JP2730234B2 - High flow and high durability fiber reinforced filling mortar with excellent salt barrier properties - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention exhibits high fluidity and high durability by blending a hydraulic substance such as cement, a water reducing agent, fine aggregate and reinforcing fiber. In particular, the present invention relates to a filling mortar for construction or civil engineering having excellent salt barrier properties.

[Conventional technology]

Cement-based mortar is a mortar used for filling defective areas of concrete that have been damaged due to poor construction or deterioration over time, filling joints for reverse-casting concrete, grouting pedestals of machinery and steel columns and steel frame foundations, etc. It is.

The required performance of this type of filled mortar is that it has good fluidity that can be easily filled into the void to be filled, there is no material separation, small shrinkage of the filled mortar, crack resistance It is excellent in durability such as salt barrier property, freeze-thaw resistance, water tightness, chemical resistance and the like. Especially in coastal areas and other areas where there is a risk of salt damage,
It is important to prevent salt damage. The salt barrier is evaluated by the chlorine diffusion coefficient.

Conventionally, as a filling mortar for grouting, a mortar designed to reduce shrinkage due to oxidative expansion of iron powder for the purpose of reducing shrinkage and to reduce shrinkage due to hydration expansion of calcium sulfoaluminate-based or lime-based. There is. Further, as a grout material having a quick-setting property, a grout material comprising an ultra-rapid hardening cement, a lime-based expanding agent, a water reducing agent, a fluidizing agent, and a fine aggregate is known. (JP-A-61-19155
0).

Also, an AC dynamic / high-strength mortar composed of cement, blast furnace quenched slag fine powder having a limited particle size, blast furnace quenched slag having a limited particle size, fine aggregate made of a metal material, and a water reducing agent is known. Kaihei 1-18845).

However, these filled mortars have the following disadvantages.

The effect of reducing shrinkage is exhibited by mixing iron powder or an expanding material into the mortar, but when the cured body is exposed to the air, there is a defect that cracks are generated by shrinkage due to drying and the durability is impaired. In addition, the effect of densifying the structure of the cured product cannot be essentially expected, and the durability such as salt barrier property, freeze-thaw resistance, water tightness, and chemical resistance is not improved.
Further, the effect of improving the fluidity cannot be obtained.

A method for adding a water reducing agent or a fluidizing agent for the purpose of improving fluidity is known. According to this method, the cured product is densified by reducing the mixing water, and the effect of improving the durability can be obtained. However, the one that technically satisfies the durability performance cannot be obtained.

In addition, a high-strength, high-flow mortar that has extremely high fluidity and does not shrink during curing in the horizontal direction is known (Japanese Patent Laid-Open No. 1-18845), but is dried by drying when exposed to the atmosphere after curing. Not enough to reduce shrinkage. Further, a blast furnace quenching slag of a specific particle size and a metal material are indispensable as the fine aggregate, and there is a disadvantage that the use of the fine aggregate is limited.

[Problems to be solved by the invention]

The present invention solves the above-mentioned drawbacks of the prior art, has good fluidity and can be easily filled into the space to be filled, has no material separation, has a small shrinkage of the filled mortar, has crack resistance, and has a high degree of resistance. An object of the present invention is to provide a highly fluid and highly durable fiber-reinforced filling mortar having excellent durability such as saltiness, freeze-thaw resistance, water tightness, chemical resistance and the like, and particularly having excellent salt barrier properties.

[Means for solving the problem]

In order to solve the above-mentioned problems, the present invention provides a cement material composition comprising cement, 5 to 30% by weight of activated silica fine powder based on cement, and 5 to 30% by weight of hydrated expandable expandable material based on cement. 1 to 5 parts by weight of water reducing agent; 100 to 250 parts by weight of fine aggregate; fiber length of 5 mm or more and 15 mm
Hereinafter, a tensile strength of 80 kgf / mm ² or more and a Young's modulus of 250
In 0 kgf / mm ² or more, 0.1 to 1.0 volume% of non-metallic reinforcing fibers and for mortar; intended to provide a high flow and high durability fiber reinforcing filler mortar with excellent shielding saline, characterized in that it contains the is there. Further, it is preferable to add a shrinkage reducing agent. In addition, the mortar of the present invention is most characterized in that it has a large resistance to cracking and has particularly excellent properties in salt shielding and water tightness.

[Action]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, cement, an active silica fine powder, a cement material composition comprising a hydrated expandable expander, a water reducing agent, a fine aggregate, and a nonmetallic reinforcing fiber. Use, by specifying the compounding ratio of each of these materials, has good fluidity that can be easily filled into the voids to be filled and there is no material separation, furthermore, the shrinkage of the filled mortar is small and cracks In order to obtain a highly fluid and highly durable fiber-reinforced filling mortar having excellent durability such as resistance, salt barrier, freeze-thaw resistance, water tightness, chemical resistance, etc. completed.

 Hereinafter, the present invention will be described in detail.

Various types of Portland cement, such as ordinary, fast-strength and sulfate-resistant, can be used for the cement referred to in the present invention, and it is a main material for imparting strength to the filled mortar.

As the activated silica fine powder, silicon, silica fume produced as a by-product when producing a silicon-containing alloy, or the like is used, and its usage is limited to 5 to 30% by weight based on the cement. The effect of the activated silica fine powder, together with the effect of densifying the mortar hardened body by the pozzolanic reaction and improving the durability, improving the dispersibility and adhesion of the reinforcing fiber, and the separation resistance and fluidity of the mortar To improve. However, these effects are hardly noticeable at less than 5% by weight, and cause a decrease in the mortar fluidity at more than 30% by weight.

As the hydrated expansion type expanding material for the purpose of reducing the shrinkage of the filling mortar, a calcium sulfoaluminate type and / or lime type expanding material can be used, and it is used in an amount of 5 to 30% by weight based on cement. If the amount is less than 5% by weight, no shrinkage-reducing effect is observed. If the amount exceeds 30% by weight, there is a risk of cracking due to hydration expansion.

The water reducing agent is a surfactant having a large water reducing effect that does not cause abnormal setting even when added in a large amount to the mortar, and is mainly composed of naphthalene sulfonate, melamine resin sulfonate and oxycarboxylate. can give. The effect is to improve the fluidity of the mortar, and 1 to 5 parts by weight is used per 100 parts by weight of the cement material composition. If the amount is less than 1 part by weight, the fluidity is not sufficiently improved, and if it exceeds 5 parts by weight, the curing reaction may be adversely affected.

As the fine aggregate, generally used natural aggregate can be used. Preferably, silica sand having a low water absorption is used, and 100 to 250 parts by weight based on 100 parts by weight of the cement material composition is used. If the amount is less than 100% by weight with respect to 100% by weight of the cement material composition, the mortar shrinkage will have an adverse effect, and if it exceeds 250 parts by weight, the fluidity will decrease and it will be difficult to perform sufficient filling work. .

The reinforcing fibers are non-metallic fibers such as vinylon, polypropylene, acrylonitrile, and glass, and have a fiber length of 20 mm or less, a tensile strength of 80 kgf / mm ² or more, and a Young's modulus of 2
Fibers of 500 kgf / mm ² or more are used in the range of 0.1-1.0% by volume of the mortar. Due to the presence of the fibers, the fiber resists cracks caused by shrinkage of the mortar, and exhibits an effect of preventing cracks. However, this effect is insufficient when the fiber content is less than 0.1% by volume, and when it exceeds 1.0% by volume, it is impossible to form fiber balls and obtain a uniform fiber dispersion. On the other hand, if the fiber length exceeds 20 mm, a fiber ball is formed, which may cause the injection hose to be blocked at the time of injection. Also, the use of metal fibers causes the injection hose to be blocked during injection. In addition, the tensile strength is 80
If it is less than kgf / mm ² , the crack resistance is insufficient, and if the Young's modulus is less than 2500 kgf / mm ² , the crack resistance is insufficient.

In the present invention, of course, water is necessary for the molding of the mortar, and water is used within a range that satisfies the fluidity required for filling the mortar, and a small amount of water is desirable.

In the present invention, a lower alcohol alkylene oxide-based or glycol ester-based shrinkage reducing agent can be used in addition to the above-mentioned components.

〔Example〕

Early strength Portland cement (average particle size 11 μm) manufactured by Mitsubishi Materials Corporation as cement, Denka CSA manufactured by Denki Kagaku Kogyo Co., Ltd. as calcium sulfoaluminate-based expander
# 20 (expanding material A); Exoda (expanding material B) manufactured by Onoda Cement Co., Ltd. as a lime-based expansive material; and silica fume (by-product of ferrosilicon alloy as an active silica fine powder) (average
0.1 μm), Kao Corporation Mighty 150 as a water reducing agent, commercially available dry silica sand (a mixture of an equal amount of No. 4, No. 5, and No. 6) as a fine aggregate, and vinylon fiber (A: fiber length 15 mm, Young's modulus 300 kgf / mm ^2, tensile strength 125k
gf / mm ² , B (comparative example): fiber length 24 mm, Young's modulus 1400 kg
f / mm ² and a tensile strength of 79 kgf / mm ² ) were used.

The components shown in Table 1 were kneaded with a predetermined amount of water in a mortar mixer for 3 minutes.

Test Nos. 1 to 7 are mortars showing examples of the present invention, and Test Nos. 8 to 14 are mortars showing comparative examples. Test No.1 ~
Table 2 shows the physical properties of the mortar according to No. 7.

According to the mortars of Test Nos. 1 to 7 of the present invention, as shown in Table 2, they have good fluidity that can be easily filled into voids to be filled, have no material separation, have low shrinkage, and are cracked. Properties with excellent durability, such as resistance, salt barrier properties, and water tightness, were obtained.

Test No. 8 Comparative Example Mortar length change was 56 days old
The mortar was 12.3 × 10 ^-4 , which was a large shrinkage.

In the comparative example mortar of Test No. 9, cracks occurred due to excessive expansion.

The flow of the mortar of the comparative example of Test No. 10 was 164 mm, which was poor in fluidity, and cracks occurred due to drying shrinkage in the test specimen exposed outdoors.

The chlorine diffusion coefficient of the comparative mortar of Test No. 11 was 7.38 × 1
The results were 0 ^-8 cm ² / sec, and the water permeability was 5.8 g. The results were inferior in durability such as water tightness and salt barrier properties and poor fiber dispersibility.

In the comparative mortar of Test No. 12, a material separation phenomenon was observed, the length change showed a relatively large value of -8.34 × 10 ^-4 at 56 days of age, and the specimen exposed outdoors was cracked by drying shrinkage. There has occurred.

The flow of the mortar of Test No. 13 Comparative Example was extremely poor at 142 mm, and the fluidity was extremely poor.

In the mortar of the comparative example of Test No. 14, fiber balls were observed during kneading, and a uniform mortar could not be obtained.

〔The invention's effect〕

According to the present invention, it has good fluidity that can be easily filled into the void portion to be filled, and there is no material separation, and further,
Shrinkage of the filled mortar is small, crack resistance,
A highly fluid and highly durable fiber-reinforced filling mortar having excellent durability such as salt barrier property, freeze-thaw resistance, water tightness, chemical resistance and the like can be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical indication C04B 111: 72

Claims (2)

(57) [Claims] 1. A cement material composition comprising cement, 5-30% by weight of activated silica fine powder based on cement, and 5-30% by weight of hydrated expandable expander based on cement.
1 to 5 parts by weight of water reducing agent; 100 to 250 parts by weight of fine aggregate; fiber length of 5 mm to 15 mm, tensile strength of 80 kgf / mm ² or more, and Young's modulus of 2500 kgf / mm ² or more Against the mortar
And 0.1 to 1.0% by volume of a non-metallic reinforcing fiber; and a highly fluid and highly durable fiber-reinforced filling mortar having excellent salt barrier properties. 2. The high-flow and high-durability fiber-reinforced filling mortar according to claim 1, further comprising a shrinkage reducing agent.