JPH09250980A - Method for testing consistency of superplasticized concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for testing the consistency of superplasticized concrete which can quantitatively evaluate the material separating resistivity and pore passability of the concrete by a method which is not so different from a conventional slump flow test. SOLUTION: The method for testing the consistency of superplasticized concrete comprises the steps of conducting slump flow test of the concrete, measuring the slump flow and 50cm flowing time, conducting a barrier slump flow test in which a barrier 3 formed by arraying vertical round steel vertical leg pieces 2 at each circumferentially equally divided position of a strap 1 is placed at a predetermined position, measuring the slump flow at that time, 50cm flowing time and coarse aggregates in and out of the barrier, and evaluating the consistency of the concrete by using the slump flow test of the former and the barrier slump flow test of the latter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for testing the consistency of high-fluidity concrete, and more specifically, for evaluating the material separation resistance and the gap permeability in addition to the fluidity of high-fluidity concrete when fresh. It relates to the test method.

[0002]

2. Description of the Related Art The most commonly used evaluation test method for measuring the consistency of high-fluidity concrete (deformation of fresh concrete mainly depending on the amount of water, or the limit of fluidity) is
It is a slump flow test. The slump flow test
It is performed according to JIS A1101, and is shown in FIG.
As shown in (a), a slump cone b on a bottom plate a of 80 cm square or more is packed with the sample in three layers, and each layer is pierced with a stick for 0 to 5 times, and the slump cone pulling start is 0, and the diameter is 50 cm Measure the flow time. It should be noted that it takes about 3 to 10 seconds for ordinary high-fluidity concrete.

After pulling up the slump cone, FIG.
As shown in (4), when the concrete c spreads on the bottom plate and is stationary, the longest part of the concrete spread and the spread in the direction orthogonal to the longest part are measured, and these are averaged to obtain a slump flow. In the figure, d is coarse aggregate. FIG. 2 shows an L-flow test apparatus. The test apparatus is formed in an L shape, and the vertical portion e is filled with two layers of the sample by projecting five times each. After that, when the partition h that separates the vertical part e and the horizontal part f is pulled out in the direction of the arrow and the concrete h is flowing, the passage time of the tip part from the opening in 5 cm and 10 cm sections is obtained by an ultrasonic sensor, Also, the amount of subsidence of the vertical portion and the amount of movement to the tip when the flow stops are measured, and the L slump value Ls and L
The L flow time, which is the flow value Lf, is converted into the L flow speed according to the respective moving distances.

In the bar arrangement flow test, as shown in FIG. 3, in the L flow tester, the reinforcing bar i of D ₁₃ is three-dimensionally arranged at 7 cm intervals in the portion where the high flow concrete flows, so that the amount of the bar is high flow concrete. Is a test for evaluating the filling property of the high-fluidity concrete by arranging it in the horizontal part f in which is flowing. FIG. 4 shows a V funnel test, in which about 10 liters of concrete is packed into a funnel part j without being hit or hit, and is filled with a single layer.
To release the concrete and measure the flow time of the concrete.

FIG. 5 shows a ring penetration test, in which a ring m made of round steel and a support rod n are suspended by a weight o and penetrated into the sample concrete q in the cylinder p by its own weight, and its sinking speed. Evaluate the consistency of concrete samples. FIG. 6 shows a cylindrical penetration test, in which a cylindrical penetration meter t in which an opening s for mortar flow is provided on the side surface of a hollow cylinder r having a closed bottom is inserted into concrete to open the opening s.
The consistency of concrete is evaluated by the amount of mortar that has flowed in more.

Various other test methods have been proposed in addition to the above, but at present, they are not standardized yet, although the material separation resistance and the gap permeability in high-fluidity concrete are important.

[0007]

Many test methods for evaluating the filling property of high-flowing concrete, such as the material separation resistance and the gap passing property, have been proposed, but any test method other than the slump flow test has been proposed. Even in such cases, special test equipment was required, and the test method was troublesome, and many were unsuitable at the construction site.

The present invention has been proposed in view of such circumstances, and an object thereof is a method in which the material separation resistance and the gap passing property of high-fluidity concrete are not much different from those of the conventional slump flow test. The point is to provide a consistency test method for high-fluidity concrete that can be quantitatively evaluated by.

[0009]

In order to achieve the above object, according to the consistency test method for high-fluidity concrete according to the present invention, a slump flow test of high-fluidity concrete is carried out, and when the concrete spreads, mechanical Is applied to evaluate the spreading and separation resistance of concrete when compared with the normal slump flow test.

According to the consistency test method for high-fluidity concrete according to the second aspect of the present invention, (a) a slump flow test is performed on the high-fluidity concrete to measure the slump flow FL and the 50 cm flow time FT ₅₀ , and (B) A barrier slump flow test was carried out in which a barrier formed by arranging vertical leg pieces in each circumferentially equal position of the band loop was arranged at a predetermined position, and a slump flow BL at this time was tested.
50 cm flow time BT ₅₀ and barrier inner and outer coarse aggregate amount B
_n is measured, and the (a) slump flow test and (b)
It is intended to evaluate the consistency of high-fluidity concrete by using the measured value of the barrier slump flow test of.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The most preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 7 shows a test jig (hereinafter referred to as a barrier) used in the consistency test method for high-fluidity concrete according to the present invention, in which a circle in the band ring 1 having a wall thickness of 2 to 5 mm, an inner diameter of 290 mm, and an outer diameter of 300 is shown. The vertical leg pieces 2 made of round steel are arranged at positions divided into 16 equal parts and welded. The barrier can be manufactured by changing the number of round steels.

Next, the test method of the present invention will be described. The terms used in this test are defined as follows.

[0013]

[Equation 1]

BL: Slump flow value with a barrier (cm) FL: Slump flow value without a barrier (cm)

[0015]

[Equation 2]

G _i : Weight ratio of coarse aggregate inside the barrier G _o : Weight ratio of coarse aggregate outside the barrier 50 cm Flow time difference = BT ₅₀ −FT ₅₀ BT ₅₀ : ₅₀ cm flow time with the barrier (seconds) FT ₅₀ : Barrier 50 cm flow time (second) not arranged Table 1 shows the relationship between the quality of the high-fluidity concrete and the evaluation items.

In the test, after the high-fluidity concrete is kneaded by a mixer, the whole is discharged to a kneading plate, and after sufficiently stirring is completed, the air amount and the slump flow are measured as in the case of ordinary concrete. For the slump test, 50 cm flow time is measured. In addition to this measurement, a barrier flow test is performed by disposing the barrier 3 composed of the band ring 1 and the vertical leg piece 2 made of round steel as described above outside the slump cone 4. In the figure, 5 is a bottom plate of 80 cm square or more on which the slump cone 4 and the barrier are placed.

The test method conforms to JIS A1101, and the barrier 3 is installed outside the slump cone 4, and the sample inside the slump cone 4 is divided into three layers and packed.
Poke each layer 0-5 times. The fixing projection provided on the bottom of the cone is removed in advance so as not to hit the barrier 3 when the cone 4 is pulled up. (Refer to FIG. 8 (a)) The flow time of 50 cm is measured with the beginning of pulling up the cone 4 as 0.

When the concrete flowing on the bottom plate 5 stands still, the longest part of the concrete 6 and the spread in the direction orthogonal to the same are measured, and these are averaged to obtain a slump flow. The amount of coarse aggregate 7 in the concrete is measured inside and outside the further spread concrete.
(See FIG. 8B.) As described above, according to the test method of the present invention, the barrier 3 mechanically gives resistance to the spread of the concrete, and how the concrete spreads when compared with the normal slump flow test, This is an evaluation of separation resistance, and in the case of high-quality high-fluidity concrete, the passage rate is close to 100%,
The 50 cm flow time is almost unchanged, and the resolution is close to 1.

Next, Table 1 shows the relationship between the quality of high-fluidity concrete and the evaluation items.

[0021]

[Table 1]

[0022]

As described above, according to the consistency test method for high-fluidity concrete of the present invention, a slump flow test is performed on high-fluidity concrete, and mechanical resistance is imparted when the concrete spreads.
By evaluating the spread and separation resistance of concrete when compared to the normal slump flow test, it is possible to perform quantitative characteristic evaluation more than the conventional slump flow test without using a special test device. Consistency test of high-fluidity concrete is easily performed at the construction site.

Further, according to the present invention, since the concrete flows in all directions from the center of the slump cone, there is less error and reproducibility in comparison with other test methods relating to the gap passing property in which the concrete flows only in one direction. Are better. Furthermore, the material separation resistance of high-fluidity concrete can be quantitatively judged by the degree of separation (ratio of inner and outer coarse aggregates).

The gap permeability of the high-fluidity concrete can be evaluated by the passage rate, and the viscosity of the high-fluidity concrete is 50
cm Flow time difference can be evaluated. Therefore, the comprehensive evaluation of the consistency of the high-fluidity concrete is performed by using the above-mentioned degree of separation and passage rate. That is, both cannot be said to be healthy high-fluidity concrete unless they both satisfy the predetermined numerical values. According to an experiment, in the case of the barrier B shown in FIG. 8, the separation factor is 1.3 or less, preferably 1.2 or less, and the passing rate is high in the high fluidity concrete having the target slump flow of about 60 to 70 cm. 70% or more, preferably 80% or more.

[Brief description of drawings]

1] (a) and (b) show the outline of the slump test,
(A) is a perspective view showing a state where the slump cone is filled with fresh concrete, and (B) is a perspective view showing a state where the slump cone is pulled up.

FIG. 2 is a perspective view showing an L flow test apparatus.

FIG. 3 is a perspective view showing a bar arrangement L flow test device.

FIG. 4 is a perspective view of a V funnel test apparatus.

5 (a) and (b) are perspective views of a ring penetration test device and a ring used in the device, respectively.

6A and 6B are respectively a front view and a side view of a cylindrical penetration gauge.

7A and 7B are a plan view and a front view of a barrier, respectively.

8 (a) and (b) show the respective states of the barrier flow test of the present invention, (a) shows a state in which the slump cone is filled with concrete in the barrier, and (b) shows the same cone pulled up from the barrier. Shows the state.

[Explanation of symbols]

 1 band ring 2 vertical leg piece 3 barrier 4 slump cone 5 bottom plate 6 concrete 7 coarse aggregate

Claims (2)

[Claims] 1. A slump flow test of high-fluidity concrete is carried out, mechanical resistance is given when the concrete spreads, and how the concrete spreads and separation resistance when compared with a normal slump flow test is evaluated. A characteristic test method for high fluidity concrete. 2. (a) A slump flow test of high-fluidity concrete is conducted to measure the slump flow FL and a 50 cm flow time FT ₅₀ , and (b) a vertical leg piece is installed at each equally divided position in the circumferential direction of the strip annulus. A barrier slump flow test is performed with barriers arranged in a row at a predetermined position, and the slump flow BL at this time, 50 cm flow time BT
₅₀ and the inner and outer coarse aggregate amount B _n of the barrier were measured, and
A method for testing the consistency of high-fluidity concrete, characterized by evaluating the consistency of high-fluidity concrete using the measured values of the slump flow test of (1) and the barrier slump flow test of (2).