JP6195890B2 - Method for producing early strength lightweight concrete - Google Patents
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Description
本発明は、構造物の構築等に用いるコンクリートの製造方法に関し、特に、軽量で、自己収縮が小さく、打設後短時間で十分な強度を得ることができる早強性軽量コンクリートの製造方法、及び、早強性軽量コンクリート製構造物の製造方法（構築方法）に関する。 The present invention relates to a method for producing concrete used for construction of a structure and the like, and in particular, a method for producing fast-strength lightweight concrete that is lightweight, has low self-shrinkage, and can obtain sufficient strength in a short time after placement, And it is related with the manufacturing method (construction method) of the structure made from early strength lightweight concrete.
橋梁（自動車道、鉄道等）の床版として、近年では、鋼板とコンクリートとを組み合わせた合成床版（鋼コンクリート合成床版）が広く採用されている。合成床版を現場で施工する場合、通常、まず底鋼板が所定の位置（鋼桁上等）に設置され、次に底鋼板の上にコンクリートが打設される。その後、次の工程に移行する前に、打設したコンクリートが十分に硬化するまで、養生期間（通常は７日程度）を経る必要がある。 In recent years, composite floor slabs (steel-concrete composite floor slabs) in which steel plates and concrete are combined are widely used as floor slabs for bridges (motorways, railways, etc.). When constructing a composite floor slab, the bottom steel plate is usually installed at a predetermined position (on a steel girder or the like), and then concrete is placed on the bottom steel plate. Then, before moving to the next step, it is necessary to pass a curing period (usually about 7 days) until the cast concrete is sufficiently cured.
合成床版の施工においては、上述の通り養生期間が必要であり、工程に占める割合が大きいという課題があるが、交通量の多い高速道路等において、合成床版への取り替え工事が実施される場合には、通行止め等の規制による交通状況への悪影響をできるだけ小さくできるように、工期の短縮化の要請がある。また、合成床版は、鋼桁等で支持されて負担を軽減できることが望ましいため、できるだけ軽量であることが求められている。 In the construction of synthetic floor slabs, the curing period is necessary as described above, and there is a problem that the ratio to the process is large. However, replacement work with synthetic floor slabs is performed on highways with high traffic volume. In some cases, there is a request to shorten the construction period so that adverse effects on traffic conditions due to restrictions such as closed roads can be minimized. Moreover, since it is desirable that the composite floor slab is supported by a steel girder or the like to reduce the burden, it is required to be as light as possible.
そこで、軽量で、かつ、短い養生期間で十分な強度が得られる早強性軽量コンクリートを簡単に製造することができれば、これを合成床版の製造に適用することにより、上記のような要請に応えることが可能となるが、従来方法による場合、高価な材料が必要となったり、また、特殊な方法を実施する必要があるなどの問題がある。 Therefore, if it is possible to easily produce light-weight, early-strength lightweight concrete that can provide sufficient strength in a short curing period, this can be applied to the production of synthetic floor slabs to meet the above requirements. Although it is possible to respond, there is a problem that an expensive material is required or a special method needs to be carried out by the conventional method.
本発明は、このような従来技術における問題を解決しようとするものであって、高価な材料を用いることなく、また、特殊な方法を採用することなく、軽量で、自己収縮が小さく、かつ、短い養生期間で十分な圧縮強度を得ることができる早強性軽量コンクリートの製造方法等を提供することを目的とする。 The present invention is intended to solve such a problem in the prior art, without using an expensive material, without employing a special method, lightweight, small self-shrinkage, and An object of the present invention is to provide a method for producing fast-strength lightweight concrete capable of obtaining sufficient compressive strength in a short curing period.
本発明に係る早強性軽量コンクリートの製造方法は、水、セメント、普通細骨材、及び、軽量粗骨材を混合し、練り混ぜ、打設し、養生してコンクリートを製造する方法において、セメントとして、早強ポルトランドセメント（ＪＩＳ Ｒ５２１０に規定される早強ポルトランドセメント）を使用し、軽量粗骨材として、絶乾密度が１．０ｇ／ｃｍ３以上１．５ｇ／ｃｍ３未満の人工軽量粗骨材を使用し、単位セメント量を３５０〜５００ｋｇ／ｍ３とし、水／セメント比を３５〜４５重量％とし、普通細骨材量を６００〜９２０ｋｇ／ｍ３とし、軽量粗骨材量を４００〜８００ｋｇ／ｍ３とすることを特徴としている。 The method for producing fast-strength lightweight concrete according to the present invention is a method for producing concrete by mixing water, cement, ordinary fine aggregate, and light coarse aggregate, kneading, placing and curing. cement, using the early-strength Portland cement (early-strength Portland cement as defined in JIS R5210), as a lightweight coarse aggregate, absolute dry density of 1.0 g / cm 3 or more 1.5 g / cm 3 less than lightweight Coarse aggregate is used, the unit cement amount is 350-500 kg / m 3 , the water / cement ratio is 35-45 wt%, the normal fine aggregate amount is 600-920 kg / m 3 , and the light coarse aggregate amount Is 400 to 800 kg / m 3 .
尚、この方法において、軽量粗骨材については、骨材工場で事前吸水された高含水状態のものを用い、更に、プレウェッティングを行って吸水させた状態で他の材料と混合することが好ましい。 In this method, the lightweight coarse aggregate may be a high moisture content pre-absorbed in an aggregate factory, and may be further mixed with other materials in a pre-wetting state. preferable.
また、原料として、更に軽量細骨材を混合してもよく、この場合、軽量細骨材として、絶乾密度が１．３ｇ／ｃｍ３以上１．８ｇ／ｃｍ３未満の人工軽量細骨材を使用し、普通細骨材量を１５０〜７００ｋｇ／ｍ３とし、軽量細骨材量を１２０〜５２０ｋｇ／ｍ３（普通細骨材容積：軽量細骨材容積＝２５：７５〜７５：２５）とすることが好ましい。この場合も、軽量骨材（軽量細骨材及び軽量粗骨材）については、骨材工場で事前吸水された高含水状態のものを用い、更に、プレウェッティングを行って吸水させた状態で他の材料と混合することが好ましい。 Further, a lightweight fine aggregate may be further mixed as a raw material. In this case, an artificial lightweight fine aggregate having a dry density of 1.3 g / cm 3 or more and less than 1.8 g / cm 3 as the lightweight fine aggregate. The amount of fine fine aggregate is 150 to 700 kg / m 3 and the amount of light fine aggregate is 120 to 520 kg / m 3 (normal fine aggregate volume: light fine aggregate volume = 25: 75 to 75:25 ) Is preferable. In this case as well, light-weight aggregates (light-weight fine aggregates and light-weight coarse aggregates) are used in a highly water-absorbed state that has been pre-absorbed in an aggregate factory, and in addition, pre-wetting and absorbing water. It is preferable to mix with other materials.
また、原料を混合する際には、更に化学混和剤を適量混合することもできる。 Further, when mixing the raw materials, an appropriate amount of a chemical admixture can be further mixed.
また、本発明に係る床版の製造方法は、上記方法を実施することによって、底鋼板又は型枠の上に早強性軽量コンクリートの層を形成することを特徴としている。 Moreover, the manufacturing method of the floor slab according to the present invention is characterized in that a layer of fast-strength lightweight concrete is formed on a bottom steel plate or a formwork by performing the above method.
本発明に係る早強性軽量コンクリートの製造方法によれば、材齢２日で、即ち、打設後２日という短い養生期間で、圧縮強度が３０Ｎ／ｍｍ２以上、単位重量が１８〜２０ｋＮ／ｍ３の早強性軽量コンクリートを製造することができる。 According to the method for producing early-strength lightweight concrete according to the present invention, the compressive strength is 30 N / mm 2 or more and the unit weight is 18 to 20 kN in a short curing period of 2 days after laying, that is, 2 days after placing. / M 3 early strength lightweight concrete can be produced.
尚、材齢２日経過時点で養生を打ち切っても、軽量骨材に含まれる水による「自己養生効果」により、長期強度の増進が得られる。更に、材齢２８日では、通常の重量のコンクリートと同程度以上の引張強度、及び、せん断強度が得られるという効果も期待することができる。また、コンクリートの打設後、特に湿潤養生を行わない場合においても、自己収縮が生じることはない。 In addition, even if the curing is discontinued when the age of two days has elapsed, the “self-curing effect” by the water contained in the lightweight aggregate can provide an increase in long-term strength. Furthermore, at the age of 28 days, it can be expected that the tensile strength and the shear strength equal to or higher than those of concrete having a normal weight can be obtained. In addition, after concrete is placed, no self-shrinkage occurs even when wet curing is not performed.
また、本発明による場合、汎用的な材料を用いて（高価な材料を用いることなく）、一般的な方法で早強性軽量コンクリートを製造することができるため、従来の軽量コンクリートと同程度のコストで実施することができる。更に、本発明による場合、硬化前のコンクリート（生コンクリート）を施工現場まで運搬し、ポンプ圧送により供給することができ、打設作業を円滑に、かつ、効率的に行うことができる。 Moreover, in the case of the present invention, since a high-strength lightweight concrete can be produced by a general method using a general-purpose material (without using an expensive material), it is comparable to conventional lightweight concrete. Can be implemented at a cost. Furthermore, according to the present invention, the uncured concrete (fresh concrete) can be transported to the construction site and supplied by pumping, and the placing work can be performed smoothly and efficiently.
本発明の第一実施形態に係る「早強性軽量コンクリートの製造方法」は、水、セメント、普通細骨材、及び、軽量粗骨材を混合し、練り混ぜ、打設し、養生してコンクリートを製造する方法において、セメントとして、早強ポルトランドセメント（ＪＩＳ Ｒ５２１０）を使用し、軽量粗骨材として、絶乾密度が１．０ｇ／ｃｍ３以上１．５ｇ／ｃｍ３未満の人工軽量粗骨材（ＪＩＳ Ａ５００２ 構造用コンクリート骨材Ｍ品（粗骨材））を使用し、単位セメント量を３５０〜５００ｋｇ／ｍ３とし、水／セメント比を３５〜４５重量％とし、普通細骨材量を６００〜９２０ｋｇ／ｍ３とし、軽量粗骨材量を４００〜８００ｋｇ／ｍ３とすることを特徴とするものである。 According to the first embodiment of the present invention, “a method for producing early-strength lightweight concrete” includes mixing water, cement, ordinary fine aggregate, and light coarse aggregate, kneading, placing and curing. In the method for producing concrete, early-strength Portland cement (JIS R5210) is used as the cement, and the light-weight coarse aggregate is an artificial light-weight rough having an absolutely dry density of 1.0 g / cm 3 or more and less than 1.5 g / cm 3. Using aggregate (JIS A5002 structural concrete aggregate M product (coarse aggregate)), unit cement amount is 350-500kg / m 3 , water / cement ratio is 35-45% by weight, ordinary fine aggregate The amount is 600 to 920 kg / m 3, and the amount of light coarse aggregate is 400 to 800 kg / m 3 .
尚、普通細骨材としては、山砂、石灰砕砂、或いは、その他の一般的な細骨材を使用することができる。また、軽量骨材（軽量粗骨材）としては、骨材工場で事前吸水された高含水状態のものを用い、更に、材料を混合する際には、軽量骨材（軽量粗骨材）に対してプレウェッティングを行い、軽量粗骨材を予め十分に吸水させた状態で他の材料と混合する。これにより、自己収縮を低減することができるほか、ポンプ圧送性を確保することができる。また、原料の混合に際しては、耐久性や施工性に応じて、化学混和剤を適宜混合することもできる。 In addition, as a normal fine aggregate, mountain sand, lime crushed sand, or other general fine aggregates can be used. In addition, as lightweight aggregate (light coarse aggregate), the one with high water content pre-absorbed in the aggregate factory is used, and when mixing materials, the lightweight aggregate (light coarse aggregate) is used. Then, prewetting is performed, and the lightweight coarse aggregate is mixed with other materials in a state where water is sufficiently absorbed in advance. As a result, self-shrinkage can be reduced, and pumpability can be secured. In addition, when mixing the raw materials, a chemical admixture can be appropriately mixed according to durability and workability.
上記方法を実施することにより、材齢２日で、即ち、打設後２日（４８時間）という短い養生期間で、圧縮強度が３０Ｎ／ｍｍ２以上、単位重量が１８〜２０ｋＮ／ｍ３の早強性軽量コンクリートを製造することができる。 By carrying out the above method, the compression strength is 30 N / mm 2 or more and the unit weight is 18 to 20 kN / m 3 at a material age of 2 days, that is, in a short curing period of 2 days (48 hours) after placement. A fast-strength lightweight concrete can be produced.
尚、軽量粗骨材として、絶乾密度が１．０ｇ／ｃｍ３未満のもの（ＪＩＳ Ａ５００２ 構造用コンクリート骨材Ｌ品（粗骨材））を使用した場合、早強性を十分に得られないという問題があり、また、絶乾密度が１．５ｇ／ｃｍ３以上のもの（ＪＩＳ Ａ５００２ 構造用コンクリート骨材Ｈ品（粗骨材））を使用した場合、軽量性を十分に得られないという問題があるため、上述の通り本実施形態においては、絶乾密度が１．０ｇ／ｃｍ３以上１．５ｇ／ｃｍ３未満の軽量粗骨材（ＪＩＳ Ａ５００２ 構造用コンクリート骨材Ｍ品（粗骨材））を使用している。更に、天然軽量粗骨材を使用する場合には、早強性を十分に得られないという問題があるため、本実施形態においては、人工軽量粗骨材を使用している。 In addition, when a light dry coarse aggregate having an absolute dry density of less than 1.0 g / cm 3 (JIS A5002 structural concrete aggregate L (coarse aggregate)) is used, sufficient early strength can be obtained. In addition, there is a problem that the dry density is 1.5 g / cm 3 or more (JIS A5002 Structural aggregate H product (coarse aggregate)), the lightness cannot be sufficiently obtained. Therefore, in the present embodiment, as described above, a light-weight coarse aggregate having an absolute dry density of 1.0 g / cm 3 or more and less than 1.5 g / cm 3 (JIS A5002 structural concrete aggregate M product (coarse) Aggregate)) is used. Further, when natural lightweight coarse aggregate is used, there is a problem that sufficient early strength cannot be obtained. Therefore, in this embodiment, artificial lightweight coarse aggregate is used.
また、単位セメント量を３５０ｋｇ／ｍ３未満とすると、早強性を十分に得られないという問題があり、また、５００ｋｇ／ｍ３を超えると、自己収縮が生じるという問題があるため、上述の通り本実施形態においては、単位セメント量を３５０〜５００ｋｇ／ｍ３としている。 Further, when the unit cement amount is less than 350 kg / m 3 , there is a problem that sufficient early strength cannot be obtained, and when it exceeds 500 kg / m 3 , there is a problem that self-shrinkage occurs. As described above, in this embodiment, the unit cement amount is set to 350 to 500 kg / m 3 .
水／セメント比については、３５重量％未満とすると、自己収縮が生じるという問題があり、また、４５重量％を超えると、早強性を十分に得られないという問題があるため、上述の通り本実施形態においては、３５〜４５重量％としている。 When the water / cement ratio is less than 35% by weight, there is a problem that self-shrinkage occurs, and when it exceeds 45% by weight, there is a problem that sufficient early strength cannot be obtained. In this embodiment, it is 35 to 45% by weight.
普通細骨材量については、６００ｋｇ／ｍ３未満とすると、早強性を十分に得られないという問題があり、また、９２０ｋｇ／ｍ３を超えると、軽量性を十分に得られないという問題があるため、上述の通り本実施形態においては、６００〜９２０ｋｇ／ｍ３としている。 Regarding the amount of ordinary fine aggregate, if it is less than 600 kg / m 3 , there is a problem that sufficient early strength cannot be obtained, and if it exceeds 920 kg / m 3 , there is a problem that light weight cannot be obtained sufficiently. Therefore, as described above, in the present embodiment, it is set to 600 to 920 kg / m 3 .
軽量粗骨材量については、４００ｋｇ／ｍ３未満とすると、軽量性を十分に得られないという問題があり、また、８００ｋｇ／ｍ３を超えると、早強性を十分に得られないという問題があるため、上述の通り本実施形態においては、４００〜８００ｋｇ／ｍ３としている。 Regarding the amount of lightweight coarse aggregate, if it is less than 400 kg / m 3 , there is a problem that lightness cannot be obtained sufficiently, and if it exceeds 800 kg / m 3 , the problem that early strength cannot be obtained sufficiently. Therefore, as described above, in the present embodiment, it is set to 400 to 800 kg / m 3 .
本発明の第二実施形態に係る「早強性軽量コンクリートの製造方法」は、水、セメント、普通細骨材、軽量粗骨材、及び、軽量粗骨材を混合し、練り混ぜ、打設し、養生してコンクリートを製造する方法において、セメントとして、早強ポルトランドセメント（ＪＩＳ Ｒ５２１０）を使用し、軽量細骨材として、絶乾密度が１．３ｇ／ｃｍ３以上１．８ｇ／ｃｍ３未満の人工軽量細骨材（ＪＩＳ Ａ５００２ 構造用コンクリート骨材Ｍ品（細骨材））を使用し、軽量粗骨材として、絶乾密度が１．０ｇ／ｃｍ３以上１．５ｇ／ｃｍ３未満の人工軽量粗骨材（ＪＩＳ Ａ５００２ 構造用コンクリート骨材Ｍ品（粗骨材））を使用し、単位セメント量を３５０〜５００ｋｇ／ｍ３とし、水／セメント比を３５〜４５重量％とし、普通細骨材量を１５０〜７００ｋｇ／ｍ３とし、軽量細骨材量を１２０〜５２０ｋｇ／ｍ３（普通細骨材容積：軽量細骨材容積＝２５：７５〜７５：２５）とし、軽量粗骨材量を４００〜８００ｋｇ／ｍ３とし、これらの材料を練り混ぜ、打設し、養生することを特徴とするものである。 According to the second embodiment of the present invention, “a method for producing early-strength lightweight concrete” includes mixing water, cement, ordinary fine aggregate, lightweight coarse aggregate, and lightweight coarse aggregate, kneading, and placing. and a method of curing to the production of concrete, cement, using the early-strength Portland cement (JIS R5210), as a lightweight fine aggregate, absolute dry density of 1.3 g / cm 3 or more 1.8 g / cm 3 less artificial lightweight fine aggregate used (JIS A5002 structural concrete aggregate M article (fine aggregate)) and, as a lightweight coarse aggregate, absolute dry density of 1.0 g / cm 3 or more 1.5 g / cm 3 Less than artificial lightweight coarse aggregate (JIS A5002 structural concrete aggregate M product (coarse aggregate)), unit cement amount is 350-500kg / m 3 and water / cement ratio is 35-45% by weight , Ordinary fine aggregate amount 150 to 700 kg / m 3 , the amount of light fine aggregate is 120 to 520 kg / m 3 (ordinary fine aggregate volume: light fine aggregate volume = 25: 75 to 75:25), and the amount of light coarse aggregate is 400 ˜800 kg / m 3, and these materials are kneaded, placed, and cured.
尚、普通細骨材としては、山砂、石灰砕砂、或いは、その他の一般的な細骨材を使用することができる。また、軽量骨材（軽量細骨材及び軽量粗骨材）としては、骨材工場で事前吸水された高含水状態のものを用い、更に、材料を混合する際には、軽量骨材（軽量細骨材及び軽量粗骨材）に対してプレウェッティングを行い、軽量細骨材及び軽量粗骨材を予め十分に吸水させた状態で他の材料と混合する。これにより、自己収縮を低減することができるほか、ポンプ圧送性を確保することができる。また、原料の混合に際しては、耐久性や施工性に応じて、化学混和剤を適宜混合することもできる。 In addition, as a normal fine aggregate, mountain sand, lime crushed sand, or other general fine aggregates can be used. As lightweight aggregates (lightweight fine aggregates and lightweight coarse aggregates), those with a high water content preabsorbed in an aggregate factory are used. Prewetting is performed on the fine aggregate and the lightweight coarse aggregate), and the lightweight fine aggregate and the lightweight coarse aggregate are mixed with other materials in a state where water is sufficiently absorbed in advance. As a result, self-shrinkage can be reduced, and pumpability can be secured. In addition, when mixing the raw materials, a chemical admixture can be appropriately mixed according to durability and workability.
上記方法を実施することにより、材齢２日で、即ち、打設後２日という短い養生期間で、圧縮強度が３０Ｎ／ｍｍ２以上、単位重量が１８〜２０ｋＮ／ｍ３の早強性軽量コンクリートを製造することができる。 By carrying out the above-mentioned method, it is a lightweight material with a compressive strength of 30 N / mm 2 or more and a unit weight of 18 to 20 kN / m 3 at a material age of 2 days, that is, a short curing period of 2 days after placement. Concrete can be manufactured.
尚、軽量細骨材として、絶乾密度が１．３ｇ／ｃｍ３未満のもの（ＪＩＳ Ａ５００２ 構造用コンクリート骨材Ｌ品（細骨材））を使用した場合、早強性を十分に得られないという問題があり、また、絶乾密度が１．８ｇ／ｃｍ３以上のもの（ＪＩＳ Ａ５００２ 構造用コンクリート骨材Ｈ品（細骨材））を使用した場合、第一実施形態に比べ更なる軽量性を十分に得られないという問題があるため、上述の通り本実施形態においては、絶乾密度が１．３ｇ／ｃｍ３以上１．８ｇ／ｃｍ３未満の軽量細骨材（ＪＩＳ Ａ５００２ 構造用コンクリート骨材Ｍ品（細骨材））を使用している。更に、天然軽量細骨材を使用する場合には、早強性を十分に得られないという問題があるため、本実施形態においては、人工軽量細骨材を使用している。 In addition, when light-weight fine aggregates with an absolute dry density of less than 1.3 g / cm 3 (JIS A5002 structural concrete aggregate L (fine aggregate)) are used, sufficient early strength can be obtained. There is also a problem that there is no problem, and when the absolute dry density is 1.8 g / cm 3 or more (JIS A5002 structural concrete aggregate H product (fine aggregate)), it is further compared to the first embodiment. Since there is a problem that sufficient lightness cannot be obtained, in the present embodiment as described above, a lightweight fine aggregate (JIS A5002 structure) having an absolute dry density of 1.3 g / cm 3 or more and less than 1.8 g / cm 3. Concrete aggregate M product (fine aggregate) is used. Furthermore, when natural lightweight fine aggregate is used, there is a problem that sufficient early strength cannot be obtained. Therefore, in this embodiment, an artificial lightweight fine aggregate is used.
また、軽量粗骨材として、絶乾密度が１．０ｇ／ｃｍ３未満のもの（ＪＩＳ Ａ５００２ 構造用コンクリート骨材Ｌ品（粗骨材））を使用した場合、早強性を十分に得られないという問題があり、また、絶乾密度が１．５ｇ／ｃｍ３以上のもの（ＪＩＳ Ａ５００２ 構造用コンクリート骨材Ｈ品（粗骨材））を使用した場合、軽量性を十分に得られないという問題があるため、上述の通り本実施形態においては、絶乾密度が１．０ｇ／ｃｍ３以上１．５ｇ／ｃｍ３未満の軽量粗骨材（ＪＩＳ Ａ５００２ 構造用コンクリート骨材Ｍ品（粗骨材））を使用している。更に、天然軽量粗骨材を使用する場合には、早強性を十分に得られないという問題があるため、本実施形態においては、人工軽量粗骨材を使用している。 Further, when a light coarse aggregate having an absolute dry density of less than 1.0 g / cm 3 (JIS A5002 structural concrete L product (coarse aggregate)) is used, sufficient early strength can be obtained. In addition, there is a problem that the dry density is 1.5 g / cm 3 or more (JIS A5002 Structural aggregate H product (coarse aggregate)), the lightness cannot be sufficiently obtained. Therefore, in the present embodiment, as described above, a light-weight coarse aggregate having an absolute dry density of 1.0 g / cm 3 or more and less than 1.5 g / cm 3 (JIS A5002 structural concrete aggregate M product (coarse) Aggregate)) is used. Further, when natural lightweight coarse aggregate is used, there is a problem that sufficient early strength cannot be obtained. Therefore, in this embodiment, artificial lightweight coarse aggregate is used.
また、単位セメント量を３５０ｋｇ／ｍ３未満とすると、早強性を十分に得られないという問題があり、また、５００ｋｇ／ｍ３を超えると、自己収縮が生じるという問題があるため、上述の通り本実施形態においては、単位セメント量を３５０〜５００ｋｇ／ｍ３としている。 Further, when the unit cement amount is less than 350 kg / m 3 , there is a problem that sufficient early strength cannot be obtained, and when it exceeds 500 kg / m 3 , there is a problem that self-shrinkage occurs. As described above, in this embodiment, the unit cement amount is set to 350 to 500 kg / m 3 .
水／セメント比については、３５重量％未満とすると、自己収縮が生じるという問題があり、また、４５重量％を超えると、早強性を十分に得られないという問題があるため、上述の通り本実施形態においては、３５〜４５重量％としている。 When the water / cement ratio is less than 35% by weight, there is a problem that self-shrinkage occurs, and when it exceeds 45% by weight, there is a problem that sufficient early strength cannot be obtained. In this embodiment, it is 35 to 45% by weight.
普通細骨材量については、１５０ｋｇ／ｍ３未満とすると、早強性を十分に得られないという問題があり、また、７００ｋｇ／ｍ３を超えると、第一実施形態に比べ更なる軽量性を十分に得られないという問題があるため、上述の通り本実施形態においては、１５０〜７００ｋｇ／ｍ３としている。 When the amount of ordinary fine aggregate is less than 150 kg / m 3 , there is a problem that sufficient early strength cannot be obtained, and when it exceeds 700 kg / m 3 , the light weight is further reduced as compared with the first embodiment. In the present embodiment, as described above, 150 to 700 kg / m 3 is used.
軽量細骨材量については、１２０ｋｇ／ｍ３未満とすると、第一実施形態に比べ更なる軽量性を十分に得られないという問題があり、また、５２０ｋｇ／ｍ３を超えると、早強性を十分に得られないという問題があるため、上述の通り本実施形態においては、１２０〜５２０ｋｇ／ｍ３としている。 When the amount of lightweight fine aggregate is less than 120 kg / m 3 , there is a problem that further lightness cannot be sufficiently obtained as compared with the first embodiment, and when it exceeds 520 kg / m 3 , the early strength In the present embodiment as described above, it is set to 120 to 520 kg / m 3 .
軽量粗骨材量については、４００ｋｇ／ｍ３未満とすると、軽量性を十分に得られないという問題があり、また、８００ｋｇ／ｍ３を超えると、早強性を十分に得られないという問題があるため、上述の通り本実施形態においては、４００〜８００ｋｇ／ｍ３としている。 Regarding the amount of lightweight coarse aggregate, if it is less than 400 kg / m 3 , there is a problem that lightness cannot be obtained sufficiently, and if it exceeds 800 kg / m 3 , the problem that early strength cannot be obtained sufficiently. Therefore, as described above, in the present embodiment, it is set to 400 to 800 kg / m 3 .
本発明の第三実施形態に係る「合成床版の製造方法」は、上記第一実施形態又は第二実施形態に係る早強性軽量コンクリートの製造方法を実施することにより、底鋼板の上に早強性軽量コンクリートの層を形成することを特徴とするものである。 According to the third embodiment of the present invention, the “synthetic floor slab manufacturing method” is performed on the bottom steel plate by carrying out the method of manufacturing the early strength lightweight concrete according to the first embodiment or the second embodiment. It is characterized by forming a layer of early strength lightweight concrete.
以下、本発明の発明者らが行った各種試験の結果を、本発明の実施例として説明する。 Hereinafter, the results of various tests conducted by the inventors of the present invention will be described as examples of the present invention.
まず、水、早強ポルトランドセメント、普通細骨材（山砂）、及び、人工軽量粗骨材（絶乾密度：１．０ｇ／ｃｍ３以上１．５ｇ／ｃｍ３未満、骨材工場で事前吸水された高含水状態のもの、プレウェッティング実施）を、表１に示す３通りの配合比率（実施例１〜３）で混合し、練り混ぜ、試験型枠内に打設した。尚、実施例１〜３の配合比率は、いずれも上記第一実施形態において説明した配合比率の範囲内となっている。 First, water, early-strength Portland cement, ordinary fine aggregate (mountain sand), and artificial lightweight coarse aggregate (absolute dryness: 1.0 g / cm 3 or more and less than 1.5 g / cm 3 , pre-aggregate at the aggregate factory The water-absorbed high water content state (prewetting was carried out) was mixed at three blending ratios (Examples 1 to 3) shown in Table 1, kneaded, and placed in a test mold. In addition, the compounding ratios of Examples 1 to 3 are all within the range of the compounding ratios described in the first embodiment.
打設後、養生期間として２日（４８時間）が経過した時点で、それぞれの圧縮強度を計測したところ、実施例１〜３のいずれについても、設計強度である３０Ｎ／ｍｍ２を超えていることが確認された。 When 2 days (48 hours) passed as the curing period after placing, when each compressive strength was measured, all of Examples 1 to 3 exceeded the design strength of 30 N / mm 2 . It was confirmed.
また、５日経過時点まで、１日毎に収縮量の計測を行ったところ、実施例１〜３のいずれについても、収縮は認められなかった。人工軽量粗骨材として骨材工場で事前吸水された高含水状態のものを用い、更に、材料の混合に際して、人工軽量粗骨材に対してプレウェッティングを実施したことにより、収縮を回避できたものと考えられる。尚、表１からも明らかなように、実施例１〜３においては、膨張材は一切配合されていない。そして上記結果より、本発明に係る方法においては、収縮を回避するために膨張材を配合する必要はない、つまり、膨張材の配合を省略することができる、という効果を期待できることが確認された。 Moreover, when the amount of contraction was measured every day until the lapse of 5 days, no contraction was observed in any of Examples 1 to 3. By using pre-wetting on the artificial lightweight coarse aggregate at the time of mixing the materials, it is possible to avoid shrinkage. It is thought that. As is clear from Table 1, in Examples 1 to 3, no expansion material is blended. From the above results, it was confirmed that in the method according to the present invention, it is not necessary to add an expanding material in order to avoid shrinkage, that is, the effect that the mixing of the expanding material can be omitted can be expected. .
次に、水、早強ポルトランドセメント、普通細骨材（山砂）、人工軽量細骨材（絶乾密度：１．３ｇ／ｃｍ３以上１．８ｇ／ｃｍ３未満、骨材工場で事前吸水された高含水状態のもの、プレウェッティング実施）、及び、人工軽量粗骨材（絶乾密度：１．０ｇ／ｃｍ３以上１．５ｇ／ｃｍ３未満、骨材工場で事前吸水された高含水状態のもの、プレウェッティング実施）を、表２に示す３通りの配合比率（実施例４〜６）で混合し、練り混ぜ、試験型枠内に打設した。尚、実施例４〜６の配合比率は、いずれも上記第二実施形態において説明した配合比率の範囲内となっている。 Next, water, early-strength Portland cement, ordinary fine aggregate (mountain sand), artificial lightweight fine aggregate (absolute dryness: 1.3 g / cm 3 or more and less than 1.8 g / cm 3 , pre-absorbed in the aggregate factory High moisture content, pre-wetting conducted) and artificial lightweight coarse aggregate (absolute dryness: 1.0 g / cm 3 or more and less than 1.5 g / cm 3 , high pre-absorbed in an aggregate factory) The ones containing water and prewetting were mixed at three blending ratios (Examples 4 to 6) shown in Table 2, kneaded, and placed in a test mold. In addition, all the mixture ratios of Examples 4 to 6 are within the range of the mixture ratios described in the second embodiment.
打設後、養生期間として２日（４８時間）が経過した時点で、それぞれの圧縮強度を計測したところ、実施例４〜６のいずれについても、設計強度である３０Ｎ／ｍｍ２を超えていることが確認された。 When 2 days (48 hours) passed as a curing period after placement, when each compressive strength was measured, all of Examples 4 to 6 exceeded the design strength of 30 N / mm 2 . It was confirmed.
また、５日経過時点まで、１日毎に収縮量の計測を行ったところ、実施例４〜６のいずれについても、収縮は認められなかった。人工軽量細骨材及び人工軽量粗骨材として骨材工場で事前吸水された高含水状態のものを用い、更に、材料の混合に際して、人工軽量細骨材、及び、人工軽量粗骨材に対してプレウェッティングを実施したことにより、収縮を回避できたものと考えられる。尚、表２からも明らかなように、実施例４〜６においても、膨張材は一切配合されていない。そして上記結果より、本発明に係る方法においては、収縮を回避するために膨張材を配合する必要はない、つまり、膨張材の配合を省略することができる、という効果を期待できることが確認された。 Moreover, when the amount of contraction was measured every day until the lapse of 5 days, no contraction was observed in any of Examples 4 to 6. Artificial lightweight fine aggregates and artificial lightweight coarse aggregates with high water content pre-absorbed in an aggregate factory are used, and when mixing materials, artificial lightweight fine aggregates and artificial lightweight coarse aggregates are used. It is considered that the pre-wetting was able to avoid contraction. In addition, as is clear from Table 2, also in Examples 4 to 6, no expansion material is blended. From the above results, it was confirmed that in the method according to the present invention, it is not necessary to add an expanding material in order to avoid shrinkage, that is, the effect that the mixing of the expanding material can be omitted can be expected. .
Claims (3)
セメントとして、早強ポルトランドセメントを使用し、
軽量細骨材として、絶乾密度が１．３ｇ／ｃｍ３以上１．８ｇ／ｃｍ３未満の人工軽量細骨材を使用し、
軽量粗骨材として、絶乾密度が１．０ｇ／ｃｍ３以上１．５ｇ／ｃｍ３未満の人工軽量粗骨材を使用し、
単位セメント量を３５０〜５００ｋｇ／ｍ３とし、
水／セメント比を３５〜４５重量％とし、
普通細骨材量を１５０〜７００ｋｇ／ｍ３とし、
軽量細骨材量を１２０〜５２０ｋｇ／ｍ３とし、
軽量粗骨材量を４００〜８００ｋｇ／ｍ３とし、
プレウェッティングを行って吸水させた状態の軽量細骨材及び軽量粗骨材を、他の材料と混合することを特徴とする早強性軽量コンクリートの製造方法。 In the method of manufacturing concrete by mixing water, cement, ordinary fine aggregate, lightweight fine aggregate, and lightweight coarse aggregate, kneading, placing, curing,
As cement, use early strong Portland cement,
As a lightweight fine aggregate, an artificial lightweight fine aggregate having an absolute dry density of 1.3 g / cm 3 or more and less than 1.8 g / cm 3 is used.
As a lightweight coarse aggregate, an artificial lightweight coarse aggregate having an absolute dry density of 1.0 g / cm 3 or more and less than 1.5 g / cm 3 is used,
The unit cement amount is 350 to 500 kg / m 3 ,
The water / cement ratio is 35 to 45% by weight,
The amount of ordinary fine aggregate is 150 to 700 kg / m 3 ,
The amount of lightweight fine aggregate is 120 to 520 kg / m 3 ,
The amount of light coarse aggregate is 400 to 800 kg / m 3 ,
A method for producing fast-strength lightweight concrete, characterized by mixing a lightweight fine aggregate and a lightweight coarse aggregate in a state of water absorption by prewetting and mixing with other materials .
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