JP2018200293A - Dry shrinkage distortion measurement device, dry shrinkage distortion measurement method, and dry shrinkage distortion estimation method - Google Patents
Dry shrinkage distortion measurement device, dry shrinkage distortion measurement method, and dry shrinkage distortion estimation method Download PDFInfo
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Abstract
Description
本発明は、セメントペースト硬化体、コンクリート、およびモルタル（以下「セメント質硬化体」という。）の乾燥収縮ひずみの終局値を、早期に精度よく測定できる装置と、該装置を用いたセメント質硬化体の乾燥収縮ひずみを測定する方法等に関する。 The present invention relates to an apparatus capable of measuring the final value of drying shrinkage strain of cement paste cured body, concrete, and mortar (hereinafter referred to as “cemented cured body”) with high accuracy at an early stage, and cementum curing using the apparatus. The present invention relates to a method for measuring dry shrinkage strain of a body.
従来、セメント質硬化体の乾燥収縮ひずみを測定する方法は、ＪＩＳ Ａ １１２９−１に規定するコンパレータを用いる方法、ＪＩＳ Ａ １１２９−２に規定するコンタクトゲージを用いる方法、およびＪＩＳ Ａ １１２９−３に規定するダイヤルゲージを用いる方法がある。しかし、これらの方法はいずれも、乾燥収縮ひずみの終局値を得るには乾燥期間が１年以上もの長期間を要するほか、所定の期間毎に、１０ｃｍ×１０ｃｍ×４０ｃｍの供試体（セメント質硬化体）の長さを測定しなければならず、測定作業に手間がかかった。 Conventionally, methods for measuring the drying shrinkage strain of a hardened cementitious material include a method using a comparator specified in JIS A 1129-1, a method using a contact gauge specified in JIS A 1129-2, and JIS A 1129-3. There is a method of using a dial gauge that regulates. However, in any of these methods, in order to obtain the final value of the drying shrinkage strain, the drying period takes a long period of one year or more, and a specimen of 10 cm × 10 cm × 40 cm (cemented hardening) is obtained every predetermined period. Body) had to be measured, and the measurement work was time consuming.
そこで、特許文献１では、コンクリートの乾燥収縮ひずみを、早期に評価する方法が提案されている。該方法は、温度８０℃における乾燥期間２８日目の乾燥収縮ひずみの実測値と、温度２０℃における最終乾燥収縮ひずみ値との関係式、または、温度８０℃における最終乾燥収縮ひずみ値と、温度２０℃における最終乾燥収縮ひずみ値との関係を、それぞれ一次式で近似した関係式を用いて、任意の長期材齢におけるコンクリートの乾燥収縮ひずみを早期に評価する方法である。しかし、この方法では、関係式を得るのに手間がかかるほか、温度８０℃における最終乾燥収縮ひずみ値と、温度２０℃における最終乾燥収縮ひずみ値との関係が線形でない場合は、評価の精度が低下する。
Therefore,
そこで、本発明はセメント質硬化体の乾燥収縮ひずみの終局値を、早期に精度よく測定できる装置と、該装置を用いたセメント質硬化体の乾燥収縮ひずみを測定する方法等を提供することを目的とする。 Therefore, the present invention provides an apparatus capable of measuring the final value of the drying shrinkage strain of the hardened cementitious material with high accuracy at an early stage, a method for measuring the dry shrinkage strain of the hardened cementitious material using the device, and the like. Objective.
本発明者は、前記目的にかなう乾燥収縮ひずみ測定装置を鋭意検討した結果、特定の形状の供試体（セメント質硬化体）の収縮を、レーザーを用いて測定すれば、前記目的を達成できることを見出し、本発明を完成させた。
すなわち、本発明は、以下の構成を有する乾燥収縮ひずみ測定装置等である。
As a result of earnestly examining a drying shrinkage strain measuring apparatus that meets the above-mentioned object, the present inventor has found that the object can be achieved by measuring the shrinkage of a specimen having a specific shape (cemented hardened body) using a laser. The headline and the present invention were completed.
That is, the present invention is a drying shrinkage strain measuring device or the like having the following configuration.
［１］（Ａ）１個以上のレーザー変位計、（Ｂ）乾燥収縮ひずみ測定用の供試体を載置するための台座、および、（Ｃ）該供試体の位置決め治具、を少なくとも含む、乾燥収縮ひずみ測定装置。
［２］前記位置決め治具が２本のピンであり、レーザー変位計と位置決め治具が、図１または図２に示す位置に設置されている、前記［１］に記載の乾燥収縮ひずみ測定装置。
［３］前記［１］または［２］に記載の乾燥収縮ひずみ測定装置の台座上に、円板状または四角板状の供試体を、該供試体の周囲の側面が位置決め治具と接触するように載置した後、
レーザー変位計を用いて供試体の周囲の側面にレーザーを照射して、レーザー変位計と供試体の周囲の側面の間の距離を測定することにより、供試体の乾燥収縮ひずみを測る、乾燥収縮ひずみ測定方法。
［４］円板状の供試体を時計回りまたは反時計回りに回転して、該供試体の周囲の側面が位置決め治具と接触した状態で、レーザー変位計と該供試体の周囲の側面の間の距離を複数回測り、これらの距離の平均値を該供試体の乾燥収縮ひずみとして求める、前記［３］に記載の乾燥収縮ひずみ測定方法。
［５］前記供試体の厚さが５〜２０ｍｍである、前記［３］または［４］に記載の乾燥収縮ひずみ測定方法。
［６］所定の乾燥期間が経過する度に、供試体を台座上に載置して乾燥収縮ひずみを測る、前記［３］〜［５］のいずれかに記載の乾燥収縮ひずみ測定方法。
［７］乾燥前の供試体と同じ形状および寸法を有する金属板（基長板）を台座上に載置して、レーザー変位計と該金属板の側面の間の距離（Ｌ１）を測定した後、該金属板に代えて前記供試体を台座上に載置して、レーザー変位計と供試体の側面の間の距離（Ｌ２）を測定し、Ｌ１とＬ２の差（Ｌ１−Ｌ２）を乾燥収縮ひずみとする、前記［３］〜［６］のいずれかに記載の乾燥収縮ひずみ測定方法。
［８］乾燥前の供試体と同じ形状および寸法を有する金属板（基長板）を台座上に載置して、レーザー変位計と該金属板の側面の間の距離を測定し、該距離（の表示）をゼロに設定した後、該金属板に代えて前記供試体を台座上に載置して、レーザー変位計と供試体の側面の間の距離を測定して乾燥収縮ひずみとする、前記［３］〜［６］のいずれかに記載の乾燥収縮ひずみ測定方法。
［９］前記［３］〜［８］のいずれかに記載の乾燥収縮ひずみ測定方法を用いて測定した乾燥収縮ひずみの終局値に０．９を乗じて得た値を、ＪＩＳ Ａ １１２９−１、ＪＩＳ Ａ １１２９−２、または、ＪＩＳ Ａ １１２９−３に準拠して測定した、乾燥期間６か月における乾燥ひずみの値として推定する、乾燥収縮ひずみ推定方法。
[1] It includes at least one (A) one or more laser displacement meters, (B) a pedestal for placing a specimen for dry shrinkage strain measurement, and (C) a positioning jig for the specimen. Drying shrinkage measuring device.
[2] The drying shrinkage strain measuring apparatus according to [1], wherein the positioning jig is two pins, and the laser displacement meter and the positioning jig are installed at the positions shown in FIG. 1 or FIG. .
[3] A disk-shaped or square plate-shaped specimen is placed on the pedestal of the drying shrinkage strain measuring apparatus according to [1] or [2], and a side surface around the specimen is in contact with a positioning jig. After placing so that
Measure the dry shrinkage strain of the specimen by irradiating the side surface around the specimen with a laser displacement meter and measuring the distance between the laser displacement meter and the circumferential side of the specimen. Strain measurement method.
[4] The disk-shaped specimen is rotated clockwise or counterclockwise, and the side surface around the specimen is in contact with the positioning jig. The distance between them is measured a plurality of times, and the average value of these distances is determined as the drying shrinkage strain of the specimen.
[5] The dry shrinkage strain measuring method according to [3] or [4], wherein the thickness of the specimen is 5 to 20 mm.
[6] The drying shrinkage strain measuring method according to any one of [3] to [5], wherein the specimen is placed on a pedestal and the drying shrinkage strain is measured each time a predetermined drying period elapses.
[7] A metal plate (base plate) having the same shape and dimensions as the specimen before drying is placed on the pedestal, and the distance (L 1 ) between the laser displacement meter and the side surface of the metal plate is measured. Then, instead of the metal plate, the specimen was placed on a pedestal, and the distance (L 2 ) between the laser displacement meter and the side of the specimen was measured, and the difference between L 1 and L 2 (L 1 -L 2) is referred to as drying shrinkage strain, the [3] drying shrinkage strain measurement method according to any one of to [6].
[8] A metal plate (base length plate) having the same shape and dimensions as the specimen before drying is placed on the pedestal, and the distance between the laser displacement meter and the side surface of the metal plate is measured. After setting (display) to zero, the specimen is placed on a base instead of the metal plate, and the distance between the laser displacement meter and the side surface of the specimen is measured to obtain a drying shrinkage strain. The drying shrinkage strain measuring method according to any one of [3] to [6].
[9] A value obtained by multiplying the final value of the dry shrinkage strain measured using the dry shrinkage strain measurement method according to any one of [3] to [8] by 0.9 is JIS A 1129-1. , A JIS A 1129-2 or JIS A 1129-3, a drying shrinkage strain estimation method for estimating a drying strain value in a drying period of 6 months measured according to JIS A 1129-3.
本発明の乾燥収縮ひずみ測定装置および乾燥収縮ひずみ測定方法は、セメント質硬化体の乾燥収縮ひずみの終局値を、早期に精度よく測定できる。
また、本発明の乾燥収縮ひずみ推定方法は、前記ＪＩＳの方法に準拠して測定したセメント質硬化体の乾燥期間６か月時点での乾燥収縮ひずみを、早期に精度よく推定できる。
さらに、本発明で用いる供試体は、ＪＩＳの方法で用いる供試体に比べて小さくて軽く、供試体を動かすなどの作業が容易なため、ＪＩＳの方法と比べて乾燥収縮ひずみの測定作業の手間を大幅に低減できる。
The drying shrinkage strain measuring apparatus and the drying shrinkage strain measuring method of the present invention can measure the final value of the drying shrinkage strain of the cementitious hardened body with high accuracy at an early stage.
In addition, the drying shrinkage strain estimation method of the present invention can quickly and accurately estimate the drying shrinkage strain at the drying period of 6 months of the hardened cementitious material measured according to the JIS method.
Furthermore, the specimen used in the present invention is smaller and lighter than the specimen used in the JIS method, and the work such as moving the specimen is easy. Can be greatly reduced.
本発明は、前記のとおりの乾燥収縮ひずみ測定装置、乾燥収縮ひずみ測定方法、および乾燥収縮ひずみ推定方法である。以下、本発明について、乾燥収縮ひずみ測定装置、乾燥収縮ひずみ測定方法、および乾燥収縮ひずみの推定方法に分けて詳細に説明する。 The present invention is the dry shrinkage strain measuring apparatus, the dry shrinkage strain measuring method, and the dry shrinkage strain estimating method as described above. Hereinafter, the present invention will be described in detail by dividing it into a dry shrinkage strain measuring device, a dry shrinkage strain measurement method, and a dry shrinkage strain estimation method.
１．乾燥収縮ひずみ測定装置
（Ａ） レーザー変位計
本発明で用いるレーザー変位計４は、特に制限されず、反射型や透過型等の市販のレーザー変位計が挙げられる。
本発明では、レーザー変位計の数を増やせばデータ数が増え、その分、測定精度が向上するが、装置はコスト高になるため、レーザー変位計の数は、好ましくは１〜４個、より好ましくは１〜２個である。
前記レーザー変位計は、台座上に載置した円板状または四角板状の供試体１の中心に向けてレーザーを照射できるように設置する。レーザー変位計の設置位置は、例えば、図１や図２に示す位置が挙げられる。
1. Drying Shrinkage Strain Measuring Device (A) Laser Displacement Meter The
In the present invention, if the number of laser displacement meters is increased, the number of data increases and the measurement accuracy is improved correspondingly. However, since the cost of the apparatus increases, the number of laser displacement meters is preferably 1 to 4, more. Preferably it is 1-2.
The laser displacement meter is installed so as to irradiate the laser toward the center of the disk-shaped or square-plate-
（Ｂ）台座
本発明で用いる台座２は、乾燥収縮ひずみ測定用の供試体を載置するために用いる。台座の形状は、特に限定されず、例えば、図１や図２に示す正方形の板状や、円板状である。また、測定精度の向上のために、台座は水平に保たれていることが好ましい。
さらに、当該台座は、熱や衝撃による変形を防止するため、好ましくはインバー鋼材を用いて製造する。
(B) Pedestal The
Further, the pedestal is preferably manufactured using Invar steel in order to prevent deformation due to heat or impact.
さらに、台座は、乾燥収縮ひずみ測定用の供試体を支持するための支持部材５を設置してもよい。支持部材を設置すると、乾燥収縮ひずみ測定用の供試体と台座の間の熱の移動を低減できるため、乾燥収縮ひずみの測定精度が向上する。
支持部材の形状は、特に制限されず、図３に示すような球状（図３では、支持部材の下部の一部が、台座に埋め込まれている。）や、柱状等が挙げられる。なお、支持部材を柱状にする場合は、上部を半球状にすることが好ましい。
支持部材の数は、３点以上あれば供試体を安定して載置できるから好ましいが、支持部材を多くすると装置の製造に手間がかかる。そのため、支持部材の数は３〜４が好ましい。また、前記支持部材は、供試体を安定して載置するためには、正三角形または正方形を形成するように設置するのが好ましい。図３は、支持部材が正方形を形成するように設置されている例である。
さらに、支持部材は、熱や衝撃による変形を防止するため、好ましくはインバー鋼材を用いて製造する。
Furthermore, the pedestal may be provided with a
The shape of the support member is not particularly limited, and includes a spherical shape as shown in FIG. 3 (in FIG. 3, a part of the lower portion of the support member is embedded in the pedestal), a columnar shape, and the like. In addition, when making a supporting member into columnar shape, it is preferable to make hemisphere an upper part.
The number of supporting members is preferably three or more because the specimen can be placed stably. However, if the number of supporting members is increased, it takes time to manufacture the apparatus. Therefore, the number of support members is preferably 3-4. In addition, the support member is preferably installed so as to form an equilateral triangle or a square in order to stably place the specimen. FIG. 3 is an example in which the support members are installed so as to form a square.
Furthermore, the support member is preferably manufactured using Invar steel material in order to prevent deformation due to heat or impact.
(Ｃ)位置決め治具
本発明で用いる位置決め治具３は、供試体の乾燥収縮ひずみを測定する際に、供試体の載置位置を決めて固定するために用いるもので、例えば、図１や図２に示すように、台座上に倒立した状態で設置してなる２本のピン等が挙げられる。図１や図２では、乾燥期間が０（ゼロ）日の時点で、円板状の供試体を台座に載置した場合、円板状の供試体の中心と台座の中心が一致するように、位置決め治具が円板状の供試体の周囲の側面と接触する位置に設置されている。なお、当該位置決め治具は、台座上のほかに台座の外側に設置しても良い。
さらに、当該位置決め治具は、熱や衝撃による変形を防止するため、好ましくはインバー鋼材を用いて製造する。
(C) Positioning jig The
Further, the positioning jig is preferably manufactured using Invar steel material in order to prevent deformation due to heat or impact.
また、本発明の乾燥収縮ひずみ測定装置は、レーザー変位計、台座、および位置決め治具を、基盤を用いて一体化して構成することが好ましい。この場合、レーザー変位計、台座、および位置決め治具を設置するために用いる基盤は、熱や衝撃による変形を防止するため、好ましくはインバー鋼材を用いて製造する。 Moreover, it is preferable that the dry shrinkage strain measuring apparatus of the present invention is configured by integrating a laser displacement meter, a pedestal, and a positioning jig using a base. In this case, the base used for installing the laser displacement meter, the pedestal, and the positioning jig is preferably manufactured using Invar steel in order to prevent deformation due to heat or impact.
２．乾燥収縮ひずみ測定方法
本発明の乾燥収縮ひずみ測定方法は、前記乾燥収縮ひずみ測定装置の台座上に、円板状または四角板状の供試体を、該供試体の周囲の側面が位置決め治具と接触するように載置した後、レーザー変位計を用いて供試体の周囲の側面にレーザーを照射して、レーザー変位計と供試体の周囲の側面の間の距離を測定することにより、供試体の乾燥収縮ひずみを測る方法である。
供試体が円板状の場合、供試体の直径は、１０〜３０ｃｍであれば、供試体の製造は容易で、また供試体の乾燥が速くなり好ましい。なお、供試体の直径は、より好ましくは１０〜２０ｃｍである。また、供試体の厚さは、５〜２０ｍｍであれば供試体は割れ難く、また供試体の乾燥がさらに速くなるため好ましい。なお、供試体の厚さは、より好ましくは６〜１８ｍｍ、さらに好ましくは７〜１５ｍｍ、特に好ましくは８〜１２ｍｍである。
また、供試体が四角板状の場合、四角板の１辺の長さは、好ましくは１０〜３０ｃｍ、より好ましくは１０〜２０ｃｍであり、さらに好ましくは、１辺の長さが１０〜３０ｃｍの正方形、特に好ましくは、１辺の長さが１０〜２０ｃｍの正方形である。１辺の長さが１０〜３０ｃｍであれば、供試体の製造は容易で、また供試体の乾燥が速くなる。また、四角板状の供試体の厚さは、好ましくは５〜２０ｍｍ、より好ましくは６〜１８ｍｍ、さらに好ましくは７〜１５ｍｍ、特に好ましくは８〜１２ｍｍである。供試体の厚さが５〜２０ｍｍであれば、供試体は割れ難く、また供試体の乾燥はさらに速くなる。
なお、本発明の乾燥収縮ひずみ測定装置の台座に支持部材が設置されている場合、該支持部材上に、円板状または四角板状の供試体の周囲の側面が位置決め治具と接触するように、該供試体を載置する。
2. Dry shrinkage strain measuring method The dry shrinkage strain measurement method of the present invention comprises a disk-shaped or square plate-shaped specimen on a pedestal of the drying shrinkage strain measuring apparatus, and a side surface around the specimen is positioned with a positioning jig. After placing it in contact, a laser displacement meter is used to irradiate the surrounding side of the specimen with a laser, and the distance between the laser displacement meter and the surrounding side of the specimen is measured. This is a method for measuring the drying shrinkage strain.
When the specimen is disk-shaped, it is preferable that the specimen has a diameter of 10 to 30 cm because the specimen can be easily manufactured and the specimen can be dried quickly. The diameter of the specimen is more preferably 10 to 20 cm. The thickness of the specimen is preferably 5 to 20 mm because the specimen is difficult to break and drying of the specimen is further accelerated. The thickness of the specimen is more preferably 6 to 18 mm, further preferably 7 to 15 mm, and particularly preferably 8 to 12 mm.
When the specimen is a square plate, the length of one side of the square plate is preferably 10 to 30 cm, more preferably 10 to 20 cm, and still more preferably the length of one side is 10 to 30 cm. A square, particularly preferably a square having a side length of 10 to 20 cm. When the length of one side is 10 to 30 cm, the specimen is easily manufactured and the specimen is dried quickly. The thickness of the square plate-shaped specimen is preferably 5 to 20 mm, more preferably 6 to 18 mm, still more preferably 7 to 15 mm, and particularly preferably 8 to 12 mm. If the thickness of the specimen is 5 to 20 mm, the specimen is difficult to break and drying of the specimen is further accelerated.
When a support member is installed on the pedestal of the drying shrinkage strain measuring device of the present invention, the side surface around the disk-shaped or square plate-shaped specimen is in contact with the positioning jig on the support member. Then, the specimen is placed.
本発明の測定方法では、所定の乾燥期間毎に、供試体を台座上に載置して乾燥収縮ひずみを測る方法である。そして、乾燥収縮ひずみの測定精度を向上させるため、好ましくは、供試体は円板状であり、該供試体を時計回りまたは反時計回りに回転して、該供試体の周囲の側面が位置決め治具と接触した状態で、レーザー変位計と供試体の周囲の側面の間の距離を、複数回、好ましくは３〜５回測る。例えば、図１に示す供試体の点ａを測定した後、供試体を時計回りに９０°回転して点ｂを測定し、さらに時計回りに９０°回転して点ｃを測定して、３点の平均値を乾燥収縮ひずみとして求める。
本発明の測定方法では、乾燥収縮ひずみの測定間隔は任意であるが、乾燥収縮ひずみの終局値を早期に得るためや、測定の手間を低減するためには、好ましくは乾燥期間１〜１０日毎、より好ましくは乾燥期間１〜７日毎である。
The measuring method of the present invention is a method of measuring the drying shrinkage strain by placing a specimen on a pedestal for each predetermined drying period. In order to improve the measurement accuracy of the drying shrinkage strain, preferably, the specimen is disk-shaped and the specimen is rotated clockwise or counterclockwise so that the side surface around the specimen is positioned and cured. While in contact with the tool, the distance between the laser displacement meter and the side surface around the specimen is measured a plurality of times, preferably 3 to 5 times. For example, after measuring point a of the specimen shown in FIG. 1, the specimen is rotated 90 ° clockwise to measure point b, and further rotated 90 ° clockwise to measure point c. The average value of the points is determined as the drying shrinkage strain.
In the measurement method of the present invention, the measurement interval of the drying shrinkage strain is arbitrary, but in order to obtain the final value of the drying shrinkage strain at an early stage or to reduce the labor of the measurement, the drying period is preferably every 1 to 10 days. More preferably, the drying period is every 1 to 7 days.
また、本発明の測定方法は、乾燥収縮ひずみをより正確に測定するために、乾燥前の供試体と同じ形状および寸法を有する金属板（基長板）を台座上に載置して、レーザー変位計と該金属板の側面の間の距離（Ｌ１）を測定した後、該金属板に代えて前記供試体を台座上に載置して、レーザー変位計と供試体の側面の間の距離（Ｌ２）を測定し、Ｌ１とＬ２の差（Ｌ１−Ｌ２）を乾燥収縮ひずみとする方法である。
また、前記測定した距離が画面上に表示される測定装置を用いる場合、本発明の測定方法は、乾燥前の供試体と同じ形状および寸法を有する金属板（基長板）を台座上に載置して、レーザー変位計と該金属板の側面の間の距離を測定し、該距離（の表示）をゼロに設定した後、該金属板に代えて前記供試体を台座上に載置して、レーザー変位計と供試体の側面の間の距離を測定して乾燥収縮ひずみとする方法である。
前記金属板（基長板）は、温度の変化による長さの変化が同じになるよう、好ましくは台座と同じ材質の金属であり、熱や衝撃による変形を防止するため、より好ましくは、インバー鋼材である。
In addition, the measurement method of the present invention is a method in which a metal plate (base plate) having the same shape and dimensions as the specimen before drying is placed on a pedestal in order to measure drying shrinkage strain more accurately. After measuring the distance (L 1 ) between the displacement meter and the side surface of the metal plate, the specimen is placed on a pedestal instead of the metal plate, and the distance between the laser displacement meter and the side surface of the specimen is measured. In this method, the distance (L 2 ) is measured, and the difference (L 1 -L 2 ) between L 1 and L 2 is set as the drying shrinkage strain.
Moreover, when using the measuring apparatus by which the measured distance is displayed on the screen, the measuring method of the present invention places a metal plate (base length plate) having the same shape and dimensions as the specimen before drying on the pedestal. And measure the distance between the laser displacement meter and the side surface of the metal plate, set the distance (indication) to zero, and place the specimen on the base instead of the metal plate. In this method, the distance between the laser displacement meter and the side surface of the specimen is measured to obtain a drying shrinkage strain.
The metal plate (base plate) is preferably a metal of the same material as the pedestal so that the change in length due to a change in temperature is the same, and more preferably in order to prevent deformation due to heat or impact. It is a steel material.
３．乾燥収縮ひずみ推定方法
本発明の乾燥収縮ひずみ推定方法は、前記いずれかの乾燥収縮ひずみ測定方法を用いて測定した乾燥収縮ひずみの終局値に０．９を乗じて得た値を、前記ＪＩＳの方法に準拠して測定した、乾燥期間６か月における乾燥ひずみの値として推定する方法である。
本発明の前記推定方法によれば、後述する実施例に示すとおり、ＪＩＳの方法に準拠して測定した乾燥期間６か月におけるセメント質硬化体の乾燥収縮ひずみの値、特に、圧縮強度が１８Ｎ／ｍｍ２以上のセメント質硬化体の乾燥収縮ひずみの値を、１００日以内という短期間で精度よく推定できる。なお、本発明が適用できるセメント質硬化体の種類は、特に限定されず、普通コンクリートのほか、収縮低減剤または膨張材を含むコンクリート（図５参照）、速硬型コンクリート、軽量コンクリート、および高強度コンクリート等のセメント質硬化体にも適用できる。
3. Dry shrinkage strain estimation method The dry shrinkage strain estimation method of the present invention is obtained by multiplying the final value of dry shrinkage strain measured by any one of the above-mentioned dry shrinkage strain measurement methods by 0.9. It is a method of estimating as a value of drying strain in a drying period of 6 months, measured according to the method.
According to the estimation method of the present invention, as shown in Examples described later, the dry shrinkage strain value of the hardened cementitious material in the drying period of 6 months measured according to the method of JIS, in particular, the compressive strength is 18N. The value of the drying shrinkage strain of the cementitious hardened body of / mm 2 or more can be accurately estimated in a short period of 100 days or less. The kind of hardened cementitious material to which the present invention can be applied is not particularly limited, and other than ordinary concrete, concrete containing a shrinkage reducing agent or an expansion material (see FIG. 5), fast-hardening concrete, lightweight concrete, and high It can also be applied to hardened cementitious materials such as high-strength concrete.
以下、本発明を実施例により説明するが、本発明はこれらの実施例に限定されない。
１．使用材料
（１）セメント（太平洋セメント社製）
(i)普通ポルトランドセメント（略号：ＮＣ）
(ii)高炉セメントＢ種（略号：ＢＢ）
(iii)中庸熱ポルトランドセメント（略号：ＭＣ）
(iv)低熱ポルトランドセメント（略号：ＬＣ）
（２）細骨材（略号：Ｓ）：山砂（表乾密度２．５６ｇ／ｃｍ３）
（３）粗骨材：砂岩砕石（略号：Ｇ）：表乾密度２．６１ｇ／ｃｍ３
（４）水（略号：Ｗ）：水道水
（５）ＡＥ減水剤：リグニンスルホン酸系ＡＥ減水剤（略号：ＬＳ）：商品名 ポゾリスＮｏ．７０［登録商標］（ＢＡＳＦ社製）
（６）ＡＥ剤：商品名 マスターエア４０４［登録商標］（ＢＡＳＦ社製）
（７）収縮低減剤（略号：ＳＲ）：テトラガードＡＳ２１（太平洋マテリアル社製）
（８）膨張材（略号：ＥＸ）：太平洋ハイパーエクスパン（太平洋マテリアル社製）
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.
1. Materials used (1) Cement (manufactured by Taiheiyo Cement)
(i) Ordinary Portland cement (abbreviation: NC)
(ii) Blast furnace cement type B (abbreviation: BB)
(iii) Medium heat Portland cement (abbreviation: MC)
(iv) Low heat Portland cement (abbreviation: LC)
(2) Fine aggregate (abbreviation: S): mountain sand (surface dry density 2.56 g / cm 3 )
(3) Coarse aggregate: Sandstone crushed stone (abbreviation: G): Surface dry density 2.61 g / cm 3
(4) Water (abbreviation: W): tap water (5) AE water reducing agent: lignin sulfonic acid-based AE water reducing agent (abbreviation: LS): trade name POZOLIS No. 70 [registered trademark] (BASF)
(6) AE agent: Trade name Master Air 404 [registered trademark] (manufactured by BASF)
(7) Shrinkage reducing agent (abbreviation: SR): Tetragard AS21 (manufactured by Taiheiyo Materials Co., Ltd.)
(8) Expansion material (abbreviation: EX): Taiheiyo Hyper Expan (manufactured by Taiheiyo Materials Co., Ltd.)
２．乾燥収縮ひずみ測定用の供試体の作製
表１に示す配合に従い、前記の各材料を容量５０リッターのパン型ミキサに一括して投入し、２分間混練した後、混練物を内径１０ｃｍ、高さ２０ｃｍの型枠に打設して成形してコンクリートを得た。次に、該コンクリートを２０℃で１日間湿空養生した後に脱型し、さらに２０℃で７日間水中養生した。水中養生した後、コンクリートの高さ方向の中央部付近を切断して、直径１０ｃｍ、厚さ１ｃｍの乾燥収縮ひずみ測定用の供試体を各３個作製した。
なお、ＪＩＳ Ａ １１０８「コンクリートの圧縮強度試験」に準拠して測定したコンクリートＡ、Ｄ、Ｆの材齢２８日の圧縮強度は、それぞれ４７Ｎ／ｍｍ２、４０Ｎ／ｍｍ２および４６Ｎ／ｍｍ２であった。
2. Preparation of specimen for measurement of drying shrinkage strain According to the formulation shown in Table 1, the above materials were all put together into a 50-liter pan mixer and kneaded for 2 minutes. A concrete was obtained by casting and molding into a 20 cm formwork. Next, the concrete was moisture-cured at 20 ° C. for 1 day, then demolded, and further cured at 20 ° C. for 7 days in water. After curing in water, the vicinity of the central portion in the height direction of the concrete was cut to prepare three specimens for measuring dry shrinkage strain each having a diameter of 10 cm and a thickness of 1 cm.
Incidentally, concrete A, as measured in accordance with JIS A 1108 "compressive strength test of the concrete", D, compressive strength at the age of 28 days F are each 47N / mm 2, 40N / mm 2 and 46N / mm 2 there were.
３．供試体の乾燥収縮ひずみの測定
前記乾燥収縮ひずみ測定用の供試体１を、室温２０±２℃、相対湿度６０±５％の条件で乾燥した。そして、乾燥期間７日毎に、乾燥収縮ひずみ測定用の供試体を、該供試体の周囲の側面が、図１に示す乾燥収縮ひずみ測定装置の位置決め治具３と接触するように台座２に載置した後、レーザー変位計４を用いて、レーザー変位計と供試体の周囲の側面の間の距離を測定した。なお、本実施例では、１個の供試体に対して３箇所（図１の点ａ、点ｂ、および点ｃ）でレーザー変位計と供試体の周囲の側面の間の距離を測定して、この平均値を当該供試体の乾燥収縮ひずみとして算出し、さらに、この３個の供試体の乾燥収縮ひずみ（平均値）を平均して、全体の乾燥収縮ひずみを算出した。その結果を図４、５と表２に示す。ただし、図４では乾燥期間５６日以降のデータの一部の記載を省略した。また、図５では乾燥期間２８日以降のデータの一部の記載を省略した。
また、比較のため、ＪＩＳ Ａ １１２９-２「モルタル及びコンクリートの長さ変化測定方法 第２部：コンタクトゲージ方法」（以下「ＪＩＳ法」という。）に準拠して、前記コンクリートＡ〜Ｆの乾燥収縮ひずみを測定した。ＪＩＳ法に準拠して測定した乾燥期間３００日までの乾燥収縮ひずみの測定値を図４、５に併記した。また、ＪＩＳ法に準拠して測定した乾燥収縮ひずみの終局値、および乾燥期間６ヶ月の乾燥収縮ひずみを表２に併記した。
3. Measurement of Drying Shrinkage Strain of Specimen The
For comparison, drying of the concrete A to F in accordance with JIS A 1129-2 “Method for measuring changes in length of mortar and concrete, Part 2: Contact gauge method” (hereinafter referred to as “JIS method”). Shrinkage strain was measured. The measured values of the drying shrinkage strain up to the drying period of 300 days measured according to the JIS method are shown in FIGS. Table 2 also shows the final value of the drying shrinkage strain measured in accordance with the JIS method and the drying shrinkage strain for a drying period of 6 months.
図４、５および表２に示すように、いずれのコンクリートも、乾燥収縮ひずみの終局値は、ＪＩＳ法では乾燥期間が１年以上経過しなければ得られないのに対し、本発明によれば、供試体の乾燥速度が大きいため、乾燥収縮ひずみの終局値は、乾燥期間が１００日以内という早期に精度よく得られる。
また、表２に示すように、本発明を用いて得た乾燥収縮ひずみの終局値に０．９を乗じるだけで、ＪＩＳ法に準拠して測定した乾燥期間６か月の乾燥収縮ひずみの値を、誤差が３．１％以下という高い精度で早期に推定できる。
As shown in FIGS. 4 and 5 and Table 2, in any concrete, the final value of the drying shrinkage strain cannot be obtained unless the drying period of one year or more is passed in the JIS method. Since the drying speed of the specimen is large, the final value of the drying shrinkage strain can be obtained with high accuracy at an early stage that the drying period is within 100 days.
Moreover, as shown in Table 2, the value of the drying shrinkage strain measured for 6 months according to the JIS method was simply multiplied by 0.9 to the final value of the drying shrinkage strain obtained using the present invention. Can be estimated early with high accuracy of an error of 3.1% or less.
１ 供試体
２ 台座
３ 位置決め治具
４ レーザー変位計（ただし、黒色の矢印はレーザーを示す。）
５ 支持部材
DESCRIPTION OF
5 Support members
Claims (9)
レーザー変位計を用いて供試体の周囲の側面にレーザーを照射して、レーザー変位計と供試体の周囲の側面の間の距離を測定することにより、供試体の乾燥収縮ひずみを測る、乾燥収縮ひずみ測定方法。 After placing a disk-shaped or square plate-shaped specimen on the pedestal of the drying shrinkage strain measuring apparatus according to claim 1 or 2 so that the side surface around the specimen is in contact with the positioning jig. ,
Measure the dry shrinkage strain of the specimen by irradiating the side surface around the specimen with a laser displacement meter and measuring the distance between the laser displacement meter and the circumferential side of the specimen. Strain measurement method.
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| JP7365127B2 (en) | 2019-03-01 | 2023-10-19 | 太平洋セメント株式会社 | How to estimate drying shrinkage strain |
| JP2020148678A (en) * | 2019-03-14 | 2020-09-17 | 太平洋セメント株式会社 | Drying shrinkage strain estimation method |
| JP7270423B2 (en) | 2019-03-14 | 2023-05-10 | 太平洋セメント株式会社 | Method for estimating drying shrinkage strain |
| WO2021042631A1 (en) * | 2019-09-06 | 2021-03-11 | 山东科技大学 | Three-dimensional movement deformation measurement system and application thereof in three-dimensional similar simulation experiment |
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