JP2005035837A - Cement composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cement composition or the like giving functions such as the suppression of lowering of flowability, the prevention of the occurrence of shrinkage crack or the suppression of neutralization to cement concrete mainly comprising eco-cement. <P>SOLUTION: The cement composition contains a material containing one or more kinds of non-hydraulic compounds selected from a group of γ-2CaO-SiO<SB>2</SB>, α-CaO-SiO<SB>2</SB>and calcium magnesium silicate and waste recycle type cement produced by using municipal refuse incineration ash as a raw material. The cement composition is suitable for the civil engineering and building application because the functions such as neutralization resistance, the suppression of the lowering of flowability, the decrease of environmental load or the prevention of shrinkage crack caused by excess strength development and features such as the effective utilization of by-products in various industries such as municipal refuse or steel making slag or the volume reduction of urban waste are given to the cement concrete mainly comprising the eco-cement. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention mainly relates to a cement composition used in the civil engineering and construction industry, and cement concrete using the same.

  In the present invention, “parts” and “%” are based on mass unless otherwise specified. Moreover, the cement concrete said by this invention is a general term for cement paste, mortar, and concrete.

  In recent years, the durability problem of concrete has been greatly highlighted. Since the water / cement ratio of concrete has a significant effect on durability, the frequency of use of high-performance water-reducing agents and high-performance AE water-reducing agents has increased rapidly and guidelines have been issued for the purpose of reducing the unit water volume. However, there is a problem that the longer the unit water volume is, the longer the usable time cannot be taken due to the larger change in consistency (fluidity). At present, sufficient maintenance and durability of the consistency are achieved. The fact is that there are no drastic measures to achieve both.

Recently, waste-based cement (hereinafter referred to as “eco-cement”), which is produced using municipal waste incineration ash as a raw material, has been in the limelight, making it difficult for alkali-aggregate reactions to occur and reducing the environmental impact. High expectations are also given from the standpoint that a volume reduction system can be established (see Patent Documents 1-3). However, compared to ordinary Portland cement, this ecocement contains 3CaO · Al ₂ O ₃ and 11CaO · 7Al ₂ O ₃ · CaCl ₂ which are calcium aluminate compounds. It had the subject that a fall was remarkable.

  Since fluidity is closely related to the occurrence of construction defects, it is an extremely important performance. Usually, cement concrete is required to maintain its fluidity for a predetermined time or more until it is held sideways from the raw concrete plant, transported to the construction site, and constructed. However, if the elapsed time until construction greatly exceeds the specified time due to traffic jams during the transport of cement concrete or troubles at the site, etc., the fluidity of the concrete will be outside the specified standards. In many cases. In such a case, there is no method other than performing a so-called refluidization treatment in which a high-performance AE water reducing agent is added and fluidized again.

  However, the reality is that only the skilled person can perform this refluidization process. Thus, today, there is a strong demand for the development of concrete that is excellent in fluidity retention performance even when eco-cement having a large decrease in fluidity is used.

  At present, as the means to reduce the change over time in the flowability of so-called eco-cement, which is produced from municipal waste, the only way to consider that the amount of unit cement is not too large is considered. . However, this method has problems such as easy material separation, poor pumpability, and increased workability due to increased viscosity.

  On the other hand, new international standards are being studied overseas, where European standards (EN standards) are the basic concept and cement materials grouped roughly into strength classes can be selected according to the purpose.

European standards (EN standards) are roughly classified 32.5N / mm ² class, 42.5N / mm ² class, and 52.5 N / mm ² class (see Non-Patent Document 1 and the like).

  On the other hand, in Japan, the quality of cement has been designed based on JIS standards. As a result, cement with good strength development under uniform specifications has been evaluated as a good cement.

As a result, the Japanese cement is classified in EN standard, only those corresponding to the cement 42.5N / mm ² class or 52.5 N / mm ² class have become the absence, blended concrete design strength is not very high Even when trying to design, in many cases, it tends to become excessive strength.

  Prevention of excessive strength is important from the viewpoint of preventing excessive heat generation due to hydration, and from the viewpoint of preventing cracking after curing by reducing the shrinkage ratio before and after curing as much as possible.

  On the other hand, it is conceivable to mix and design concrete that does not have a very high design strength by reducing the amount of cement per unit volume using cement with excellent strength development. There was a problem that the amount becomes small, the material is easily separated, and the concrete has a high bleeding rate, that is, a so-called “shabu-con”.

  When a concrete structure is constructed using such concrete, macroscopic defects are likely to occur, and it has been difficult to construct a durable concrete structure.

As described above, the EN standard is characterized by the preparation of 32.5 N / mm ² class cement that is easy to mix and design concrete that is not very high in design strength.

  At present, the mainstream of this cement is limestone mixed cement. The limestone mixed cement is a cement obtained by mixing a large amount of fine limestone powder with Portland cement, and can realize both prevention of excess strength and improvement of material separation resistance.

  Limestone fine powder can be regarded as an inert powder from the standpoint of strength development, and has the advantage that it provides only material separation resistance and does not cause extra strength or heat of hydration. Against this background, research on limestone mixed cement has been actively conducted in Japan.

Here, if the so-called eco-cement, which is produced from municipal waste, and limestone fine powder are combined into a 32.5 N / mm ² class cement, the unit powder amount can be secured easily, resulting in excess It is expected that it will not be necessary to add new eco-cement. Therefore, it is considered that the change with time of the fluidity of cement concrete mainly composed of ecocement can be reduced.

  However, limestone is an important raw material in many industries. Limestone is a precious natural resource for Japan, which has few resources, and simply using it in concrete leads to depletion of resources, so it is eagerly desired to use it more effectively as an industrial raw material. Furthermore, limestone mixed cement has a weak point that it is easily neutralized.

As a result of intensive studies to solve the above-mentioned problems of limestone mixed cement, the present inventor has found that γ-2CaO · SiO _{2 that} has not been found to have utility value as a cement admixture until now has strength development and material separation. It was found that the resistance is equivalent to that of limestone fine powder and has a neutralization suppressing function not found in limestone fine powder, and was filed earlier (see Patent Documents 4 to 5).

It has been found that this cement admixture containing γ-2CaO · SiO ₂ not only suppresses neutralization of Portland cement, but also has an effect of reducing hydration heat generation. That is, by suppressing the heat generation at the time of hydration of Portland cement, it is possible to suppress the heat shrinkage after curing and to suppress the occurrence of cracks in the cured body.

Therefore, the present inventor has focused on steelmaking slag, which is an industrial by-product and contains non-hydraulic substances such as γ-2CaO · SiO _{2, and} uses these non-hydraulic substances as admixtures. The use of the contained cement composition was examined.

  Comparing the cement composition using the admixture of the present invention and the cured product using the cement composition using the lime fine powder admixture, the compressive strength is the same if the admixture amount is the same. And the calorific value at the time of hydration is small, and it was found that the neutralization suppression effect is better than the cured product using the lime fine powder admixture.

Moreover, it leads also to the effective utilization of the steelmaking slag in which the effective utilization method is not discovered until now, ie, an electric furnace reduction | restoration period slag, a stainless steel slag, a hot metal pretreatment slag, a converter slag, etc. Furthermore, since the amount of clinker blended can be reduced by utilizing these slags, attention was paid to the point that the cement composition can be a low environmental load type.
Japanese Unexamined Patent Publication No. 07-165446 JP 10-279332 A Japanese Patent Laid-Open No. 11-199301 International Publication No. 03/016234 Pamphlet Japanese Patent Application No. 2003-084495 Koji Goto, Shunsuke Habara, Internationalization of cement standards-Outline and direction of European standards, Cement and concrete, No.631, pp1-8, 1999

  The present invention is mainly composed of eco-cement, and has excellent properties such as neutralization resistance, fluidity reduction suppression, environmental load reduction, and prevention of shrinkage cracking due to the development of excessive strength. To provide a cement concrete composition that leads to effective use.

The present invention relates to a substance containing one or more non-hydraulic compounds selected from the group consisting of γ-2CaO · SiO ₂ , α-CaO · SiO ₂ and calcium magnesium silicate, and municipal waste incineration ash. It is a cement composition containing waste-use cement manufactured as a raw material, and the total content of aluminate phase and ferrite phase in waste-use cement manufactured using municipal waste incineration ash as a raw material is 20 % Of the cement composition, wherein the content of fluorine contained in the substance containing the non-hydraulic compound is 2% or less. The cement composition is characterized in that the substance containing a hydraulic compound is steelmaking slag, and the content of the non-hydraulic compound contained in the substance containing the non-hydraulic compound is 65% or more. The A The cement composition according to symptom, a said cement composition γ-2CaO · SiO ₂ content of substances containing non-hydraulic compound is characterized in that 35% or more, said cement composition Cement concrete containing

  The waste-use type cement (eco-cement) manufactured using the municipal waste incineration ash as a raw material in the present invention is not particularly limited. There are two types of ecocement: normal ecocement and fast-cure ecocement.

Ordinary eco-cement has a very low chlorine content, the main component of the aluminate phase is 3CaO · Al ₂ O ₃ , and the fast-cure eco-cement has a high chlorine content and the main component of the aluminate phase is 11CaO · 7Al ₂ O. ₃・ CaCl ₂ is different. What is common to ordinary eco-cement and fast-cure eco-cement is that the content of aluminate phase and ferrite phase is much higher than ordinary portland cement. Specifically, the total amount of aluminate phase and ferrite phase is 20% or more. And since there are many aluminate phases and ferrite phases, the change with time of fluidity is large, and the resistance to neutralization is also small.

The present invention, the term aluminate phase and are _{CaO · Al 2 O 3, 12CaO} · 7Al 2 O 3, is a generic term for 3CaO · Al ₂ O _3, calcium ferrite phase aluminosilicate ferrite _{4CaO · Al 2 O 3 · Fe} 2 O ₃ is pointed out.

The cement composition of the present _{invention, γ-2CaO · SiO 2,} α -type wollastonite _{(α-CaO · SiO 2)} , Meruvi Night 3CaO · MgO · 2SiO _2, Akerumanaito 2CaO · MgO · 2SiO _2, Monch Celite CaO · One of the features is that a substance containing one or two or more non-hydraulic compounds selected from the group consisting of calcium magnesium silicates such as MgO · SiO ₂ is used. In the present invention, steel slag can also be used as a substance containing these non-hydraulic compounds (hereinafter simply referred to as non-hydraulic substance).

Each non-hydraulic substance used in the present invention contains one or more non-hydraulic compounds selected from the group consisting of γ-2CaO · SiO ₂ , α-type wollastonite, and / or calcium magnesium silicate. There is no particular limitation as long as it is. When steelmaking slag is used as the non-hydraulic substance, it is possible to use one or more steelmaking slags.

  The steelmaking slag as used in the present invention is a general term for slag generated in the steelmaking process, and specifically includes electric furnace reduction period slag, hot metal pretreatment slag, converter slag, and stainless steel slag.

The present inventors have found that the present invention is effective as long as it contains a non-hydraulic compound among the steelmaking slags. That is, even one of the above steelmaking slags is not subject to the present invention for those containing β-2CaO · SiO ₂ and not containing non-hydraulic compounds such as γ-2CaO · SiO ₂ , It is necessary to contain a non-hydraulic compound. The content of the non-hydraulic compound is preferably 65% or more, and more preferably 70% or more. If the total of non-hydraulic compounds is less than 65%, it may cause a change in consistency over time, and the neutralization suppressing effect may be reduced.

The content of γ-2CaO · SiO _{2 in} the non-hydraulic substance is not particularly limited, but is preferably 35% or more, more preferably 45% or more of the whole non-hydraulic substance. Further, the upper limit of the content of γ-2CaO · SiO ₂ is not particularly limited. In steelmaking slag, γ-2CaO · SiO ₂ content is more electric furnace reduction period slag or stainless slag is preferred.

The non-hydraulic substance contains γ-2CaO · SiO ₂ and preferably contains 60% or more of the non-hydraulic compound, and more preferably contains 70% or more of the non-hydraulic compound.

Although the non-aqueous elemental components of each of the rigid material is not particularly limited, _{specifically, CaO, SiO 2, Al 2} O 3, MnO 2, F, and MgO and the like as the major chemical component, other , TiO ₂ , Na ₂ O, S, P ₂ O ₅ , Fe ₂ O _{3 and the} like.

Further, the compounds other than those described above contained in the non-hydraulic substance are not particularly limited, and may contain a small amount of a hydraulic compound or the like as long as the object of the present invention is not impaired. The compound contained in the non-hydraulic substances such as dicalcium silicate 2CaO · SiO _2, such as beta-type and α-type, tri-calcium silicate 3CaO · SiO ₂ and rankinite night 3CaO · 2SiO ₂ and beta-type wollastonite (beta -CaO · SiO ₂₎ calcium such as silicates, 12CaO · 7Al ₂ O _3, calcium aluminate such as _{11CaO · 7Al 2 O 3 · CaF} 2 or 3CaO · Al ₂ O _3, gehlenite 2CaO · Al ₂ O ₃ · SiO calcium aluminosilicates such as ₂ or anorthite _{CaO · Al 2 O 3 · 2SiO} 2, a mixed crystal of Akerumanaito 2CaO · MgO · 2SiO ₂ and gehlenite _{2CaO · Al 2 O 3 · SiO} 2 melilite, free lime, free magnesia , Calcium ferrite 2CaO · Fe ₂ O ₃ , Calcium aluminoferrite 4CaO · Al ₂ O ₃ · Fe ₂ O ₃ , Leucite (K ₂ O, Na ₂ O) · Al ₂ O ₃ · SiO ₂ , Spinel MgO · Al ₂ O ₃ and magnetite Fe ₃ O ₄ may be included.

Some steelmaking slag has a high content of hydraulic compound. The hydraulic compounds here are calcium aluminates such as CaO · Al ₂ O ₃ , 12CaO · 7Al ₂ O ₃ , 11CaO · 7Al ₂ O ₃ · CaF ₂ , 3CaO · Al ₂ O ₃ , calcium aluminoferrite 4CaO -Al ₂ O ₃ · Fe ₂ O ₃ , calcium ferrite 2CaO · Fe ₂ O ₃ , free lime, free magnesia, dicalcium silicate 2CaO · SiO ₂ such as β-type and α-type, and the like. The number of these hydraulic compounds is preferably small, and the total of the hydraulic compounds is preferably 35% or less, more preferably 30% or less. When the total of the hydraulic compounds exceeds 35%, it may cause a change in consistency over time, and the neutralization suppressing effect may be reduced.

Some steelmaking slag has a high fluorine content. The steelmaking slag containing fluorine, 12CaO · 7Al ₂ O ₃ except that exists in a solid solution the form _{11CaO · 7Al 2 O 3 · CaF} 2 fluorines some γ-2CaO · SiO ₂ Kasupidin (Cuspidine) ( 3CaO · 2SiO ₂ · CaF ₂ ). In some cases, 12CaO · 7Al ₂ O ₃ or 11CaO · 7Al ₂ O ₃ · CaF ₂ and free CaF ₂ coexist as a fluorine source. γ-2CaO · SiO ₂ has a remarkable neutralization-inhibiting effect, but compounds containing fluorine such as 11CaO · 7Al ₂ O ₃ · CaF ₂ and caspidine have no neutralization-inhibiting effect. In many steelmaking slags, the effect of suppressing neutralization may not be significant.

  Moreover, since fluorine inhibits the setting and hardening of Portland cement, it may cause setting delay and poor hardening. Furthermore, fluorine is a substance subject to the regulation of the Law Concerning Promotion of Improvement of Management and Management of Grasp of Specific Chemical Substances in the Environment (PRTR Law), and those containing a large amount of fluorine are not preferable from the viewpoint of environmental conservation.

  The total fluorine content of the non-hydraulic substance is preferably 2.0% or less, more preferably 1.5% or less, regardless of the form of the non-hydraulic substance. If the total fluorine content exceeds 2.0%, a sufficient neutralization suppressing effect may not be obtained, and the setting / curing properties may be deteriorated. Furthermore, as described above, there is a concern about fluorine elution from a cured Portland cement using the same, which is not preferable from the viewpoint of environmental problems.

Some steelmaking slag contains a large amount of 12CaO · 7Al ₂ O ₃ exhibiting rapid setting or rapid hardening or 11CaO · 7Al ₂ O ₃ · CaF _{2 in} which fluorine is dissolved. The use of steelmaking slag with a low content of these compounds is preferable from the viewpoints of ensuring fluidity and a pot life unless a setting retarder is used in combination.

That is, the content of 12CaO · 7Al ₂ O ₃ and / or 11CaO · 7Al ₂ O ₃ · CaF _{2 in} the steelmaking slag is not particularly limited, but is preferably 25% or less, and more preferably 15% or less. If the total of 12CaO · 7Al ₂ O ₃ and / or 11CaO · 7Al ₂ O ₃ · CaF ₂ in this admixture exceeds 25%, the neutralization inhibitory effect may be reduced, fluidity may be deteriorated, The use time may not be secured, and if a setting retarder is used, the fluidity can be adjusted, but it is difficult to set an appropriate amount of use, and sufficient fluidity retention effect cannot be obtained or the setting is poor. There is a case.

Blaine specific surface area of the non-hydraulic substances, but are not particularly limited, can be used at about 1,500~8,000cm ² / g, preferably 2,000~6,000cm ² / g, 3,000~5,000cm ² / g is more preferred. If it is less than 1,500 cm ² / g, a sufficient neutralization suppressing effect may not be obtained, and if it exceeds 8,000 cm ² / g, workability may be deteriorated.

  The amount of the non-hydraulic substance used is not particularly limited, but is usually preferably 5 to 50 parts, more preferably 10 to 30 parts with respect to 100 parts of the cement composition composed of ecocement and the non-hydraulic substance. preferable. If it is less than 5 parts, the effect of the present invention may not be sufficiently obtained, and if it is used in excess of 50 parts, strength development may be deteriorated.

  In this invention, you may use together well-known cement other than the cement composition of this invention. As well-known cements, various portland cements such as normal, early strength, super early strength, low heat, and moderate heat, various mixed cements obtained by mixing these portland cements with blast furnace slag, fly ash, or silica, and limestone powder Etc., filler cement mixed with blast furnace slow-cooled slag fine powder, alumina cement, and the like, and one or more of these can be used in combination.

The particle size of the cement composition of the present invention is not particularly limited since it depends on the purpose and application of use, generally preferably 2,000~8,000cm ^{2 /} g in Blaine specific surface area value, 3,000～5,000Cm ² / g is more preferred. If it is less than 2,000 cm ² / g, sufficient strength development may not be obtained, and if it exceeds 8,000 cm ² / g, workability may deteriorate.

  In the present invention, in addition to aggregates such as sand and gravel, blast furnace granulated slag fine powder, limestone fine powder, fly ash, silica fume and other admixtures, water reducing agent, AE water reducing agent, high performance water reducing agent, high performance AE water reducing agent, antifoaming agent, thickening agent, rust preventive agent, antifreeze agent, shrinkage reducing agent, polymer, setting modifier, fiber material such as steel fiber, vinylon fiber, carbon fiber, clay mineral such as bentonite, and In addition, one or more of anion exchangers such as hydrotalcite can be used as long as the object of the present invention is not substantially inhibited.

  In the present invention, the mixing method of each material is not particularly limited, and the respective materials may be mixed at the time of construction, or a part or all of them may be mixed in advance.

  Any existing device can be used as the mixing device, and for example, a tilting barrel mixer, an omni mixer, a Henschel mixer, a V-type mixer, and a Nauta mixer can be used.

  The cement composition of the present invention is effective for reducing the fluidity, reducing the environmental burden, preventing shrinkage cracks due to the development of excess strength, and by-products of various industries such as municipal waste and steelmaking slag. It is suitable for civil engineering and construction applications because it can be used, reduced in volume of urban waste, and neutralized resistance to eco-cement.

A cement composition was prepared by blending ecocement and various non-hydraulic substances as shown in Table 1. Then, the unit cement amount of composition 330 kg / m ^3, unit water ^{185kg / m 3, s / a} = 46%, the measurement of the air volume 4.5 ± 1.5% of the concrete were prepared and fluidity of aging (evaluated as slump loss) Went. In addition, compression strength and neutralization resistance were also evaluated. The results are also shown in Table 1. A high-performance AE water reducing agent was used so that the slump value of concrete would be 18 ± 1.5 cm.

<Materials used>
Eco-cement (1): Average eco-cement, Pacific Ocean Cement Co., Ltd., 3CaO · SiO ₂ content of 45.3%, β-2CaO · SiO 2 content of _{16.0%, 3CaO · Al 2 O} 3 content of 14.9%, 4CaO · Al ₂ O ₃ · Fe ₂ O ₃ content 11.9%. The total of the aluminate phase and ferrite phase is 26.8%.
Eco-cement (2): rapid-type eco-cement, Pacific Ocean Cement Co., Ltd., 3CaO · SiO ₂ content of 48.4%, β-2CaO · SiO 2 content of _{8.5%, 11CaO · 7Al 2 O} 3 · CaCl 2 content of 16.2% _{, 4CaO · Al 2 O 3 ·} Fe 2 O 3 content of 6.7%. Total of aluminate phase and ferrite phase is 22.9%.
Non-hydraulic substance A: γ-2CaO · SiO ₂ , compounded with 2 moles of calcium carbonate and 1 mole of silicon dioxide, fired at 1,450 ° C. Specific gravity 3.01, Blaine specific surface area 4,000cm ² / g.
Non-hydraulic substance B: α-type wollastonite, synthetic product. Specific gravity 2.93, Blaine specific surface area 4,000cm ² / g.
Non-hydraulic substance C: Melvinite, synthetic product. Specific gravity 3.33, Blaine specific surface area 4,000cm ² / g.
Non-hydraulic substance D: Electric furnace reduction period slag, oxide equivalent CaO content 52%, oxide equivalent SiO ₂ content 27%, Al ₂ O ₃ content 11%, MgO content 0.5%, fluorine content 0.7 %, S content 0.5%. The main compound phases are about 45% γ-2CaO · SiO ₂ content, about 20% α-type wollastonite, and about 25% 12CaO · 7Al ₂ O ₃ solid solution, specific gravity 3.06, and Blaine specific surface area 4,000cm ² / g. Non-hydraulic compound content is approximately 65%, the sum of 45% γ-2CaO · SiO ₂ content and 20% α-type wollastonite content.
Non-hydraulic substance E: stainless slag, CaO content 52%, SiO ₂ content 28%, MgO content 10%, Al ₂ O ₃ content 7%, Na ₂ O content 0.5%, fluorine content 0.5% . The main compound phases are about 35% γ-2CaO · SiO ₂ content, about 44% melvinite, about 14% 12CaO · 7Al ₂ O ₃ solid solution, and about 4% free magnesia. Specific gravity 3.14, Blaine specific surface area 4,000cm ² / g. The non-hydraulic compound content is approximately 79%, the sum of 35% γ-2CaO · SiO ₂ content and 44% melvinite content.
Non-hydraulic substance F: Electric furnace reduction period slag, oxide equivalent CaO content 53%, oxide equivalent SiO ₂ content 35%, Al ₂ O ₃ content 4%, MgO content 6%, fluorine content 1.5 %, S content 0.5%. The main compound phase is approximately 40% γ-2CaO · SiO ₂ content, 14% caspidine, 40% mervinite, specific gravity 3.04, and Blaine specific surface area 4,000 cm ² / g. The non-hydraulic compound content is about 95%, which is the sum of the γ-2CaO · SiO ₂ content of 40%, the caspidine content of 14%, and the mervinite content of 40%.
Non-hydraulic substance G: Electric furnace reduction period slag, oxide equivalent CaO content 53%, oxide equivalent SiO ₂ content 26%, Al ₂ O ₃ content 13%, MgO content 5%, fluorine content 2.0 %, S content 0.5%. The main compound phase is about 40% γ-2CaO · SiO ₂ , 12% caspidine, 18% melvinite, and about 25% 12CaO · 7Al ₂ O ₃ solid solution, specific gravity 3.03, and Blaine specific surface area 4,000cm ² / g. The non-hydraulic compound content is approximately 70%, which is the sum of 40% γ-2CaO · SiO ₂ content, 12% caspidine content and 18% mervinite content.
Non-hydraulic substance H: Limestone powder, pulverized limestone from Aomi mine, Niigata Prefecture, specific gravity 2.71, specific surface area of Blaine 4,000cm ² / g.
Non-hydraulic substances I: silica rock powder, pulverized No. 7 silica sand, specific gravity 2.64, Blaine specific surface area of 4,000 cm ² / g.
Calcium carbonate: Grade 1 reagent, commercial silicon dioxide: Grade 1 reagent, commercial water: Tap water sand: Niigata Himekawa, specific gravity 2.62
Gravel: from Himekawa, Niigata Prefecture, crushed stone, specific gravity 2.64
High-performance AE water reducing agent: polycarboxylic acid, commercially available <Measurement method>
Slump loss: The slump value was measured according to JIS A 1101, and the slump value after 60 minutes was subtracted from the slump value after kneading to obtain the slump loss value.
Compressive strength: Concrete was packed in a mold to form a 10 cmφ × 20 cm cylindrical molded body, and the compressive strength at 28 days of age was measured according to JIS A 1108.
Neutralization resistance (accelerated neutralization test): Concrete is packed into a mold to create a 10cmφ × 20cm columnar molded body, which is subjected to 20 ° C water curing until the age of 28 days. Neutralization was promoted for 12 weeks in an environment with a relative humidity of 60% and carbon dioxide concentration of 5%. After accelerated neutralization, a phenolphthalein 1% alcohol solution was applied to the concrete cross section to confirm the neutralization depth, and the neutralization resistance was evaluated.

Similar to Experimental Example 1 except that non-hydraulic substance A was used and the amount of non-hydraulic substance used in 100 parts of cement composition composed of ecocement and non-hydraulic substance was changed as shown in Table 2. went. The results are also shown in Table 2. For comparison, the same operation was performed when the non-hydraulic substance H was used.

注：実験No.2-9およびNo.2-10は断面全体にわたって中性化されていたため、
中性化深さを50mm以上とした。

Note: Experiments No. 2-9 and No. 2-10 were neutralized throughout the cross section,
The neutralization depth was set to 50 mm or more.

The cement composition of the present invention is a so-called eco-cement-based cement concrete that has functions such as neutralization resistance, fluidity reduction suppression, environmental load reduction, and shrinkage cracking due to excessive strength development, It is suitable for civil engineering and construction applications because it can be used to effectively use by-products of various industries such as steel and steelmaking slag and volume reduction of urban waste.

Claims (7)

Manufactured from materials containing one or more non-hydraulic compounds selected from the group consisting of γ-2CaO · SiO ₂ , α-CaO · SiO ₂ and calcium magnesium silicate, and municipal waste incineration ash A cement composition containing waste-use cement. The cement composition according to claim 1, wherein the total content of the aluminate phase and the ferrite phase in the waste-use cement produced from municipal waste incineration ash is 20% or more. The cement composition according to claim 1 or 2, wherein the content of fluorine contained in the substance containing the non-hydraulic compound is 2% or less. The cement composition according to any one of claims 1 to 3, wherein the substance containing a non-hydraulic compound is steelmaking slag. The cement composition according to any one of claims 1 to 4, wherein the content of the non-hydraulic compound contained in the substance containing the non-hydraulic compound is 65% or more. Cement composition according to one of claims 1 to 5, γ-2CaO · SiO ₂ content of substances containing non-hydraulic compound is characterized in that 35% or more. Cement concrete containing the cement composition according to one of claims 1 to 6.