JP5666151B2 - Estimation method of compressive strength of cement mortar - Google Patents
Estimation method of compressive strength of cement mortar Download PDFInfo
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- JP5666151B2 JP5666151B2 JP2010054856A JP2010054856A JP5666151B2 JP 5666151 B2 JP5666151 B2 JP 5666151B2 JP 2010054856 A JP2010054856 A JP 2010054856A JP 2010054856 A JP2010054856 A JP 2010054856A JP 5666151 B2 JP5666151 B2 JP 5666151B2
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- 238000000034 method Methods 0.000 title claims description 19
- 239000011083 cement mortar Substances 0.000 title claims description 17
- 239000004568 cement Substances 0.000 claims description 50
- 239000002245 particle Substances 0.000 claims description 40
- 230000036571 hydration Effects 0.000 claims description 31
- 238000006703 hydration reaction Methods 0.000 claims description 31
- 239000011347 resin Substances 0.000 claims description 10
- 229920005989 resin Polymers 0.000 claims description 10
- 239000004020 conductor Substances 0.000 claims description 7
- 238000000151 deposition Methods 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 6
- 239000002893 slag Substances 0.000 claims description 6
- 238000005498 polishing Methods 0.000 claims description 4
- 238000002360 preparation method Methods 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 11
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 8
- 239000011400 blast furnace cement Substances 0.000 description 8
- 239000004570 mortar (masonry) Substances 0.000 description 8
- 239000004576 sand Substances 0.000 description 7
- 229910052799 carbon Inorganic materials 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 239000000470 constituent Substances 0.000 description 5
- 229910052500 inorganic mineral Inorganic materials 0.000 description 5
- 239000011707 mineral Substances 0.000 description 5
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 4
- 239000011398 Portland cement Substances 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 3
- 230000008021 deposition Effects 0.000 description 3
- 229910003460 diamond Inorganic materials 0.000 description 3
- 239000010432 diamond Substances 0.000 description 3
- 239000003822 epoxy resin Substances 0.000 description 3
- 229920000647 polyepoxide Polymers 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000010191 image analysis Methods 0.000 description 2
- 239000003350 kerosene Substances 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 229910052580 B4C Inorganic materials 0.000 description 1
- 239000006004 Quartz sand Substances 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- -1 and the like Chemical compound 0.000 description 1
- INAHAJYZKVIDIZ-UHFFFAOYSA-N boron carbide Chemical compound B12B3B4C32B41 INAHAJYZKVIDIZ-UHFFFAOYSA-N 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 238000000295 emission spectrum Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 238000010884 ion-beam technique Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- PSZYNBSKGUBXEH-UHFFFAOYSA-N naphthalene-1-sulfonic acid Chemical compound C1=CC=C2C(S(=O)(=O)O)=CC=CC2=C1 PSZYNBSKGUBXEH-UHFFFAOYSA-N 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229920001225 polyester resin Polymers 0.000 description 1
- 239000004645 polyester resin Substances 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 238000000611 regression analysis Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/10—Production of cement, e.g. improving or optimising the production methods; Cement grinding
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- Analysing Materials By The Use Of Radiation (AREA)
Description
本発明は、セメントモルタルを破壊することなく、セメントモルタルの圧縮強さを推定する方法に関する。 The present invention relates to a method for estimating the compressive strength of cement mortar without destroying the cement mortar.
従来、モルタルの圧縮強さは、セメント、水および砂を混練した後、当該混練物を所定の型枠に入れて供試体を作成し、次いで、当該供試体を各材齢まで水中養生した後に、圧縮強さ試験機を用いて測定していた。
しかし、前記従来の方法では、測定時に供試体が破壊されるため、各材齢毎に供試体を多数作成してその強度を個々に測定しなければならず、供試体の作成と強度測定に多くの労力および時間が費やされるほか、セメント等の供試体の構成材料が多量に必要であった。
Conventionally, the compressive strength of mortar is obtained by kneading cement, water, and sand, then putting the kneaded product in a predetermined form to create a specimen, and then curing the specimen under water to each age. It was measured using a compressive strength tester.
However, in the conventional method, the specimen is destroyed at the time of measurement, so it is necessary to prepare a large number of specimens for each age and measure their strengths individually. A lot of labor and time are consumed, and a large amount of constituent material of the specimen such as cement is required.
そこで、モルタルの圧縮強さ測定に要する労力等を削減し得る方法として、圧縮強さの推定方法が幾つか提案されている。
例えば、特許文献１には、セメント製造プラントの運転において、品質管理情報として収集した、セメント中のクリンカー構成鉱物及び添加材の量の情報、クリンカー構成鉱物の結晶構造の情報、クリンカーの少量成分の量の情報、およびセメントの粉末度及び４５μｍ残分の情報を、過去に蓄積されているそれら情報及びモルタル圧縮強さ実測データの間の重回帰分析を基に求めたモルタル圧縮強さの推定式に適用することにより、モルタル圧縮強さを推定する方法が記載されている。
また、特許文献２には、固化体にレーザーパルスを照射してプラズマを誘起させ、プラズマの発光スペクトル中の特定成分元素（例えばCa）の中性原子線とイオン線との発光強度比により固化体の強度を検出又は測定する方法が記載されている。
Thus, several methods for estimating compressive strength have been proposed as methods for reducing the labor required for measuring the compressive strength of mortar.
For example, Patent Document 1 discloses information on the amount of clinker constituent minerals and additives in cement, information on the crystal structure of clinker constituent minerals, and information on the minor components of clinker collected as quality control information in the operation of a cement manufacturing plant. Estimating formula of mortar compressive strength obtained based on multiple regression analysis between information of quantity, cement fineness and 45 μm residual information, and accumulated information in the past and measured data of mortar compressive strength A method for estimating the mortar compressive strength by applying to the above is described.
In Patent Document 2, plasma is induced by irradiating a solidified body with a laser pulse, and solidified according to the emission intensity ratio between a neutral atomic beam and an ion beam of a specific component element (for example, Ca) in the emission spectrum of the plasma. A method for detecting or measuring body strength is described.
しかし、特許文献１に記載の推定方法では、必要な情報がクリンカー構成鉱物及び添加材の量、クリンカー構成鉱物の結晶構造、クリンカーの少量成分の量およびセメントの粉末度及び４５μｍ残分と多岐に渡って必要であり、また、特許文献１の図１から分かるように、モルタル圧縮強さの推定式の推定精度は十分とは云えない。
また、特許文献２に記載の推定方法では、レーザー誘起プラズマ発生装置、発光検知器、分光光度計およびコンピュータ等の大掛かりで高価なシステムが必要になり、当該方法を実施するとコスト高になる虞がある。
However, in the estimation method described in Patent Document 1, necessary information varies widely such as the amount of clinker constituent mineral and additive, the crystal structure of the clinker constituent mineral, the amount of minor components of the clinker, the fineness of cement, and the remaining 45 μm. Further, as is apparent from FIG. 1 of Patent Document 1, the estimation accuracy of the estimation formula for the mortar compression strength is not sufficient.
In addition, the estimation method described in Patent Document 2 requires a large and expensive system such as a laser-induced plasma generator, a light emission detector, a spectrophotometer, and a computer, and the implementation of this method may increase costs. is there.
従って、本発明は、簡便な操作により高い精度でセメントモルタルの圧縮強さを推定する方法を提供することを目的とする。 Therefore, an object of the present invention is to provide a method for estimating the compressive strength of cement mortar with high accuracy by a simple operation.
本発明者らは、上記課題を解決するために鋭意研究した結果、特定の２つの試料を作成し、特定の画像解析手段を用いて測定して求めたセメント粒子またはスラグ粒子（以下「水硬性粒子」という。）の水和率に基き、セメントモルタルの圧縮強さを極めて正確に推定することができる方法を見出し、本発明を完成した。
即ち、本発明は、（１）材齢ｔ日のセメントペースト硬化体及び水和率ゼロのセメントペースト硬化体の表面を研磨し導電材を蒸着して試料を作成する試料作成工程と、（２）前記２つの試料の反射電子像から材齢ｔ日のセメントペースト硬化体における水硬性粒子の水和率を算出する水和率算出工程と、（３）セメントペースト硬化体における圧縮強さと水硬性粒子の水和率との相関を示す回帰式を予め求めておき、前記材齢ｔ日のセメントペースト硬化体における水硬性粒子の水和率を前記回帰式に代入することによって材齢ｔ日のセメントペースト硬化体における圧縮強さの推定値を算出する圧縮強さ推定工程とからなり、且つ前記水硬性粒子が高炉スラグ粒子を含むセメントモルタルの圧縮強さの推定方法である。
As a result of earnest research to solve the above-mentioned problems, the present inventors made two specific samples and measured cement particles or slag particles (hereinafter referred to as “hydraulic properties”) obtained by measurement using specific image analysis means. Based on the hydration rate of “particles”), a method capable of extremely accurately estimating the compressive strength of cement mortar was found, and the present invention was completed.
That is, the present invention includes (1) a sample preparation step of preparing a sample by polishing the surfaces of a cement paste hardened body of age t and a cement paste hardened body having a hydration rate of zero and depositing a conductive material; ) A hydration rate calculating step for calculating the hydration rate of the hydraulic particles in the cement paste cured body of the age t from the reflected electron images of the two samples; and (3) the compressive strength and hydraulic property in the cement paste cured body. A regression equation showing a correlation with the hydration rate of the particles is obtained in advance, and the hydration rate of the hydraulic particles in the cement paste cured body of the material age t is substituted into the regression equation to obtain the material age t days. Ri Do and a compressive strength estimation step of calculating the estimated value of the compressive strength in the cement paste cured product is and the method of estimating the compressive strength of cement mortar the hydraulic particles containing blast furnace slag particles.
本発明によれば、簡便な操作により高い精度で、セメントモルタルの圧縮強さを推定することができる。 According to the present invention, the compressive strength of cement mortar can be estimated with high accuracy by a simple operation.
以下、本発明について詳細に説明する。
（１）試料作成工程
試料作成工程は、以下の（i）〜（vi）からなる。
（i）セメントおよび水、または、セメント、水および砂を混練した後、型枠に入れ、所定の材齢に達するまで封緘養生して脱型するか、または、打設後２４時間で脱型し所定の材齢に達するまで水中養生して、硬化体を得る。
（ii）前記硬化体を切断装置を用いて切断して切断片を得る。
（iii）前記切断片をアセトン中に浸漬してセメントおよび高炉スラグの水和を止めた後、Ｄ−乾燥して乾燥体を得る。
（iv）前記乾燥体に、樹脂を含浸させ樹脂が硬化した後、この乾燥体の表面を研磨し導電材を蒸着して、試料を作成する。
（v）未水和のセメントペーストを模擬するため、前記（i）で作成した硬化体と同一のセメント体積率となるように、セメント−樹脂混合供試体を作成する。
（vi）前記（v）のセメント−樹脂混合供試体も、樹脂が硬化した後、（iv）と同様に表面を研磨し導電材を蒸着して試料とする。
Hereinafter, the present invention will be described in detail.
(1) Sample preparation process The sample preparation process includes the following (i) to (vi).
(I) Cement and water, or cement, water and sand are kneaded and then put into a mold and sealed until they reach the specified age, or they are demolded, or demolded 24 hours after placing Then, it is cured in water until a predetermined age is reached, and a cured body is obtained.
(Ii) The cured body is cut using a cutting device to obtain a cut piece.
(Iii) The cut pieces are immersed in acetone to stop the hydration of cement and blast furnace slag, and then D-dried to obtain a dried product.
(Iv) After impregnating the dried body with resin and curing the resin, the surface of the dried body is polished and a conductive material is deposited to prepare a sample.
(V) In order to simulate an unhydrated cement paste, a cement-resin mixed specimen is prepared so as to have the same cement volume ratio as the hardened body prepared in (i).
(Vi) The cement-resin mixed specimen of (v) is also used as a sample by polishing the surface and depositing a conductive material in the same manner as (iv) after the resin is cured.
ここで（i）において、セメントは、高炉セメント、普通ポルトランドセメント、早強ポルトランドセメント、中庸熱ポルトランドセメントおよび低熱ポルトランドセメント等から選ばれる１種または２種以上が使用できる。特に、高炉セメントが好適である。砂は特に限定されず、標準砂、珪砂、砕砂等が使用できる。
セメントに対する水の添加量、または、セメントおよび砂に対する水の添加量は、試料が成形できる量であれば良く、例えば水の添加量はセメント１００重量部に対し２０〜７０重量部が、また、砂の添加量はセメント１００重量に対し５０〜５００重量部が、試料の成形上好適である。必要に応じて流動性を確保するために減水剤を使用してもよい。減水剤はナフタレンスルホン酸系やポリカルボン酸系等、市販のものから適宜選択する。特に、次の工程である反射電子画像観察の便宜から、試料はセメントと水のみを混練したセメントペーストの硬化体が好ましい。また、養生温度は２０℃が好ましい。
（ii）において、切断装置はダイヤモンドカッター等の公知の装置が使用できる。また、切断片の大きさは、鮮明な反射電子画像を得るために、例えば、縦４ｃｍ、横２ｃｍ、厚さ１ｃｍの大きさが好ましい。
（iv）において、樹脂は、例えば、エポキシ樹脂、（メタ）アクリル系樹脂、ポリエステル系樹脂等が挙げられる。樹脂の浸透性を考慮すると低粘度の樹脂がよく、例えば、樹脂の粘度は２０℃で２００ｃＰ以下が好適である。また、研磨材は、シリコーンカーバイド研磨材、ボロンカーバイド研磨材、ダイヤモンドペースト、アルミナ粉末等が挙げられる。また、導電材は、炭素、白金パラジウム、金等が挙げられ、特に炭素が好ましい。導電材の蒸着膜を形成する方法としては、特に限定されるものではなく、従来公知の方法により行うことができる。
Here, in (i), the cement can be one or more selected from blast furnace cement, ordinary Portland cement, early-strength Portland cement, moderately hot Portland cement, low heat Portland cement and the like. Blast furnace cement is particularly preferable. The sand is not particularly limited, and standard sand, quartz sand, crushed sand and the like can be used.
The amount of water added to the cement or the amount of water added to the cement and sand may be an amount that allows the sample to be molded. For example, the amount of water added is 20 to 70 parts by weight with respect to 100 parts by weight of cement, The amount of sand added is preferably 50 to 500 parts by weight based on 100 parts by weight of cement. A water reducing agent may be used as necessary to ensure fluidity. The water reducing agent is appropriately selected from commercially available products such as naphthalene sulfonic acid and polycarboxylic acid. In particular, for the convenience of observation of reflected electron images, which is the next step, the sample is preferably a hardened body of cement paste in which only cement and water are kneaded. The curing temperature is preferably 20 ° C.
In (ii), a known device such as a diamond cutter can be used as the cutting device. The size of the cut piece is preferably 4 cm long, 2 cm wide, and 1 cm thick in order to obtain a clear reflected electron image, for example.
In (iv), examples of the resin include an epoxy resin, a (meth) acrylic resin, and a polyester resin. Considering the permeability of the resin, a low-viscosity resin is preferable. For example, the viscosity of the resin is preferably 200 cP or less at 20 ° C. Examples of the abrasive include silicone carbide abrasive, boron carbide abrasive, diamond paste, and alumina powder. Examples of the conductive material include carbon, platinum palladium, gold, and the like, and carbon is particularly preferable. The method for forming the vapor-deposited film of the conductive material is not particularly limited, and can be performed by a conventionally known method.
（２）水和率算出工程
水和率算出工程は、以下の（ａ）〜（ｄ）からなる。
また、水和率を算出するための画像解析のフローチャートを図１に示す。
（ａ）反射電子検出器を備えた走査型電子顕微鏡を用いて、水和率ゼロの試料と推定したい材齢（材齢ｔ日）の試料それぞれの導電材蒸着面の反射電子像（図２）を取得する（Ｓｔｅｐ１）。走査型電子顕微鏡は更にエネルギー分散型Ｘ線定量装置を備えていれば、より効果的な測定ができる。なお、走査型電子顕微鏡の観察倍率は５００倍が好ましい。
（ｂ）（ａ）で取得した反射電子像のノイズを除去する処理をする（Ｓｔｅｐ２）。ノイズの除去処理としては、移動平均フィルタやメディアンフィルタ等による処理が挙げられる。ノイズが除去処理された画像を基にして、グレイレベルの頻度分布（図３）を得る。未水和の水硬性粒子部分に対応する輝度の範囲（例えば、高炉セメントＢ種のセメントペーストにおける未水和セメントならば、濃度は１７６〜２５５であり、未水和の高炉スラグならば、濃度は１５０〜１７５である）を閾値として設定し、２値化像を得る（Ｓｔｅｐ３）。この２値化像の面積率を面積率を算出する。
（ｃ）前記水硬性粒子の面積率を下記式に代入して、水硬性粒子の水和率を算出する。
Ｒｔ＝{１−（Ｓｉ−Ｓｔ）／Ｓｉ}×１００ …（Ａ）
Ｒｔ；材齢ｔ日の水硬性粒子の水和率（％）
Ｓｉ；水和率ゼロの未水和の水硬性粒子の面積率（％）
Ｓｔ；材齢ｔ日の未水和の水硬性粒子の面積率（％）
ここで、水硬性粒子とは、セメント粒子、またはセメント粒子および高炉スラグ粒子をいう。
(2) Hydration rate calculation step The hydration rate calculation step includes the following (a) to (d).
A flowchart of image analysis for calculating the hydration rate is shown in FIG.
(A) Using a scanning electron microscope equipped with a backscattered electron detector, a backscattered electron image of a conductive material vapor deposition surface of each sample having a hydration rate of zero and a sample of an age (material age t days) to be estimated (FIG. 2) ) Is acquired (Step 1). If the scanning electron microscope further includes an energy dispersive X-ray quantitative apparatus, more effective measurement can be performed. The observation magnification of the scanning electron microscope is preferably 500 times.
(B) A process of removing noise from the reflected electron image acquired in (a) is performed (Step 2). Examples of noise removal processing include processing by a moving average filter, a median filter, and the like. Based on the noise-removed image, a gray level frequency distribution (FIG. 3) is obtained. The range of brightness corresponding to the unhydrated hydraulic particle part (for example, the concentration is 176 to 255 for unhydrated cement in the cement paste of type B blast furnace cement B, and the concentration for unhydrated blast furnace slag Is a threshold value, and a binarized image is obtained (Step 3). The area ratio is calculated from the area ratio of the binarized image.
(C) The area ratio of the hydraulic particles is substituted into the following formula to calculate the hydration ratio of the hydraulic particles.
R t = {1− (S i −S t ) / S i } × 100 (A)
R t : Hydration ratio (%) of hydraulic particles at age t
S i ; Area ratio (%) of unhydrated hydraulic particles having zero hydration rate
S t : Area ratio (%) of unhydrated hydraulic particles on day t
Here, the hydraulic particles refer to cement particles, or cement particles and blast furnace slag particles.
（３）圧縮強さ推定工程
予め、セメントモルタルの圧縮強さと水硬性粒子の水和率との相関を示す回帰式を求める。ここで、セメントモルタルの圧縮強さは、例えば、ＪＩＳ Ｒ ５２０１に従って測定するのが好ましい。次に、任意の材齢の水硬性粒子の水和率を前記回帰式に代入し、当該材齢のセメントモルタルの圧縮強さの推定値を算出する。
(3) Compressive strength estimation step A regression equation showing the correlation between the compressive strength of cement mortar and the hydration rate of hydraulic particles is obtained in advance. Here, the compressive strength of the cement mortar is preferably measured according to, for example, JIS R 5201. Next, the hydration rate of hydraulic particles of any age is substituted into the regression equation, and an estimated value of the compressive strength of the cement mortar of the age is calculated.
以下、実施例を挙げて本発明を説明する。
１．セメントモルタルの圧縮強さの測定
ＪＩＳ Ｒ ５２０１に従って高炉セメントＢ種（太平洋セメント社製）のモルタルを作成し、２０℃で封緘養生して、材齢１日、３日、７日、２８日および９１日のモルタルの圧縮強さを測定した。その結果、各材齢の圧縮強さは、材齢1日で５Ｎ／ｍｍ２、材齢３日で１８Ｎ／ｍｍ２、材齢７日で３２Ｎ／ｍｍ２、材齢２８日で５５Ｎ／ｍｍ２、材齢９１日で７２Ｎ／ｍｍ２であった。
Hereinafter, the present invention will be described with reference to examples.
1. Measurement of compressive strength of cement mortar Prepare mortar of blast furnace cement type B (manufactured by Taiheiyo Cement Co., Ltd.) according to JIS R 5201, seal and cure at 20 ° C., age 1, 3, 7, 28 and The compressive strength of the mortar on day 91 was measured. As a result, compressive strength of each wood age, age of 1 day at 5N / mm 2, 18N / mm 2 at 3 days the age, 32N / mm 2 at an age of 7 days, 55N / mm at an age of 28 days 2 and the material age was 72 N / mm 2 at 91 days.
２．水和率の算出
ＪＩＳ Ｒ ５２０１に従い、高炉セメントＢ種（太平洋セメント社製）のセメントぺーストを混練した後、型枠に入れ封緘養生して、材齢１日、３日、７日、２８日および９１日の高炉セメントペースト硬化体を作成した。
次に、ダイヤモンドカッターを用いて当該高炉セメントペースト硬化体を、縦４ｃｍ、横２ｃｍ、厚さ１ｃｍの大きさに切断し、当該切断片をアスピレータによる減圧環境下にてアセトン中に０．５時間浸漬した後、Ｄ−乾燥して乾燥体を得た。
当該乾燥体に、常温硬化型の低粘性エポキシ樹脂（商品名：スペシフィックス−２０、丸本ストルアス社製）を含侵・硬化後、表面をＳｉＣ
研磨材（＃４００、８００、１０００、１２００）およびアルミナ粉末（３μｍ、１μｍ、０．５μｍ）とケロシンを用いて研磨を行った。次に、常法により当該研磨面にカーボン蒸着を施して試料を作成した。
水和率ゼロのセメントペーストを模擬するため、高炉セメントの体積率を前記セメントペーストと一致させた高炉セメント−エポキシ樹脂混合硬化体を作成した。
当該硬化体も、前記と同様に表面をＳｉＣ 研磨材（＃４００、８００、１０００、１２００）およびアルミナ粉末（３μｍ、１μｍ、０．５μｍ）とケロシンを用いて研磨を行った。次に、常法により当該研磨面にカーボン蒸着を施した。
カーボン蒸着面に電子線が当たるように、反射電子検出器を備えた走査型電子顕微鏡（装置名；ＪＳＭ−７００１Ｆ、日本電子社製）に当該試料を載置し、蒸着面の反射電子像〈図３〉を取得した。ここで観察条件は、加速電圧が１５ｋＶ、照射電流が４４０ｐＡ、ワーキングディスタンスが１０ｍｍ、観察倍率が５００倍とした。観測の際、統計的変動を考慮し、１試料毎に２０
視野の画像をランダムに取得した。１視野の観察範囲は２５０μｍ×１７２μｍ、１視野の画素数は２５６０×１９２０および１画素あたりのサイズは０．１μｍ×０．１μｍとした。
前記反射電子像について、以下のように画像処理を行い、水和率を算出した。なお、画像処理は、市販の画像解析ソフト（製品名：ＮａｎｏＨｕｎｔｅｒＮＳ２Ｋ-Ｐｒｏ、ナノシステム社製）を用いて行った。
前記反射電子像の、ノイズは移動平均フィルタを利用してノイズ除去した。当該ノイズ除去した反射電子像について、未水和の水硬性粒子部分（グレイレベル１７６〜２５５）を抽出し、２値化画像を取得した。なお、水硬性粒子の内、セメント粒子として、Ｃ３Ｓ、Ｃ２Ｓ、Ｃ３ＡおよびＣ４ＡＦの主要セメント鉱物の粒子を採用した。
前記水硬性粒子部分の面積率を前記（Ａ）式に代入して、水硬性粒子の水和率を算出した。その結果、水硬性粒子の水和率は、材齢1日で２５％、材齢３日で３７％、材齢７日で４２％、材齢２８日で５０％、材齢９１日で５５％であった。
2. Calculation of hydration rate In accordance with JIS R 5201, cement paste of blast furnace cement type B (manufactured by Taiheiyo Cement Co., Ltd.) was kneaded, then placed in a mold and sealed and cured. The hardened blast furnace cement paste was manufactured on the 1st and 91st.
Next, the hardened blast furnace cement paste is cut into a size of 4 cm in length, 2 cm in width, and 1 cm in thickness using a diamond cutter, and the cut piece is placed in acetone for 0.5 hour in a vacuum environment using an aspirator. After soaking, it was D-dried to obtain a dried product.
The dried product is impregnated and cured with a room-temperature-curing low-viscosity epoxy resin (trade name: Specifix-20, manufactured by Marumoto Struers).
Polishing was performed using an abrasive (# 400, 800, 1000, 1200), alumina powder (3 μm, 1 μm, 0.5 μm) and kerosene. Next, carbon deposition was performed on the polished surface by a conventional method to prepare a sample.
In order to simulate a cement paste having a hydration rate of zero, a blast furnace cement-epoxy resin mixed hardened body in which the volume ratio of blast furnace cement was matched with that of the cement paste was prepared.
The surface of the cured body was also polished using a SiC abrasive (# 400, 800, 1000, 1200), alumina powder (3 μm, 1 μm, 0.5 μm) and kerosene as described above. Next, carbon deposition was performed on the polished surface by a conventional method.
The sample is placed on a scanning electron microscope (device name: JSM-7001F, manufactured by JEOL Ltd.) equipped with a backscattered electron detector so that the electron beam strikes the carbon deposition surface. Figure 3> was obtained. The observation conditions here were an acceleration voltage of 15 kV, an irradiation current of 440 pA, a working distance of 10 mm, and an observation magnification of 500 times. Considering statistical fluctuations during observation, 20 per sample
Random images of the field of view were acquired. The observation range for one field of view was 250 μm × 172 μm, the number of pixels for one field of view was 2560 × 1920, and the size per pixel was 0.1 μm × 0.1 μm.
The reflected electron image was subjected to image processing as follows to calculate the hydration rate. The image processing was performed using commercially available image analysis software (product name: NanoHunter NS2K-Pro, manufactured by Nanosystem).
Noise from the reflected electron image was removed using a moving average filter. From the reflected electron image from which noise was removed, unhydrated hydraulic particle portions (gray levels 176 to 255) were extracted to obtain a binarized image. Among the hydraulic particles, C 3 S, C 2 S, C 3 A and C 4 AF main cement mineral particles were used as cement particles.
The hydration rate of the hydraulic particles was calculated by substituting the area ratio of the hydraulic particle portion into the equation (A). As a result, the hydration rate of the hydraulic particles is 25% at the age of 1 day, 37% at the age of 3 days, 42% at the age of 7 days, 50% at the age of 28 days, and 55 at the age of 91 days. %Met.
３．圧縮強さと面積率との間の回帰式
前記セメントモルタルの圧縮強さと前記水硬性粒子の面積率とから、以下の回帰式を求めた。
Ｙ＝８０−５Ｘ３．４３３９
Ｙ；セメントモルタルの圧縮強さ（Ｎ／ｍｍ２）
Ｘ；水硬性粒子の面積率（％）
分散の値が０．９９７４となったことから、圧縮強さと面積率との相関は極めて高いことが分かる。
3. Regression formula between compressive strength and area ratio The following regression formula was determined from the compressive strength of the cement mortar and the area ratio of the hydraulic particles.
Y = 80-5X 3.4339
Y: Compressive strength of cement mortar (N / mm 2 )
X: Area ratio of hydraulic particles (%)
Since the dispersion value is 0.9974, it can be seen that the correlation between the compressive strength and the area ratio is extremely high.
Claims (3)
前記２つの試料の反射電子像から材齢ｔ日のセメントペースト硬化体における水硬性粒子の水和率を算出する水和率算出工程と、
セメントペースト硬化体における圧縮強さと水硬性粒子の水和率との相関を示す回帰式を予め求めておき、前記材齢ｔ日のセメントペースト硬化体における水硬性粒子の水和率を前記回帰式に代入することによって材齢ｔ日のセメントペースト硬化体における圧縮強さの推定値を算出する圧縮強さ推定工程と
からなり、且つ前記水硬性粒子が高炉スラグ粒子を含むことを特徴とするセメントモルタルの圧縮強さの推定方法。 A sample preparation step of polishing a surface of a cement paste cured body of age t and a cement paste cured body of zero hydration rate and depositing a conductive material to create a sample;
A hydration rate calculating step of calculating the hydration rate of the hydraulic particles in the cement paste cured body of age t from the reflected electron images of the two samples;
A regression equation showing a correlation between the compressive strength and the hydration rate of the hydraulic particles in the cement paste cured body is obtained in advance, and the hydration rate of the hydraulic particles in the cement paste cured body at the age of t is the regression equation. Ri Do and a compressive strength estimation step of calculating the estimated value of the compressive strength in the cement paste cured product of wood-old day t by substituting the, and the hydraulic particles comprising a blast furnace slag particles A method for estimating the compressive strength of cement mortar.
Ｒｔ＝{１−（Ｓｉ−Ｓｔ）／Ｓｉ}×１００
但し、Ｒｔ；材齢ｔ日のセメントペースト硬化体における水硬性粒子の水和率（％）
Ｓｉ；水和率ゼロのセメントペースト硬化体における未水和の水硬性粒子の面積率（％）
Ｓｔ；材齢ｔ日のセメントペースト硬化体における未水和の水硬性粒子の面積率（％） In the hydration rate calculating step, the area ratio of the unhydrated hydraulic particles obtained from the backscattered electron images of the two samples is substituted into the following formula, and the hydraulic particles in the cement paste cured body at the age of t The method for estimating the compressive strength of cement mortar according to claim 1, wherein the hydration rate of the cement mortar is calculated.
R t = {1- (S i −S t ) / S i } × 100
However, R t ; Hydration rate of hydraulic particles (%) in hardened cement paste of age t
S i ; Area ratio (%) of unhydrated hydraulic particles in the cement paste cured body having zero hydration rate
S t : Area ratio (%) of unhydrated hydraulic particles in the cement paste hardened material at age t
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