JPH0726693Y2 - Equipment for measuring water content and air content of concrete before solidification - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a device for measuring the water content and air content of a tooth, pre-solidified concrete.

[Background of the invention]

Since the strength of concrete is determined by the water / cement ratio, it is very important to measure the water content of the unconsolidated concrete before solidification, especially in the construction of large concrete structures. Therefore, it is required to measure the water content of the concrete which does not harden before pouring.

Further, in order to know the strength of concrete, it is important to measure the amount of air contained in the concrete.

However, at present, there is no measuring instrument that can immediately measure the water content and air content of concrete before pouring, so that there is a problem that the quality control of concrete cannot be sufficiently performed.

[Purpose of device]

This invention was made in consideration of the above points, and a measuring device for water content and air content of concrete before solidification that can immediately measure the water content of concrete that has not solidified yet before pouring. The purpose is to provide.

[Means for achieving the purpose]

In order to achieve the above object, the present invention, on a pedestal for mounting a bottomed cylindrical container, at the one position sandwiching the peripheral wall of the container placed on this pedestal, the neutron source and the other of the same A fast neutron detector is arranged at a position, and a flange for fixing the lid of the air amount measuring device is provided around the upper end of the bottomed cylindrical container.

[Action]

Filling concrete before solidification in a cylindrical container, emitting fast neutrons from a neutron source, if you measure the number of fast neutrons passing through the cylindrical container with a fast neutron detector, you can measure the density of hydrogen. Since the hydrogen nuclei in the concrete before solidification exist as a component of water, the amount of water can be obtained if the density of hydrogen is known. Also, by placing a lid of the air amount measuring device on the upper end opening of a cylindrical container filled with concrete and fixing the lid using a flange provided around the outer periphery of the container, the air amount of the concrete can be measured by the measuring device. Can be measured.

〔Example〕

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

As shown in the figure, the cylindrical container 1 is made of a metal material having excellent alkali resistance and is formed to have a diameter and a depth that are substantially equal to each other. It is designed to store concrete A.

On the pedestal 3 on which the cylindrical container 1 is arranged, a neutron beam source 4 is arranged at one position sandwiching the peripheral wall of the cylindrical container 1, and a unit 6 of a fast neutron detector 5 is arranged at the other side thereof. A portion of the outer periphery of the peripheral wall except the unit 6 is covered with the fast neutron moderator 7.

The gantry 3 is provided with a positioning metal fitting 8 for setting the cylindrical container 1 in a fixed position, and the gantry 3 has
A scale 9 that supports the cylindrical container 1 and weighs it, and a calculation display 10 that displays the amount of water, the weight, and the amount of air are set.

The measuring device of the present invention has the above-mentioned structure. To measure the water content of concrete before solidification, as shown in FIG.
Concrete A as a sample is filled in the cylindrical container 1, and neutrons are emitted from the neutron source 4 into the cylindrical container 1,
The fast neutron detector 5 penetrating the inside of the cylindrical container 1 detects and counts the number, and the hydrogen content is measured to obtain the water content.
Digitally display with the weight of. The relationship between the neutron count rate ratio and the water density is as shown in FIG.

As described above, the principle of measuring the total water content of concrete using a radioisotope is as follows.

The fast neutrons (neutrons with high energy) emitted from the neutron source gradually lose energy while repeating elastic scattering with the nuclei of various elements that make up the substance, and eventually become thermal neutrons (neutrons with low energy). change.
The energy lost when elastically scattered depends greatly on the mass of the colliding partner element. It is extremely large for hydrogen nuclei of the same mass as neutrons, and small for nuclei of larger mass than neutrons. Therefore, when the density of hydrogen nuclei in the substance increases, the number of fast neutrons decreases and the number of thermal neutrons increases.

Therefore, by sandwiching the cylindrical container 1 filled with concrete A that has not solidified yet, by disposing a neutron source on one side and a fast neutron detector on the other side, and measuring the number of fast neutrons passing through the container, hydrogen is obtained. The density of can be measured.
Since the hydrogen nuclei in the concrete that has not yet solidified exist as a component of water (H ₂ O), the water content can be obtained if the density of hydrogen is known.

Next, since the cylindrical container 1 used for measuring the amount of water has a flange 2 provided around the upper end, as shown in FIG.
It can be used as it is as a container for measuring the air content of concrete before solidification.

To measure the amount of air in concrete before solidification, use the air chamber 11
The lid 12 provided with is placed on the cylindrical container 1, the lid 12 is fixed to the cylindrical container 1 with the fastener 13 using the flange 2 and the packing, the cylindrical container 1 is sealed, and the exhaust port 14, Close the pressure adjusting valve 15 and the water injection port 16, and use the air hand pump 17 to create the air chamber 11.
The pressure is increased, the valve 18 is opened, and after confirming that the pointer of the pressure gauge 19 is stable and stationary, the numerical value is read and used as the apparent air amount of concrete A. The moisture amount and the air amount are measured at the same time. it can. The measurement of the amount of air in the above-mentioned solidified concrete is defined by the well-known JIS standard A1128, and the relationship between the volume of the cylindrical container 1 and the air chamber 11, the pressure value by the air handle pipe 17, and the air by the pressure gauge 19 The reading of the amount and the like may follow this regulation.

〔effect〕

As described above, according to the present invention, the neutron source is arranged on one side of the peripheral wall of the cylindrical container and the fast neutron detector is arranged on the other side. The water content of concrete can be measured immediately, the water content of concrete immediately before placing can be measured on site, and the quality control of concrete can be sufficiently performed. In addition, since the flange for fixing the lid of the air amount measuring device was provided around the outer peripheral edge of the upper part of the cylindrical container, the air amount of the concrete before solidification can be measured using the cylindrical container, and the cylindrical container can measure the water content and the air. It can be used for quantity measurement, and both measurements can be performed immediately and continuously.

[Brief description of drawings]

FIG. 1 is a front view of a notched part of a measuring device according to the present invention, FIG. 2 is a plan view of the same, FIG. 3 is a front view of a partly cutaway showing an air amount measurement state, and FIG. 4 is a neutron count rate ratio. It is a graph which shows the relationship of water density. 1 ... Cylindrical container, 2 ... Flange, 4 ... Neutron source,
5: Fast neutron detector.

Claims (1)

[Scope of utility model registration request] 1. A fast neutron detector is arranged at the same position as the neutron beam source at one position sandwiching the peripheral wall of the container placed on this mount on a mount on which a bottomed cylindrical container is mounted. A moisture content and air content measurement device for pre-solidifying concrete, wherein a flange for fixing a lid of the air content measurement device is provided around the upper end of the bottomed cylindrical container.