Mortar materials and hardened mortar products

Abstract

The objective is to provide a mortar material that yields a hardened mortar product with excellent hardening properties, water absorption, and compressive strength. [Solution] A mortar material is used that contains a water-soluble organic monomer (A), a water-swellable clay mineral (B), cement (C), aggregate (D), and water, characterized in that the total amount of the water-soluble organic monomer (A) and the water-swellable clay mineral (B) is 2 to 30% by mass, the total amount of the cement (C) and the aggregate (D) is 40 to 95% by mass, and the amount of water is 5 to 40% by mass.

Description

Technical Field

[0001] The present invention relates to a mortar material and a hardened mortar product.

Background Art

[0002] In recent years, the cavity formation underground in road structures has become apparent, and countermeasures against it have become an urgent issue. For the restoration of roads sunken due to cavity formation, inorganic fillers are often used in many cases, but this is a temporary measure and there is a risk that cavity formation under the road surface may recur.

[0003] Under such circumstances, as a method for treating road subsidence caused by damage to underground sewer pipes, a method has been proposed in which crushed stones are laid around the damaged part of the pipe, and then an expansive resin is filled into the cavity and expanded to fill the cavity with the expanded resin (see, for example, Patent Document 1).

[0004] However, the resin material used in this method has problems such as material deterioration due to hydrolysis and difficulty in filling the cavity without gaps, so that further inflow of water cannot be prevented. Therefore, there has been a demand for a filling material that can absorb the inflowing water and fill the voids without gaps and has excellent compressive strength.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The problem to be solved by the present invention is to provide a mortar material that can obtain a hardened mortar product having excellent curability, water absorption, and compressive strength.

Means for Solving the Problems

[0007] The inventors have discovered that water-soluble organic monomers, water-swellable clay minerals, cement, aggregates, and mortar materials containing water can solve the above problems, and have completed the present invention.

[0008] In other words, the present invention provides a mortar material characterized by containing a water-soluble organic monomer (A), a water-swellable clay mineral (B), cement (C), aggregate (D), and water. [Effects of the Invention]

[0009] The mortar material of the present invention yields a hardened mortar product with excellent hardening properties, water absorption, and compressive strength, making it suitable for use as a filler for underground cavities, a concrete repair material, a ground improvement material, a waterproofing material, and the like. [Modes for carrying out the invention]

[0010] The mortar material of the present invention contains a water-soluble organic monomer (A), a water-swellable clay mineral (B), cement (C), aggregate (D), and water.

[0011] The polymer of the water-soluble organic monomer obtained from the water-soluble organic monomer (A) forms a three-dimensional network structure together with the water-swellable clay mineral (B), and becomes a component of the organic-inorganic composite hydrogel.

[0012] Examples of the water-soluble organic monomer (A) include monomers having a (meth)acrylamide group, monomers having a (meth)acryloyloxy group, and acrylic monomers having a hydroxyl group.

[0013] Examples of monomers having the (meth)acrylamide group include acrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, N-methylacrylamide, N-ethylacrylamide, N-isopropylacrylamide, N-cyclopropylacrylamide, N,N-dimethylaminopropylacrylamide, N,N-diethylaminopropylacrylamide, acryloylmorpholin, methacrylamide, N,N-dimethylmethacrylamide, N,N-diethylmethacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, N-isopropylmethacrylamide, N-cyclopropylmethacrylamide, N,N-dimethylaminopropylmethacrylamide, N,N-diethylaminopropylmethacrylamide, and N,N'-methylenebisacrylamide.

[0014] Examples of monomers having the (meth)acryloyloxy group include methoxyethyl acrylate, ethoxyethyl acrylate, methoxyethyl methacrylate, ethoxyethyl methacrylate, methoxymethyl acrylate, and ethoxymethyl acrylate.

[0015] Examples of acrylic monomers having a hydroxyl group include 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate.

[0016] Among these, monomers having a (meth)acrylamide group are preferred from the viewpoint of solubility, compressive strength of the resulting organic-inorganic hydrogels, and adhesion between hydrogels, with acrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, N-isopropylacrylamide, acryloylmorpholine, and N,N'-methylenebisacrylamide being more preferred, and N,N-dimethylacrylamide, acryloylmorpholine, and N,N'-methylenebisacrylamide being even more preferred.

[0017] The water-soluble organic monomer (A) mentioned above may be used alone or in combination of two or more types.

[0018] The water-swellable clay mineral (B) forms a three-dimensional network structure together with the polymer of the water-soluble organic monomer and becomes a component of the organic-inorganic hydrogel.

[0019] The water-swellable clay mineral is not particularly limited, and examples thereof include water-swellable smectites such as water-swellable hectorite, water-swellable montmorillonite, and water-swellable saponite; water-swellable mica such as water-swellable synthetic mica. Among these, from the viewpoint of the stability of the dispersion liquid, water-swellable hectorite and water-swellable montmorillonite are preferable, and water-swellable hectorite is more preferable.

[0020] As the water-swellable clay mineral (B), those derived from nature, synthesized ones, and those with modified surfaces can also be used. Examples of the water-swellable clay mineral with a modified surface include phosphonic acid-modified synthetic hectorite, fluorine-modified synthetic hectorite, etc. From the viewpoint of the strength and adhesiveness of the obtained organic-inorganic composite hydrogel, it is preferable to use phosphonic acid-modified synthetic hectorite.

[0021] In addition, the above-mentioned water-swellable clay mineral (B) may be used alone or in combination of two or more.

[0022] Examples of the cement (C) include ordinary Portland cement, rapid-hardening cement, early-strength Portland cement, ultra-early-strength Portland cement, medium-heat Portland cement, low-heat Portland cement, blast furnace cement, silica cement, fly ash cement, etc. In addition, these cements (C) may be used alone or in combination of two or more.

[0023] Examples of the aggregate (D) include crushed stone, sandstone, gypsum stone, marble, quartz, granite, limestone, silica stone, silica sand, river sand, etc. In addition, these aggregates (D) may be used alone or in combination of two or more.

[0024] Examples of the water include ion-exchanged water, distilled water, tap water, etc.

[0025] The total amount of the water-soluble organic monomer (A) and the water-swelling clay mineral (B) in the mortar material of the present invention is preferably 2 to 30% by mass, more preferably 3 to 25% by mass, because the balance between water absorption and compressive strength is further improved.

[0026] The total amount of the cement (C) and the aggregate (D) in the mortar material of the present invention is preferably 40 to 90% by mass, more preferably 45 to 85% by mass, because the balance between water absorption and compressive strength is further improved.

[0027] Water in the mortar material of the present invention is preferably 5 to 40% by mass, more preferably 8 to 35% by mass, because the balance between water absorption and compressive strength is further improved.

[0028] The water-soluble organic monomer (A) in the mortar material of the present invention is preferably 1 to 29% by mass, more preferably 2 to 24% by mass, because the balance between water absorption and compressive strength is further improved.

[0029] The water-swelling clay mineral (B) in the mortar material of the present invention is preferably from 0.1 to 29% by mass, more preferably from 1 to 23% by mass, because the balance between water absorption and compressive strength is further improved.

[0030] The cement (C) in the mortar material of the present invention is preferably 10 to 60% by mass, more preferably 10 to 50% by mass, because the balance between water absorption and compressive strength is further improved.

[0031] The aggregate (D) in the mortar material of the present invention is preferably 30 to 80% by mass, more preferably 35 to 75% by mass, because the balance between water absorption and compressive strength is further improved.

[0032] The mortar material of the present invention can be easily obtained, for example, by blending the cement (C) and the aggregate (D) with a mixture of the water-soluble organic monomer (A), the water-swelling clay mineral (B) and water.

[0033] The mortar material of the present invention contains the water-soluble organic monomer (A), the water-swellable clay mineral (B), the cement (C), the aggregate (D), and water, but may also contain other compounds as needed.

[0034] Examples of the other compounds mentioned above include organic solvents, organic crosslinking agents, preservatives, thickeners, polymerization inhibitors, fillers, UV absorbers, pigments, low shrinkage agents, antioxidants, plasticizers, flame retardants, stabilizers, reinforcing agents, rust inhibitors, and the like.

[0035] Examples of the aforementioned organic solvents include alcohol compounds such as methanol, ethanol, propanol, isopropyl alcohol, and 1-butanol; ether compounds such as ethyl ether and ethylene glycol monoethyl ether; amide compounds such as dimethylformamide and N-methylpyrrolidone; and ketone compounds such as acetone and methyl ethyl ketone.

[0036] Among these, from the viewpoint of dispersibility of water-swellable clay minerals, it is preferable to use alcohol compounds, more preferably methanol, ethanol, n-propyl alcohol, or isopropyl alcohol, and even more preferably methanol or ethanol. These organic solvents may be used alone or in combination of two or more.

[0037] The mortar material of the present invention yields a hardened mortar containing an organic-inorganic composite hydrogel having a three-dimensional network structure formed by a polymer of the water-soluble organic monomer (A) and the water-swellable clay mineral (B), through the polymerization reaction of the water-soluble organic monomer (A). Because this hardened mortar contains an organic-inorganic composite hydrogel, it exhibits excellent water absorption and compressive strength.

[0038] By incorporating a polymerization initiator (E) and a polymerization accelerator (F) into the mortar material of the present invention, polymerization of the water-soluble organic monomer (A) proceeds easily, and a hardened mortar product containing an organic-inorganic composite hydrogel is obtained.

[0039] The polymerization initiator (E) is not particularly limited, but examples include water-soluble peroxides such as potassium peroxodisulfate, ammonium peroxodisulfate, sodium peroxodisulfate, and t-butyl hydroperoxide; and water-soluble azo compounds such as 2,2'-azobis(2-methylpropionamidine) dihydrochloride and 4,4'-azobis(4-cyanovaleric acid). Among these, water-soluble peroxides are preferred from the viewpoint of interaction with the water-swellable clay mineral (B), and potassium peroxodisulfate, ammonium peroxodisulfate, and sodium peroxodisulfate are more preferred. These polymerization initiators (E) may be used alone or in combination of two or more.

[0040] The molar ratio of the polymerization initiator (E) to the water-soluble organic monomer (A) (polymerization initiator (E) / water-soluble organic monomer (A)) is preferably 0.01 or higher, more preferably 0.02 to 0.1, and even more preferably 0.04 to 0.1.

[0041] Examples of the polymerization accelerator (F) include tertiary amine compounds such as N,N,N',N'-tetramethylethylenediamine and 3-dimethylaminopropionitrile; thiosulfates such as sodium thiosulfate and ammonium thiosulfate; and ascorbic acids such as L-ascorbic acid and sodium L-ascorbate. Among these, tertiary amine compounds are preferred from the viewpoint of affinity and interaction with water-swellable clay minerals, and N,N,N',N'-tetramethylethylenediamine is more preferred. These polymerization accelerators (F) may be used alone or in combination of two or more.

[0042] Since the polymerization accelerator (F) can further promote polymerization without causing the mortar material to aggregate, it is preferable that the amount of the polymerization accelerator (F) is 0.01 to 1 part by mass, and more preferably 0.05 to 0.5 parts by mass, per 100 parts by mass of the total amount of the water-soluble organic monomer (A) and water-swellable clay mineral (B).

[0043] The mortar cured product of the present invention contains a polymer of the water-soluble organic monomer (A), but the polymerization method of the water-soluble organic monomer (A) is not particularly limited and can be carried out by known methods. Specifically, examples include radical polymerization by heating or ultraviolet irradiation, and radical polymerization utilizing redox reactions.

[0044] The polymerization temperature is not particularly limited, but 5 to 80°C is preferred, and 20 to 80°C is more preferred because polymerization is more promoted.

[0045] The polymerization time varies depending on the type of polymerization initiator (E) and polymerization accelerator (F), but is typically carried out between several tens of seconds and 24 hours. In particular, for radical polymerization utilizing heating or redox, a polymerization time of 1 to 24 hours is preferred, and 5 to 24 hours is more preferred. A polymerization time of 1 hour or more is preferable because it allows the polymer of the water-swellable clay mineral (B) and the water-soluble organic monomer (A) to form a three-dimensional network. On the other hand, since the polymerization reaction is almost completed within 24 hours, a polymerization time of 24 hours or less is preferable.

[0046] The mortar material of the present invention yields a hardened mortar product with excellent hardening properties, water absorption, and compressive strength, making it suitable for use as a filler for underground cavities, a concrete repair material, a ground improvement material, and the like.

[0047] The mortar material of the present invention can be easily used to fill cavities using, for example, an injection gun or hose. [Examples]

[0048] The present invention will be described in more detail below with reference to specific examples.

[0049] (Example 1: Preparation of mortar material (1)) A homogeneous, transparent aqueous solution was prepared by mixing 15 parts by mass of water, 0.5 parts by mass of phosphonic acid-modified synthetic hectorite (LAPONITE RDS, manufactured by BIC Chemie Japan Co., Ltd.), 0.5 parts by mass of phosphonic acid-modified synthetic hectorite (LAPONITE S-482, manufactured by BIC Chemie Japan Co., Ltd.), 3 parts by mass of phosphonic acid-modified synthetic hectorite (LAPONITE EP, manufactured by BIC Chemie Japan Co., Ltd.), 2 parts by mass of N,N-dimethylacrylamide, 1 part by mass of acryloylmorpholin, 4 parts by mass of 2-hydroxyethyl methacrylate, and 5 parts by mass of N,N'-methylenebisacrylamide and stirring. Then, mortar material (1) was prepared by adding 30 parts by mass of ordinary Portland cement and 26 parts by mass of silica sand to this aqueous solution.

[0050] [Evaluation of curing properties] To 100 parts by mass of the mortar material (1) obtained above, 0.2 parts by mass of sodium persulfate and 4 parts by mass of an 8% tetramethylethylenediamine aqueous solution were added. The mixture was then placed in a Φ50 × 100 mm container, leveled, and left to stand at 23°C. The time until the mortar hardened and could be demolded from the container was measured to evaluate its hardening properties.

[0051] [Evaluation of water absorption] Mortar hardened samples, prepared using the same procedure as for hardening evaluation, were cured at 23°C for 7 days after demolding, and then weighed. Subsequently, these hardened samples were immersed in water for 24 hours, the surface water was lightly wiped off with a cloth, and the weight was quickly measured. The water absorption rate was then calculated using the following formula. Water absorption rate (%) = ((Weight of test specimen after immersion in water) - (Weight of test specimen before immersion in water)) / (Weight of test specimen before immersion in water) × 100

[0052] [Evaluation of compressive strength] Mortar hardened material, prepared using the same procedure as for hardening evaluation, was cured at 23°C for 7 days after demolding. This hardened mortar was subjected to a compression test at 23°C according to JIS-A1108, and the compressive strength (MPa) was measured (test speed: 0.6 N / mm² / second). 2 The test used was the "Autograph AG-25TB" manufactured by Shimadzu Corporation.

[0053] (Examples 2-6: Preparation of mortar materials (2)-(6)) Except for changing the raw material composition used in Example 1 as shown in Table 1, mortar materials (2) to (6) were prepared in the same manner as in Example 1, and then their various physical properties were evaluated.

[0054] (Comparative Examples 1-4: Preparation of Mortar Materials (R1)-(R4)) Except for changing the raw material composition used in Example 1 as shown in Table 2, mortar materials (R1) to (R4) were prepared in the same manner as in Example 1, and then their various physical properties were evaluated.

[0055] Table 1 shows the composition and evaluation results of the mortar materials (1) to (6) obtained above.

[0056] [Table 1]

[0057] Table 2 shows the composition and evaluation results of the mortar materials (R1) to (R4) obtained above.

[0058] [Table 2]

[0059] The ingredients listed in the table are as follows: DMAA: Dimethylacrylamide ACMO: Acryloylmorpholin HEMA: 2-hydroxyethyl methacrylate MBAA: N,N'-Methylenebisacrylamide LAPONITE RDS: Manufactured by BIC Chemie Japan Co., Ltd., phosphonic acid-modified synthetic hectorite. LAPONITE S-482: Manufactured by Bic Chemie Japan Co., Ltd., phosphonic acid-modified synthetic hectorite. LAPONITE EP: Manufactured by BIC Chemie Japan Co., Ltd., phosphonic acid-modified synthetic hectorite. Standard Portland Cement: Manufactured by NCC Corporation Fast-setting cement: Manufactured by Onoda Chemico Co., Ltd., ultra-fast-setting super jet cement Polyurethane foam (1): Manufactured by Nippon Pufftem Co., Ltd., Mocofoam

[0060] The mortar materials of the present invention in Examples 1 to 6 were confirmed to yield mortar hardened products with excellent curability, water absorption, and compressive strength.

[0061] On the other hand, Comparative Example 1 is an example that does not contain the water-swellable clay mineral (B), which is an essential component of the present invention, and it was confirmed that its water absorption was insufficient.

[0062] Comparative Example 2 is an example that does not contain the water-soluble organic monomer (A), which is an essential component of the present invention, but it was confirmed that the water absorption was insufficient.

[0063] Comparative Example 3 is an example that does not contain cement (C), which is an essential component of the present invention, but it was confirmed that the compressive strength after water absorption was insufficient.

[0064] Comparative Example 4 is an example in which foamed urethane was used instead of the water-soluble organic monomer (A) and water-swellable clay mineral (B), which are essential components of the present invention, but it was confirmed that the water absorption was insufficient.

Claims

1. A mortar material characterized by containing a water-soluble organic monomer (A), a water-swellable clay mineral (B), cement (C), aggregate (D), and water.

2. The mortar material according to claim 1, wherein the total amount of the water-soluble organic monomer (A) and water-swellable clay mineral (B) is 2 to 30% by mass, the total amount of the cement (C) and aggregate (D) is 40 to 90% by mass, and the amount of water is 5 to 40% by mass.

3. The mortar material according to claim 2, wherein the water-soluble organic monomer (A) is a monomer having a (meth)acrylamide group.

4. A hardened mortar product obtained by hardening the mortar material according to any one of claims 1 to 3.

Images