JP2014006183A - Quality control method for admixture of dredged soil and steelmaking slag - Google Patents
Quality control method for admixture of dredged soil and steelmaking slag Download PDFInfo
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本発明は、浚渫土と製鋼スラグとを混合し、強度改質を行って土木資材として使用する際の、品質管理方法に関する。 The present invention relates to a quality control method when mixing clay and steelmaking slag, performing strength modification and using it as a civil engineering material.
一般に、浚渫土に製鋼スラグを混合した混合物（以下浚渫土・製鋼スラグ混合材と記す）は、強度発現する特性があり、浅場・干潟の造成材や埋立材としての利用が行われている（例えば特許文献１）。 In general, a mixture of steelmaking slag mixed with dredged soil (hereinafter referred to as dredged material / steelmaking slag mixed material) has the property of developing strength, and is used as a construction material or landfill material for shallow and tidal flats ( For example, Patent Document 1).
この浚渫土・製鋼スラグ混合材を、建設資材として使用する場合においては、改良目標値を一軸圧縮強さで３０〜３００ｋＮ／ｍ２、あるいはコーン指数で第３種改良土の４００ｋＮ／ ｍ２以上とする場合が多い。 When using this clay / steel slag mixed material as a construction material, the improvement target value is 30 to 300 kN / m 2 in terms of uniaxial compressive strength, or 400 kN / m 2 or more of the third type improved soil in terms of cone index. In many cases.
また、浚渫土・製鋼スラグ混合材の発現強度は、粒度分布、含水比等の浚渫土の性状によっても異なるが、一般に浚渫土に対して製鋼スラグが１０〜３０ｖｏｌ％含まれている必要がある。 Moreover, although the expression strength of the clay-steel slag mixed material varies depending on the properties of the clay, such as the particle size distribution and the water content ratio, it is generally necessary that the steelmaking slag is contained in an amount of 10-30 vol% with respect to the clay. .
一方、浚渫土・製鋼スラグ混合材における製鋼スラグの粒径が強度発現に大きく影響を及ぼすことも知られており、全粒径が７５μｍ以上である場合と、７５μｍ以下である場合とでは、一軸圧縮強さが大きく異なる実験例が知られている（非特許文献１） On the other hand, it is also known that the particle size of steelmaking slag in the clay and steelmaking slag mixed material has a great influence on the strength development, and it is uniaxial when the total particle size is 75 μm or more and 75 μm or less. An experimental example in which the compressive strength is greatly different is known (Non-patent Document 1).
浚渫土と製鋼スラグの混合材の品質管理方法としては、製鋼スラグの比重が３程度と浚渫土よりも大きいことを利用し、配合試験あるいは配合条件から計算で求めた混合材の湿潤密度との比較から製鋼スラグの混合状況を確認する方法がある（例えば非特許文献２）。 As a quality control method for the mixed material of dredged material and steelmaking slag, the specific gravity of steelmaking slag is about 3 and larger than the dredged material. There is a method of confirming the mixing state of steelmaking slag from comparison (for example, Non-Patent Document 2).
また、浚渫土・製鋼スラグ混合材の一軸圧縮強さについて、材令７日の強度から２８日強度を予測する手法が用いられる場合があるが、養生期間が７日間必要であり、現場での品質管理への適用は困難である。 In addition, for the uniaxial compressive strength of the clay and steelmaking slag mixed material, there is a case where a method of predicting the 28-day strength from the strength of the material age 7 days is used, but the curing period is required for 7 days. Application to quality control is difficult.
このような浚渫土・製鋼スラグ混合材を使用した建設土木工事においては、事前の配合試験等により、浚渫土に対する製鋼スラグの添加量を決定するが、実際の施工では製鋼スラグの添加量が不十分な場合、製鋼スラグの含有量にばらつきがある場合等、目標強度が得られない場合がある。 In civil engineering works using such a mixture of dredged soil and steelmaking slag, the amount of steelmaking slag added to the dredged material is determined by preliminary blending tests, etc. If sufficient, the target strength may not be obtained, for example, when the content of steelmaking slag varies.
即ち、浚渫土に製鋼スラグを添加する場合において、連続式添加の場合には、ベルトコンベア等で定量切り出しする等の方法を採るが、その設定にズレが生じたりする場合があり、このため、事前の配合試験においては製鋼スラグの配合を２５％とした場合でも、実際には２０％だったり、２７％だったりとバラつきが生じることがあり、その場合には、実施工が、事前配合試験による所定の強度に達しない場合が生じるという問題がある。 That is, when steelmaking slag is added to the clay, in the case of continuous addition, a method such as quantitative cutting with a belt conveyor or the like is adopted, but there may be a deviation in the setting. Even if the steelmaking slag compounding is 25% in the pre-mixing test, it may actually vary as 20% or 27%. There is a problem that a predetermined strength due to may not be reached.
また、製鋼スラグの化学成分は、ＣａＯ・ＳｉＯ２・ＦｅＯ等で、浚渫土の添加によって固まる性質を有しており、その硬化の程度は、ＣａＯの含有量によって異なり、同じ量の製鋼スラグを混合したとしても、ＣａＯの含有量や、粒径が異なることによって硬化の程度が異なり、一般には粒径２５ｍｍ以下の製鋼スラグを用いることが多いが、添加量が同じ２５％であっても、細粒分が多かったり、粗粒分が多いなどのバラつきが生じる可能性があり、細粒分が多い場所で強度が発現しやすく、粗粒が多い場所は強度が発現しにくくなり、事前の配合試験と同等の強度に達しない場合が生じるという問題がある。 In addition, the chemical component of steelmaking slag is CaO · SiO 2 · FeO, etc., which has the property of solidifying with the addition of clay, the degree of hardening depends on the content of CaO, and the same amount of steelmaking slag is used. Even if mixed, the degree of hardening differs depending on the content of CaO and the particle size, and generally steelmaking slag having a particle size of 25 mm or less is often used, but even if the addition amount is the same 25%, There is a possibility that variations such as a large amount of fine particles or a large amount of coarse particles may occur, and strength is likely to develop in places where there are many fine particles, and strength is difficult to develop in places where there are many coarse particles. There is a problem that it may not reach the same strength as the compounding test.
更に混練状態においても、事前の配合試験においては、小型のミキサーで均一に混練するが、実施工で規模が大きくなった場合の混練には、管中混合方式、バージ内混合方式（バックホウ混合方式）、連続式ミキサー方式などがある。 Furthermore, even in the kneaded state, in a previous compounding test, the mixture is uniformly kneaded with a small mixer. ), Continuous mixer system.
管中混合方式は、空気圧送用のホッパー内に、製鋼スラグと浚渫土を所望の割合で投入し、該ホッパーの下端から混合物を送泥管内に送り出し、これをプラグ流として空気圧送するものであり、送泥管中内の空気圧送中に管壁との摩擦抵抗によって浚渫土と製鋼スラグが混合されるようにし、送泥管の排出口からは、高速でプラグ流が噴射されるため、サイクロンにて流速を減衰するとともに搬送用の空気を分離し、サイクロン下より混合材を自然流下速度で排出させている。 In-pipe mixing method, steelmaking slag and clay are put in a desired ratio into a pneumatic feed hopper, the mixture is fed into the mud feed pipe from the lower end of the hopper, and this is pneumatically fed as a plug flow. Yes, so that the clay and steelmaking slag are mixed by frictional resistance with the pipe wall during pneumatic feeding in the mud pipe, and the plug flow is injected at high speed from the outlet of the mud pipe, The cyclone attenuates the flow velocity and separates the air for transportation, and discharges the mixed material from the cyclone at a natural flow rate.
バックホウ混合方式は、バージ内の浚渫土に製鋼スラグを投入し、これをバックホウによって混合させるものであり、連続式ミキサー方式は、ホッパー内にベルトコンベア等によって浚渫土と製鋼スラグとを、ホッパー下端の連続式ミキサーによって混合しつつ連続して送り出すものである。 In the backhoe mixing method, steelmaking slag is poured into the clay in the barge and mixed with the backhoe. The continuous mixer is used for continuous feeding while mixing.
特に、バックホウ等を用いたバージ内混合方式は、装置が簡単であり、使用中の損耗も他に比べて少ないため、コスト的に有利であるが、混練時間の長短によって均質混合の程度が異なり、またバージの四隅や底部に混合が不十分な場所ができる可能性があり均質な混合がなされない部分が生じ、強度の発現も位置によってばらつきが生じるという問題がある。 In particular, the in-barge mixing method using a backhoe or the like is advantageous in terms of cost because the apparatus is simple and wear during use is less than others, but the degree of homogeneous mixing varies depending on the length of the kneading time. In addition, there may be places where the mixing is insufficient at the four corners and the bottom of the barge, and there is a portion where homogeneous mixing is not performed, and there is a problem that the strength expression varies depending on the position.
この他、上述した従来の浚渫土・製鋼スラグ混合材の品質管理として測定される湿潤密度から、発現強度を予測する方法も考えられるが、湿潤密度のばらつきが大きく強度との相関は必ずしも高くないという問題がある。 In addition, a method of predicting the expression strength from the wet density measured as the quality control of the conventional clay-steel slag mixed material described above may be considered, but the variation in the wet density is large and the correlation with the strength is not necessarily high. There is a problem.
更に、上述した浚渫土・製鋼スラグ混合材の一軸圧縮強さについて、材令７日の強度から２８日強度を予測するでは、養生期間が７日間必要であり、結果が得られるのが７日後であるため、現場の品質管理として使用することは難しい。 Furthermore, with regard to the uniaxial compressive strength of the above-mentioned clay-steel slag mixed material, if the 28-day strength is predicted from the strength of the material age 7 days, a curing period of 7 days is required, and the result is obtained after 7 days. Therefore, it is difficult to use it as on-site quality control.
本発明は、このような従来の問題に鑑み、浚渫土・製鋼スラグ混合材の品質管理として、浚渫土・製鋼スラグ混合材中に含まれている製鋼スラグの量が所定の強度発現に必要な量であるか否かを迅速に判断し、浚渫土に対して適切に製鋼スラグが混合され、目標強度の発現状況を予測することができる浚渫土・製鋼スラグ混合材の品質管理方法の提供を目的としてなされたものである。 In view of such a conventional problem, the present invention, as a quality control of the clay and steelmaking slag mixed material, the amount of steelmaking slag contained in the clay and steelmaking slag mixed material is necessary for the predetermined strength expression. Providing a quality control method for dredged / steel slag mixed materials that can quickly determine whether the amount is sufficient, and steelmaking slag is appropriately mixed with the dredged soil, and the target strength can be predicted. It was made as a purpose.
請求項１に記載の本発明の特徴は、予め定められた浚渫土と製鋼スラグとの配合条件に従って混合された浚渫土・製鋼スラグ混合材から採取した試料中から蛍光X線分析によりカルシウム含有量を測定する工程、前記測定によるカルシウム含有量の測定値を、予め求めておいた浚渫土・製鋼スラグ混合材のカルシウム含有量と一軸圧縮強さ等の強度との相関に照らし合わせて強度発現を予測する工程、前記強度発現の予測値が目標強度を達成しているか否かの判定工程、該判定工程にて予測値が目標強度に達成していた場合に、供試体を作成し、これを高温養生する工程、前記高温養生による短期強度から将来の発現強度を予測する工程、前記将来の発現強度の予測値が目標強度に達成しているか否かを判定する工程、以上の工程を経ることを特徴としてなる浚渫土・製鋼スラグ混合材の品質管理方法にある。 The feature of the present invention as set forth in claim 1 is that the calcium content is determined by fluorescent X-ray analysis from a sample taken from a mixture of clay and steelmaking slag mixed according to a predetermined mixing condition of clay and steelmaking slag. The measurement of the calcium content by the above-mentioned measurement, the strength expression in the light of the correlation between the calcium content of the clay and steelmaking slag mixed material obtained in advance and the strength such as uniaxial compressive strength A step of predicting, a step of determining whether or not the predicted value of the intensity expression has achieved the target strength, and when the predicted value has reached the target strength in the determination step, create a test specimen, Steps of high-temperature curing, step of predicting future expression intensity from short-term strength due to high-temperature curing, step of determining whether or not the predicted value of future expression intensity has achieved the target intensity, and passing through the above steps. The It is in the quality control method of mixed clay and steelmaking slag as a feature.
本発明においては、予め定められた浚渫土と製鋼スラグとの配合条件に従って混合された浚渫土・製鋼スラグ混合材から採取した試料中から蛍光X線分析によりカルシウム含有量を測定する工程、前記測定によるカルシウム含有量の測定値を、予め求めておいた浚渫土・製鋼スラグ混合材のカルシウム含有量と一軸圧縮強さ等の強度との相関に照らし合わせて強度発現を予測する工程、前記強度発現の予測値が目標強度を達成しているか否かの判定工程、該判定工程にて予測値が目標強度に達成していた場合に、供試体を作成し、これを高温養生する工程、前記高温養生による短期強度から将来の発現強度を予測する工程を経ることによって、短期間での混練性の判定、発現強度の予測が可能であり、適切な品質管理が可能である。 In the present invention, the step of measuring the calcium content by fluorescent X-ray analysis from a sample collected from a mixed material of the clay and steelmaking slag mixed according to the predetermined mixing conditions of the clay and steelmaking slag, the measurement A step of predicting the strength expression in light of the correlation between the calcium content of the kneaded clay and steelmaking slag mixture obtained in advance and the strength such as uniaxial compressive strength, and the like. Step of determining whether or not the predicted value of the target value has achieved the target strength, and when the predicted value has reached the target strength in the determination step, a step of creating a specimen and curing it at a high temperature, the high temperature By passing through the process of predicting the future expression strength from the short-term strength due to curing, it is possible to determine kneadability in a short period of time and to predict the expression strength, and appropriate quality control is possible.
また、浚渫土・製鋼スラグ混合材は、浚渫土の性状（細粒分含有率、液性限界等）や添加混合されている製鋼スラグの粒度分布やカルシウム含量の違いによって、発現強度が大きく異なり、事前に浚渫土の土質試験を行っていても浚渫の途中で浚渫土の性状が変化することもあるが、こうした場合でも適切な品質管理が可能である。 In addition, the mixing strength of dredged material and steelmaking slag varies greatly depending on the properties of the dredged material (fine grain content, liquid limit, etc.) and the particle size distribution and calcium content of the steelmaking slag added and mixed. Even if the soil quality test of the dredged soil is conducted in advance, the characteristics of the dredged soil may change during the dredging, but even in such a case, appropriate quality control is possible.
本発明に係る品質管理方法の手順を図１に示す。
ａ．配合条件設定
まず、浚渫土含水比、製鋼スラグ添加量を変化させた配合試験を実施し、所定の強度が得られる配合条件を決定する。
The procedure of the quality control method according to the present invention is shown in FIG.
a. Blending condition setting First, a blending test in which the moisture content of the clay and the steelmaking slag addition amount are changed is carried out, and the blending condition for obtaining a predetermined strength is determined.
この配合条件設定は、使用を予定している浚渫土の含水率、及び製鋼スラグの粒度分布や組成に基づいて、これらを混合することによって所望の強度が得られると思われる混合率を想定し、混合率及び全体の含水率、フロー値を変化させた数種類の浚渫土・製鋼スラグ混合材配合例を作成し、それらについてそれぞれについて複数種類の試験練を行い、養生固化させた試験体を作成し、それらの強度を測定し、実施工に必要な強度範囲にあるものを選択することによって、実施工のための配合条件設定を行う。この例では必要な強度範囲を３０kN/m2以上とし、これに該当する配合例は表1の如く、製鋼スラグ２５Ｖｏｌ％に対し、浚渫土＋加水分が７５％であった。
表１
この際、強度を測定した試料についてCa含有量を測定し、カルシウム含有量と強度の相関を確認する（図2）
ｂ．浚渫土と製鋼スラグの混合
This blending condition setting is based on the moisture content of the clay that is planned to be used, and the mixing rate at which the desired strength can be obtained by mixing them based on the particle size distribution and composition of the steelmaking slag. We prepared several examples of blending of clay and steelmaking slag with various mixing ratios, total moisture content, and flow values, and each of them was subjected to multiple types of tests and cured and solidified specimens. Then, by measuring those strengths and selecting those in the strength range necessary for the construction work, the blending conditions for the construction work are set. In this example, the necessary strength range was set to 30 kN / m 2 or more. As shown in Table 1, the corresponding blending example was 75% of the clay and the water content with respect to 25 vol% of the steelmaking slag.
Table 1
At this time, the Ca content of the sample whose strength was measured was measured, and the correlation between the calcium content and the strength was confirmed (Figure 2).
b. Mixing of clay and steelmaking slag
上記配合条件設定に基づいて浚渫土と製鋼スラグとを混合する。混合方法としては、前述した管中混合方式、バージ内混合方式（バックホウ混合方式）、連続式ミキサー方式など、各種の混合方法を適宜選択して浚渫土と製鋼スラグとを混合する。
ｃ．浚渫土・製鋼スラグ混合材の資料採取
The clay and the steelmaking slag are mixed based on the blending condition setting. As a mixing method, various mixing methods, such as the mixing method in a pipe | tube mentioned above, the mixing method in a barge (backhoe mixing method), a continuous mixer method, are selected suitably, and a clay and steelmaking slag are mixed.
c. Collection of dredged material and steelmaking slag mixed material
上記ｂに示した手順によって混合した浚渫土・製鋼スラグ混合材の試料を採取する。この試料は後述するカルシウム含有量を測定するためのものであり、上記ｂの混合作業が終了したものについて、異なった個所から複数の試料を採取する。 A sample of the clay-steel slag mixed material mixed by the procedure shown in b above is taken. This sample is for measuring the calcium content to be described later, and a plurality of samples are collected from different locations with respect to the sample for which the mixing operation b has been completed.
本例では、浚渫土・製鋼スラグ混合材試料の採取は、空気圧送出口の混合材を１時間に１回、１００ｇずつ採取した。混合材量に換算すると３００ｍ３毎に１００ｇずつ採取し、それぞれについて同様の蛍光Ｘ線分析を実施した。
ｄ．蛍光Ｘ線分析によるカルシウム含有量測定
In this example, the sample of the clay / steel slag mixed material was sampled 100 g of the mixed material at the pneumatic outlet once every hour. When converted into the amount of the mixed material, 100 g was sampled every 300 m 3, and the same fluorescent X-ray analysis was performed for each sample.
d. Calcium content measurement by X-ray fluorescence analysis
上記ｃにおいて採取した浚渫土・製鋼スラグ混合材試料中に含まれるカルシウム含有量を蛍光Ｘ線分析器などにより計測する。本例においては、可搬式で現場での計測が可能な株式会社堀場製作所製ハンドヘルド型蛍光Ｘ線分析装置 ＭＥＳＡポータブル（商標）」を使用した。 The calcium content contained in the clay / steel slag mixed material sample collected in c is measured with a fluorescent X-ray analyzer or the like. In this example, a handheld fluorescent X-ray analyzer MESA Portable (trademark) manufactured by HORIBA, Ltd., which is portable and capable of on-site measurement, was used.
製鋼スラグは最大粒径２５ｍｍのものが使用される場合が多く、浚渫土と製鋼スラグの混合物についてそのままでは蛍光Ｘ線分析が困難であるため、２ｍｍ以下程度に調整した。即ち、採取した混合材を、赤外線水分計等を用いて200℃で加熱し、水分率の時間変化が0.20％/min以下になるまで乾燥後、２ｍｍ篩通過分のうち数ｇを用いて蛍光Ｘ線分析装置で分析した。
ｅ．カルシウム含有量の判定
Steelmaking slag having a maximum particle size of 25 mm is often used, and since it is difficult to perform fluorescent X-ray analysis on a mixture of clay and steelmaking slag as it is, it was adjusted to about 2 mm or less. That is, the collected mixed material is heated at 200 ° C. using an infrared moisture meter or the like, dried until the time change of the moisture content is 0.20% / min or less, and then fluorescent using several g of the 2 mm sieve passage. Analysis was performed with an X-ray analyzer.
e. Determination of calcium content
事前に実施した製鋼スラグ、浚渫土単体のカルシウム含有量の測定結果との比較により、浚渫土・製鋼スラグ混合材の製鋼スラグの含有状況を確認する。 The steelmaking slag content of steelmaking slag in the mixed material of steelmaking and steelmaking slag is confirmed by comparison with the measurement results of the calcium content of the steelmaking slag and the clay alone.
製鋼スラグ、浚渫土単体のカルシウム含有量の計算は、例えば表１に示す如き混合材配合の場合、浚渫土に含まれるカルシウムと製鋼スラグに含まれるカルシウムの量から、製鋼スラグ中の2mm以下分の比率を25％として、混合材中のカルシウム含量を試算すると、表２のように８％となる。
表２
Table 2
この数値と、上記ｄにおいて測定した測定値が近似していれば、配合条件を満たしていると判定する。この測定値が、これと大きく異なる場合は、各材料の添加状況や混練状況の確認を行う。 If this numerical value is close to the measured value measured in d, it is determined that the blending condition is satisfied. If this measured value is significantly different from this, the addition status and kneading status of each material are confirmed.
Ca含有量に偏りがある場合、各材料の供給状況の確認や混練性の改善を行う。混練性について、バックホウ混合の場合には、混合時間の延長、管中混合方式の場合には圧送距離の延長等の見直しを行う。
ｆ．カルシウム含有量からの発現強度予測
If the Ca content is uneven, check the supply status of each material and improve kneadability. Regarding kneadability, review the extension of mixing time in case of backhoe mixing and extension of pumping distance in case of mixing in tube.
f. Expression strength prediction from calcium content
上記ｄにおいて測定した測定値が配合条件を満たしている場合には、その測定結果から強度発現予測を行う。（この強度発現予測は、上記ａにおける配合条件設定の際に浚渫土・製鋼スラグ混合材のカルシウム含有量と一軸圧縮強さ等の強度との相関を予め求め、図２中の実線で示す如きグラフを作成しておき、各測定値カルシウム含有量測定結果の数値を該グラフに当てはめて、発現強度を予測する。） When the measured value measured in d satisfies the blending conditions, strength expression is predicted from the measurement result. (This strength expression prediction is based on the correlation between the calcium content of the clay and steelmaking slag mixed material and the strength such as uniaxial compressive strength when setting the blending conditions in the above a, as shown by the solid line in FIG. A graph is prepared, and the numerical value of each measurement value calcium content measurement result is applied to the graph to predict the expression intensity.)
Caの測定結果が８パーセントであった場合、図２のグラフより、２８日強度が目標値である３０ｋＮ／ｍ２を超えると判断する。
ｇ．予測値の目標達成判定
上記ｆで求めた予測値が、目標強度に達していない場合には、再度配合条件を見直す。
When the measurement result of Ca is 8 percent, it is determined from the graph of FIG. 2 that the 28-day strength exceeds the target value of 30 kN / m 2 .
g. Determination of target achievement of predicted value When the predicted value obtained in f above does not reach the target strength, the blending conditions are reviewed again.
この条件の見直しは、スラグ添加量の増加、浚渫土への加水量削減、強度発現の補助材として高炉スラグ微粉末の添加などを設定し直す。
ｈ．供試体を高温で養生
The review of this condition will re-set the addition of slag addition, reduction of water addition to dredged soil, and addition of blast furnace slag fine powder as an auxiliary material for strength development.
h. Curing specimen at high temperature
上記ｇの予測値の目標が達成されている場合には、一軸圧縮強度試験（ＪＩＳ Ａ １２１６）用の供試体（製鋼スラグの粒径が５ｍｍ以下の場合は直径５ｃｍ×高さ１０ｃｍ、製鋼スラグの粒径が２５ｍｍ以下の場合は直径１０ｃｍ×高さ２０ｃｍ）を作成し、これを４０〜６０℃で定温恒温機を使用して養生する。
ｉ．短期強度からの発現強度の予測
When the target of the predicted value of g is achieved, a specimen for a uniaxial compressive strength test (JIS A 1216) (when the particle diameter of the steelmaking slag is 5 mm or less, the diameter is 5 cm × the height is 10 cm, the steelmaking slag In the case where the particle diameter is 25 mm or less, a
i. Prediction of expression intensity from short-term intensity
浚渫土に所定量の製鋼スラグが含まれていても、表３に示すように混練が短い場合には十分に混練した場合と比較して強度が大きく低下する場合がある。
表３ 混練時間と発現強度の測定例
Table 3 Measurement examples of kneading time and expression strength
このため、一軸圧縮試験の供試体を作成し、養生温度を上げることにより強度発現の促進を図り、表４に示すように４０〜６０℃に温度を上げた条件での短期強度の結果から、通常の２０℃での材令２８日等の発現強度の予測を行う。
表４ 養生温度と一軸圧縮強さ測定例
Table 4 Measurement example of curing temperature and uniaxial compressive strength
表４においては、常温に近い２０℃での養生による２８日強度が４２．３ｋＮ／ｍ２であり、４０℃での養生では７日間で２０℃養生の２８日強度を超えている。６０℃での養生では３日で２０℃での養生の２８日強度に達している。この結果から、４０℃では７日強度、６０℃では３日強度を測定することによって２０℃での２８日強度を予測できる。 In Table 4, the 28-day strength by curing at 20 ° C. close to normal temperature is 42.3 kN / m 2, and the curing at 40 ° C. exceeds the 28-day strength of 20 ° C. curing in 7 days. In curing at 60 ° C, the strength of curing at 20 ° C in 28 days is reached in 3 days. From this result, the 28-day strength at 20 ° C. can be predicted by measuring the 7-day strength at 40 ° C. and the 3-day strength at 60 ° C.
浚渫土・製鋼スラグ混合材は、浚渫土の性状（細粒分含有率、液性限界等）によって、発現強度が大きく異なる。事前に浚渫土の土質試験を行っていても浚渫の途中で浚渫土の性状が変化することもある。こうした場合でも高温養生で発現強度の確認を行うことにより、適切な品質管理が可能である。
ｊ．予測値の目標達成判定
The expression strength of the clay / steel slag mixed material varies greatly depending on the properties of the clay (content of fine particles, liquid limit, etc.). Even if a soil quality test is performed in advance, the characteristics of the soil may change during the dredging. Even in such a case, appropriate quality control is possible by confirming the expression strength by high-temperature curing.
j. Target achievement judgment of predicted value
上記ｉにおける３日一軸圧縮強さによる２８日一軸圧縮強さの予測値が目標を達成していない場合には、前述と同様に配合条件の見直しを行う。
ｋ．打設
When the predicted value of the 28-day uniaxial compressive strength based on the 3-day uniaxial compressive strength in i does not achieve the target, the blending conditions are reviewed as described above.
k. Casting
上記ｉにおける高温短期用養生によって所望の強度が推定できた場合に、同条件よって浚渫土・製鋼スラグ混合材を調製し、施工現場への打設を行う。 When the desired strength can be estimated by the high-temperature short-term curing in i above, a clay / steel slag mixed material is prepared under the same conditions and placed on the construction site.
Claims (1)
前記測定によるカルシウム含有量の測定値を、予め求めておいた浚渫土・製鋼スラグ混合材のカルシウム含有量と一軸圧縮強さ等の強度との相関に照らし合わせて強度発現を予測する工程、
前記強度発現の予測値が目標強度を達成しているか否かの判定工程、
該判定工程にて予測値が目標強度に達成していた場合に、供試体を作成し、これを高温養生する工程、
前記高温養生による短期強度から将来の発現強度を予測する工程、
前記将来の発現強度の予測値が目標強度に達成しているか否かを判定する工程、
以上の工程を経ることを特徴としてなる浚渫土・製鋼スラグ混合材の品質管理方法。 A step of measuring the calcium content by fluorescent X-ray analysis from a sample taken from a clay-steel slag mixed material mixed according to a predetermined mixing condition of the clay and steelmaking slag,
A step of predicting the strength expression in light of the correlation between the calcium content of the clay and steelmaking slag mixed material obtained in advance and the strength such as the uniaxial compressive strength, the measured value of the calcium content by the measurement,
A step of determining whether or not the predicted value of the intensity expression has achieved a target intensity,
When the predicted value has reached the target strength in the determination step, a step of creating a specimen and curing it at a high temperature,
Predicting the future expression intensity from the short-term intensity by the high-temperature curing,
Determining whether the predicted value of the future expression intensity has reached the target intensity,
A quality control method for a clay-steel slag mixed material characterized by undergoing the above processes.
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