JP2011232280A - Method for estimating amount of fly ash in concrete - Google Patents

Method for estimating amount of fly ash in concrete Download PDF

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JP2011232280A
JP2011232280A JP2010105021A JP2010105021A JP2011232280A JP 2011232280 A JP2011232280 A JP 2011232280A JP 2010105021 A JP2010105021 A JP 2010105021A JP 2010105021 A JP2010105021 A JP 2010105021A JP 2011232280 A JP2011232280 A JP 2011232280A
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fly ash
amount
sample
concrete
liquid separation
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JP5698918B2 (en
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Akira Nishida
朗 西田
Toyoharu Nawa
豊春 名和
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Hokkaido University NUC
Shimizu Construction Co Ltd
Shimizu Corp
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Shimizu Construction Co Ltd
Shimizu Corp
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Abstract

PROBLEM TO BE SOLVED: To measure the amount of fly ash in fresh concrete into which fly ash is incorporated easily and in a short time.SOLUTION: Coarse aggregates collected to take out a sample are separated from fresh concrete into which fly ash is incorporated by wet screening (using a 0.5 mm sieve). Hydrochloric acid is added into a sample obtained by wet screening to dissolve cement and hydration products by a selective dissolution method, further followed by solid-liquid separation using centrifugal separation to separate cement and the hydration products. Fine aggregates having a low specific gravity are separated by heavy liquid separation using a sodium polytungstate solution (heavy liquid). The residual solid content is dried and weighed to estimate the fly ash amount (substitution rate) in the fresh concrete collected from the residual solid content.

Description

本発明はコンクリート中のフライアッシュ量の推定方法に係り、フライアッシュが混入されたフレッシュコンクリート中のフライアッシュ量を、短時間で簡易に測定することができるコンクリート中のフライアッシュ量の推定方法に関する。   The present invention relates to a method for estimating the amount of fly ash in concrete, and relates to a method for estimating the amount of fly ash in concrete that can easily and quickly measure the amount of fly ash in fresh concrete mixed with fly ash. .

フライアッシュはコンクリートの発熱制御、アルカリ骨材反応の抑制といった効果を持つ優れた混和材である。しかしながら、コンクリート製造時にフライアッシュ混入量を間違えば、所定強度の確保が難しく、また、セメントと置換して混入されたフライアッシュを目視判断するのも困難である。このため、フライアッシュを混入したコンクリートを取り扱う工事現場あるいはコンクリートプラントにおいて、フライアッシュがコンクリートに適正に混入(置換)されているか否かの確認を、簡易で精度良く行える品質管理方法が求められている。   Fly ash is an excellent admixture that has the effects of controlling the heat generation of concrete and suppressing alkali-aggregate reaction. However, if the amount of fly ash mixed at the time of concrete production is wrong, it is difficult to ensure a predetermined strength, and it is also difficult to visually determine the fly ash mixed by replacing cement. For this reason, there is a need for a quality control method that can easily and accurately check whether fly ash is properly mixed (replaced) in concrete at construction sites or concrete plants that handle concrete mixed with fly ash. Yes.

既往の試験方法として、土木学会規準に「混和材として用いたフライアッシュの置換率試験方法(案)」が制定されている(非特許文献1)。   As a past test method, “Method of testing replacement rate of fly ash used as admixture (draft)” has been established in the Japan Society of Civil Engineers (Non-Patent Document 1).

土木学会編,「混和材として用いたフライアッシュの置換率試験方法(案)(JSCE−D503−1999),土木学会規準,1999年,p.79〜82Edited by Japan Society of Civil Engineers, “Test method for substitution rate of fly ash used as admixture (draft) (JSCE-D503-1999), Japan Society of Civil Engineers, 1999, p. 79-82.

非特許文献1に開示された試験方法は、設備の整った試験室での試料分析を前提としており、1回の測定のために、試料の水和停止処理、3時間程度の炉乾燥等を行う必要がある。また、強熱減量のために電気炉を用いて750℃加熱を1時間程度行うことが規定されている。このように、試験に要する時間が5時間以上かかる上、試験に必要な設備を考慮すると、レディミクストコンクリート(生コン)プラントやコンクリート荷卸し地等の現場での試験実施は困難である。そのため、フライアッシュを混入したコンクリートを打設する前に、そのフレッシュコンクリートに含まれるフライアッシュ量が調合設計通りであることを確認する試験方法としては適さない。そこで、本発明の目的は上述した従来の技術が有する問題点を解消し、簡易な試験手順により、短時間でフライアッシュを混入したフレッシュコンクリートに含まれるフライアッシュ量を推定できる試験方法を提供することにある。   The test method disclosed in Non-Patent Document 1 is premised on sample analysis in a well-equipped test room. For one measurement, hydration stop processing of the sample, oven drying for about 3 hours, etc. are performed. There is a need to do. Further, it is specified that heating at 750 ° C. is performed for about 1 hour using an electric furnace in order to reduce ignition. In this way, the time required for the test takes 5 hours or more, and considering the equipment required for the test, it is difficult to carry out the test in the field such as a ready mixed concrete (green concrete) plant or a concrete unloading site. Therefore, before placing concrete mixed with fly ash, it is not suitable as a test method for confirming that the amount of fly ash contained in the fresh concrete is as designed. Accordingly, an object of the present invention is to provide a test method that solves the problems of the conventional techniques described above and can estimate the amount of fly ash contained in fresh concrete mixed with fly ash in a short time by a simple test procedure. There is.

上記目的を達成するために、本発明のコンクリート中のフライアッシュ量の推定方法は、試料を取り出すために採取された、フライアッシュが混入されたフレッシュコンクリートからウェットスクリーニングにより粗骨材分を分離し、選択溶解法によりセメントおよび水和生成物を分離し、さらに所定比重の重液を用いた重液分離により軽比重細骨材分を分離し、残留固形分を乾燥して秤量し、該残留固形分から前記採取されたフレッシュコンクリート中のフライアッシュ量を推定することを特徴とする。   In order to achieve the above object, according to the method for estimating the amount of fly ash in concrete according to the present invention, coarse aggregate content is separated by wet screening from fresh concrete mixed with fly ash, which is collected for taking out the sample. Then, the cement and hydrated product are separated by the selective dissolution method, the light specific gravity fine aggregate is further separated by heavy liquid separation using a heavy liquid having a predetermined specific gravity, the residual solid content is dried and weighed, and the residual The amount of fly ash in the collected fresh concrete is estimated from the solid content.

前記ウェットスクリーニングでは、0.5mmふるいを通過した懸濁水を吸引ろ過して固液分離し、加熱乾燥して試料を得るようにする。   In the wet screening, the suspension water that has passed through the 0.5 mm sieve is subjected to suction filtration, solid-liquid separation, and heat drying to obtain a sample.

前記選択溶解法では、前記ウェットスクリーニングにより得られた試料に塩酸を添加してセメントおよび水和生成物を溶解させ、さらに遠心分離により固液分離して、前記水和生成物を除去し、加熱乾燥して試料を得るようにする。   In the selective dissolution method, hydrochloric acid is added to the sample obtained by the wet screening to dissolve the cement and the hydrated product, followed by solid-liquid separation by centrifugation to remove the hydrated product and heating. Dry to get sample.

重液分離では、試料にポリタングステン酸ナトリウム溶液を添加し、固形分を沈殿させた液を吸引ろ過して固液分離し、加熱乾燥して前記残留固形分を得るようにする。   In the heavy liquid separation, a sodium polytungstate solution is added to a sample, and the liquid in which the solid content is precipitated is subjected to suction filtration, solid-liquid separation, and heat drying to obtain the residual solid content.

前記残留固形分に、前記選択溶解により溶解したフライアッシュ分と前記ポリタングステン酸ナトリウム溶液の比重より大きなフライアッシュ分とを含める補正を行って、フライアッシュ量を推定する。   The amount of fly ash is estimated by correcting the residual solid content to include the fly ash dissolved by the selective dissolution and the fly ash greater than the specific gravity of the sodium polytungstate solution.

以上の解決手段によれば、フライアッシュを混入したコンクリートを扱う工事現場あるいはコンクリートプラントにおいて、フレッシュコンクリート中のフライアッシュ量を、簡易で精度良く算出することができるという効果を奏する。   According to the above solution, the amount of fly ash in the fresh concrete can be easily and accurately calculated at a construction site or a concrete plant handling concrete mixed with fly ash.

本発明のコンクリート中のフライアッシュ量の推定方法による推定試験の作業手順を示したフローチャート。The flowchart which showed the work procedure of the estimation test by the estimation method of the amount of fly ash in the concrete of this invention. 図1の手順のうち、ウェットスクリーニングの手順を示したフローチャート。The flowchart which showed the procedure of the wet screening among the procedures of FIG. 図1の手順のうち、選択溶解作業の手順を示したフローチャート。The flowchart which showed the procedure of the selective melt | dissolution operation | work among the procedures of FIG. 図1の手順のうち、重液分離作業の手順を示したフローチャート。The flowchart which showed the procedure of the heavy liquid separation operation | movement among the procedures of FIG. フライアッシュ置換率の設定値と推定値との関係を示した相関グラフ。The correlation graph which showed the relationship between the setting value of a fly ash substitution rate, and an estimated value.

以下、本発明のコンクリート中のフライアッシュ量の推定方法の実施するための形態として、以下の実施例について添付図面を参照して説明する。   Hereinafter, the following examples will be described with reference to the accompanying drawings as modes for carrying out the method for estimating the fly ash amount in concrete according to the present invention.

本発明の推定方法のための試験(以下、推定試験と呼ぶ。)の大枠の手順は、図1に示したフローチャートの通りである。本発明の推定試験では、普通ポルトランドセメント(以下、記号としてはCと略記する。)の一部をフライアッシュ(以下、記号としてはFAと略記する。)で置換したフライアッシュコンクリートのフレッシュコンクリート内に混入されたフライアッシュ量を求める。   A general procedure of a test for the estimation method of the present invention (hereinafter referred to as an estimation test) is as shown in the flowchart of FIG. In the estimation test of the present invention, the inside of fresh concrete of fly ash concrete in which part of ordinary Portland cement (hereinafter abbreviated as C) was replaced with fly ash (hereinafter abbreviated as FA). The amount of fly ash mixed in is obtained.

まず、推定試験の対象となる、所定量のフレッシュコンクリート(30リットル程度)から、ウェットスクリーニングにより(S100)モルタルを30〜50g程度採取する。そのウェットスクリーニング工程によってふるいを通過した懸濁水を吸引ろ過で固液分離し、残留固形分を加熱乾燥させ、所定粒径以下の固形微粒分(セメント、フライアッシュ、微粒砂)を回収する(S200,S300)。固形微粒分からなる試料に対して所定割合で塩酸を添加して加熱し、セメント成分を溶解させ、不溶残分を回収するために吸引ろ過で固液分離した後に、加熱乾燥させる選択溶解を行う(S400)。次いで、重液としてポリタングステン酸ナトリウム溶液(以下、SPT溶液と記す。)を用いてフライアッシュのみを分離する重液分離を行う(S500)。その後、試料を加熱乾燥し、秤量する(S700)。その後、フライアッシュの回収率を考慮した補正を行いFA量を計算する(S800)。この推定試験によれば、設定したフライアッシュ混入量に対して+5〜−5%内の誤差でフライアッシュ置換率の推定が可能であることが確認された。また、試験に要した時間は1.5時間/回程度であり、現場において簡易的にフライアッシュ量を推定できる。   First, about 30 to 50 g of mortar is collected from a predetermined amount of fresh concrete (about 30 liters) to be subjected to an estimation test by wet screening (S100). The suspension water that has passed through the sieve in the wet screening step is subjected to solid-liquid separation by suction filtration, and the residual solid content is heated and dried to collect solid fine particles (cement, fly ash, fine sand) having a predetermined particle size or less (S200). , S300). Hydrochloric acid is added to a sample consisting of solid fine particles at a predetermined rate and heated to dissolve the cement component, and after solid-liquid separation by suction filtration to recover insoluble residue, selective dissolution is performed by heating and drying ( S400). Next, heavy liquid separation is performed to separate only fly ash using a sodium polytungstate solution (hereinafter referred to as an SPT solution) as a heavy liquid (S500). Thereafter, the sample is dried by heating and weighed (S700). Thereafter, correction is performed in consideration of the fly ash recovery rate, and the FA amount is calculated (S800). According to this estimation test, it was confirmed that the fly ash replacement rate can be estimated with an error within +5 to -5% with respect to the set fly ash mixing amount. Further, the time required for the test is about 1.5 hours / time, and the fly ash amount can be easily estimated at the site.

以下、推定試験の詳細な作業手順について、フローチャート(図1〜図4)を参照して説明する。
[コンクリート採取〜ウェットスクリーニング]
コンクリートの採取は、試験可能な採取地において、JIS A 1115(フレッシュコンクリートの採取方法)に従って行う。コンクリートプラントの場合は、練り上がりコンクリート排出口で、レディミクストコンクリートの場合にはコンクリート荷卸し地点等で試験に必要な分量を採取する(図1,S100)。その後、ウェットスクリーニングを行い、試験対象となる試料を採取する(図2,S200)。ウェットスクリーニングでは、0.5mm目合いのふるいを用い、試料を水道水で洗いながらふるい分ける。0.5mmふるいを通過した微粒分と洗浄に用いた水の懸濁水をステンレスボウル等の容器に受けて回収する(S210,220)。この懸濁水を、定量ろ紙をろ過材として用いた吸引ろ過装置によって吸引ろ過し、定量ろ紙上に試料を回収する。このとき、懸濁水を撹拌させながら吸引ロートへ導き、吸引ロートの壁面に付着した試料も回収するようにする(S230)。次いで、このろ紙上の試料を乾燥するために、ろ紙ごと電子レンジで5〜10分程度加熱乾燥する(図1,S300)。
[選択溶解]
Hereinafter, a detailed work procedure of the estimation test will be described with reference to flowcharts (FIGS. 1 to 4).
[Concrete sampling-wet screening]
The concrete is collected according to JIS A 1115 (Fresh Concrete Collection Method) at a testable sampling site. In the case of a concrete plant, an amount necessary for the test is collected at a kneaded concrete discharge port, and in the case of ready-mixed concrete, at a concrete unloading point or the like (FIG. 1, S100). Thereafter, wet screening is performed, and a sample to be tested is collected (FIG. 2, S200). In wet screening, a 0.5 mm sieve is used, and the sample is screened while washing with tap water. The fine particles having passed through the 0.5 mm sieve and the suspended water used for washing are received in a container such as a stainless bowl and collected (S210, 220). The suspension water is suction filtered by a suction filtration device using a quantitative filter paper as a filter medium, and a sample is collected on the quantitative filter paper. At this time, the suspension water is guided to the suction funnel while being stirred, and the sample adhering to the wall surface of the suction funnel is also collected (S230). Next, in order to dry the sample on the filter paper, the filter paper is heated and dried in a microwave oven for about 5 to 10 minutes (FIG. 1, S300).
[Selective dissolution]

このときの試料にはフライアッシュに加え、セメント分が含有しているため、フライアッシュの回収率を高めるために、セメント分を溶解除去する。そのための選択溶解の手順について、図3を参照して説明する。
(S300)で回収した乾燥試料を、約1gずつに分けて複数本の遠沈管(50ml容量)に小分けする(S410)。このとき、回収した試料全体を電子天秤上に置き、そこから1gずつ採取し、遠沈管に入れるようにすると効率が良い。この方法ですべての試料を複数本数の遠沈管へ移す。次いで、試料の入った遠沈管1本につき塩酸(2N)を約30ml加えて撹拌した後、遠沈管をウォーターバスにセットする(S420,430)。ウォーターバスは、120回/分で振とうさせながら60℃で15分加熱する(S440)。加熱終了後、遠沈管を遠心分離機にセットし、4000rpmで1分間遠心分離し、壁面に付着した微粒子を管内に残すように上澄み水を捨てる。その後、試料に洗浄用蒸留水を加え、上記と同条件で遠心分離を行い、上澄みを捨てる作業を3回繰り返す(S450,460)。その後、試料の水分を完全除去した乾燥試料とするため、遠沈管ごと電子レンジで加熱する(S470)。なお、乾燥した試料は次の手順である重液分離が正しく行えるように、粉砕しておくことが好ましい(S480)。
Since the sample at this time contains cement in addition to fly ash, the cement is dissolved and removed in order to increase the recovery rate of fly ash. The selective dissolution procedure for this will be described with reference to FIG.
The dried sample collected in (S300) is divided into approximately 1 g portions and subdivided into a plurality of centrifuge tubes (50 ml capacity) (S410). At this time, it is efficient to place the entire collected sample on an electronic balance, collect 1 g each from it, and place it in a centrifuge tube. In this way, all samples are transferred to multiple centrifuge tubes. Next, after adding about 30 ml of hydrochloric acid (2N) to each centrifuge tube containing the sample and stirring, the centrifuge tube is set in a water bath (S420, 430). The water bath is heated at 60 ° C. for 15 minutes while shaking at 120 times / minute (S440). After completion of heating, the centrifuge tube is set in a centrifuge and centrifuged at 4000 rpm for 1 minute, and the supernatant water is discarded so that the fine particles adhering to the wall surface remain in the tube. Thereafter, the operation of adding distilled water for washing to the sample, centrifuging under the same conditions as above, and discarding the supernatant is repeated three times (S450, 460). Thereafter, in order to obtain a dry sample from which the moisture in the sample has been completely removed, the centrifuge tube is heated in a microwave oven (S470). In addition, it is preferable to grind the dried sample so that the heavy liquid separation which is the next procedure can be performed correctly (S480).

なお、この作業は、遠沈管、ウォーターバス、遠心分離器を用いずに、全試料をビーカーに入れ、試料1gに対して2N塩酸を30gの割合で加えて、ホットスターラーを用いて加熱してもよい。加熱後は懸濁水を定量ろ紙を用いて吸引ろ過して微粒分を回収し、ろ紙ごと電子レンジで加熱する。乾燥した試料を別のビーカーに移すようにしてもよい。
[重液分離]
In this work, all samples were put into a beaker without using a centrifuge tube, a water bath, and a centrifuge, 2N hydrochloric acid was added at a rate of 30 g to 1 g of the sample, and heated using a hot stirrer. Also good. After heating, the suspension water is suction filtered using a quantitative filter paper to collect fine particles, and the whole filter paper is heated in a microwave oven. The dried sample may be transferred to another beaker.
[Heavy liquid separation]

次に、重液としてポリタングステン酸ナトリウム溶液(SPT溶液)を用いてフライアッシュのみを分離する重液分離の手順について、図4を参照して説明する。重液分離用のSPT溶液として、あらかじめ蒸留水を用いて比重2.50の溶液して調製しておく。乾燥した試料が入った遠沈管に、約20ml/本のSPT溶液を添加して撹拌した後、静置する(S510,520)。その後、遠沈管内の浮遊物及び上澄みを吸引ろ過によって回収する(S530)。このとき、遠沈管を少し傾けた状態で回転させて液面上部の壁面に付着している試料も回収する。吸引ろ過後、SPT溶液が吸引ビン内に溜まるため、一旦ポンプを停止し、別容器に回収することが好ましい。ろ紙上の試料を洗浄するために、吸引ろ過を行いながら蒸留水で3回程度洗浄する(S540)。洗浄された回収試料を電子レンジで加熱する(図1,S600)。さらに、加熱終了後試料質量を秤量する(S700)。この秤量結果とフライアッシュの回収率の補正値を用いて最終的に、FA置換率、FA量を算出する(S800)。FA量の算出に当たっては、使用されているフライアッシュの銘柄や塩酸による溶解分、重液分離における沈殿分を考慮してフライアッシュの回収率の補正係数を設定しておくことが好ましい。   Next, a heavy liquid separation procedure for separating only fly ash using a sodium polytungstate solution (SPT solution) as a heavy liquid will be described with reference to FIG. As an SPT solution for heavy liquid separation, a solution having a specific gravity of 2.50 is prepared in advance using distilled water. About 20 ml / tube of the SPT solution is added to the centrifuge tube containing the dried sample and stirred, and then allowed to stand (S510, 520). Thereafter, the suspended matter and supernatant in the centrifuge tube are collected by suction filtration (S530). At this time, the centrifuge tube is rotated in a slightly inclined state, and the sample adhering to the wall surface above the liquid level is also collected. Since the SPT solution accumulates in the suction bottle after the suction filtration, it is preferable to stop the pump once and collect it in a separate container. In order to wash the sample on the filter paper, it is washed about 3 times with distilled water while performing suction filtration (S540). The washed recovered sample is heated in a microwave oven (FIG. 1, S600). Further, after the heating, the sample mass is weighed (S700). Finally, the FA replacement rate and the FA amount are calculated using the weighing result and the correction value of the fly ash recovery rate (S800). In calculating the amount of FA, it is preferable to set a correction coefficient for the recovery rate of fly ash in consideration of the brand of fly ash used, the dissolved content of hydrochloric acid, and the precipitated content in heavy liquid separation.

補正係数としては、既存データを参考にして設定することができるが、具体的は、あらかじめ選択溶解で塩酸で溶解してしまうフライアッシュ分、比重2.5以上のフライアッシュ分の割合をキャリブレーションにより求めておくことにより、より正確な補正係数を設定してフライアッシュの回収率を求めることができ、これにより正確なFA置換率、すなわちFA量の正確な推定を行うことができる。
[試験例]
The correction factor can be set with reference to existing data. Specifically, the ratio of fly ash that is dissolved in hydrochloric acid by selective dissolution in advance and the fraction of fly ash with a specific gravity of 2.5 or more are calibrated. Thus, it is possible to set a more accurate correction coefficient and obtain the fly ash recovery rate, thereby making it possible to accurately estimate the FA replacement rate, that is, the FA amount.
[Test example]

以下に、本発明のコンクリート中のフライアッシュ量の推定方法を用いてフライアッシュの置換率を求めた試験例(フライアッシュ量推定試験)について、表1〜表3を参照して説明する。   Below, the test example (fly ash amount estimation test) which calculated | required the substitution rate of the fly ash using the estimation method of the fly ash amount in the concrete of this invention is demonstrated with reference to Table 1-Table 3. FIG.

あらかじめ2種類のFA置換率(ケースNo.1:30%,ケースNo.2:15%)に設定されたコンクリートの調合内容を表1に示す。さらにこのコンクリート調合に基づいて製造したコンクリートの性状試験結果を表2に示す。   Table 1 shows the concrete mixing contents set in advance for two types of FA replacement ratios (Case No. 1: 30%, Case No. 2: 15%). Furthermore, the property test result of the concrete manufactured based on this concrete mixture is shown in Table 2.

[表1]

Figure 2011232280
[表2]
Figure 2011232280
[Table 1]
Figure 2011232280
[Table 2]
Figure 2011232280

さらに、回収された微粒分から回収されたFA量に対する補正計算を以下のように行い、置換率(FA置換率)を算出した。
[結合材率(Bp)、結合材量(Ba)の算出]
表1のコンクリート調合条件から、結合材率(Bp)を算出する。
Bp=Bwt×100/(Wwt+Bwt+Swt)=29.26(%) …(式1)
ここで、Wwt:単位水量(kg/cm3),Bwt:単位結合材量(kg/cm3),
Swt:単位細骨材量(kg/cm3
さらに、式1で求めた結合材率(Bp)と回収モルタル量との関係から結合材量(Ba)
を算出する。すなわち、
Ba=a×Bp/100 …(式2)
a:回収したモルタル量(g),Bp:結合材率(%)
[補正FA量(b')の算出]
推定試験を行っては、使用したフライアッシュが塩酸で溶解した量および重液分離で沈殿した量をキャリブレーションにより求めておくことが好ましいが、発明者の既往試験結果をもとに、今回の推定試験ではフライアッシュ回収率を80%として補正FA量の算出を行った。
b’=b/0.8 …(式3)
ここで、b:推定試験で得られた回収FA量(g)
以上の計算より、FA置換率(Af)は、式2,式3から
Af=b’×100/Ba
Further, correction calculation for the amount of FA recovered from the recovered fine particles was performed as follows to calculate the replacement rate (FA replacement rate).
[Calculation of Binder Ratio (Bp) and Binder Amount (Ba)]
From the concrete blending conditions in Table 1, the binder ratio (Bp) is calculated.
Bp = Bwt × 100 / (Wwt + Bwt + Swt) = 29.26 (%) (Formula 1)
Where, Wwt: unit water amount (kg / cm 3 ), Bwt: unit binder amount (kg / cm 3 ),
Swt: Unit fine aggregate amount (kg / cm 3 )
Furthermore, the amount of the binder (Ba) is calculated from the relationship between the binder ratio (Bp) obtained by Equation 1 and the recovered mortar amount.
Is calculated. That is,
Ba = a × Bp / 100 (Formula 2)
a: recovered mortar amount (g), Bp: binder ratio (%)
[Calculation of corrected FA amount (b ')]
It is preferable to carry out an estimation test to determine the amount of fly ash used dissolved in hydrochloric acid and the amount precipitated by heavy liquid separation by calibration.However, based on the results of previous tests by the inventors, In the estimation test, the corrected FA amount was calculated with a fly ash recovery rate of 80%.
b ′ = b / 0.8 (Formula 3)
Here, b: recovered FA amount obtained in the estimation test (g)
From the above calculation, the FA substitution rate (Af) is calculated from the following formulas (2) and (3): Af = b ′ × 100 / Ba

この推定試験結果および補正計算結果を表3及び図5に示す。図5に示したように、この推定試験結果では、推定誤差が+5〜−5%の範囲内での推定が可能であることが確認できた。   The estimation test result and the correction calculation result are shown in Table 3 and FIG. As shown in FIG. 5, in this estimation test result, it was confirmed that the estimation error can be estimated within the range of +5 to -5%.

[表3]

Figure 2011232280
[Table 3]
Figure 2011232280

なお、本発明は上述した実施例に限定されるものではなく、各請求項に示した範囲内での種々の変更が可能である。すなわち、請求項に示した範囲内で適宜変更した技術的手段を組み合わせて得られる実施形態も、本発明の技術的範囲に含まれる。   In addition, this invention is not limited to the Example mentioned above, A various change within the range shown to each claim is possible. In other words, embodiments obtained by combining technical means appropriately changed within the scope of the claims are also included in the technical scope of the present invention.

Claims (5)

試料を取り出すために採取された、フライアッシュが混入されたフレッシュコンクリートからウェットスクリーニングにより粗骨材分を分離し、選択溶解法によりセメントおよび水和生成物を分離し、さらに所定比重の重液を用いた重液分離により軽比重細骨材分を分離し、残留固形分を乾燥して秤量し、該残留固形分から前記採取されたフレッシュコンクリート中のフライアッシュ量を推定することを特徴とするコンクリート中のフライアッシュ量の推定方法。   Coarse aggregates are separated by wet screening from fresh concrete mixed with fly ash collected for sample removal, cement and hydrated products are separated by selective dissolution method, and heavy liquid with a specific gravity is added. A concrete characterized in that a light specific gravity fine aggregate is separated by heavy liquid separation used, a residual solid content is dried and weighed, and a fly ash amount in the collected fresh concrete is estimated from the residual solid content. Method for estimating the amount of fly ash in the inside. 前記ウェットスクリーニングでは、0.5mmふるいを通過した懸濁水を吸引ろ過して固液分離し、加熱乾燥して試料を得ることを特徴とする請求項1に記載のコンクリート中のフライアッシュ量の推定方法。   The estimation of fly ash content in concrete according to claim 1, wherein in the wet screening, the suspension water that has passed through the 0.5 mm sieve is subjected to suction filtration, solid-liquid separation, and heat drying to obtain a sample. Method. 前記選択溶解法では、前記ウェットスクリーニングにより得られた試料に塩酸を添加してセメントおよび水和生成物を溶解させ、さらに遠心分離により固液分離して、前記水和生成物を除去し、加熱乾燥して試料を得ることを特徴とする請求項1に記載のコンクリート中のフライアッシュ量の推定方法。   In the selective dissolution method, hydrochloric acid is added to the sample obtained by the wet screening to dissolve the cement and the hydrated product, followed by solid-liquid separation by centrifugation to remove the hydrated product and heating. The method for estimating the amount of fly ash in concrete according to claim 1, wherein the sample is obtained by drying. 重液分離では、試料にポリタングステン酸ナトリウム溶液を添加し、固形分を沈殿させた液を吸引ろ過して固液分離し、加熱乾燥して前記残留固形分を得ることを特徴とする請求項1に記載のコンクリート中のフライアッシュ量の推定方法。   The heavy liquid separation is characterized in that a sodium polytungstate solution is added to a sample, a liquid in which a solid content is precipitated is subjected to suction filtration to perform solid-liquid separation, and heat drying to obtain the residual solid content. The method for estimating the amount of fly ash in concrete according to 1. 前記残留固形分に、前記選択溶解により溶解したフライアッシュ分と前記ポリタングステン酸ナトリウム溶液の比重より大きなフライアッシュ分とを含める補正を行って、フライアッシュ量を推定することを特徴とする請求項1に記載のコンクリート中のフライアッシュ量の推定方法。   The amount of fly ash is estimated by performing correction to include the fly ash dissolved by the selective dissolution and the fly ash larger than the specific gravity of the sodium polytungstate solution in the residual solid content. The method for estimating the amount of fly ash in concrete according to 1.
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