JP4791229B2 - Hydrated cured body having reinforcing bars excellent in neutralization resistance and salt damage resistance and method for producing the same - Google Patents
Hydrated cured body having reinforcing bars excellent in neutralization resistance and salt damage resistance and method for producing the same Download PDFInfo
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- JP4791229B2 JP4791229B2 JP2006097648A JP2006097648A JP4791229B2 JP 4791229 B2 JP4791229 B2 JP 4791229B2 JP 2006097648 A JP2006097648 A JP 2006097648A JP 2006097648 A JP2006097648 A JP 2006097648A JP 4791229 B2 JP4791229 B2 JP 4791229B2
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- 238000006386 neutralization reaction Methods 0.000 title claims description 43
- 230000003014 reinforcing effect Effects 0.000 title claims description 29
- 150000003839 salts Chemical class 0.000 title claims description 24
- 238000004519 manufacturing process Methods 0.000 title claims description 13
- 239000002893 slag Substances 0.000 claims description 68
- 239000010881 fly ash Substances 0.000 claims description 53
- 229910000831 Steel Inorganic materials 0.000 claims description 37
- 239000010959 steel Substances 0.000 claims description 37
- 239000004568 cement Substances 0.000 claims description 33
- 238000009628 steelmaking Methods 0.000 claims description 32
- 239000000843 powder Substances 0.000 claims description 30
- 239000011400 blast furnace cement Substances 0.000 claims description 24
- 239000011398 Portland cement Substances 0.000 claims description 23
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims description 15
- 239000000920 calcium hydroxide Substances 0.000 claims description 15
- 235000011116 calcium hydroxide Nutrition 0.000 claims description 15
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims description 15
- 239000000203 mixture Substances 0.000 claims description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 12
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 9
- 239000012535 impurity Substances 0.000 claims description 6
- 229910052715 tantalum Inorganic materials 0.000 claims description 6
- 229910052726 zirconium Inorganic materials 0.000 claims description 6
- 229910052799 carbon Inorganic materials 0.000 claims description 5
- 229910052748 manganese Inorganic materials 0.000 claims description 5
- 229910052757 nitrogen Inorganic materials 0.000 claims description 5
- 229910052698 phosphorus Inorganic materials 0.000 claims description 5
- 229910052717 sulfur Inorganic materials 0.000 claims description 5
- 229910052719 titanium Inorganic materials 0.000 claims description 5
- 229910052804 chromium Inorganic materials 0.000 claims description 4
- 229910052802 copper Inorganic materials 0.000 claims description 4
- 229910052742 iron Inorganic materials 0.000 claims description 4
- 229910052750 molybdenum Inorganic materials 0.000 claims description 4
- 229910052721 tungsten Inorganic materials 0.000 claims description 4
- 239000004567 concrete Substances 0.000 description 36
- 230000007797 corrosion Effects 0.000 description 27
- 238000005260 corrosion Methods 0.000 description 27
- 238000012360 testing method Methods 0.000 description 25
- 239000000463 material Substances 0.000 description 15
- 238000001723 curing Methods 0.000 description 14
- 230000000694 effects Effects 0.000 description 12
- 239000002245 particle Substances 0.000 description 12
- 229910001566 austenite Inorganic materials 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 8
- 230000036571 hydration Effects 0.000 description 7
- 238000006703 hydration reaction Methods 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 6
- 238000002156 mixing Methods 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 239000003513 alkali Substances 0.000 description 5
- 239000011150 reinforced concrete Substances 0.000 description 5
- 239000011230 binding agent Substances 0.000 description 4
- 238000009472 formulation Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 238000005098 hot rolling Methods 0.000 description 4
- 238000001556 precipitation Methods 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 229910001294 Reinforcing steel Inorganic materials 0.000 description 3
- 239000002585 base Substances 0.000 description 3
- 239000001569 carbon dioxide Substances 0.000 description 3
- 229910002092 carbon dioxide Inorganic materials 0.000 description 3
- 239000011362 coarse particle Substances 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 238000005242 forging Methods 0.000 description 3
- 238000004898 kneading Methods 0.000 description 3
- 230000007774 longterm Effects 0.000 description 3
- 229910000734 martensite Inorganic materials 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 150000004767 nitrides Chemical class 0.000 description 3
- 230000002829 reductive effect Effects 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 239000003112 inhibitor Substances 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- KJFMBFZCATUALV-UHFFFAOYSA-N phenolphthalein Chemical compound C1=CC(O)=CC=C1C1(C=2C=CC(O)=CC=2)C2=CC=CC=C2C(=O)O1 KJFMBFZCATUALV-UHFFFAOYSA-N 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 230000009257 reactivity Effects 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- 238000009736 wetting Methods 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 239000002956 ash Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005536 corrosion prevention Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- YXVFQADLFFNVDS-UHFFFAOYSA-N diammonium citrate Chemical compound [NH4+].[NH4+].[O-]C(=O)CC(O)(C(=O)O)CC([O-])=O YXVFQADLFFNVDS-UHFFFAOYSA-N 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000009415 formwork Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 150000004677 hydrates Chemical class 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 210000003205 muscle Anatomy 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 230000000638 stimulation Effects 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
- C04B28/10—Lime cements or magnesium oxide cements
-
- 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
-
- 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
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
- Furnace Details (AREA)
Description
本発明は、乾湿が繰り返される海岸等の、中性化と塩害が進みやすい環境下で用いる構造物での利用に好適な、耐中性化性および耐塩害性に優れた鉄筋を有する水和硬化体およびその製造方法に関するものである。 The present invention is suitable for use in a structure used in an environment where neutralization and salt damage are likely to proceed, such as a coast where dryness and humidity are repeated, and is hydrated with a reinforcing bar excellent in neutralization resistance and salt damage resistance. The present invention relates to a cured body and a method for producing the same.
鉄筋コンクリートは、コンクリート中のアルカリ成分によって鉄筋の表面に不動態皮膜が形成されるため鉄筋が防食され、長期に渡って強度と耐久性を発揮する構造部材である。したがって、コンクリートが中性化すると不動態皮膜が破壊され鉄筋が腐食し、構造物部材として機能しなくなる。 Reinforced concrete is a structural member that exhibits strength and durability over a long period of time because the passive component film is formed on the surface of the reinforcing bar by the alkali components in the concrete, thereby preventing corrosion of the reinforcing bar. Therefore, when the concrete is neutralized, the passive film is destroyed and the rebar is corroded, so that it does not function as a structural member.
近年は、コンクリートの骨材の入手事情が悪化し、例えば、アルカリ骨材反応を生じる可能性がある安山岩等を骨材として使用せざるを得ない場合がある。アルカリ骨材反応によりコンクリートにひび割れを生じた場合、コンクリートの中性化が急速に進行し、鉄筋が腐食する等の問題がある。また良質な骨材を使用したコンクリートの場合であっても、これを乾湿が繰り返される等の中性化が進みやすい環境下で使用した際には、コンクリートの中性化よって鉄筋表面の不動態皮膜が破壊されて鉄筋が腐食し、発生した錆に起因する体積膨張によってコンクリートが剥落する。当然のことながら、鉄筋と外界との間に存在するコンクリートの厚み（かぶり厚）を増大させることにより、中性化が鉄筋の表面に到達する時間を遅延させることができるが、コンクリートのかぶり厚の増大により構造物が大型化するためコストが増大するという問題がある。 In recent years, the availability of concrete aggregates has deteriorated, and for example, andesite that may cause an alkali aggregate reaction may be used as an aggregate. When cracks occur in the concrete due to the alkali aggregate reaction, there is a problem that the neutralization of the concrete proceeds rapidly and the reinforcing bars corrode. Even in the case of concrete using high-quality aggregates, if it is used in an environment where neutralization is likely to proceed, such as repeated drying and wetting, the neutralization of the concrete causes the passivation of the reinforcing bar surface. The coating is destroyed and the rebar is corroded, and the concrete is peeled off by volume expansion caused by the generated rust. Naturally, increasing the thickness of the concrete (cover thickness) between the reinforcing bar and the outside world can delay the time for neutralization to reach the surface of the reinforcing bar. There is a problem that the cost increases because the structure becomes larger due to the increase in the size of the structure.
上記のような鉄筋コンクリートの耐中性化性を向上する手段としては、一般に水セメント比を小さくする方法が知られている。 As a means for improving the neutralization resistance of reinforced concrete as described above, a method of reducing the water-cement ratio is generally known.
一方、製鋼スラグと高炉スラグ微粉末とを主原料とし、コンクリートの代替が可能な水和硬化体が特許文献１及び非特許文献１に開示されている。 On the other hand, Patent Document 1 and Non-Patent Document 1 disclose a hydrated hardened body that can use steelmaking slag and blast furnace slag fine powder as main raw materials and can replace concrete.
これらの水和硬化体をコンクリートの代替として用いることで、製鉄所で大量に発生するスラグを有効利用することができる。
しかし、鉄筋コンクリートの耐中性化性を向上させるために水セメント比を小さくする方法は、アルカリ骨材反応を生じることがない良質な骨材を用いたときは有効であるが、アルカリ骨材反応を生じる骨材を用いた場合は効果がない。また、水セメント比を小さくすると高コストとなるばかりでなく、コンクリートの自己収縮が大きくなるという弊害を生じる。 However, the method of reducing the water-cement ratio in order to improve the neutralization resistance of reinforced concrete is effective when using high-quality aggregates that do not cause alkali-aggregate reaction, but alkali-aggregate reaction. There is no effect when using aggregates that cause Moreover, if the water-cement ratio is reduced, not only the cost is increased, but also the self-shrinkage of the concrete is increased.
一方、上記の特許文献１、非特許文献１の水和硬化体をコンクリート代替として用いた場合の耐中性化性については、特許文献１に開示された水和硬化体は用途を路盤材、建築・土木材等としている程度で不明瞭であり、非特許文献１に開示された水和硬化体は、対象を鉄筋を含有しない無筋コンクリート代替に限定しているため、どちらについても性能自体が不明である。そこで、これらの水和硬化体の耐中性化性を本発明者らが調べたところ、極めてばらつきが大きく、鉄筋コンクリート代替として安定して使用することが困難であることがわかった。 On the other hand, regarding the neutralization resistance when the hydrated cured body of Patent Document 1 and Non-Patent Document 1 is used as a concrete substitute, the hydrated cured body disclosed in Patent Document 1 is used for roadbed materials, The hydration hardened body disclosed in Non-Patent Document 1 is unclear to the extent that it is used for construction and earthwork, etc., and the target is limited to the replacement of unreinforced concrete that does not contain reinforcing bars. Is unknown. Then, when the present inventors investigated the neutralization resistance of these hydrated cured bodies, it was found that the dispersion was extremely large and it was difficult to stably use as a substitute for reinforced concrete.
このように従来の技術を用いては、コンクリートや製鋼スラグと高炉スラグ微粉末等を材料とした水和硬化体の中性化を抑止して鉄筋の腐食を防止することは限界がある。 As described above, there is a limit to prevent corrosion of reinforcing bars by suppressing neutralization of a hydrated and hardened body made of concrete, steelmaking slag, blast furnace slag fine powder, or the like using conventional techniques.
したがって本発明の目的は、このような従来技術の課題を解決し、中性化が進みやすいような環境条件においても長期の耐久性を有する構造物部材とすることができる耐中性化性および耐塩害性に優れた鉄筋を有する水和硬化体およびその製造方法を提供することにある。 Therefore, the object of the present invention is to solve the problems of the prior art, and to make the structure member having long-term durability even under environmental conditions where neutralization is likely to proceed, An object of the present invention is to provide a hydrated cured product having a reinforcing bar excellent in salt damage resistance and a method for producing the same.
このような課題を解決するための本発明の特徴は以下の通りである。
（１）鉄筋を内部に有する水和硬化体が、少なくともＣａＯ／ＳｉＯ ２ が質量比で１．５未満、且つ、ＣａＯ濃度が２５質量％未満の製鋼スラグと高炉スラグ微粉末とフライアッシュとを含有し、前記フライアッシュの含有量が１００ｋｇ／ｍ3以上であり、水和硬化体が、さらにポルトランドセメント、ＪＩＳ Ｒ ５２１１「高炉セメント」に適合するＢ種の高炉セメント、ＪＩＳ Ｒ ５２１３「フライアッシュセメント」に適合するＢ種のフライアッシュセメント、消石灰から選ばれる１種または２種以上を含有し、その含有率が［ポルトランドセメント（ｋｇ／ｍ 3 ）＋高炉セメント（ｋｇ／ｍ 3 ）×０．６＋フライアッシュセメント（ｋｇ／ｍ 3 ）×０．８５＋消石灰（ｋｇ／ｍ 3 ）］／［フライアッシュ（ｋｇ／ｍ 3 ）＋フライアッシュセメント×０．１５（ｋｇ／ｍ 3 ）］で０．４５以下であり、且つ、前記製鋼スラグの含有量が１９７５ｋｇ／ｍ 3 以上であり、且つ、前記混合物中における高炉セメントに由来する高炉スラグ微粉末以外の高炉スラグ微粉末の含有量が１００ｋｇ／ｍ 3 以上であり、さらに前記鉄筋が質量％でＣ：0.001mass%超、0.3mass%未満、Ｎ：0.001mass％超、0.3mass%未満、Ｃｒ：5.0mass%超、15.0mass%未満、Ｓｉ：0.1mass%超、4.0mass%未満、Ｍｎ：0.1mass%超、4.0mass%未満、Ｃｏ：0.01mass%超、1.0mass%未満、Ａｌ：0.04mass%未満、Ｐ：0.04mass%未満、およびＳ：0.03mass%未満を含有し、残部がＦｅおよび不可避的不純物からなるＣｒ添加鋼であることを特徴とする耐中性化性および耐塩害性に優れた鉄筋を有する水和硬化体。
（２）Ｃｒ添加鋼がさらに、Ｖ：1.0mass％未満、Ｗ：1.0mass%未満のいずれか１種以上を含有することを特徴とする（１）に記載の耐中性化性および耐塩害性に優れた鉄筋を有する水和硬化体。
（３）Ｃｒ添加鋼がさらに、Ｎｉ：3.0mass％未満、Ｃｕ：3.0mass％未満、およびＭｏ：3.0mass%未満の中から選ばれる１種又は２種以上を含有することを特徴とする（１）または（２）に記載の耐中性化性および耐塩害性に優れた鉄筋を有する水和硬化体。
（４）Ｃｒ添加鋼がさらに、Ｎｂ：1.0mass％未満、Ｔｉ：1.0mass％未満、Ｔａ：1.0mass％未満、Ｚｒ：1.0mass％未満およびＢ：0.01mass%未満の中から選ばれる１種又は２種以上を含有することを特徴とする（１）ないし（３）のいずれか１つに記載の耐中性化性および耐塩害性に優れた鉄筋を有する水和硬化体。
（５）耐中性化性および耐塩害性に優れた鉄筋を有する水和硬化体の製造方法であって、［ポルトランドセメント（ｋｇ／ｍ 3 ）＋高炉セメント（ｋｇ／ｍ 3 ）×０．６＋フライアッシュセメント（ｋｇ／ｍ 3 ）×０．８５＋消石灰（ｋｇ／ｍ 3 ）］／［フライアッシュ（ｋｇ／ｍ 3 ）＋フライアッシュセメント×０．１５（ｋｇ／ｍ 3 ）］で０．４５以下になるように、少なくとも、ポルトランドセメント、ＪＩＳ Ｒ ５２１１「高炉セメント」に適合するＢ種の高炉セメント、ＪＩＳ Ｒ ５２１３「フライアッシュセメント」に適合するＢ種のフライアッシュセメント、消石灰から選ばれる１種または２種以上と、ＣａＯ／ＳｉＯ ２ が質量比で１．５未満、且つ、ＣａＯ濃度が２５質量％未満の製鋼スラグと、高炉スラグ微粉末と、フライアッシュとを水と混合し、得られた混合物を硬化するステップを含み、前記フライアッシュの含有量が１００ｋｇ／ｍ 3 以上であり、且つ、前記製鋼スラグの含有量が１９７５ｋｇ／ｍ 3 以上であり、且つ、前記混合物中における高炉セメントに由来する高炉スラグ微粉末以外の高炉スラグ微粉末の含有量が１００ｋｇ／ｍ 3 以上であり、前記鉄筋が質量％でＣ：0.001mass%超、0.3mass%未満、Ｎ：0.001mass％超、0.3mass%未満、Ｃｒ：5.0mass%超、15.0mass%未満、Ｓｉ：0.1mass%超、4.0mass%未満、Ｍｎ：0.1mass%超、4.0mass%未満、Ｃｏ：0.01mass%超、1.0mass%未満、Ａｌ：0.04mass%未満、Ｐ：0.04mass%未満、およびＳ：0.03mass%未満を含有し、残部がＦｅおよび不可避的不純物からなるＣｒ添加鋼であることを特徴とする耐中性化性および耐塩害性に優れた鉄筋を有する水和硬化体の製造方法。
The features of the present invention for solving such problems are as follows.
(1) A hydrated hardened body having a reinforcing bar in its interior comprises steelmaking slag, blast furnace slag fine powder, and fly ash having a CaO / SiO 2 ratio of less than 1.5 and a CaO concentration of less than 25% by mass. And the content of the fly ash is 100 kg / m 3 or more, and the hydrated cured product is a B-type blast furnace cement, JIS R 5213 “fly ash”, which is further compatible with Portland cement, JIS R 5211 “blast furnace cement”. B type fly ash cement suitable for “cement”, containing one or more selected from slaked lime, the content of which is [Portland cement (kg / m 3 ) + blast furnace cement (kg / m 3 ) × 0 .6Tasu fly ash cement (kg / m 3) × 0.85 + slaked lime (kg / m 3)] / [ fly ash (kg / m 3) + Furaia' Yusemento × 0.15 (kg / m 3) ] in is 0.45 or less, and the content of the steel slag is at 1975kg / m 3 or more, and, blast furnace slag derived from blast furnace cement in the mixture The content of blast furnace slag fine powder other than fine powder is 100 kg / m 3 or more, and the rebar is in mass% C: more than 0.001 mass%, less than 0.3 mass%, N: more than 0.001 mass%, less than 0.3 mass% , Cr: more than 5.0 mass%, less than 15.0 mass%, Si: more than 0.1 mass%, less than 4.0 mass%, Mn: more than 0.1 mass%, less than 4.0 mass%, Co: more than 0.01 mass%, less than 1.0 mass%, Al : Less than 0.04 mass%, P: Less than 0.04 mass%, and S: Less than 0.03 mass%, with the balance being Cr-added steel consisting of Fe and inevitable impurities. Hydrated hardened body with rebars with excellent salt damage.
(2) Cr-added steel further contains at least one of V: less than 1.0 mass% and W: less than 1.0 mass%. Hydrated hardened body with rebar having excellent properties.
(3) The Cr-added steel further contains one or more selected from Ni: less than 3.0 mass%, Cu: less than 3.0 mass%, and Mo: less than 3.0 mass% ( A hydrated cured product having a reinforcing bar excellent in neutralization resistance and salt damage resistance as described in 1) or (2).
(4) The Cr-added steel is further selected from Nb: less than 1.0 mass%, Ti: less than 1.0 mass%, Ta: less than 1.0 mass%, Zr: less than 1.0 mass%, and B: less than 0.01 mass%. or two or more, characterized in that it contains (1) to (3)耐中of resistance and hydrated cured product having excellent reinforcing bars to salt damage resistance according to any one of.
(5) A method for producing a hydrated and cured body having reinforcing bars excellent in neutralization resistance and salt damage resistance, [Portland cement (kg / m 3 ) + blast furnace cement (kg / m 3 ) × 0. 6 + fly ash cement (kg / m 3 ) × 0.85 + slaked lime (kg / m 3 )] / [fly ash (kg / m 3 ) + fly ash cement × 0.15 (kg / m 3 )] It is selected from at least Portland cement, Type B blast furnace cement compatible with JIS R 5211 “Blast furnace cement”, Type B fly ash cement compatible with JIS R 5213 “Fly ash cement”, and slaked lime so as to be 45 or less. and one or more, less than 1.5 at CaO / SiO 2 mass ratio, and, the steelmaking slag CaO concentration is less than 25 wt%, and blast furnace slag, fly A Mesh is mixed with water, comprising the step of curing the resulting mixture, the content of the fly ash is not more 100 kg / m 3 or more and the content of the steelmaking slag be 1975kg / m 3 or more And the content of the blast furnace slag fine powder other than the blast furnace slag fine powder derived from the blast furnace cement in the mixture is 100 kg / m 3 or more, the rebar is in mass%, C: more than 0.001 mass%, 0.3 mass% Less than, N: more than 0.001 mass%, less than 0.3 mass%, Cr: more than 5.0 mass%, less than 15.0 mass%, Si: more than 0.1 mass%, less than 4.0 mass%, Mn: more than 0.1 mass%, less than 4.0 mass%, Co: steel containing more than 0.01 mass%, less than 1.0 mass%, Al: less than 0.04 mass%, P: less than 0.04 mass%, and S: less than 0.03 mass%, the balance being Fe and inevitable impurities Hydration-hardening with rebars with excellent neutralization resistance and salt damage resistance The method of production.
本発明によれば、耐中性化性と耐塩害性に優れることから、鉄筋に対する防食性に優れた水和硬化体が得られる。このため、中性化により従来の鉄筋コンクリートが短期間で崩壊するような環境下においても、長期間の使用が可能な構造物を提供できる。 According to this invention, since it is excellent in neutralization resistance and salt damage resistance, the hydration hardening body excellent in the corrosion resistance with respect to a reinforcing bar is obtained. For this reason, the structure which can be used for a long period of time can be provided even in the environment where the conventional reinforced concrete collapses in a short period of time by neutralization.
本発明では、水和硬化体の材料を最適化することにより、従来のコンクリートや製鋼スラグと高炉スラグ微粉末等を材料とした水和硬化体よりも耐中性化性に優れた水和硬化体が得られ、これをＣｒ添加鋼からなる鉄筋と組み合わせることで、高塩分濃度を含有し乾湿が繰り返される中性化および塩害の進みやすい環境下においても長期の耐久性を有する構造物部材として使用できることを見出し、本発明を完成した。 In the present invention, by optimizing the material of the hydrated hardened body, the hydration hardening having better neutralization resistance than conventional hydrated hardened bodies made of concrete, steelmaking slag and blast furnace slag fine powder, etc. As a structural member that has a long-term durability even in an environment where neutralization and salt damage are likely to occur, it contains high salinity and repeats drying and wetting by combining it with a reinforcing bar made of Cr-added steel. The present invention has been completed by finding that it can be used.
まず水和硬化体を構成する材料について説明する。 First, materials constituting the hydrated cured body will be described.
なお、本発明において、水和硬化体における（水和硬化体中の）含有量（配合量）とは、水和硬化体の配合原料となる各材料（混練用の水や混和剤なども含む）を混合した混合物中における含有量を意味する。本発明における水和硬化体は、配合原料となる材料を混合して形成した混合物を硬化させたものである。 In the present invention, the content (in the hydrated cured body) (in the hydrated cured body) of the hydrated cured body includes each material (including kneading water and admixture) that is a raw material for blending the hydrated cured body. ) In the mixed mixture. The hydrated cured product in the present invention is obtained by curing a mixture formed by mixing materials to be blended raw materials.
本発明の水和硬化体は、製鋼スラグと、高炉スラグ微粉末と、フライアッシュとを含有する。 The hydrated cured product of the present invention contains steelmaking slag, blast furnace slag fine powder, and fly ash.
水和硬化体の材料のうち、製鋼スラグは、骨材および結合材、さらに水和硬化体の中性化抑止材として作用する。骨材として作用させるための製鋼スラグの粒度分布は、コンクリート用の細骨材や粗骨材に相当するような粒度とし、粒径が０．０７５ｍｍ以上程度、また最大粒径が４０ｍｍ以下程度とすることが好ましい。また、結合材として作用させるための製鋼スラグは微粉であることが好ましく、粒径が０．１５ｍｍ未満程度であることが好ましい。したがって、結合材としての粒径と骨材としての粒径をそれぞれ満足するスラグ粒子が含まれている適当な粒度分布を有する製鋼スラグ（例えば、或る条件で粉砕処理した製鋼スラグやその粉砕処理後に篩分した製鋼スラグ）を使用することが望ましい。中性化抑止材として作用させるための製鋼スラグは、ＣａＯ／ＳｉＯ2が質量比で１．５以上、またはＣａＯ濃度が２５質量％以上であることが好ましい。ＣａＯ／ＳｉＯ2が質量比で１．５以上、またはＣａＯ濃度が２５質量％以上の製鋼スラグは、製鋼スラグ中のＣａＯ成分が長期間にわたり水和硬化体中に含まれる水に溶解し、水和硬化体を弱アルカリ性に保ち、中性化を抑止する。より好ましくは、ＣａＯ／ＳｉＯ2が質量比で２．０以上、またはＣａＯ濃度が３０質量％以上である。一般にＣａＯ／ＳｉＯ2、ＣａＯ濃度が高くなると製鋼スラグ中の遊離ＣａＯ（ｆｒｅｅ−ＣａＯ）による水和膨張性が大きくなるが、水和硬化体の膨張安定性が確保されれば問題がないことから、これらの上限値は特に規定しない。 Among the materials of the hydrated hardened body, the steelmaking slag acts as an aggregate and a binder, and further as a neutralization inhibitor for the hydrated hardened body. The particle size distribution of the steelmaking slag for acting as an aggregate is a particle size corresponding to fine aggregate or coarse aggregate for concrete, the particle size is about 0.075 mm or more, and the maximum particle size is about 40 mm or less. It is preferable to do. Moreover, it is preferable that the steelmaking slag for making it act as a binder is a fine powder, and it is preferable that a particle size is less than about 0.15 mm. Accordingly, a steelmaking slag having an appropriate particle size distribution containing slag particles satisfying the particle size as a binder and the particle size as an aggregate (for example, steelmaking slag pulverized under a certain condition and its pulverization treatment). It is desirable to use steelmaking slag that is sieved later. The steelmaking slag for acting as a neutralization inhibiting material preferably has a CaO / SiO 2 ratio of 1.5 or more, or a CaO concentration of 25% by mass or more. CaO / SiO 2 is in a weight ratio of 1.5 or more, or CaO concentration of 25 mass% or more steel slag is dissolved in water CaO component in the steelmaking slag is contained in the hydrated cured body over a long period of time, water Keep the Japanese cured body weakly alkaline and suppress neutralization. More preferably, CaO / SiO 2 is 2.0 or more by mass ratio, or the CaO concentration is 30% by mass or more. Generally, when the CaO / SiO 2 and CaO concentrations are increased, the hydration expansion due to free CaO (free-CaO) in the steelmaking slag increases, but there is no problem if the expansion stability of the hydrated cured body is ensured. These upper limits are not specified.
また、製鋼スラグは通常の砂利等の骨材と異なりアルカリ骨材反応を起こさないため、水和硬化体そのものの耐久性が優れるだけでなく、アルカリ骨材反応に起因するひび割れの発生も抑制できるので、ひび割れを介した中性化が起こらず、水和硬化体中の鉄筋の防食の観点からも好ましい。 In addition, steelmaking slag does not cause an alkali-aggregate reaction unlike ordinary gravel aggregates, so that not only the durability of the hydrated hardened body itself is excellent, but also the occurrence of cracks due to the alkali-aggregate reaction can be suppressed. Therefore, neutralization through cracks does not occur, which is preferable from the viewpoint of corrosion prevention of reinforcing steel in the hydrated cured body.
水和硬化体の材料として高炉スラグ微粉末を用いるのは、潜在水硬性を有する高炉スラグ微粉末が製鋼スラグによりアルカリ刺激を受け効率的に水和反応するためだけでなく、従来のコンクリートよりも硬化物が緻密な組織を有するため、水和硬化体の中性化の原因となる二酸化炭素の透過を著しく抑制できるからである。また、高炉スラグ微粉末と製鋼スラグ中の遊離ＣａＯ（ｆｒｅｅ−ＣａＯ）が反応し、製鋼スラグの水和膨張を抑制するためである。高炉スラグ微粉末としてはＪＩＳ Ａ ６２０６「コンクリート用高炉スラグ微粉末」を特に好ましく用いることができる。 The reason why blast furnace slag fine powder is used as a material for the hydrated hardened body is not only because the blast furnace slag fine powder having latent hydraulic properties is subjected to alkali stimulation by steelmaking slag and efficiently hydrates but also more than conventional concrete. This is because, since the cured product has a dense structure, the permeation of carbon dioxide that causes neutralization of the hydrated cured product can be remarkably suppressed. Moreover, it is because the free blast furnace slag fine powder and free CaO (free-CaO) in the steelmaking slag react to suppress the hydration expansion of the steelmaking slag. As the blast furnace slag fine powder, JIS A 6206 “Blast furnace slag fine powder for concrete” can be particularly preferably used.
高炉スラグ微粉末の水和硬化体中の配合量は、１００〜６００ｋｇ／ｍ3であることが好ましい。１００ｋｇ／ｍ3未満ではコンクリート代替として必要な１８Ｎ／ｍｍ2以上の圧縮強度が得られない場合があり、６００ｋｇ／ｍ3を超えると強度の増加はほとんど無く不経済となるためである。高炉スラグ微粉末のより好ましい配合量は、２００〜４００ｋｇ／ｍ3である。 The blending amount of the blast furnace slag fine powder in the hydrated cured product is preferably 100 to 600 kg / m 3 . If it is less than 100 kg / m 3 , the compressive strength of 18 N / mm 2 or more necessary as a concrete substitute may not be obtained, and if it exceeds 600 kg / m 3 , there is almost no increase in strength and it becomes uneconomical. A more preferable blending amount of the blast furnace slag fine powder is 200 to 400 kg / m 3 .
水和硬化体の材料としてフライアッシュを用いるのは、ポゾラン反応性を有するフライアッシュが製鋼スラグや高炉スラグ微粉末と長期にわたり反応し、生成した水和ゲルが組織中の空隙を埋めることにより、硬化物が従来のコンクリートに比較して極めて緻密な組織を有するようになり、水和硬化体の中性化の原因となる二酸化炭素の透過を著しく抑制できるからである。このためには、フライアッシュを１００ｋｇ／ｍ3以上含有する必要がある。フライアッシュを１００ｋｇ／ｍ3とすることにより、平均細孔径は普通コンクリートが約０．１μｍであるのに対し、本発明の水和硬化体では約０.０１μｍと約１／１０となる。また、フライアッシュは、フライアッシュと製鋼スラグ中の遊離ＣａＯが反応し、製鋼スラグの水和膨張を抑制する効果がある。フライアッシュの上限値は特に設定しないが、３００ｋｇ／ｍ3を超えると水を加えて練混ぜた後のフレッシュな状態の粘性が高くなり、ワーカビリティが悪化する。また製鋼スラグの水和膨張を抑制する効果も変わらず不経済となる。フライアッシュはＪＩＳ Ａ ６２０１「コンクリート用フライアッシュ」を用いることが好ましいが、原粉および加圧流動床灰等の使用も可能である。 The fly ash is used as the material of the hydrated cured body because the fly ash having pozzolanic reactivity reacts with steelmaking slag and blast furnace slag fine powder for a long time, and the generated hydrated gel fills the voids in the structure. This is because the cured product has an extremely dense structure as compared with conventional concrete and can significantly suppress the permeation of carbon dioxide which causes neutralization of the hydrated cured body. For this purpose, it is necessary to contain 100 kg / m 3 or more of fly ash. By setting the fly ash to 100 kg / m 3 , the average pore diameter is about 0.1 μm for ordinary concrete, whereas it becomes about 0.01 μm and about 1/10 for the hydrated cured product of the present invention. Further, fly ash has an effect of suppressing hydration expansion of steel slag by reacting fly ash with free CaO in the steel slag. The upper limit of fly ash is not particularly set, but if it exceeds 300 kg / m 3 , the viscosity of a fresh state after adding water and kneading becomes high, and workability deteriorates. Moreover, the effect which suppresses the hydration expansion | swelling of steelmaking slag is also uneconomical. As fly ash, JIS A 6201 “Fly Ash for Concrete” is preferably used, but raw powder, pressurized fluidized bed ash and the like can also be used.
水和硬化体の材料として、さらにポルトランドセメント、高炉セメント、フライアッシュセメント、エコセメント、消石灰から選ばれる１種または２種以上を配合することが好ましく、ポルトランドセメント、高炉セメント、フライアッシュセメント、エコセメント、消石灰から選ばれる１種または２種以上の含有率は［ポルトランドセメント（ｋｇ／ｍ3）＋高炉セメント（ｋｇ／ｍ3）×０．６＋フライアッシュセメント（ｋｇ／ｍ3）×０．８５＋消石灰（ｋｇ／ｍ3）］／［フライアッシュ（ｋｇ／ｍ3）＋フライアッシュセメント×０．１５（ｋｇ／ｍ3）］で０．４５以下であることが好ましい。カルシウム成分を含むこれらのセメント、消石灰を加えることにより、フライアッシュのポゾラン反応が効率的に生じ、平均細孔径は水和硬化体形成後１ヶ月で約０.０１μｍとなり、短期間で組織を緻密にすることができるためである。つまり、水和硬化体の中性化の原因となる炭酸ガスや水蒸気の浸透・透過を著しく抑制できるからである。このような観点から、［ポルトランドセメント（ｋｇ／ｍ3）＋高炉セメント（ｋｇ／ｍ3）×０．６＋フライアッシュセメント（ｋｇ／ｍ3）×０．８５＋消石灰（ｋｇ／ｍ3）］／［フライアッシュ（ｋｇ／ｍ3）＋フライアッシュセメント×０．１５（ｋｇ／ｍ3）］の値は、０．４５以下が好ましく、さらに好ましくは０．４０以下である。下限は特に設けないが、０．１５以上とすることで上記効果が得られるので好ましい。 As a material for the hydrated cured body, one or more selected from Portland cement, blast furnace cement, fly ash cement, eco cement and slaked lime are preferably added. Portland cement, blast furnace cement, fly ash cement, eco The content of one or more selected from cement and slaked lime is [Portland cement (kg / m 3 ) + blast furnace cement (kg / m 3 ) × 0.6 + fly ash cement (kg / m 3 ) × 0. 85 + slaked lime (kg / m 3 )] / [fly ash (kg / m 3 ) + fly ash cement × 0.15 (kg / m 3 )] is preferably 0.45 or less. By adding these cements containing calcium components and slaked lime, the pozzolanic reaction of fly ash occurs efficiently, and the average pore diameter becomes about 0.01 μm in one month after the formation of the hydrated cured body, and the structure becomes dense in a short period of time. It is because it can be made. That is, the penetration and permeation of carbon dioxide gas and water vapor that cause neutralization of the hydrated cured product can be remarkably suppressed. From such a viewpoint, [Portland cement (kg / m 3 ) + blast furnace cement (kg / m 3 ) × 0.6 + fly ash cement (kg / m 3 ) × 0.85 + slaked lime (kg / m 3 )] / The value of [fly ash (kg / m 3 ) + fly ash cement × 0.15 (kg / m 3 )] is preferably 0.45 or less, and more preferably 0.40 or less. Although the lower limit is not particularly provided, it is preferable that the lower limit is 0.15 or more because the above-described effect can be obtained.
なお、本発明におけるポルトランドセメントとは、ＪＩＳ Ｒ ５２１０「ポルトランドセメント」に記載されている、普通ポルトランドセメント、早強ポルトランドセメント、超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、低熱ポルトランドセメント、耐硫酸塩ポルトランドセメントのことである。また、高炉セメントとは、ＪＩＳ Ｒ ５２１１「高炉セメント」に記載されているＡ種、Ｂ種、Ｃ種のことである。また、フライアッシュセメントとは、ＪＩＳ Ｒ ５２１３「フライアッシュセメント」に記載のＡ種、Ｂ種、Ｃ種のことである。また、エコセメントとは、ＪＩＳ Ｒ ５２１４「エコセメント」のことである。 The Portland cement in the present invention is described in JIS R 5210 “Portland cement”, ordinary Portland cement, early-strength Portland cement, super-early-strength Portland cement, moderately hot Portland cement, low heat Portland cement, sulfate resistant salt Portland cement. Further, the blast furnace cement is A type, B type or C type described in JIS R 5211 “Blast furnace cement”. Moreover, fly ash cement is A class, B class, and C class as described in JIS R 5213 “fly ash cement”. Ecocement is JIS R 5214 “Ecocement”.
次に、本発明で用いる鉄筋について説明する。尚、無筋の水和硬化体は、耐中性化性が優れていない場合でも問題とはならない。 Next, the reinforcing bars used in the present invention will be described. In addition, the non-muscle hydrated cured product does not cause a problem even when the resistance to neutralization is not excellent.
鉄筋に用いるＣｒ添加鋼としては、Ｃ：0.001mass%超、0.3mass%未満、Ｎ：0.001mass％超、0.3mass%未満、Ｃｒ：5.0mass%超、15.0mass%未満、Ｓｉ：0.1mass%超、4.0mass%未満、Ｍｎ：0.1mass%超、4.0mass%未満、Ｃｏ：0.01mass%超、1.0mass%未満、Ａｌ：0.04mass%未満、Ｐ：0.04mass%未満、およびＳ：0.03mass%未満を含有し、残部がＦｅおよび不可避的不純物であるものを用い、さらに、Ｖ：1.0mass％未満、Ｗ：1.0mass%未満のいずれか１種以上を含有することが好ましい。また、さらに、Ｎｉ：3.0mass％未満、Ｃｕ：3.0mass％未満、およびＭｏ：3.0mass%未満の中から選ばれる１種又は２種以上を含有すること、さらに、Ｎｂ：1.0mass％未満、Ｔｉ：1.0mass％未満、Ｔａ：1.0mass％未満、Ｚｒ：1.0mass％未満およびＢ：0.01mass%未満の中から選ばれる１種又は２種以上を含有することが好ましい。 As Cr-added steel used for reinforcing steel, C: more than 0.001 mass%, less than 0.3 mass%, N: more than 0.001 mass%, less than 0.3 mass%, Cr: more than 5.0 mass%, less than 15.0 mass%, Si: 0.1 mass% More than, less than 4.0 mass%, Mn: more than 0.1 mass%, less than 4.0 mass%, Co: more than 0.01 mass%, less than 1.0 mass%, Al: less than 0.04 mass%, P: less than 0.04 mass%, and S: 0.03 mass It is preferable to use a material containing less than% and the balance being Fe and inevitable impurities, and further containing at least one of V: less than 1.0 mass% and W: less than 1.0 mass%. Furthermore, Ni: less than 3.0 mass%, Cu: less than 3.0 mass%, and Mo: containing one or more selected from less than 3.0 mass%, furthermore, Nb: less than 1.0 mass%, It is preferable to contain one or more selected from Ti: less than 1.0 mass%, Ta: less than 1.0 mass%, Zr: less than 1.0 mass%, and B: less than 0.01 mass%.
以下、各化学成分の限定理由について説明する。 Hereinafter, the reasons for limiting each chemical component will be described.
Ｃ：0.001mass％超、0.3mass％未満とする。
Ｃは、オーステナイト相および炭化物の生成元素である。オーステナイト相は、溶接部において、マルテンサイト組織を生じて強度を向上させ、また微細炭化物も強度の向上に寄与する。しかしながら、Ｃ含有量が0.001mass％以下ではオーステナイト相および炭化物の生成量が少なすぎて強度不足となり、一方0.3mass％以上では硬くなり過ぎて靱性の劣化を招く。従って、Ｃ量は0.001mass％超、0.3mass％未満の範囲に限定する。
C: Over 0.001 mass% and less than 0.3 mass%.
C is an austenite phase and carbide forming element. The austenite phase produces a martensite structure in the welded portion to improve the strength, and fine carbides also contribute to the strength improvement. However, if the C content is 0.001 mass% or less, the austenite phase and the amount of carbide generated are too small and the strength is insufficient. On the other hand, if it is 0.3 mass% or more, it becomes too hard and the toughness is deteriorated. Therefore, the C amount is limited to a range of more than 0.001 mass% and less than 0.3 mass%.
Ｎ：0.001mass％超、0.3mass%未満とする。
Ｎも、オーステナイト相および窒化物の生成元素であり、オーステナイト相は溶接部において、マルテンサイト組織を生じて強度を向上させ、また微細窒化物も強度を向上させる。しかしながら、Ｎ含有量が0.001mass％以下ではオーステナイト相および窒化物の生成量が少な過ぎて強度不足となり、一方0.3mass％以上になると硬くなり過ぎて靱性の劣化を招く。従って、Ｎ量は0.001mass％超、0.3mass％未満の範囲に限定する。なお、特に強度を高めたい場合には、Ｃ、Ｎをそれぞれ0.02mass％以上、より好ましくは0.03mass％以上とすることが望ましい。
N: Over 0.001 mass% and less than 0.3 mass%.
N is also an austenite phase and nitride-forming element. The austenite phase generates a martensite structure in the welded portion to improve the strength, and the fine nitride also improves the strength. However, if the N content is 0.001 mass% or less, the austenite phase and the amount of nitride produced are too small and the strength is insufficient. On the other hand, if it is 0.3 mass% or more, it becomes too hard and the toughness is deteriorated. Therefore, the N amount is limited to a range of more than 0.001 mass% and less than 0.3 mass%. In particular, when it is desired to increase the strength, C and N are each preferably 0.02 mass% or more, more preferably 0.03 mass% or more.
Ｃｒ:5.0mass%超、15.0mass%未満とする。
Ｃｒは、本発明における耐食性の改善成分として重要な元素である。本発明で対象にする鉄筋として、コンクリート中において長期使用が可能となるレベルの耐食性を確保するためには、少なくとも5.0mass％超のＣｒが必要である。一方、Ｃｒ量が15.0mass％以上になると、耐食性は良くなるものの、コストアップになるだけでなく、フェライト相の生成量が多くなって溶接部の靱性不足となる。従って、Ｃｒ量は5.0mass％超、15.0mass％未満の範囲に限定する。
Cr: More than 5.0 mass% and less than 15.0 mass%.
Cr is an important element as a component for improving corrosion resistance in the present invention. In order to ensure the corrosion resistance at a level that enables long-term use in concrete, the reinforcing steel targeted in the present invention requires at least 5.0 mass% of Cr. On the other hand, when the Cr content is 15.0 mass% or more, the corrosion resistance is improved, but not only the cost is increased, but the amount of ferrite phase generated is increased and the toughness of the welded portion is insufficient. Therefore, the Cr content is limited to a range of more than 5.0 mass% and less than 15.0 mass%.
Ｓｉ:0.1mass%超、4.0mass%未満とする。
Ｓｉは、脱酸剤として有用な元素であるが、含有量が0.1mass％以下では十分な脱酸効果が得られず、一方4.0mass％以上になると硬くなって機械的性質の劣化を招く。従って、Ｓｉ量は0.1mass％超、4.0mass％未満の範囲に限定する。
Si: Over 0.1 mass% and less than 4.0 mass%.
Si is an element useful as a deoxidizer, but if the content is 0.1 mass% or less, a sufficient deoxidation effect cannot be obtained. On the other hand, if it is 4.0 mass% or more, it becomes hard and deteriorates mechanical properties. Therefore, the amount of Si is limited to a range of more than 0.1 mass% and less than 4.0 mass%.
Ｍｎ：0.1mass%超、4.0mass%未満とする。
Ｍｎも、Ｃと同様、オーステナイト相生成元素であるが、含有量が0.1mass％以下ではオーステナイト相の生成が不十分となるため、溶接部のマルテンサイト組織が少なくなって、強度不足となる。一方、Ｍｎ含有量が4.0mass％以上になると鋼中に残存する介在物が多くなって耐食性が劣化する。従って、Ｍｎ量は0.1mass％超、4.0 mass％未満の範囲に限定する。
Mn: More than 0.1 mass% and less than 4.0 mass%.
Mn is also an austenite phase-forming element like C, but if the content is 0.1 mass% or less, the austenite phase is not sufficiently generated, so the martensitic structure of the welded portion is reduced and the strength is insufficient. On the other hand, when the Mn content is 4.0 mass% or more, the inclusions remaining in the steel increase and the corrosion resistance deteriorates. Therefore, the amount of Mn is limited to the range of more than 0.1 mass% and less than 4.0 mass%.
Ｃｏ：0.01mass%超、1.0mass%未満とする。
Ｃｏは、本発明の重要な成分であり、このＣｏ添加によってコンクリート中でのＣｒ添加鋼素地の腐食速度を低減して耐食性の向上を図ることができる。少量のＣｏによるこのような耐食性の向上効果は、アルカリ環境で、しかも溶存酸素によるカソード反応も制限されるコンクリート中において初めて見出されたものである。ここに、Ｃｏ含有量が0.01mass％以下では上記の効果を十分に得ることができず、一方1.0mass％以上になると上記の効果は飽和に達し、むしろコストの上昇を招くので、Ｃｏ量は0.01mass％超、1.0mass％未満の範囲に限定する。
Co: Over 0.01 mass% and less than 1.0 mass%.
Co is an important component of the present invention, and the addition of Co can reduce the corrosion rate of the Cr-added steel base in the concrete and improve the corrosion resistance. Such an effect of improving the corrosion resistance by a small amount of Co has been found for the first time in concrete in which the cathode reaction due to dissolved oxygen is restricted in an alkaline environment. Here, when the Co content is 0.01 mass% or less, the above effect cannot be sufficiently obtained. On the other hand, when the Co content is 1.0 mass% or more, the above effect reaches saturation, and rather causes an increase in cost. Limited to a range of more than 0.01 mass% and less than 1.0 mass%.
Ａｌ：0.04mass%未満とする。
Ａｌは、脱酸剤として有用な元素である。Ｓｉによる脱酸が不十分な場合にはＡｌによる脱酸が行われるが、その含有量が0.04mass％以上になると介在物が多くなって耐食性が劣化する。従って、Ａｌは0.04mass％未満で含有させることとする。
Al: Less than 0.04 mass%.
Al is an element useful as a deoxidizer. When deoxidation with Si is insufficient, deoxidation with Al is performed. However, when the content is 0.04 mass% or more, inclusions increase and corrosion resistance deteriorates. Therefore, Al is contained at less than 0.04 mass%.
Ｐ：含有量が0.04mass%未満とする。
Ｐ含有量が0.04mass％以上になると、靱性等の機械的性質の劣化が顕著になるので、Ｐ量は0.04mass％未満に制限する。
P: The content is less than 0.04 mass%.
When the P content is 0.04 mass% or more, deterioration of mechanical properties such as toughness becomes remarkable, so the P content is limited to less than 0.04 mass%.
Ｓ：0.03mass%未満とする。
Ｓは、Ｍｎと結合してＭｎＳを形成し、初期発銹起点となる。またＳは、結晶粒界に偏析して、粒界脆化を促進する有害元素でもあるので、極力低減することが好ましい。特にＳ含有量が0.03mass％以上になるとその悪影響が顕著になるので、Ｓ量は0.03mass％未満に制限する。
S: Less than 0.03 mass%.
S combines with Mn to form MnS and serves as an initial starting point. S is also a harmful element that segregates at the grain boundaries and promotes embrittlement of the grain boundaries, so it is preferable to reduce S as much as possible. In particular, when the S content is 0.03 mass% or more, the adverse effect becomes remarkable, so the S content is limited to less than 0.03 mass%.
以上、必須成分および抑制成分について説明したが、本発明では、その他にも以下に述べる各種元素を適宜含有させることができる。 As described above, the essential component and the suppressing component have been described. However, in the present invention, various elements described below can be appropriately contained.
さらに、Ｖ：1.0mass％未満、Ｗ：1.0mass%未満のいずれか１種以上を含有することが好ましい。 Furthermore, it is preferable to contain any one or more of V: less than 1.0 mass% and W: less than 1.0 mass%.
Ｖ：1.0mass％未満とする。
Ｖを添加することにより、Ｃｒ炭窒化物の析出が少なくなって、耐食性が向上する。また、Ｖは、Ｃｒ添加鋼素地の耐食性の向上にも寄与する。特にコンクリート中という腐食環境では、Ｖは少量の添加でも耐食性向上に有効に寄与するという知見が得られた。しかしながら、含有量が1.0mass％以上になると上記の効果は飽和に達し、むしろコストの上昇を招くことになる。従って、Ｖは1.0mass％未満で含有させることとする。
V: Less than 1.0 mass%.
By adding V, the precipitation of Cr carbonitride is reduced and the corrosion resistance is improved. V also contributes to the improvement of the corrosion resistance of the Cr-added steel base. In particular, in a corrosive environment such as in concrete, it was found that V can contribute effectively to improving corrosion resistance even when added in a small amount. However, when the content is 1.0 mass% or more, the above effect reaches saturation, and rather costs increase. Therefore, V is contained at less than 1.0 mass%.
Ｗ：1.0mass%未満とする。
Ｗは、Ｖと同様、Ｃｒ炭窒化物の析出を少なくして耐食性を向上させるだけでなく、Ｃｒ添加鋼素地の耐食性の向上にも寄与する。特にコンクリート中という腐食環境では、Ｗは、Ｖと同様、少量の添加でも耐食性向上に有効に寄与するという知見が得られた。しかしながら、含有量を1.0mass％以上にすると機械的性質の劣化を招くので、Ｗは1.0mass％未満で含有させることとする。
W: Less than 1.0 mass%.
W, like V, not only improves the corrosion resistance by reducing the precipitation of Cr carbonitride, but also contributes to the improvement of the corrosion resistance of the Cr-added steel base. In particular, in a corrosive environment such as in concrete, it was found that W, like V, can contribute effectively to improving corrosion resistance even when added in a small amount. However, if the content is 1.0 mass% or more, the mechanical properties are deteriorated. Therefore, W is contained at less than 1.0 mass%.
さらに、Ｎｉ：3.0mass％未満、Ｃｕ：3.0mass％未満、およびＭｏ：3.0mass%未満の中から選ばれる１種又は２種以上を含有することが好ましい。 Furthermore, it is preferable to contain one or more selected from Ni: less than 3.0 mass%, Cu: less than 3.0 mass%, and Mo: less than 3.0 mass%.
Ｎｉ：3.0mass％未満とする。
Ｎｉは、Ｃｒ添加鋼の活性溶解を低減して耐食性を向上させる有用元素であるが、含有量を3.0mass％以上にするとコストの上昇を招くので、Ｎｉは3.0mass％未満で含有させることとする。
Ni: Less than 3.0 mass%.
Ni is a useful element that reduces the active dissolution of Cr-added steel and improves the corrosion resistance. However, if the content is 3.0 mass% or more, the cost is increased, so Ni should be contained at less than 3.0 mass%. To do.
Ｃｕ：3.0mass％未満とする。
Ｃｕも、Ｃｒ添加鋼の活性溶解を低減して耐食性を向上させる作用があるが、含有量が3.0mass％以上になると逆に耐食性が劣化する傾向にあるので、Ｃｕは3.0mass％未満で含有させることとする。
Cu: Less than 3.0 mass%.
Cu also has the effect of reducing the active dissolution of Cr-added steel and improving the corrosion resistance. However, when the content exceeds 3.0 mass%, the corrosion resistance tends to deteriorate, so Cu is contained at less than 3.0 mass%. I will let you.
Ｍｏ：3.0mass%未満とする。
Ｍｏも、Ｃｒ添加鋼の耐食性を向上させる上で極めて有効な元素であるが、3.0mass％以上の添加はコストの上昇を招くため、Ｍｏは3.0mass％未満で含有させることとする。
Mo: Less than 3.0 mass%.
Mo is also an extremely effective element for improving the corrosion resistance of Cr-added steel. However, since addition of 3.0 mass% or more causes an increase in cost, Mo is contained at less than 3.0 mass%.
さらに、Ｎｂ：1.0mass％未満、Ｔｉ：1.0mass％未満、Ｔａ：1.0mass％未満、Ｚｒ：1.0mass％未満およびＢ：0.01mass%未満の中から選ばれる１種又は２種以上を含有することが好ましい。 Furthermore, Nb: less than 1.0 mass%, Ti: less than 1.0 mass%, Ta: less than 1.0 mass%, Zr: less than 1.0 mass% and B: less than 0.01 mass%, or one or more types selected from It is preferable.
Ｎｂ：1.0mass％未満、Ｔｉ：1.0mass％未満、Ｔａ：1.0mass％未満、Ｚｒ：1.0mass％未満とする。
Ｎｂ、Ｔｉ、ＴａおよびＺｒはいずれも、Ｃｒ炭窒化物の析出を少なくして耐食性を向上させる働きがある。しかしながら、いずれも1.0mass％以上では機械的性質を劣化させるので、これらの元素は単独添加、複合添加いずれの場合にも1.0mass％未満で含有させるものとする。
Nb: Less than 1.0 mass%, Ti: less than 1.0 mass%, Ta: less than 1.0 mass%, Zr: less than 1.0 mass%.
Nb, Ti, Ta, and Zr all have a function of improving the corrosion resistance by reducing the precipitation of Cr carbonitride. However, since mechanical properties deteriorate at 1.0 mass% or more, these elements should be contained at less than 1.0 mass% in both cases of single addition and composite addition.
Ｂ：0.01mass%未満とする。Ｂは、Ｎと結合することにより、Ｃｒ窒化物の析出を少なくして耐食性を向上させる作用がある。しかしながら、含有量が0.01mass％以上だと、鋼材製造時の熱間加工性が劣化するので、Ｂは0.01mass％未満で含有させるものとする。 B: Less than 0.01 mass%. B, when combined with N, has the effect of reducing the precipitation of Cr nitride and improving the corrosion resistance. However, if the content is 0.01 mass% or more, the hot workability at the time of manufacturing the steel material deteriorates, so B is contained at less than 0.01 mass%.
上記以外の残部はＦｅおよび不可避的不純物である。 The balance other than the above is Fe and inevitable impurities.
上記の化学組成を有する鉄筋の製造に際しては、特別な制限はなく、通常の製造方法に従って製造すれば良い。参考のため、代表的な製造条件を以下の（Ａ）〜（Ｃ）に示す。 There is no particular limitation on the production of the reinforcing bar having the above chemical composition, and it may be produced according to a normal production method. For reference, typical production conditions are shown in the following (A) to (C).
（Ａ）精錬工程：高炉溶銑を転炉にてＣｒを添加しつつ脱炭したもの、またはスクラップ等のＦｅ、Ｃｒ原料を電気炉にて溶解した溶鋼を、ＶＯＤ等により脱炭、成分調整したものを、連続鋳造にてブルームとするか、または造塊によりインゴットを製造する。 (A) Refining process: Blast furnace hot metal decarburized while adding Cr in the converter, or molten steel in which Fe and Cr raw materials such as scrap were melted in an electric furnace were decarburized and the components were adjusted The product is made into a bloom by continuous casting, or an ingot is manufactured by ingot forming.
（Ｂ）熱間圧延工程：ブルームまたはインゴットを、１１００〜１２００℃に加熱したのち、熱間圧延または熱間鍛造により５０ｍｍ角程度のビレットとする。このビレットを、再び１１００℃程度に加熱したのち、線棒圧延機により１５ｍｍφ程度の棒鋼とする。 (B) Hot rolling process: After heating a bloom or an ingot to 1100-1200 degreeC, it is set as a billet about 50 square mm by hot rolling or hot forging. This billet is heated again to about 1100 ° C., and then is made into a steel bar of about 15 mmφ by a wire rod rolling mill.
（Ｃ）仕上工程：熱間圧延により製造した棒鋼は、そのまま使用することが可能であるが、必要に応じて適当な熱処理により強度を調整する。また、より耐食性を向上させる場合には、熱間圧延後、場合によっては熱処理後の棒鋼に、ショットブラスト、さらには硝酸＋ふっ酸等による脱スケール処理を施す。 (C) Finishing step: The steel bar produced by hot rolling can be used as it is, but the strength is adjusted by an appropriate heat treatment if necessary. In order to further improve the corrosion resistance, the steel bar after hot rolling and, in some cases, after heat treatment is subjected to a descaling treatment by shot blasting, and further nitric acid + hydrofluoric acid.
熱間でのスケールを除去するためにショット−酸洗処理を行う他に、水和硬化体中での腐食環境が弱い場合には、ショットのみまたは脱スケールなしでもよい。さらに、熱間鍛造−圧延により棒鋼を製造した後に、強度を調整するための熱処理を施してもよい。 In addition to performing the shot-pickling treatment to remove the hot scale, if the corrosive environment in the hydrated cured body is weak, only the shot or no descaling may be performed. Furthermore, after manufacturing a steel bar by hot forging and rolling, a heat treatment for adjusting the strength may be performed.
水和硬化体は、上記の材料を配合して、水を加えて混練して、所定の型枠等に打ち込んで養生して製造する。打ち込みの際に鉄筋を配筋して、鉄筋を有する水和硬化体とする。 The hydrated cured body is produced by blending the above materials, adding water, kneading, and driving and curing in a predetermined formwork or the like. Reinforcing bars are placed during driving to obtain a hydrated hardened body having reinforcing bars.
水和硬化体の養生方法は、所定の強度が確保できれば、通常コンクリートにおいて用いられる水中養生、現場養生、蒸気養生等の何れの方法をも用いることができる。 As a curing method for the hydrated cured body, any method such as underwater curing, on-site curing, and steam curing that are usually used in concrete can be used as long as a predetermined strength can be secured.
製鋼スラグは表１に示す化学成分、物性値（最大粒径、粗粒率、細骨材率、表乾密度）のものを用いた（製鋼スラグＮｏ．Ａ、Ｂ）。ＣａＯ／ＳｉＯ2が質量比で１．５未満、かつＣａＯ濃度が２５質量％未満であり、中性化抑止材として作用しにくい製鋼スラグである。 Steelmaking slags having the chemical components and physical properties shown in Table 1 (maximum particle diameter, coarse particle ratio, fine aggregate ratio, surface dry density) were used (steelmaking slag Nos. A and B). It is a steelmaking slag that has a CaO / SiO 2 mass ratio of less than 1.5 and a CaO concentration of less than 25% by mass and is unlikely to act as a neutralization inhibitor.
粗粒率とはＪＩＳ Ａ ０２０３に記載の番号３１１５の粗粒率のことである。細骨材率とは全粒度の製鋼スラグ量に対する粒径５ｍｍ以下の製鋼スラグ量の絶対容積比を百分率で表した値である。 The coarse particle ratio is the coarse particle ratio of No. 3115 described in JIS A 0203. The fine aggregate rate is a value representing the absolute volume ratio of the amount of steelmaking slag having a particle size of 5 mm or less with respect to the amount of steelmaking slag of all particle sizes as a percentage.
鉄筋は、以下のようにして製造した。表２〜表５に示す化学成分を有する鋼塊５０ｋｇを真空溶解した。ついで、鋼塊の表面５ｍｍを研削したのち、１２００℃、１ｈの焼鈍を施し、熱間鍛造により５０ｍｍ角のビレットとした。このビレットに１１００℃、１ｈの焼鈍を施したのち、線棒圧延機により２５ｍｍφの棒鋼とした。ついで、この棒鋼に、ショットブラストと３％ふっ酸−１２％硝酸の混合酸による脱スケール処理を施し、鋼種Ａ〜ＡＺの鉄筋を製造した。 The reinforcing bars were manufactured as follows. 50 kg of steel ingots having chemical components shown in Tables 2 to 5 were melted in vacuum. Next, after grinding 5 mm of the surface of the steel ingot, annealing was performed at 1200 ° C. for 1 h, and a billet of 50 mm square was formed by hot forging. The billet was annealed at 1100 ° C. for 1 h, and then a 25 mmφ steel bar was formed by a wire rod rolling mill. Then, the steel bar was descaled with a mixed acid of shot blast and 3% hydrofluoric acid-12% nitric acid to produce steel bars A to AZ.
表６〜表８に示す配合（配合Ｎｏ．１〜１１）により水和硬化体の材料をミキサで練混ぜ、φ１００×２００ｍｍの型枠に流し込み、養生してＮｏ．１〜４９の圧縮強度測定用のテストピースを製作した。 According to the formulations shown in Tables 6 to 8 (Formulation Nos. 1 to 11), the hydrated cured material was kneaded with a mixer, poured into a mold of φ100 × 200 mm, cured, and no. Test pieces for measuring compressive strength of 1 to 49 were manufactured.
高炉スラグ微粉末はＪＩＳ Ａ ６２０６「コンクリート用高炉スラグ微粉末」における高炉スラグ微粉末４０００を、フライアッシュはＪＩＳ Ａ ６２０１「コンクリート用フライアッシュ」におけるII種を使用した。ポルトランドセメントは、ＪＩＳ Ｒ ５２０１「ポルトランドセメント」に適合する普通ポルトランドセメントを用いた。高炉セメントは、ＪＩＳ Ｒ ５２１１「高炉セメント」に適合するＢ種を用いた。フライアッシュセメントは、ＪＩＳ Ｒ ５２１３「フライアッシュセメント」に適合するＢ種を用いた。消石灰は、ＪＩＳ Ｒ ９００１に適合する工業用消石灰・特号を使用した。混和剤は、ＪＩＳ Ａ ６２０４に適合するポリカルボン酸系の高性能ＡＥ減水剤を使用した。 Blast furnace slag fine powder used was blast furnace slag fine powder 4000 in JIS A 6206 “Blast furnace slag fine powder for concrete”, and fly ash used type II in JIS A 6201 “Fly ash for concrete”. As the Portland cement, ordinary Portland cement conforming to JIS R 5201 “Portland cement” was used. As the blast furnace cement, type B suitable for JIS R 5211 “blast furnace cement” was used. As the fly ash cement, type B conforming to JIS R 5213 “fly ash cement” was used. As the slaked lime, industrial slaked lime / special name conforming to JIS R 9001 was used. As the admixture, a polycarboxylic acid-based high-performance AE water reducing agent conforming to JIS A 6204 was used.
圧縮強度の測定は、ＪＩＳ Ａ １１０８「コンクリートの圧縮強度試験方法」にしたがって行った。養生条件は標準養生２８日とした。また、同時に表２〜表５に示す鋼種の鉄筋を中心部に挿入したφ１００×２００ｍｍの中性化促進試験用のテストピースをＮｏ．１〜４９の各製造条件に付き２体製作した。養生条件は標準養生２８日とした。中性化促進試験は、標準養生２８日後のテストピースをＣＯ2濃度５％、温度４０℃、湿度６０％ＲＨの条件で９１日間暴露後、１体を５０ｍｍピッチで輪切りしたものについて、中性化深さを測定し、その平均値より評価した。中性化深さの測定は、フェノールフタレイン1％溶液噴霧法によって、無変色部を中性化部とした。 The compressive strength was measured in accordance with JIS A 1108 “Concrete compressive strength test method”. The curing conditions were standard curing 28 days. At the same time, a test piece for a neutralization promotion test of φ100 × 200 mm in which steel bars of the steel types shown in Tables 2 to 5 were inserted in the center was No. Two pieces were manufactured for each manufacturing condition of 1 to 49. The curing conditions were standard curing 28 days. The neutralization promotion test is a test piece that was exposed to a test piece after 28 days of standard curing for 91 days under conditions of CO 2 concentration 5%, temperature 40 ° C, and humidity 60% RH. The chemical depth was measured and evaluated from the average value. The neutralization depth was measured by using a 1% solution spray method of phenolphthalein to make the non-colored portion a neutralized portion.
中性化促進試験を終えた試験体のうち輪切りにしなかったものを、耐塩害性試験に供した。耐塩害性試験は、６０℃の３％ＮａＣｌ水溶液に３日間浸漬した後に６０℃、５０％ＲＨの恒温恒湿槽で４日間乾燥することを１サイクルとし、これを１００サイクル繰り返した後に水和硬化体を破壊して鉄筋を取り出し、鉄筋を１０ｍａｓｓ％の水素クエン酸アンモニウム水溶液で除錆し、腐食面積率と最大腐食深さをマイクロメーターで測定した。 Of the specimens that had been subjected to the neutralization promotion test, those that were not cut into pieces were subjected to a salt damage resistance test. In the salt damage resistance test, one cycle consists of immersing in a 3% NaCl aqueous solution at 60 ° C. for 3 days and then drying in a constant temperature and humidity bath at 60 ° C. and 50% RH for one cycle. The hardened body was destroyed and the rebar was taken out. The rebar was derusted with a 10 mass% aqueous solution of ammonium hydrogen citrate, and the corrosion area ratio and the maximum corrosion depth were measured with a micrometer.
また、比較のために製鋼スラグおよび高炉スラグ微粉末を用いない、普通コンクリートのテストピース（Ｎｏ．５０）を作製した。表９の配合（配合Ｎｏ．１２）によりコンクリートの材料をミキサで練り混ぜ、φ１００×２００ｍｍの型枠に流し込み、養生して、圧縮強度測定用、中性化促進試験用および耐塩害性試験用のテストピースを製作した。圧縮強度測定用のテストピースの養生条件は標準養生２８日とした。圧縮強度試験、中性化促進試験および耐塩害性試験は上記と同じように行なった。なお、骨材はＪＩＳ Ａ １１４５「骨材のアルカリシリカ反応性試験方法（化学法）」による試験において、「無害」と判定された良質なものを用いた。 For comparison, a test piece (No. 50) of ordinary concrete that does not use steelmaking slag and blast furnace slag fine powder was prepared. Mix the concrete material with a mixer according to the formulation shown in Table 9 (mixing No. 12), pour it into a mold of φ100 × 200 mm, cure it, and measure it for compressive strength measurement, neutralization promotion test, and salt damage resistance test The test piece was made. The curing conditions for the test pieces for compressive strength measurement were standard curing 28 days. The compressive strength test, neutralization acceleration test, and salt damage resistance test were performed in the same manner as described above. The aggregate used was a high-quality one determined to be “harmless” in the test according to JIS A 1145 “Aggregate Alkali Silica Reactivity Test Method (Chemical Method)”.
圧縮強度測定結果、中性化促進試験結果および耐塩害性試験結果を表６〜表９に併せて示す。製鋼スラグと高炉スラグ微粉末とフライアッシュを少なくとも含有し、フライアッシュを１００ｋｇ／ｍ3以上含有する水和硬化体と所定の鋼組成を有する鉄筋を組み合わせた場合（テストピースＮｏ．１〜２２）には、良質な骨材を用いた水セメント比（水結合材比）５０％のテストピースＮｏ．５０（配合Ｎｏ．１２）の普通コンクリートよりも中性化深さが小さく、優れた耐中性化性を示した。一方、本発明範囲外の比較例の水和硬化体（テストピースＮｏ．２３〜４９）は、良質な骨材を用いた水セメント比５０％の普通コンクリート（テストピースＮｏ．５０）よりも耐中性化性に劣り、耐塩害性試験後に鉄筋の腐食が認められた。 The compression strength measurement results, the neutralization promotion test results, and the salt damage resistance test results are also shown in Tables 6 to 9. When steelmaking slag, blast furnace slag fine powder and fly ash are contained, and a hydrated hardened body containing fly ash at 100 kg / m 3 or more and a reinforcing bar having a predetermined steel composition are combined (test pieces No. 1 to 22) The test piece No. with a water cement ratio (water binder ratio) of 50% using high-quality aggregates. The neutralization depth was smaller than that of ordinary concrete of No. 50 (Formulation No. 12), and excellent neutralization resistance was exhibited. On the other hand, the comparative hydrated cured body (test pieces No. 23 to 49) outside the scope of the present invention is more resistant than ordinary concrete (test piece No. 50) with a water cement ratio of 50% using high-quality aggregates. It was inferior in neutralization property, and corrosion of the reinforcing bars was observed after the salt damage resistance test.
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