JPS59202279A - Grouting material for reinforcement of structure - Google Patents

Abstract

PURPOSE:To provide the titled material having excellent water-proofness and durability and strong adhesion to inorganic materials, prepared by mixing cement, polymer, aggregate and water. CONSTITUTION:The grouting material for reinforcement of a structure based on polymer cement mortar is prepared by mixing 100pts.wt. cement (e.g. colloid cement or expanding cement), 2-50pts.wt. polymer (e.g. styrene/butadiene rubber or ethylene/vinyl acetate copolymer), 20-300pts.wt. aggregate (e.g. silica sand or fly ash having a particle diameter of about 2mm. or smaller) and 40-70pts.wt. water.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a graft material for reinforcing structures, and more specifically, the present invention relates to a graft material for reinforcing structures, and more specifically, it is used to inject into structures such as concrete lining of roads, concrete box girders of bridges, bridge piers, and concrete buildings. , Polymer cement tA, ψri [;
Concerning graft materials.

Conventionally, cement mortar and epoxy resin have been used as grafting materials for internal corporations when the above-mentioned structures, especially concrete structures, have become neutralized or deteriorated over time, and have also been used as grafting materials for backfilling of roads. Cement mortar was used.

However, cement mortar generally has the disadvantage of being prone to cracking due to long-term physical effects such as drying shrinkage or chemical effects such as acids and salts, and epoxy resins have a sufficiently high curing strength. This is presumably due to poor compatibility with cement mortar, but there was a tendency for cracks to occur in the concrete surrounding the injected resin.

The purpose of the present invention is to eliminate the drawbacks of the conventional graft materials mentioned above and provide a highly durable and waterproof graft material for reinforcing structures. 50 parts by weight and @1 aggregate 20-30
0 parts by weight and 40 to 70 parts by weight of water.

Specific examples of the cement used in the present invention include ordinary Portland cement, early-strength Portland cement, Portland cement such as Colloy F cement, mixed cement such as fly ash cement, expandable cement, and alumina cement. Particularly preferred are Floy F cement and expandable cement that expands or does not shrink when the cement hardens. Expanding materials mixed with expandable cement, shrinkable materials, etc. are used.

The polymer used in the present invention is also called a polymer admixture, and is present as a polymer in the cured graft material of the present invention, and is mixed for the purpose of improving its impact resistance, adhesion to structures, waterproofness, etc. Specific examples include synthetic rubbers such as natural rubber, chloroprene rubber, getadiene rubber, styrene-getadiene rubber, acrylonitrile-butadiene rubber, methyl methacrylate-getadiene rubber, polyvinyl acetate, ethylene-vinyl acetate copolymer, and styrene-acrylic copolymer. Polyvinyl chloride, polyvinylidene chloride, vinyl polypropionate, and the like can be mentioned. Most of these materials, except for natural rubber, are synthesized by emulsion polymerization, and then stabilizers, antifoaming agents, etc. are added as necessary, and they are usually used in the form of emulsions or latexes.

Among the first-generation polymers, styrene-butadiene rubber, atarylonitrile-butadiene rubber, and ethylene-acetic acid are preferred due to their waterproof properties, adhesion to inorganic materials such as cement structures and bricks, flexibility, impact strength, and economic efficiency. Vinyl copolymers, styrene-acrylic copolymers, and the like are preferred, with styrene-getadiene rubber and ethyne-vinyl acetate copolymers being particularly preferred. However, if the amount of these polymers is too small, the above effect will not be achieved, and if it is too large, the strength of the graft material after hardening will be insufficient. be done.

As aggregate, so-called fine aggregate, in which 85% or more of the aggregate has a particle size of 5% or less, is often used, but for example, coarse aggregate is used together with fine aggregate for backfilling of barriers. obtain. As the fine aggregate, silica sand containing silicic anhydride as a main component and having a particle size of 2% or less, particularly 1% or less is preferably used, and as the lightweight paste, fly ash or the like is used. If the amount of aggregate is too small, the strength etc. of the gract material after hardening will be insufficient, and if it is too large, the fluidity will decrease, so the amount used is 20 to 300 parts by weight, preferably 50 parts by weight, per 100 parts by weight of cement. ~200 parts by weight. If it is injected into a cracked structure or the main purpose is to stop water, reduce the amount of aggregate used and add a waterproofing agent as described below. If the amount of water is too large, the strength of the hardened graft material will be insufficient and furthermore, extremely fine voids will remain in the hardened graft material due to evaporation of water, reducing durability. Since the hydration reaction will be insufficient and the fluidity will be poor, it is recommended that the total amount of water contained in the polymer latex and the water added at the site be 40 to 70 parts by weight per 100 parts by weight of cement. The amount is 50 to 70 parts by weight.

As will be described later, the gruct material of the present invention has greater waterproofing performance as a single product than conventional cement mortar, but it is also possible to add various waterproofing agents for the purpose of providing even better waterproofing. good.

A suitable example of the waterproofing agent is an amorphous aluminum silicate or a hydrate thereof having a molar ratio of aluminum silicate to silicon dioxide of 1:1 to 1:10.

Amorphous aluminum silicate refers to a periodic arrangement of each atom of silicic aluminum, that is, almost no crystal lattice is observed. When taking the X-ray powder diffraction spectrum of the above aluminum silicate, which is used as the intensity of the diffraction line, the characteristic peak that would necessarily occur if a crystal lattice exists at a length that allows a gentle chevron pattern to be obtained does not appear. be judged.

The above-mentioned amorphous aluminum silicate can be produced by, for example, dissolving aluminum sulfate and sodium silicate in appropriate amounts of water, mixing the aqueous solutions, and reacting the two while adjusting the pH, temperature, etc. in the reaction solution. can get. By adjusting reaction conditions such as temperature, a product having an appropriate molar ratio of aluminum oxide to silicon dioxide can be synthesized. In terms of good solubility in aqueous alkaline solutions, the more silicon dioxide in aluminum silicate, that is, the lower the above molar ratio, the better; however, when considering ease of production, the molar ratio of aluminum oxide to silicon dioxide It is most preferable that the ratio is approximately 1:9.

On the other hand, the above-mentioned amorphous aluminum silicate also exists as a hydrate in the clay minerals of volcanic ash layers, and is collectively called allophane, including cases where it contains a small amount of crystalline part. Reports that a crystal lattice exists have not been disparaged. The molar ratio of aluminum oxide to silicon dioxide in allophane is 1:1 to 1:2, but when comparing the above-mentioned amorphous aluminum silicate with the same molar ratio and allophane, the reason is not clear, but the alkaline content The solubility of synthetic amorphous aluminum citrate is much better.

In the present invention, the synthetic amorphous aluminum silicate is usually used, but natural amorphous aluminum silicate may be used in some cases.

The amount of amorphous aluminum silicate used is usually 113 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of cement.

Polymer cement compositions such as the graft material of the present invention are suitable for use in reinforcing structures or municipal water because they have superior waterproof properties, adhesion to inorganic materials such as concrete and bricks, and fluidity compared to conventional cement compositions. It is preferable as a graft material.

That is, according to the findings of the present inventors, for example, when styrene-getadiene rubber or ethylene-vinyl acetate copolymer is used as the polymer in a polymer cement composition, the tensile adhesive strength of the polymer cement composition to bricks is equal to that of the conventional one. The strength of the cement composition is about 3 to 10 times, and the adhesive strength to concrete is about 4 to 7 times, and the JISA
The waterproof performance of the composition measured in accordance with 1404 is approximately 4
0 to 60 times higher (for both adhesive strength and waterproof performance, ordinary Portland cement is used as the cement, and Gui sand with a particle size of 1 fi or less is used as the aggregate, and the polymer-cement ratio, water-cement ratio, and polymer specifications are normal). Comparison of compositions within the range of use).

Furthermore, under similar conditions, the vertical axis shows the water-cement ratio (about α35 to about (L65)), and the horizontal axis shows the polymer-cement ratio (O to about 0.4).
If we draw an equal flow value (measured according to A STMC 124) curve as, the water-cement ratio to obtain the same flow value is about 10 to It is understood that the polymer cement composition has better fluidity than that of the polymer cement composition.

Ru.

Many of the cracks that occur on the surface of weakened existing concrete structures are minute, with a width Q of 5% or less, and injection pipes are installed at appropriate intervals along the cracks in such structures. After installation (often cutting the concrete surface and gluing and fixing the wide end of the pipe with epoxy resin), the graft material is pumped using a compressor or plunger pump (at a pressure of 2 to 5 d/d). It is then filled into the cracks via a pipe.

On the other hand, if the crack width of the structure is about 0.2 to 4%, it is possible to inject the graft material without attaching the pipe. For example, place many pieces of paper tape at right angles to the crack.
After pasting at intervals, a thin layer of hot-melt sealing material is applied, and after curing, the tape is peeled off to form an injection port.

Thereafter, a mechanical injection nozzle is brought into contact with the injection port to inject the graft material.

Furthermore, it is virtually impossible to completely eliminate voids between the back of the concrete lining of the tunnel and other mountains. In the case of so-called backfill injection, which involves injecting into such voids, after drilling a through hole from the lining surface to the back side and pushing in the injection pipe, the graft material is injected slowly at first and then without interruption. After the void is completely filled by continuous injection (injection pressure of about 3 to 5 K9/d), the injection hole is closed to finish. The above-mentioned drilling of the through holes and insertion of the pipes may be performed in advance during concrete lining, and the backfilling may be performed immediately after the lining work is completed.

Furthermore, the graft material of the present invention is suitable for use in reinforcing concrete box girders of bridges, brick structures, and the like.

The presence and position of a relatively large gap created in a box girder or the like is confirmed by, for example, ultrasonic diagnostics before the graft material is injected.

The graft material for reinforcing structures of the present invention has the structure described above, and the amount of cement, polymer, aggregate, and water is specified, and it has better waterproofness, fluidity, and fluidity than conventional cement mortar.
Even without concrete, etc., a sufficiently waterproof and reinforced solid structure can be obtained with good workability and at a much lower cost than when using epoxy SI resin.

Examples of the present invention are shown below.

Example personnel: SBR emulsion 200 instant (viscosity 80CP
S or less, solid content 4596, water 110) Silica sand
1000 (particle size α5% or less, 9096 or more) synthetic amorphous aluminum silicate
9 to 10 (molar ratio of aluminum oxide to silicon dioxide 1:9) The above personnel, material B, and 500 g of water were well mixed and stirred to obtain a homogeneous polymer cement mortar.

The curing and expansion characteristics of this mortar after 7 days of age were approximately 0.03 to 104% (measured in accordance with the JISA 1125 comparator method) in terms of rate of change.

On the other hand, 2 m'' of the above polymer cement mortar was applied to a concrete floor that had been constructed for about 3 years at a ratio of 5 to 9/d, cured at room temperature and air-dried, and after 3 days, water was applied using a water spraying device. Water was sprinkled at a rate of 100//m' every day for 60 minutes during the day and 60 minutes at night in an area of approximately 5TI including the entire surface of the coating layer, and this watering was continued for one year, but the floor surface and polymer cement mortar layer were No peeling occurred, confirming the performance of the above-mentioned aluminum guic acid as a waterproofing material.

The above polymer cement mortar was used as a graft material on a @way where a gap of approximately α5d existed between the zenith of the tunnel and the back of the lining, and the other parts were densely concreted.

7111 cases of water leakage in concrete were classified.

A through hole is set at σ from the lining surface at the top to the back side with an inner diameter of 3
Insert the 5% pipe and add the above graft material to 3-4 to 9/9
It was fed at a pressure of cII to completely fill the gap and close the through hole. The water leakage stopped after a few days, and the condition remained in good condition six months later.

Patent issuer Sekisui Chemical Co., Ltd. Representative Mototoshi Fujinuma

Claims (1)

[Claims] L: A graft material for reinforcing a structure, which contains 5 to 50 parts by weight of polymer, 20 to 300 parts by weight of aggregate, and 40 to 70 parts by weight of water per 100 parts by weight of cement. . 2 The cement is Colloy F cement I! The graft material described in Section IJ1. The graft material according to item 1 or 2, wherein the cement is an expandable cement. 3. The graft material according to items 1 to 3, wherein the raw polymer is an ethylene-vinyl acetate copolymer. 5. The graft material according to @1 to @3, wherein the halimer is styrene-getadiene rubber.