JPH0957738A - Method for kneading highly fluid concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently perform kneading without decreasing manufacturing capability as far as possible by a method wherein gravel are fed until power of a mixer reaches the limit value of the loading capacity during dry mixing and the remaining gravel are fed again when kneading is performed with adding of water after dry mixing. SOLUTION: When the whole amt. of measured gravel can be fed until power of a mixer reaches the preset limit value of the loading capacity, the whole amt. of the measured material is dry-mixed and when in the midway for feeding the whole amt. of the measured gravel, it reaches the limit value of the loading capacity, feeding of gravel is once stopped and dry mixing is performed at the max. amt. of kneading in accordance with the loading capacity of the power of the mixer and after dry mixing is performed for a specified time, water and a chemical admixture are then fed. At this moment, it is judged whether the measured gravel remain under unfed condition and when there exist unfed gravel, the remaining gravel are fed and when there exists no unfed gravel, kneading is performed at the stage where water and the chemical admixture are fed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for kneading high-fluidity concrete with a mixer in a ready-mixed concrete manufacturing plant.

[0002]

2. Description of the Related Art In recent years, concrete called "high performance concrete", "high fluidity concrete" or "superfluidized concrete" having excellent separation resistance and extremely high fluidity has been developed.

The concrete having a high fluidity is obtained by using a conventional concrete as a base concrete, on which a thickening agent such as a cellulose-based admixture, a cement-based material, an admixture such as fly ash and silica fume, and a high-performance water reducing agent are added. In addition, it is manufactured by kneading.

Therefore, in order to use powder materials more frequently than conventional concrete, in order to improve their dispersion, sand, gravel, cement, powder, etc. are mixed in advance without adding water. In some cases, the material is kneaded dry and then water is added to perform the original kneading.

[0005]

However, when this kneading is performed, voids are formed between the respective materials to increase the apparent volume and load the mixer power. The amount is appropriately reduced to about 50 to 80% for kneading. For this reason, it is inevitable that the manufacturing capacity will decrease.

In view of the above points, an object of the present invention is to provide a method for kneading high-fluidity concrete in which a decrease in production capacity in a plant is suppressed as much as possible.

[0007]

In order to achieve the above object, the present invention is to knead concrete materials such as sand, gravel, and cement by a mixer for a predetermined time, and then add water for kneading. In the kneading method of the high-fluidity concrete, the load capacity limit value is set in the vicinity of the maximum allowable load capacity of the mixer power in advance, and the gravel is added until the mixer power reaches the load capacity limit value during the kneading, and the remaining The gravel is characterized by being added again when water is added and kneading is performed after empty kneading.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for kneading high-fluidity concrete according to the present invention, when the concrete material is kneaded, the gravel is added to the preset load capacity limit value of the mixer power as much as possible. Since the concrete material is dry-kneaded and then water is added and the remaining gravel is added, efficient kneading can be performed without reducing the production capacity as much as possible.

[0009]

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

FIG. 1 shows an essential part of a ready-mixed concrete manufacturing plant. Reference numeral 1 denotes a twin-screw mixer for kneading concrete materials, in which two parallel kneading shafts 2 and 2 ′ are kneading tanks 3. And is rotatably supported in opposite directions, and the kneading shafts 2 and 2 ′ are provided with a large number of arms 4 projecting perpendicularly to the axis so as to form a spiral shape along the axis.
A kneading blade 5 is attached to the tip of the kneading material, and the kneading material is moved along the axis while being kneaded by the kneading blade 5 and kneaded.

A measuring tank for measuring various kneading materials is arranged above the biaxial mixer 1, and 6 is a gravel measuring tank, and the gravel storage bin is arranged above the gravel measuring tank 6. Gravel is discharged from (not shown) and a predetermined amount is weighed.

Reference numeral 7 denotes a sand measuring tank, which discharges and measures the sand from a sand storage bin (not shown) arranged above the sand measuring tank 7.

Reference numeral 8 denotes a cement measuring tank, which dispenses and measures the cement from a cement storage bottle (not shown) arranged above the cement measuring tank.

Reference numeral 9 denotes an admixture material measuring tank for measuring admixture materials such as fly ash and silica fume, and the admixture material is dispensed from an admixture material storage bin (not shown) arranged above the admixture material measuring tank 9. And weigh.

A water measuring tank 10 measures a predetermined amount of kneading water. Further, 11 is an admixture measuring tank arranged above the water measuring tank 10 and is arranged so that the admixture measured by the admixture measuring tank 11 can be introduced into the water measuring tank 10.

These measuring tanks are operated by an operation panel (not shown) of the plant, and various kinds of weighed materials are introduced into the twin-screw mixer 1 in accordance with the dispensing order preset on the operation panel. ing.

Next, the procedure for kneading and manufacturing high-fluidity concrete by means of this ready-mixed concrete manufacturing plant will be explained based on the flowcharts of FIGS.

2 and 3 are flow charts showing a procedure for kneading high-fluidity concrete using the mixer 1 of the ready-mixed concrete manufacturing plant, and S1 to S17 show respective steps of the kneading procedure.

First, before the operation of the plant, as shown in FIG. 2, the load capacity limit value of the mixer power is set on the operation panel of the plant as an initial setting (S1). The load capacity limit value of the mixer power is set near the maximum allowable load capacity of the mixer power as shown in FIG. 4, and the mixer capacity is used to the maximum extent near the maximum allowable load capacity during kneading. Then, it is determined whether or not the setting is to be ended (S2). When the setting is to be performed again, the process returns to step S1.

Next, proceeding to the operation starting operation shown in FIG. 3, the mixer is driven (S3) to prepare for kneading the materials. Then, various materials such as gravel, sand, cement, various powders, water and admixtures are weighed (S4). When the weighing of various materials is completed, water, gravel other than the admixture, sand, cement,
The powder is started to be charged into the mixer in a preset charging order (S5). At this time, the gravel is set to be input last.

Then, the detection of the mixer power is also started when the introduction of various materials into the mixer is started, and the load power of the mixer rapidly increases with the addition of the material as shown in FIG. Therefore, it is determined whether or not the mixer power value has reached a preset load capacity limit value (S6), and if the load capacity limit value has not yet been reached, it is determined whether the gravel input has been completed ( S7), if not completed,
The process returns to step S6, the gravel is continuously supplied, and when the gravel is already completely supplied, the process proceeds to step S10.

When the mixer power reaches the load capacity limit value, it is judged whether or not the gravel has been completely charged (S8). If the gravel has already been completely charged, the process proceeds to step S10 to start kneading.

If the gravel charging is not completed yet, the gravel charging is once stopped (S9), and the mixer is kneaded so that the load power is within the allowable maximum load capacity (S).
10).

As described above, when the total amount of the measured gravel can be added before reaching the preset load capacity limit value of the mixer power, the total amount of the measured material is dry-kneaded and the measured amount of the gravel is reduced. When the load capacity limit value is reached while the entire amount is being charged, the gravel charging is stopped once and the kneading is performed at the maximum kneading amount according to the load capacity of the mixer power.

When the dry kneading is carried out for a predetermined time, then water,
Add an admixture (S11). When water is added, the load power of the mixer decreases as shown in FIG. It is judged whether or not the gravel measured here remains in the unfilled state (S1
2) If there is unfilled gravel, add the remaining gravel (S1
3) Kneading is performed (S14). When there is no unfilled gravel, kneading is performed at the stage where water and an admixture are added.

After kneading with all the measured materials for a predetermined time, it is discharged from the mixer (S15) and it is judged whether the operation is completed (S16). When the operation is completed, the driving of the mixer is stopped (S17). When the operation is continued and the operation is continued, the process returns to step S4 and the above procedure is repeated from the measurement of various materials.

When setting the load capacity limit value, 50% to 50% of the maximum allowable load power value of the mixer power is set.
It is advisable to set it arbitrarily within the range of 100% so that it can correspond to various types of high-fluidity concrete.

[0028]

As described above, according to the method for kneading high-fluidity concrete of the present invention, the load capacity limit value is set in the vicinity of the maximum allowable load capacity of the mixer power in advance, and the mixer power is loaded at the load capacity limit first. The gravel was added until the value was reached and kneading was performed, and after the completion of the kneading, water was added and the remaining gravel was added to perform kneading, so that the mixer power can be used to the maximum effectiveness. It is possible to efficiently manufacture high-fluidity concrete without reducing the manufacturing capacity as much as possible.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a main part of a ready-mixed concrete manufacturing plant.

FIG. 2 is a flow chart showing a kneading procedure of high fluidity concrete of the present invention.

FIG. 3 is a flow chart showing a kneading procedure of high fluidity concrete of the present invention.

FIG. 4 is a graph showing a transition of load power of the mixer with the progress of kneading.

[Explanation of symbols]

 1 ... Biaxial mixer 6 ... Gravel measuring tank 7 ... Sand measuring tank 8 ... Cement measuring tank 9 ... Admixture material measuring tank 10 ... Water measuring tank 11 ... Admixture measuring tank

Claims (1)

[Claims] 1. A kneading method for high-fluidity concrete in which sand, gravel, cement, etc., which are concrete materials, are kneaded by a mixer for a predetermined time, and then water is added to knead them, and the mixer power is allowed in advance. A load capacity limit value is set near the maximum load capacity, gravel is added until the mixer power reaches the load capacity limit value at the time of the above-mentioned kneading, and the remaining gravel is re-mixed at the time of adding water after kneading and kneading. A method for kneading high-fluidity concrete characterized by being added