JPH10170507A - Method and apparatus for measurement of material segregation of concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method which is capable of simply measuring material segregation of concrete that has not been esterblished and to provide a simple measuring apparatus for the method so that the property of the concrete used for a placing operation is grasped more precisely and that the waste of a sample is eliminated so as to contribute saving resources. SOLUTION: A frame body 1, which holds a slide rod 2 so as to be freely movable in the up-and-down direction is attached to a bottomed cylindrical container 20, which is used for an air content test or the like. In addition, a penetration blade 3 which sinks into soft mortar, which comes into contact with a coarse aggregate interposed in the mortar and whose sinking operation is regulated is attached to the lower end of the slide rod 2. Then, a size in which the penetration blade 3 sinks into a concrete sample inside the container 20 is measured, and the segregation state of its material is grasped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of measuring the separation of unconsolidated concrete material (coarse aggregate and mortar) and a measuring apparatus therefor.

[0002]

2. Description of the Related Art As is well known, concrete is composed of mortar composed of cement, fine aggregate, admixture, and water, and coarse aggregate. It is also a well-known fact that the properties of concrete differ depending on the mixing ratio thereof, and fresh concrete having properties according to the purpose of use and the method of casting must be used for placing concrete. Therefore, it is necessary to test whether or not the fresh concrete to be used is suitable before casting.

Generally, as a test of this fresh concrete, a slump test specified in JIS A 1101 and an air amount test specified in JIS A 1128 are performed.

In the above-mentioned slump test, after filling a sample into a slump cone of a specified size, the cone is pulled up, and the fluidity of the sample, which has been deformed and settled by its own weight (slump value), is measured. To be tested. In addition, the air amount test is usually performed using an air meter composed of a cylindrical container having an open top surface, and an air chamber, a lid portion provided with a pressure gauge, and the like. More airtight,
It measures the amount of air in concrete by a predetermined procedure.

[0005] In addition to the fluidity measured by the above-mentioned slump test, resistance to separation of coarse aggregate and mortar of concrete is important as a property to be provided by concrete to be cast. In the case of concrete, it is general to judge by visually observing how the concrete sample collapses in the slump test.

In recent years, techniques such as so-called high-fluidity concrete, which use a high-performance water reducing agent and have significantly improved fluidity as compared with conventional concrete, have been developed and put into practical use. In general, the resistance to material separation tends to decrease as the fluidity of concrete increases, and in the production and construction of these concretes with high fluidity, it is necessary to accurately examine the material separation resistance as well as the fluidity. Testing and evaluation are extremely important issues than conventional concrete.

[0007] In the construction of concrete having high fluidity, generally, material separation is performed by separating mortar component and coarse aggregate when concrete flows in a formwork, or separation of coarse aggregate after completion of concrete placement. Appears in the form of settling.

[0008] A technique for measuring the resistance to such separation phenomena has not been established at present. At present, in the above-mentioned slump test, the spread of a circular shape (slump flow) due to the flow of a concrete sample is measured to determine the fluidity. At the same time as the index, it is often qualitatively determined by visually observing whether or not the coarse aggregate is uniformly spread together with the mortar. As a proposal of a method for quantitatively evaluating the separation resistance of high-fluidity concrete, only an application as Japanese Patent Application Laid-Open No. Hei 7-120458 can be seen.

[0009] Japanese Unexamined Patent Publication No. Hei 7-120458 discloses a wheel-shaped form having an opening through which fresh concrete can be charged and discharged. Using a device that is rotated at a speed, the fresh concrete put into the mold is allowed to flow under predetermined conditions, then concrete is collected from a predetermined position in the form, two places, and included in the concrete. The amount of each of the aggregates to be removed was removed from the mortar and then weighed to determine the separation between the aggregate and the mortar.

[0010]

As a method for evaluating the material separation resistance of concrete having high fluidity, the above-mentioned method of visually observing the spread and uniformity of the coarse aggregate at the time of slump flow measurement is a matter of course. However, quantitative evaluation and judgment are impossible, and it is extremely difficult to estimate the separation resistance of concrete at the time of casting based on the observed state of concrete.

In the invention disclosed in Japanese Patent Application Laid-Open No. 7-120458, a test on material separation of concrete is possible, but a dedicated large-scale test apparatus equipped with a driving device for rotating the formwork is required. There was a problem that.

[0012] In this method, concrete is collected from two places in the mold after being subjected to a test apparatus, and the concrete is washed with a sieve to remove the mortar, and the remaining aggregate is removed. It is necessary to measure the weight in a predetermined (front-dry) state, and there is a problem that the operation is complicated and the work efficiency is poor.

Further, in this method, a new fresh concrete sample is required in addition to the sample used in the slump test, the air amount test, etc. in order to measure the concrete separation state, and resources are wasted for the test. It also has the problem of consuming it.

Further, in the conventional method including the method disclosed in Japanese Patent Application Laid-Open No. 7-120458, how the coarse aggregate in the concrete cast in the formwork is separated over time.
It is impossible to quantitatively predict and judge what kind of coarse aggregate will settle and eventually harden in the distribution of coarse aggregate. It was necessary to perform tests such as placing a core specimen and collecting a core specimen to check the distribution of the coarse aggregate.

An object of the present invention is to improve the problems of the above-described conventional apparatus and method.

[0016]

In order to solve the above-mentioned problems, the present invention according to the first aspect of the present invention provides a concrete sample stored in a container having an open upper surface and a predetermined weight and shape. The penetrating blades with the weight are placed so that they can descend by their own weight, and the sedimentation size of the penetrating blades over time is measured, so that the state of separation of coarse aggregate and mortar in concrete is grasped. This is a method for measuring material separation of concrete.

According to a second aspect of the present invention, in accordance with the first aspect of the present invention, the sedimentation size is measured by using the penetrating blade formed in an H-shape in a plan view with respect to the surface of the concrete sample. The process is performed in two steps at two positions rotated by a plane.

According to a third aspect of the present invention, as the container and the concrete sample used in the method according to the first or second aspect, those used in an air volume test are used.

According to a fourth aspect of the present invention, the apparatus used in the above method is engaged with a container containing concrete,
The frame comprises a frame mounted on the container and a slide rod held vertically movably by the frame and having a penetrating blade attached to a lower end, and the slide rod has an upper end capable of loading a weight. Protrudingly provided on the frame body, the frame body,
It is characterized in that a scale or a mark is provided so that the moving dimension of the slide rod can be visually checked.

According to a fifth aspect of the present invention, in the device according to the fourth aspect, the frame body is engageable with the air amount test container, and the penetrating blade has a size capable of being immersed in the air amount test container. There is a feature.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on the illustrated embodiments.

FIG. 1 is a front view showing a concrete material separation measuring apparatus according to the present invention set on a container.
2 is a plan view thereof, and FIG. 3 is a sectional view taken along line AA of FIG. As shown in FIG.
A frame 1 is fixed to the upper surface of the frame 1 and a slide rod 2 is vertically movably held by the frame 1.

The frame 1 is a container 20 having an open top.
A ring-shaped horizontal portion 1a in contact with the upper edge of the vertical portion 1b, and a vertical portion 1b straddling the horizontal portion 1a and standing above the center thereof
In the vertical portion 1b, nylon slide bearings 4 and 5 having through holes are vertically mounted.

The slide rod 2 includes the slide bearings 4,
5 is vertically penetrated, and a penetrating blade 3 (see FIG. 4) formed by combining two metal plates 3a, 3a in a cross shape is attached to the lower end. A weight receiver 6 is fixed to the upper end side of the slide rod 2 protruding from the frame body 1 with a screw, and a ring-shaped weight 7 inserted into the slide rod 2 on the weight receiver 6 is held immovable downward. Like that.

In FIG. 3, reference numeral 10 denotes a screw mounted on one side of the vertical portion 1 b of the frame 1 so that the tip of the frame 1 is pressed against the slide rod 2 to restrict the slide of the slide rod 2. The stopper knob 8 is a linear scale attached to the vertical portion 1b of the frame 1 in parallel with the slide rod 2;
Denotes a mark provided on the slide rod 2 to indicate the starting point at the start of measurement, and 9 denotes a set screw for connecting and fixing the frame 1 to the container 20.

The concrete material separation measuring apparatus of the present invention has the above-described configuration.

The shape of the container 20 to which the above-mentioned material separation measuring device is attached is not particularly limited as long as the container 20 has an open upper surface capable of accommodating fresh concrete. It is preferable to use a container having a bottomed cylindrical shape and a container for an air flow test (having a specification of 190 mm in inner diameter and 180 mm in inner depth). Therefore, the size of the penetrating blade 3 is determined so as to correspond to this.

Next, the method for measuring the material separation of concrete of the present invention using the above-described apparatus will be described.

First, while holding the concrete sample 21 used in this test inside the container 20 after the air amount test, the frame 1 is placed as shown in FIG. Then, the frame 1 is fixed to the container 20. At this time, the slide rod 2 is fixed in advance by a stopper knob 10 so as not to be slid so that the lower end of the penetrating blade 3 comes to a position in contact with the surface of the concrete. A weight 7 having a predetermined weight is attached to an upper portion of the slide rod 2.

Next, when the stopper knob 10 is loosened to release the fixing of the slide rod 2, the slide rod 2 tends to descend by its own weight including the penetrating blade 3 and the weight 7, and the penetrating blade 3
It comes into contact with the upper surface of the sample 21 at a predetermined pressure. At this time, the fresh concrete as a sample is
1a and the coarse aggregate 21b are uniformly mixed, so that the penetrating blade 3
The contact with b prevents further lowering.
FIG. 9 is a simplified plan view of the main part showing the state at the start of the test.

If left in this state for a while, separation of the coarse aggregate 21b and the mortar 21a starts, and the coarse aggregate 21b
The penetrating blades 3 held in the step (1) start descending as shown in FIG. 6 with the sedimentation of the coarse aggregate 21b into the concrete sample 21.

As time passes, the separation of the coarse aggregate 21b and the mortar 21a progresses, and the penetrating blades 3 further settle in the concrete sample 21 as shown in FIG.

As the process proceeds, the sedimentation speed of the penetrating blades 3 into the concrete sample 21 gradually decreases, and becomes stable in the state shown in FIGS. 8 and 10. In the experiment in which two metal plates 3a, 3a each having a thickness of about 1 mm, a width and a height of 100 mm and a height of 10 mm were combined in a cross shape, and a weight of 300 g was loaded as a weight, It took about 30 minutes to shift to this state.

In this state, a mark 2a provided on the slide rod 2
By measuring the position to which the straight blade 8 provided on the frame 2 has moved, the descending dimension of the penetrating blade 3 is determined, and how much separation between the coarse aggregate 21b and the mortar 21a has occurred. But you can understand.

When an experiment was carried out under the same conditions as above using a container 20 for an air flow test device having a depth of 180 mm, when the dropping dimension was 65 mm or more, an obstacle caused by material separation of concrete during casting was found. Turned out to be happening. As described above, in the method of the present invention, the settling dimension of the penetrating blades 3 has a correlation with the material separation of the concrete, so that by measuring the dimension, the degree of the material separation of the concrete can be quantitatively grasped.

In the case of a sample in which the degree of material separation is remarkable and the sedimentation of the coarse aggregate has already progressed to a certain extent at the start of the measurement by the present apparatus, the degree of material separation is quantitatively evaluated immediately after the start of the measurement. Will be measured.

In the above, two metal plates 3 are used as the penetrating blades 3.
Although a combination of a and 3a in a cross shape has been illustrated, the penetrating blade 3 may be of any type as long as it has a bottom area enough to sink into the soft mortar 21a. It may be formed in an I shape or an H shape in plan view as shown in FIG. In addition, when using such a penetrating blade that is not centrally symmetric, after performing the measurement in the same manner as described above, once raising the penetrating blade,
It is desirable that the measurement be repeated once again at a position rotated by 90 ° with respect to the concrete sample, and that the measurement of the sedimentation size be performed in two steps in two steps, since more accurate measurement becomes possible.

Further, the weight of the weight 7 loaded on the slide rod 2 and the time required for measurement may be determined within the minimum error range from experimental data under various conditions.

Furthermore, in the above description, an example was shown in which the material separation measurement was performed following the air amount test using a measuring device that engages with the air amount test container 20. The point is that the penetrating vanes to be loaded are placed on the sample, and the material separation of concrete is measured from the sedimentation dimensions.The container containing concrete is different from the one for the air volume test. Alternatively, only the material separation measurement may be performed separately from the air amount test using a new sample.

[0040]

As described above, according to the first aspect of the present invention, the material separation of the concrete can be grasped very easily by measuring the settling dimension of the penetrating blade mounted on the concrete. This makes it possible to quantitatively grasp the separation resistance of concrete at the time of casting in a normal quality control test, and furthermore, the distribution state of coarse aggregate in concrete after the completion of casting, The presence / absence can be directly estimated and evaluated.

According to the second aspect of the present invention, more accurate measurement of concrete material separation becomes possible by performing measurement at two places using a penetrating blade having an H shape in plan view.

According to the third aspect of the present invention, by using the container and the concrete sample used for the air amount test, the labor required for preparing for the material separation measurement of the concrete is reduced, and the work efficiency is improved. In addition, concrete samples conventionally required separately for individual tests are now commonized, which has an excellent effect on resource saving.

The invention according to claim 4 realizes a device capable of measuring the material separation of concrete with a simple configuration and at low cost without using any driving source, etc., and the introduction is facilitated and the handling property is improved. Also improve.

According to the fifth aspect of the present invention, in addition to the effect of the fourth aspect of the present invention, the cost of the apparatus can be further reduced by attaching the material separation measuring device to the air volume test container. There is an effect of getting off.

[Brief description of the drawings]

FIG. 1 is a front view showing a state in which a concrete material separation measuring device according to the present invention is set on a container.

FIG. 2 is a plan view of the material separation measuring device shown in FIG.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a plan view of a penetrating blade used in the apparatus of the present invention.

FIG. 5 is a simplified sectional view of a container and an apparatus for explaining the method of the present invention, showing a state before the start of measurement.

FIG. 6 is a simplified sectional view of a container and an apparatus for explaining the method of the present invention, showing a state immediately after the start of measurement.

FIG. 7 is a simplified sectional view of a container and an apparatus for explaining the method of the present invention, showing a state where material separation has progressed.

FIG. 8 is a simplified cross-sectional view of a container and apparatus for explaining the method of the present invention, showing a state in which material separation is almost completed.

FIG. 9 is a simplified plan view of a main part of FIG. 5;

FIG. 10 is a simplified plan view of a main part of FIG. 8;

FIG. 11 is a plan view showing another example of the penetrating blade used in the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Frame 1a Horizontal part 1b Vertical part 2 Sliding rod 2a Mark 3 Penetrating blade 3a Metal plate 4,5 Slide bearing 6 Weight receiver 7 Weight 8 Straight 9 Set screw 10 Stopper knob 20 Container 21 Concrete sample 21a Mortar 21b Coarse aggregate

Continuation of front page (72) Inventor Koichi Ono 19-106 Kamikoya Nishihimurocho, Sakyo-ku, Kyoto-shi

Claims (5)

[Claims] 1. A penetrating blade having a predetermined weight and shape is placed on a concrete sample accommodated in a container having an open top so as to be able to descend by its own weight, and a sedimentation dimension of the penetrating blade with time is measured. A method for measuring the material separation of concrete, characterized in that the state of separation of coarse aggregate and mortar in concrete is grasped by doing so. 2. Using a penetrating blade formed in an H-shape in plan view, the measurement of sedimentation size is divided into two steps at two positions where the penetrating blade is rotated by 90 ° with respect to the surface of the concrete sample. 2. The method for measuring material separation of concrete according to claim 1, wherein 3. The method for measuring material separation of concrete according to claim 1, wherein the container and the concrete sample used for the air amount test are used. 4. A frame which is engaged with a container containing concrete and is mounted on the container, and a slide rod which is vertically movably held by the frame and has a penetrating blade attached to a lower end thereof. The slide rod is provided with an upper end protruding above the frame so that a weight can be loaded thereon, and the frame is provided with a scale or a mark for visually observing a moving dimension of the slide rod. Concrete material separation measuring device. 5. The concrete according to claim 4, wherein the frame is formed so as to be engageable with the air amount test container, and the penetrating blade is formed so as to be immersed in the air amount test container. Material separation measuring device.