Rust preventive composition and rust preventive treatment method

Abstract

To provide a rust inhibitor composition that is used to apply rust-inhibiting treatment, delaying the start of rust generation, and also improves flowability for improved workability.SOLUTION: A rust inhibitor composition contains cement and a salt fixer, and further contains at least one non-hydraulic compound selected from the group consisting of γ-2CaO SiO2, 3CaO 2SiO2, α-CaO SiO2 and calcium magnesium silicate.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a rust preventive composition and a rust prevention treatment method thereof, and particularly to a rust preventive composition for suppressing corrosion of steel materials inside concrete, such as steel bars, steel frames, steel plates, steel wires inside prestressed concrete, etc., and preventing the occurrence of rust, and a rust prevention treatment method thereof.

Background Art

[0002] In the repair work of concrete structures, cross-section repair work is carried out to remove the deteriorated part and newly apply repair mortar. At that time, a rust prevention treatment is performed for the purpose of preventing rusting of steel materials such as exposed steel bars.

[0003] Conventional rust preventive agents include nitrites, chromates, silicates, and phosphates in the inorganic system, and organic phosphate esters, ester salts, organic acids, sulfonic acids, amines, alkylphenols, mercaptans, and nitro compounds in the organic system (see Non-Patent Document 1).

[0004] As a rust preventive agent for steel bars when performing the cross-section repair method, nitrite-based rust preventive agents are often used, and they are used by directly applying them to the steel bars, applying a mixture with a polymer emulsion, or applying a mixture with a hydraulic substance such as cement. When used in combination with cements, a polymer for cement admixture is blended for the purpose of retaining nitrite on the steel bar surface for a long time and reducing the permeability of chloride ions and oxygen to maintain a better rust prevention effect, and it may be applied.

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, although the nitrite-based rust preventive agent often used in the cross-section repair method can be directly applied to the reinforcing bars, rust may occur if the cross-section is not repaired immediately after application. In addition, a mixture of cement and a polymer for mixing with cement is preferable in that rust is less likely to occur on the reinforcing bars even if the cross-section is not repaired immediately after application, but a sufficient effect cannot be obtained. Furthermore, there was a problem of poor workability due to an increase in viscosity and a decrease in fluidity after mixing. Therefore, an object of the present invention is to provide a rust preventive agent composition that prolongs the time until rusting occurs and improves workability by increasing fluidity through rust prevention treatment.

Means for Solving the Problems

[0007] As a result of intensive studies to solve the above problems, the present inventor has found that by using a rust preventive agent composition containing cement, a salt-fixing material, and one or more non-hydraulic compounds selected from the group consisting of γ-2CaO·SiO 2 、3CaO·2SiO 2 、α-CaO·SiO 2 and calcium magnesium silicate, the time until rusting occurs can be prolonged and workability can be improved by increasing fluidity.

[0008] The present invention is a rust preventive agent composition containing cement, a salt-fixing material, and one or more non-hydraulic compounds selected from the group consisting of γ-2CaO·SiO 2 、3CaO·2SiO 2 、α-CaO·SiO 2 and calcium magnesium silicate, further a rust preventive agent composition containing Li in the non-hydraulic compound, and further a rust preventive agent composition containing a polymer for mixing with cement, and a rust prevention treatment method using the rust preventive agent composition.

Effects of the Invention

[0009] By performing rust prevention treatment using the rust preventive composition of the present invention, the time until rusting occurs can be extended, the fluidity can be increased, and the workability can be improved.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the present invention will be described in detail. In the present invention, parts and % are shown on a mass basis unless otherwise specified.

[0011] The rust preventive composition of the present invention contains cement and a salt immobilizing material, and further contains one or more non-hydraulic compounds selected from the group consisting of γ-2CaO·SiO 2 , 3CaO·2SiO 2 , α-CaO·SiO 2 and calcium magnesium silicate. In addition, the rust preventive composition preferably further contains Li in the non-hydraulic compound, and the content of Li in the non-hydraulic compound is preferably 0.001 to 1.0% by mass in terms of oxide conversion. It is presumed that this predetermined amount of Li promotes the formation of vaterite, which is a type of calcium carbonate, among the carbonations of C-S-H (calcium silicate hydrate), and it is considered that a denser hardened state can be obtained by carbonation (salting), and the rust preventive effect can be easily obtained. In addition, the rust preventive composition preferably further contains a cement admixture polymer. Here, "containing Li in the non-hydraulic compound" means that Li 2 O is included in the non-hydraulic compound (the presence can be confirmed by ICP emission spectroscopic analysis), but Li 2 O is not identified by X-ray diffraction measurement (no distinct peak of Li 2 O is seen), which means that it is not simply a state where the non-hydraulic compound and the Li compound are physically mixed. Such a state can be obtained by mixing the respective raw materials and performing heat treatment at a high temperature of 1,000 °C or higher. The rust prevention treatment method of the present invention is a rust prevention treatment method using the rust preventive composition described in any of the above. The components of the above rust inhibitor composition and the like will be described below.

[0012] [Cement] The cement used in the present invention is not particularly limited. Generally, various Portland cements such as ordinary, early-strength, ultra-early-strength, low-heat, and medium-heat Portland cements, and various blended cements obtained by mixing blast furnace slag, fly ash, or silica with these Portland cements, filler cements mixed with limestone powder, gypsum, or finely ground blast furnace slag, and Portland cements such as environment-friendly cements (eco-cements) manufactured using municipal waste incineration ash or sewage sludge incineration ash as raw materials, as well as commercially available cement-based solidifying materials used in ground improvement works and commercially available fine particle cements can be mentioned. One or more of these can be used. Also, those adjusted by increasing or decreasing the amount of components usually used in cement can also be used.

[0013] [Salt Fixing Agent] The salt fixing agent used in the present invention is a calcium aluminate compound (hereinafter, may be referred to as a CA compound), which is obtained by mixing a raw material containing calcium oxide and a raw material containing alumina, etc., and performing heat treatment such as firing in a kiln or melting in an electric furnace, and is a general term for compounds having CaO and Al 2 O 3 as the main components. A calcium-aluminum composite oxide containing nitrite ions between layers may also be used. In the present invention, the composition has a CaO / Al 2 O 3 molar ratio in the range of 0.15 to 0.7. Even if, for example, SiO 2 or R 2 O (R is an alkali metal) is contained in the CA compound, it can be used as long as the object of the present invention is not impaired. The CaO / Al 2 O 3 molar ratio of the CA compound is 0.15 to 0.7, and preferably 0.4 to 0.6. If it is less than 0.15, the shielding effect of chloride ions may not be sufficiently obtained. Conversely, if it exceeds 0.7, flash setting may occur and the workable time may not be ensured. The powder fineness of the CA compound is preferably 2000 - 7000 cm 2 / g in terms of the Blaine specific surface area value (hereinafter referred to as the Blaine value), more preferably 3000 - 6000 cm 2 / g, and most preferably 4000 - 5000 cm 2 / g. If the CA compound is coarse-grained, a sufficient chloride ion shielding effect may not be obtained. If the fineness exceeds 7000 cm 2 / g, rapid hardening may occur and the workable time may not be ensured. The amount of the salt-fixing material used is preferably 3 - 35 parts by mass, more preferably 3 - 30 parts by mass, and even more preferably 5 - 20 parts by mass with respect to 100 parts by mass of cement. When the amount is 3 parts by mass or more, the rust prevention effect is excellent when used in combination with cement, and when it is 35 parts by mass or less, the workability is excellent.

[0014] [Non-hydraulic compound] The non-hydraulic compound used in the present invention is one or more selected from the group consisting of γ-2CaO·SiO 2 , 3CaO·2SiO 2 , α-CaO·SiO 2 and calcium magnesium silicate. By mixing these, the fluidity is increased, natural carbonation is promoted to make it dense, and the rust prevention effect is excellent.

[0015] The salt-fixing material / non-hydraulic compound ratio (mass ratio), which is the value obtained by dividing the value of the amount of the salt-fixing material by the value of the amount of the non-hydraulic compound, is preferably 0.2 - 3.5, more preferably 0.3 - 3.3, and even more preferably 0.5 - 2.0. When the salt-fixing material / non-hydraulic compound ratio is in such a range, the rust preventive agent is excellent in rust prevention effect and workability.

[0016] (γ-2CaO·SiO 2 ) γ-2CaO·SiO 2 refers to the compound represented by 2CaO·SiO 2 and is known as the low-temperature phase among the compounds represented by it. The high-temperature phases are α-2CaO·SiO 2 and α’-2CaO·SiO 2 , β-2CaO·SiO2 They are completely different. All of these are represented by 2CaO·SiO 2 , but their crystal structures and densities are different.

[0017] (3CaO·2SiO 2 ) 3CaO·2SiO 2 refers to a mineral containing CaO in pseudo-wollastonite, called rankinite. It is a mineral that is chemically stable without hydration activity, but has a large carbonation promotion effect and excellent rust prevention effect.

[0018] (α-CaO·SiO 2 ) α-CaO·SiO 2 (α-type wollastonite) is a compound represented by CaO·SiO 2 and is known as the high-temperature phase, which is completely different from the low-temperature phase β-CaO·SiO 2 . All of these are represented by CaO·SiO 2 , but their crystal structures and densities are different.

[0019] Naturally occurring wollastonite is the low-temperature phase β-CaO·SiO 2 . β-CaO·SiO 2 has needle-like crystals and is used as an inorganic fibrous substance such as wollastonite fiber, etc., but there is no carbonation promotion effect like α-CaO·SiO 2 according to this embodiment.

[0020] (calcium magnesium silicate) Calcium magnesium silicate is a general term for CaO-MgO-SiO 2 system compounds. In this embodiment, it is preferably merwinite represented by 3CaO·MgO·2SiO 2 (C 3 MS 2 ). According to merwinite, a large carbonation promotion effect can be achieved.

[0021] [Li] The above non-hydraulic compound may be one kind or two or more kinds. However, the Li content in the non-hydraulic compound is 0.001 to 1.0% in terms of oxide conversion, preferably 0.005 to 1.0%, more preferably 0.010 to 0.90%, and even more preferably 0.015 to 0.80%. When the Li content is 0.001% or more and 1.0% or less in terms of oxide conversion, a carbonation promotion effect can be obtained and the cost is also low. The Li content in terms of oxide conversion can be measured by the method described in the examples. In addition, when there are two or more non-hydraulic compounds, the Li content refers to the content of Li in terms of oxide conversion with respect to the total of the two or more non-hydraulic compounds.

[0022] Among the above non-hydraulic compounds, especially γ-2CaO·SiO 2 is accompanied by a pulverization phenomenon called dusting during production, so it requires less energy for grinding compared to other compounds, has a large carbonation promotion effect over a long period of time, and on the other hand, is preferable in that it has a large rust prevention effect when combined with blast furnace cement at a low water binder ratio.

[0023] The non-hydraulic compound according to this embodiment is obtained by blending a CaO raw material, a SiO 2 raw material, an MgO raw material, and, if necessary, an Li raw material in a predetermined molar ratio and performing heat treatment. Examples of the CaO raw material include calcium carbonate such as limestone, calcium hydroxide such as slaked lime, by-product slaked lime such as acetylene by-product slaked lime, and fine powder generated from waste concrete blocks. SiO 2 Examples of the raw material include silica stone, clay, and various siliceous dusts generated as industrial by-products typified by silica fume and fly ash. Examples of the MgO raw material include magnesium hydroxide, basic magnesium carbonate, and dolomite. Examples of the Li raw material include lithium carbonate. When Li is contained in the CaO raw material, SiO 2 raw material, and MgO raw material, it is not necessary to newly add an Li raw material. CO derived from non-energy during heat treatment 2From the reduction of the discharge amount, one or more selected from industrial by-products containing CaO, such as by-product slaked lime, fine powder generated from waste concrete blocks, municipal waste incineration ash, and sewage sludge incineration ash, can be used. Among them, the use of by-product slaked lime with a small amount of impurities compared to other industrial by-products is more preferable.

[0024] Examples of by-product slaked lime include by-product slaked lime by-produced in the production process of acetylene gas by the calcium carbide method (there are wet products and dry products depending on the difference in the acetylene gas production method), and by-product slaked lime contained in the dust captured in the wet dust collection process of the calcium carbide electric furnace, such as acetylene by-product slaked lime. The by-product slaked lime contains, for example, 65 to 95% (preferably 70 to 90%) of calcium hydroxide, and in addition, 1 to 10% of calcium carbonate and 0.1 to 6.0% (preferably 0.1 to 3.0%) of iron oxide. These ratios can be confirmed by fluorescence X-ray measurement and the mass loss (Ca(OH) 2 : around 405°C to 515°C, CaCO 3 : around 650°C to 765°C) measured by differential thermal gravimetric analysis (TG-DTA). The volume average particle diameter measured by the laser diffraction / scattering method is about 50 to 100 μm. Further, the moisture content measured by the drying loss method in JIS K 0068 "Method for Measuring Moisture in Chemical Products" is preferably 10% or less. Also, it may contain sulfur compounds such as CaS, A1 2 S 3 、and CaC 2 ·CaS, etc., but preferably 2% or less.

[0025] The heat treatment at a high temperature of 1,000°C or higher described above is not particularly limited, but can be performed, for example, by a rotary kiln or an electric furnace. The heat treatment temperature is not uniquely determined, but is usually carried out in the range of about 1,000 to 1,800°C, and often in the range of about 1,200 to 1,600°C.

[0026] This embodiment can also use industrial by-products containing the non-hydraulic compound described above. In this case, impurities coexist. Examples of such industrial by-products include steelmaking slag.

[0027] CaO raw materials, SiO 2 The raw materials of MgO may contain impurities, but there is no particular problem as long as the effects of the present invention are not inhibited. Specific examples of the impurities include, for example, Al 2 O 3 、Fe 2 O 3 、TiO 2 、MnO, Na 2 O, K 2 O, S, P 2 O 5 、F, B 2 O 3 、chlorine and the like. In addition, the coexisting compounds include free calcium oxide, calcium hydroxide, calcium aluminate, calcium aluminosilicate, calcium ferrite, calcium aluminoferrite, calcium phosphate, calcium borate, magnesium silicate, leucite (K 2 O, Na 2 O)·Al 2 O 3 ·SiO 2 、spinel MgO·Al 2 O 3 、magnetite Fe 3 O 4 、the aforementioned CaS, A1 2 S 3 、and sulfur compounds such as CaC 2 ·CaS and the like.

[0028] Among these impurities, the content of S (sulfur) in the non-hydraulic compound is preferably 1.0% or less, more preferably 0.7% or less, and still more preferably 0.5% or less in terms of oxide (SO 3 ). By being 1.0% or less, a sufficient carbonation promotion effect can be obtained, and the setting and hardening properties can be made within an appropriate range. The content of S in terms of oxide (SO 3 ) can be measured by fluorescence X-ray measurement. In addition, S (sulfur) in the non-hydraulic compound may be present as long as it is about 2% in terms of oxide conversion.

[0029] In this rust preventive composition, the content of the non-hydraulic compound (when there are multiple types, the content in the total amount) is preferably 1 to 50% with respect to 100 parts by mass of cement, more preferably 2 to 25%, and even more preferably 3 to 15%. Note that γ-2CaO·SiO 2 Other hydraulic 2CaO·SiO 2 may be mixed, and the maximum mixing amount can be up to 35%.

[0030] In the non-hydraulic compound, the content of γ-2CaO·SiO 2 is preferably 35% or more, and more preferably 45% or more. Also, the upper limit of the content of γ-2CaO·SiO 2 is not particularly limited. Among steelmaking slags, electric furnace reduction period slag or stainless steel slag with a high content of γ-2CaO·SiO 2 is preferred.

[0031] Also, in the non-hydraulic compound, from the viewpoint of more easily expressing its effect, as chemical components, in 100 parts by mass of the non-hydraulic compound, Li 2 O is 0.001 to 1.0 part by mass, CaO is 45 to 70 parts by mass, SiO 2 is 30 to 55 parts by mass, and Al 2 O 3 is preferably contained in an amount of 0 to 10 parts by mass. The content of Li 2 O can be measured by the method described in the examples below. Also, CaO, SiO 2 , and Al 2 O 3 can be measured by fluorescent X-ray analysis. As chemical components, in 100 parts by mass of the non-hydraulic compound, Li 2 O is 0.002 to 0.5 part by mass, CaO is 60 to 70 parts by mass, SiO 2 is 30 to 45 parts by mass, and Al 2 O 3 is more preferably contained in an amount of 0.5 to 5 parts by mass. Furthermore, as chemical components, in 100 parts by mass of the non-hydraulic compound, Li 2 O, CaO, SiO 2 , and Al 2 O3 The total is preferably 90 parts by mass or more, more preferably 95 to 100 parts by mass.

[0032] As a method for quantifying the non-hydraulic compound in this rust preventive composition, examples include the Rietveld method by powder X-ray diffraction.

[0033] The Blaine specific surface area of this rust preventive composition is not particularly limited, but is preferably 1,500 cm 2 / g or more, and the upper limit is preferably 8,000 cm 2 / g or less. Among these, 2,000 to 6,000 cm 2 / g is more preferable, and 4,000 to 6,000 cm 2 / g is most preferable. When the Blaine specific surface area is 2,000 cm 2 / g or more, good fluidity can be obtained, the carbonation promotion effect becomes large, and a sufficient rust prevention effect can be obtained. Also, when it is 8,000 cm 2 / g or less, the grinding power during grinding does not increase, it is economical, and weathering is suppressed, and deterioration of quality over time can be suppressed.

[0034] [Polymer for mixing with cement] The polymer for mixing with cement (hereinafter referred to as cement polymer) used in the present invention is a polymer that has generally been used for mixing with cement and is used for the purpose of improving durability such as neutralization, salt damage, and freezing damage. For example, rubber latex such as acrylonitrile-butadiene rubber, styrene-butadiene rubber, chloroprene rubber, and natural rubber, synthetic resin emulsions such as ethylene-vinyl acetate copolymer, polyacrylate copolymer, vinyl versatate copolymer, styrene-acrylate copolymer, and liquid polymers typified by epoxy resin and unsaturated polyester resin. Among these, one or a mixture of two or more thereof can also be used. The amount of the cement polymer used is preferably 5 to 70 parts by mass, more preferably 10 to 60 parts by mass, based on 100 parts by mass of the cement. When the amount is 5 parts by mass or more, the rust prevention effect is excellent when used in combination with the cement, and when the amount is 70 parts by mass or less, the workability is excellent.

[0035] [Mixture] In the rust preventive agent composition of the present invention, pozzolan substances that are stimulated and cured by alkalis, which are hydraulic substances other than cement, calcium aluminates that can impart rapid hardening properties, and mixtures thereof can be used in combination within a range that does not adversely affect the quality.

[0036] [Aggregate] It is also possible to use sand as an aggregate in the rust preventive agent composition and appropriately mix the sand to use it as mortar.

[0037] [Others] In addition, in the rust preventive agent composition of the present invention, within a range that does not adversely affect the quality, calcium carbonate, magnesium silicate, slag powder, clay powder, carbon black, surfactant, fibers, thickeners, clay minerals, setting accelerators, setting retarders, waterproofing agents, water reducing agents, defoaming agents, rapid hardening materials, foaming agents, pigments, gas foaming substances, expansion materials, shrinkage reducing agents, and chelating agents such as sodium ethylenediaminetetraacetate, water-soluble sulfur-containing organic compounds or their salts, fragrances, deodorants, antibacterial agents, preservatives and other various additives can be used in combination.

[0038] The construction method of the rust preventive agent composition of the present invention is not particularly limited. For example, it may be sprayed onto the reinforcing bars using a sprayer or applied with a brush.

Examples

[0039] Hereinafter, the present invention will be further described based on experimental examples of the present invention, but the present invention is not limited thereto.

[0040] Experimental Example 1 A rust preventive composition was prepared in the formulation shown in Table 1 with respect to 100 parts by mass of cement. Water was added to 100 parts by mass of the obtained rust preventive composition so that the water / rust preventive composition ratio was constant (water / rust preventive composition ratio: 50%) to prepare a rust preventive agent. The fluidity of the prepared rust preventive agent and the time until rusting occurred were tested using the prepared rust preventive agent. The results are shown in Table 1 below.

[0041] [Materials Used] · Cement: Ordinary Portland cement (commercial product) · Salt fixing agent: Calcium aluminate compound (CaO / Al 2 O 3 Molar ratio: 0.5, Blaine value: 4000 cm 2 / g). Reagent grade calcium carbonate and reagent grade aluminum oxide were mixed at a predetermined ratio. Next, the mixed sample was melted at 1500 °C in an electric furnace and then slowly cooled to synthesize calcium aluminate. Then, the synthesized sample was pulverized so that the Blaine specific surface area value was 4000 cm 2 / g. · Non-hydraulic compound A: Li-containing γ-2CaO·SiO 2 . Reagent grade calcium carbonate and reagent grade silicon dioxide were mixed at a molar ratio of 2:1, and further, reagent grade lithium carbonate was mixed so that the Li content in the mixture was 0.0005 to 1.1% (internal substitution) in terms of oxide (Li 2 O). The mixture was heat-treated at 1400 °C for 2 hours, allowed to cool to room temperature, and then pulverized to a Blaine specific surface area of 4,000 cm 2 / g. · Non-hydraulic compound B: Li-containing α-CaO·SiO 2 . Reagent grade calcium carbonate and reagent grade silicon dioxide were mixed at a molar ratio of 1:1, and further, reagent grade lithium carbonate was mixed so that the Li content in the mixture was 0.0005 to 1.1% (internal substitution) in terms of oxide (Li 2 O). The mixture was heat-treated at 1500 °C for 2 hours, allowed to cool to room temperature, and then pulverized to a Blaine specific surface area of 4,000 cm 2 / g. · Non-hydraulic compound C: β-2CaO·SiO 2 。Reagent grade calcium carbonate and reagent grade silicon dioxide were mixed at a molar ratio of 2:1. The mixture was heat-treated at 1,400 °C for 2 hours, allowed to cool to room temperature, then pulverized and subjected to XRD. The heat treatment was repeated until the peak of γ-2CaO·SiO 2 disappeared. After only the peak of β-2CaO·SiO 2 was confirmed, it was pulverized to a Blaine specific surface area of 4,000 cm 2 / g. In addition, the Li content in oxides of non-hydraulic compounds A to C was measured by an ICP emission spectrometer (manufactured by Hitachi High-Technologies Corporation, VISTA-PRO). And from the absolute calibration curve method using a diluted ICP mixed solution (manufactured by SPEX, XSTC-22), it was confirmed that the Li content was the same as the charged amount. The measurement conditions are as follows. · Li measurement wavelength: 670.783 nm · BG correction: Fitting curve method · Standard solution for calibration curve: Dilute the ICP mixed solution (manufactured by SPEX, XSTC-22) and use it · Calibration curve range: 0 - 5 mg / L (5-point calibration curve of 0 mg / L, 0.1 mg / L, 0.5 mg / L, 1 mg / L, 5 mg / L) · Quantitative determination by absolute calibration curve method · Polymer for cement mixing: Vinyl acetate·vinyl versatate copolymer (powder, commercially available product) · Water: Tap water

[0042] [Measurement method] <Fluidity> JIS flow: Conforms to JIS R 5201. <Time until rusting> On the surface of a D16 reinforcing bar (SD295 of JIS standard product), the prepared rust preventive agent was applied at a coating amount of approximately 150 g / m 2Apply it with a brush so that it becomes like this, place the steel bars coated with the rust preventive agent in a constant temperature and high humidity chamber at a temperature of 20 °C and a relative humidity of 100%, and measure the time from when it was applied until rust was visually confirmed on the steel bars. The number of tests was 3 for each example, and the average value of the measured time was taken as the time until rusting occurred.

[0043]

Table 1

[0044] From the results in Table 1, it was found that by containing a salt-fixing material and a non-hydraulic compound containing a specific non-hydraulic material, the fluidity can be further increased and the time until rusting can be lengthened.

Industrial Applicability

[0045] The rust preventive agent composition of the present invention contains a specific non-hydraulic material, which can increase the fluidity, improve the time until rusting, and can be widely used for corrosion inhibition of steel materials inside concrete such as steel bars, steel frames, steel plates, steel wires inside prestressed concrete, and prevention of rust generation.

Claims

1. Containing cement and a salt immobilizing material, and further containing one or more non-hydraulic compounds selected from the group consisting of γ-2CaO·SiO ２ , 3CaO·2SiO ２ , α-CaO·SiO ２ and calcium magnesium silicate A rust preventive composition in which the salt immobilizing material is a calcium aluminate compound.

2. The rust preventive composition according to claim 1, wherein Li is contained in the non-hydraulic compound, and the content rate of Li in the non-hydraulic compound is 0.001 to 1.0 mass% in terms of oxide.

3. The rust preventive composition according to claim 1 or 2, further containing a polymer for cement admixture.

4. A rust prevention treatment method using the rust preventive composition according to any one of claims 1 to 3.

Images