JP5973826B2 - Foam mortar - Google Patents

Description

The present invention relates to a foam mortar used in the civil engineering and construction fields. In particular, the present invention relates to a lightweight gap filler used in places where vibrations are constantly applied, such as existing roads, railways, and waterways.

Lightweight void filling material is lightweight and its cured product has low strength. From the point of view of underground and tunnel backside cavities and voids, embankments, cavities and voids such as underdrains (hereinafter simply referred to as voids including cavities and voids). ) Backfill material.

Examples of a method for producing this lightweight gap filling material include a method in which cement, water, and a foaming agent are vigorously stirred in a mortar mixer, and air is entrained and dispersed in the mortar (Patent Documents 1 to 3). . This method is often used because it is foamed at the construction site, so it does not require transportation costs and has good workability.

However, when filling cavities and voids that are constantly vibrated on existing roads, railways, waterways, etc., if the amount of air entrained in the lightweight void filling material is 50% or more, the bubbles become unstable and harden. There was a problem that bubbles were not crushed or defoamed before being reduced to become lightweight.

  On the other hand, foamed concrete which has little drying shrinkage and is rapidly hardened has been proposed (Patent Documents 4 to 6). However, there is no description about fine powder cement.

JP-A-9-77546 JP-A-57-143098 JP-A-5-112911 Japanese Patent Laid-Open No. 11-100250 JP 2003-55024 A Japanese Patent Laid-Open No. 11-116350

As a result of repeating various studies to solve the above-mentioned problems, the present inventor uses, for example, an ultralight foam mortar using a fine powder cement having a brane value of 6000 cm ² / g or more and a setting accelerator in a foam mortar. The present invention was completed by obtaining knowledge that a bubble mortar with less settlement was obtained.

That is, the present invention, Ri Blaine the name contained 6000 cm ² / g or more of a fine powder cement and set-accelerating material, and a Ru bubble mortar greens contain bubbles above 50%, procoagulant material However, the foam mortar is 10 to 30 parts by mass with respect to 100 parts by mass of the fine powder cement, the setting accelerator is the bubble mortar containing calcium aluminate, and the setting accelerator is sulfate. The foam mortar containing the foam mortar further containing a setting retarder, and the fine powder cement is the foam mortar containing slag. In the flow test of JHSA 313, the flow value is 200 mm or more. This is a foam mortar that has a flow value of 200 mm or less within 30 minutes after being held for at least minutes.

According to the present invention, a bubble mortar with less settlement is obtained.

Hereinafter, the present invention will be described in detail.

The bubble mortar containing bubbles used in the present invention (hereinafter simply referred to as bubble mortar) is a mixture of bubbles in the mortar by vigorously stirring the mortar and the foaming agent in a mortar mixer. The foaming agent is made into an aqueous solution and supplied continuously to a foaming device together with air, for example, a foamed product such as a shaving cream mixed with mortar. The amount of air bubbles (air amount) in the foam mortar used in the present invention is preferably 50% or more, more preferably 60% or more, and most preferably 70% or more. If it is 50% or more, the bubble mortar becomes light and the heat insulation is improved. The amount of bubbles is measured by, for example, the Japan Highway Public Corporation Standard JHSA313 air mortar and air milk test method.

The mortar used in the present invention is a general term for cement paste and cement mortar.

The cement used in the present invention refers to a fine powder cement having a brain value (brane specific surface area) of 6000 cm ² / g or more. Blaine value of cement is preferably not less than ^{7000cm 2 / g, 8000cm 2 /} g or more is more preferable.

As the cement, specifically, various Portland cements such as normal strength, early strength, and ultra-early strength, which have been pulverized and classified so as to have a brain value of 6000 cm ² / g or more can be used. Further, the respective materials may be mixed after being pulverized or classified separately.

The cement used in the present invention preferably contains slag. Examples of the slag used in the present invention include blast furnace slag by-produced from a blast furnace, steelmaking slag by-produced from a converter, an electric furnace, and the like. Among these, blast furnace slag is preferable and amorphous blast furnace slag is more preferable in terms of strength development.

The amount of slag used is preferably 10 to 95 parts by weight, more preferably 40 to 90 parts by weight, and most preferably 50 to 80 parts by weight in a total of 100 parts by weight of cement and slag. If the amount is less than 10 parts by mass, the amount of alkali eluted from the cement may increase, and the pH value may increase. If the amount exceeds 95 parts by mass, strength development may deteriorate.

The cement used in the present invention may be mixed with silica and fly ash in these Portland cements.

The foam mortar used in the present invention contains a foaming agent. A foaming agent is not specifically limited, For example, surfactant, animal protein, etc. can be used.

The usage-amount of a foaming agent is not specifically limited, Usually, 0.1-1 mass part is preferable with respect to 100 weight part of cement in foam mortar. If the amount is less than 0.1 parts by mass, the bubbles may be unstable, and even if the amount exceeds 1 part by mass, the effect of addition cannot be expected.

Examples of foaming agents include powders and solutions. In the case of powder, it can be used by mixing in cement. When using a solution, the concentration of the foaming agent aqueous solution varies depending on the type of foaming agent and is not particularly limited, but it is usually preferable to use an aqueous solution having a solid content concentration of 1 to 10% by mass. .

As a method of using the foaming agent, the foaming agent is mixed and foamed simultaneously with other materials to be foamed and foamed into a foam mortar, and the foaming agent is mixed with water to make an aqueous solution. There is a preform method in which bubbles that are supplied and continuously produced are mixed with mortar to form bubble mortar. Although the construction equipment is simple in the mixed foam method, when the ratio of bubbles to be contained is 50% or more, the introduced bubbles may become unstable. The present invention is a technique particularly effective in a mixed foam system.

The water mixed with the cement is not particularly limited, and it is usually possible to use fresh water. The usage-amount of water is not specifically limited, 70-120 mass parts is preferable with respect to 100 mass parts of cement. If it is less than 70 mass parts, fluidity | liquidity may worsen, and when 120 mass parts is exceeded, intensity | strength expression may be overdue.

In the present invention, it is preferable to use a setting accelerator and eliminate the fluidity within 30 minutes after maintaining the fluidity for 5 minutes or more. For example, from the point of securing working time for filling and filling in a state where air bubbles are stabilized, in the flow test of JHS A313, the flow value of 200 mm or more is kept for 5 minutes or more and then flows within 30 minutes. The value is preferably 200 mm or less.

  As the setting accelerator used in the present invention, silicate represented by water glass, aluminum salt represented by aluminum sulfate and alum, aluminate represented by calcium aluminate (calcium aluminate) and sodium aluminate Etc. Among these, from the viewpoint of strength development, aluminate is preferable, and calcium aluminate is more preferable.

Calcium aluminate is produced by subjecting a CaO raw material, an Al ₂ O ₃ raw material, or the like to a heat treatment such as firing or melting, and has CaO and Al ₂ O ₃ as effective components as chemical components. And when CaO is C and Al ₂ O ₃ is A, the main component is a mineral composition represented by C ₁₂ A ₇ , CA, CA ₂ , C ₃ A, etc. Can also be used. Of these, amorphous calcium aluminate is preferred.

In the present invention, calcium sulfoaluminate produced using a CaO raw material, an Al ₂ O ₃ raw material, a CaSO ₄ raw material, or the like can be used in the same manner as calcium aluminate. Further, when SiO ₂ is S, those having a mineral composition represented by C ₂ AS can be used in the present invention in the same manner as calcium aluminate.

The brane value of calcium aluminate is preferably 6,000 cm ² / g or more. If it is less than 6,000 cm ² / g, the stability of the bubbles may be impaired.

When calcium aluminate is used, it is preferable to mix calcium aluminate and sulfate from the viewpoint of fluidity retention and strength development (hereinafter referred to as calcium aluminate or a mixture of calcium aluminate and sulfate. It may be called a hard material). Examples of the sulfate include alkali metal sulfates such as sodium sulfate and potassium sulfate, alkaline earth metal sulfates such as calcium sulfate, and the like. Among these, calcium sulfate (gypsum) is preferable, anhydrous gypsum is more preferable, and type II anhydrous gypsum is most preferable.

The brane value of the sulfate is preferably 6,000 cm ² / g or more. If it is less than 6,000 cm ² / g, the stability of the bubbles may be impaired.

The amount of sulfate used is preferably 50 to 200 parts by weight, more preferably 100 to 150 parts by weight, per 100 parts by weight of calcium aluminate. If the amount is less than 50 parts by mass, the elongation of the strength may be reduced. If the amount exceeds 200 parts by mass, the strength expression may be deteriorated.

In order to improve the kneading of the foam mortar and the pumpability, it is preferable to use a setting retarder in a timely manner.

The setting retarder is not particularly limited, and examples thereof include organic acids and alkali metal carbonates. Of these, oxycarboxylic acids and alkali metal carbonates are preferably used in combination. Examples of oxycarboxylic acids include oxycarboxylic acids such as citric acid, tartaric acid, and gluconic acid, and salts thereof. Of the oxycarboxylic acids, citric acid is preferred. Examples of the alkali metal carbonates include alkali metal carbonates such as sodium carbonate and potassium carbonate, and alkali metal bicarbonates such as sodium hydrogen carbonate and potassium hydrogen carbonate. Of these, potassium carbonate is preferred. One or more of them can be used.

When the oxycarboxylic acid and the alkali metal carbonate are used in combination, the mixing ratio of the oxycarboxylic acid and the alkali metal carbonate is preferably 5 to 200 parts by mass, more preferably 10 to 100 parts by mass with respect to 100 parts by mass of the alkali metal carbonate.

The usage-amount of a setting retarder is not specifically limited, Usually, 0.1-2 mass parts is preferable with respect to a total of 100 mass parts of a cement and a setting accelerator. If the amount is less than 0.1 parts by mass, the setting may be too early and the work may not be performed. If the amount exceeds 2 parts by mass, the setting may be poor and the bubbles may become unstable.

10-30 mass parts is preferable with respect to 100 mass parts of cement, and, as for the usage-amount of a setting accelerator, 10-20 mass parts is more preferable. If it is less than 10 parts by weight, the effect of improving the stability of the bubbles may deteriorate, and if it exceeds 30 parts by weight, thermal expansion may occur.

These setting accelerators can be used by mixing with fine powder cement. In particular, it is preferable to blend so as to eliminate fluidity within 30 minutes from the viewpoint of stabilization of bubbles. If it exceeds 30 minutes, the bubbles may become unstable, and the bubbles may disappear to increase the bubbles, or the bubbles may be removed to increase the density. However, if the fluidity is reduced too quickly, the work time for filling does not exist. Therefore, it is preferable to keep the flow value of 200 mm or more for 5 minutes or more.

In the present invention, various cement admixtures and cement admixtures such as aggregates, water reducing agents, waterproofing agents, and shrinkage reducing agents can be used in addition to cement, foaming agents, setting accelerators and water. When using a powder such as an aggregate, it is preferable to use a powder having a brain value of 6000 cm ² / g or more.

Hereinafter, further description will be given based on experimental examples of the present invention.

Experimental example 1
Condensation with respect to 100 parts by mass of cement shown in Table 1, 0.5 part by mass of foaming agent, amount of setting accelerator shown in Table 1, amount of water shown in Table 1, total of 100 parts by mass of cement and setting accelerator 0.5 parts by mass of the retarder was kneaded with a mixer to produce a bubble mortar. Thereafter, physical properties of the bubble mortar were measured. The results are also shown in Table 1.

<Materials used>
Cement a: Fine powder cement having a brane value of 3970 cm ² / g (mixed 50 parts by weight of ordinary Portland cement and 50 parts by weight of blast furnace slag to prepare a brane value)
Cement b: Fine powder cement having a brane value of 6100 cm ² / g (mixed 40 parts by weight of ordinary Portland cement and 60 parts by weight of blast furnace slag to prepare a brane value)
Cement c: Fine powder cement having a brane value of 8020 cm ² / g (mixed 30 parts by weight of ordinary Portland cement and 70 parts by weight of blast furnace slag to prepare a brane value)
Foaming agent: Commercial product, surfactant system, 97% by mass of active ingredient powder coagulation promoter: calcium aluminate / anhydrous gypsum mixed at a ratio of 1 / 1.5 mass setting retarder: citric acid / mixed product water of potassium carbonate were mixed at a mass ratio of 3/7: tap water ordinary Portland cement: commercially blast furnace slag: commercially calcium aluminate: C ₁₂ a ₇ calcium aluminate was quenched corresponding heat-treated product of the composition Nate, amorphous, brain value 6000cm ² / g
Anhydrous gypsum: type II anhydrous gypsum, brain value 6000 cm ² / g
Citric acid: Commercial product Potassium carbonate: Commercial product

<Measurement method>
Stability test (subsidence amount): After filling a foam mortar into a mold having a diameter of 10 cm and a height of 20 cm, a vibration of 2 times / min was applied to the mold for 60 minutes, and the amount of settlement was measured. The calculation formula for the amount of settlement is as follows.
Subsidence amount (%) = (height when the flow value becomes 200 mm or less) / (height immediately after filling the mold) × 100.
Density: Measured by filling bubble mortar into a 1 liter container.
Flow test: Measure the time from the production of the bubble mortar until the flow value becomes 200 mm or less by the Japan Highway Public Corporation Standard JHS A313 flow test.
Air volume: Measured by Japan Highway Public Corporation Standard JHS A313 air mortar and air milk test method.
Brain value: Measured according to JIS R 5201.
Compressive strength: Measure the compressive strength of a given age according to JIS R 5201.

According to the present invention, it is possible to obtain an ultralight mortar in which bubbles are stable, rapid construction is possible, and settlement is small. The bubble mortar of the present invention can fill a space where a vibration is applied for a long time, for example, a tunnel, a road, a railroad, a waterway, and can be used as a substitute for soil. When the amount of bubbles in the bubble mortar is 50% or more, the weight becomes ultra-light and heat insulation can be improved.

If the amount of bubbles is simply increased, the bubble mortar will sink, and heat insulation and workability may not be obtained. INDUSTRIAL APPLICABILITY The present invention can provide a lightweight cellular mortar that does not sacrifice both fluidity and strength development and that can obtain heat insulation and workability. By using finely divided cement, it is possible to prevent the mortar from sinking before hardening.

Claims (7)

Ri Blaine value the name contained 6000 cm ² / g or more of a fine powder cement and set-accelerating material, and Ru bubble mortar greens contain bubbles 50% or more. Set accelerating material, per 100 parts by weight of fine powder cement, foam mortar according to claim 1, wherein 10 to 30 parts by weight. The foam mortar according to claim 1 or 2 , wherein the setting accelerator contains calcium aluminate. The foam mortar according to claim 3 , wherein the setting accelerator contains a sulfate. Furthermore, one of claims bubble mortar of claims 1-4 containing retarding material. 1 wherein the foam mortar of claims 1 to 5 in which the fine powder cement containing slag. In the flow test of JHS A313, after holding the state of the above flow values 200mm 5 minutes or more, the flow value is below 200mm within 30 minutes claim 1-1 Claims bubble mortar out of six.