii).

From the equations (v) and (vii), the amount of addition in which the same amount of shaft torque drop ΔT2 can be obtained with each of the correction water and the correction admixture is obtained. In terms of the relationship ratio,

## EQU8 ## WΔT2: AdΔT2 = β: α (viii)

Therefore, in order to add an appropriate amount of the correction admixture and the correction water to obtain the shaft torque drop of ΔT2 obtained by the formula (ii), the correction for obtaining the shaft torque drop of ΔT2 only with the correction water is required. Β: α in the corrected water addition amount WΔT2 when performing
Is performed such that the correction admixture is also added so that Therefore, the correction admixture amount Ad ′ actually added is:

## EQU9 ## Ad ′ = WΔT2 × α / (β + α) (ix), and the actually added correction water amount W ′ is

W '= WΔT2-Ad' (x)

[0046]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an example of an embodiment of the present invention, which shows an example of a high-fluidity concrete production facility. Thus,
Reference numeral 1 denotes a mixer. The mixer 1 is driven by a motor 2 to knead highly fluid concrete.

Reference numeral 3 denotes a cement storage hopper, and reference numeral 4 denotes a cement weighing hopper. The cement weighing hopper 4 weighs the cement 5 supplied from the cement storage hopper 3, and supplies the measured cement 5 to the mixer 1. It has become.

Reference numeral 6 denotes a sand storage hopper, and 7 denotes a sand weighing hopper. The sand weighing hopper 7 weighs the sand 8 supplied from the sand storage hopper 6 and supplies the measured sand 8 to the mixer 1. It has become.

Reference numeral 9 denotes a gravel storage hopper, and 10 denotes a gravel measuring hopper. The gravel measuring hopper 10 measures the gravel 11 input from the gravel storage hopper 9, and
Is supplied to the mixer 1.

Reference numeral 12 denotes a water measuring hopper, which measures the water 14 flowing through the flow control valve 13 and supplies the measured water 14 to the mixer 1. .

Reference numeral 15 denotes a correction water measuring hopper. The correction water measuring hopper 15 measures the correction water 17 flowing through the flow control valve 16 by the load detector 18 and switches the measured correction water 17 on / off valve. 47 to the mixer 1.

Reference numeral 19 denotes an admixture weighing hopper. The admixture weighing hopper 19 measures the admixture 21 flowing through the flow control valve 20, and supplies the measured admixture 21 to the mixer 1. It has become.

Reference numeral 22 denotes a correction admixture weighing hopper. The correction admixture weighing hopper 22 measures the correction admixture 24 flowing through the flow control valve 23 by the load detector 25, and 24 is supplied to the mixer 1 via the on-off valve 48.

Reference numeral 26 denotes an inverter, which supplies a drive current 27 to the motor 2.

Reference numeral 28 denotes a rotation speed detector which detects the rotation speed of the mixer 1 and outputs a rotation speed detection signal 2
9 is output.

Reference numeral 30 denotes a power meter, which measures the power supplied from the inverter device 26 to the motor 2 and outputs a power value measurement signal 31.

Reference numeral 32 denotes a shaft torque calculator. The shaft torque calculator 32 obtains a shaft torque of the mixer 1 based on the rotation speed detection signal 29 and the power value measurement signal 31, and outputs a shaft torque signal 33. It has become.

Numeral 34 is a shaft torque stable state judging device.
It is determined whether or not the value of the shaft torque signal 33 output from 2 has become stable for a certain period of time or more.
The calculation start command signal 35 is output when 3 becomes stable.

Numeral 36 denotes a data storage, which stores a data signal 37 relating to the correction water 17 and the correction admixture 24 (see the graphs of FIGS.
Expressions (i) to (x) are output.
The data signal 37 also has a target shaft torque T2.2a, a torque drop amount TMIX, and proportional constants α and β.

Numeral 38 denotes an arithmetic unit for calculating the amounts of the correction water 17 and the correction admixture 24 (see the above-mentioned equations (x) and (ix)). A quantity signal 40 is output.

Reference numeral 41 denotes a correction water metering controller. The correction water metering controller 41 is configured to open and close the flow control valve 16 by giving a valve opening / closing command signal 42 to the flow control valve 16. A valve opening / closing command signal 42 is supplied to the flow control valve 16 based on the corrected water metering signal 43 from the vessel 18 to close the flow control valve 16.

Reference numeral 44 denotes a correction admixture metering controller. The correction admixture metering controller 44 provides a valve opening / closing command signal 45 to the flow control valve 23 to open the flow control valve 23. A valve opening / closing command signal 45 is given to the flow control valve 23 based on the corrected admixture metering signal 46 from the load detector 25 to close the flow control valve 23.

Next, the operation of this embodiment will be described.

In the high-fluidity concrete production facility shown in FIG. 1, when producing high-fluidity concrete, a predetermined amount of cement 5 stored in the cement storage hopper 3 is weighed by the cement weighing hopper 4 and sand is stored. Hopper 6
A predetermined amount of the sand 8 stored in the gravel storage hopper 9 is weighed by the sand weighing hopper 7, and a predetermined amount of the gravel 11 stored in the gravel storage hopper 9 is weighed by the gravel weighing hopper 10.
A predetermined amount of water 14 is measured by a water measuring hopper 12, a predetermined amount of admixture 21 from a flow rate control valve 20 is measured by an admixture measuring hopper 19, and the mixture is measured into the mixer 1 started to be driven by the motor 2. Cement 5, sand 8, gravel 11, water 14,
The admixture 21 is charged, and the mixer 1 is rotated at a predetermined rotation speed to start kneading. The motor 2 is driven by a drive current 27 from an inverter device 26.

When the motor 2 is operated, the rotation speed of the mixer 1 is detected by the rotation speed detector 28,
8, a rotation speed detection signal 29 is output, and the power supplied from the inverter device 26 to the motor 2 is measured by the power meter 3
0, and a power value measurement signal 3
1 is output.

The shaft torque calculator 32 calculates the shaft torque of the mixer 1 based on the rotation speed detection signal 29 and the power value measurement signal 31, and outputs a shaft torque signal 33.

The change with time of the shaft torque T of the mixer 1 is shown in FIG.
As shown in the figure, once the kneading starts, it increases once, decreases as the high-fluidity concrete approaches the kneading state, and becomes almost constant and stable when it is almost in the kneading state (the tendency is that the shaft torque T is slightly increased). Decrease).

When the stable state of the shaft torque T continues for a certain period of time, a calculation start command signal 35 is given from the shaft torque stable state determination unit 34 to the calculation unit 38, and the calculation unit 38
Finally, based on the data signal 37 from the data storage 36, the corrected admixture amount Ad 'and the corrected water amount W' are finally obtained by the equations (ix) and (x), and the corrected water amount W 'is corrected. The corrected admixture amount Ad 'is output to the corrected admixture metering controller 44 as the corrected admixture amount signal 40 as the water amount signal 39 and the corrected admixture amount Ad'.

The correction water metering controller 41 and the correction admixture metering controller 44 simultaneously output valve opening / closing command signals 42 and 45 and supply them to the flow control valves 16 and 23. open. Therefore, the correction water 17 flows into the correction water measuring hopper 15, and the correction admixture 24 flows into the correction admixture measuring hopper 22.

Correction water 1 flowing into correction water measuring hopper 15
7 and the weight of the correction admixture 24 flowing into the correction admixture measurement hopper 22 are detected by the load detectors 18 and 25, and are supplied to the correction water measurement controller 41 and the correction admixture measurement controller 44.

When the weight of the correction water 17 and the weight of the correction admixture 24 reach a predetermined weight, the correction water metering controller 41
And the valve opening / closing command signal 4 from the correction admixture metering controller 44.
2, 45 are given to the flow control valves 16, 23 and closed,
The on-off valves 47 and 48 are opened, and the correction water 17 in the correction water weighing hopper 15 and the correction admixture 24 in the correction admixture weighing hopper 22 are supplied into the mixer 1 and mixing is continued.

The correction water 17 and the correction admixture 24 are mixed with the mixer 1
If the mixture is further kneaded for a certain period of time after the simultaneous injection into the inside, a high-fluid concrete in which the slump flow value SF and the rotation time value RT fall within the target ranges is produced.

Since the correction water 17 and the correction admixture 24 are simultaneously charged into the mixer 1, the kneading time is shortened as compared with a case where the correction water and the correction admixture are input to the mixer at a staggered time. Highly fluid concrete can be manufactured efficiently.

It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention.

[0076]

According to the method and the equipment for producing high-fluidity concrete of the present invention, the correction water and the correction admixture during the production of high-fluidity concrete can be simultaneously supplied to the mixer, so that high-fluidity concrete is produced. The time required for the production is shortened, and highly fluid concrete can be produced efficiently.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of an example of a method and a facility for producing high-fluidity concrete according to the present invention.

FIG. 2 is a graph showing a relationship between a change in shaft torque of a mixer and time when producing high-fluidity concrete in the present invention.

FIG. 3 is a graph showing a relationship between a slump flow value or a funnel time value and a shaft torque at the start of correction addition when producing high-fluidity concrete in the present invention.

FIG. 4 is a graph showing a relationship between a slump flow value or a roast time value and a shaft torque at the end of kneading when producing high-fluidity concrete in the present invention.

FIG. 5 is a graph showing a relationship between a slump flow value or a funnel time value and a shaft torque at the end of kneading when producing high-fluidity concrete in the present invention.

FIG. 6 is a graph showing a relationship between a corrected water addition amount and a shaft torque drop amount when producing a high fluidity concrete in the present invention.

FIG. 7 is a graph showing a relationship between a correction admixture addition amount and a shaft torque drop amount when producing a high fluidity concrete in the present invention.

FIG. 8 is a graph showing the relationship between time and shaft torque when producing high-fluidity concrete by conventional prior kneading.

FIG. 9 is a graph showing the relationship between time and shaft torque when producing high-fluidity concrete by conventional two-stage kneading.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mixer 5 Cement 8 Sand (fine aggregate) 11 Gravel (coarse aggregate) 14 Water 15 Correction water measurement hopper 16 Flow control valve (first flow control valve) 17 Correction water 21 Admixture 22 Correction admixture measurement hopper 23 Flow control valve (second flow control valve) 24 Correction admixture 32 Shaft torque calculator 33 Shaft torque signal 34 Shaft torque stable state determiner 36 Data storage 37 Data signal 38 Calculation unit 39 Correction water amount signal 40 Correction admixture amount Signal 41 Corrected water metering controller 42 Valve open / close command signal 44 Corrected admixture metering controller 45 Valve open / close command signal T-axis torque T2.1 Axis torque T2.2 Axis torque

Claims (2)

[Claims] 1. A cement, a fine aggregate, a coarse aggregate, water, and an admixture, each of which is measured, are charged into a mixer to start kneading, and a shaft torque when the mixer is driven is reduced from a maximum value to substantially decrease. When a certain stable and required shaft torque is obtained, a predetermined amount of corrected water and a corrected admixture are charged into the mixer at substantially the same time, and the mixture is further kneaded until the specified shaft torque is obtained. Method. 2. A mixer for mixing the metered and charged cement, fine aggregate, coarse aggregate, water and admixture, and a mixer for measuring the correction water supplied through the first flow control valve. A corrective admixture measuring hopper configured to be charged into the mixer, a corrective admixture measuring hopper configured to measure the corrective admixture supplied via the second flow control valve, and to input the corrected admixture into the mixer. A shaft torque calculator for calculating the shaft torque of the shaft; a shaft torque stable state determiner for determining whether or not the shaft torque is stable based on the shaft torque signal obtained by the shaft torque calculator; When the torque reaches a required stable value, an arithmetic unit for calculating the amount of the correction water and the correction admixture to be input to the mixer based on the data signal from the data storage, and a correction water amount signal obtained by the arithmetic unit. The valve opening / closing command signal is sent to the first flow control valve based on the A corrected water metering controller that outputs a signal, and the second
And a correction admixture measurement controller that outputs a valve opening / closing command signal to the flow control valve of the above, so that the correction water and the correction admixture can be supplied to the mixer almost simultaneously from the correction water measurement hopper and the correction admixture measurement hopper. A production facility for high-fluidity concrete, characterized in that: