JP4893083B2 - Hydraulic composition - Google Patents

Description

The present invention relates to a grout material excellent in fluidity and strength characteristics, which is used for repairing and reinforcing various civil engineering structures.
Furthermore, the present invention relates to a grout material excellent in fluidity and strength characteristics, a mortar composition thereof, and a cured body thereof, which are used for filling a gap in a joint sleeve of a deformed reinforcing bar for joining concrete members.

  Grout that fills the gap of the joint sleeve used for the method of joining precast reinforced concrete members on site for the purpose of building construction with improvement and progress of construction and labor saving of construction work due to lack of skilled workers As a material, Patent Document 1 discloses a grout mortar composition containing cement, ultrafine powder, an expansion material, a high-performance water reducing agent, and a heavy aggregate.

The trend of super-high-rise, large-scale, and complex buildings has progressed, and high-strength mortar with a compressive strength of 80 N / mm ² or more used for building these buildings is disclosed in Patent Document 2 as cement. And a granular cement clinker and a water reducing agent, ultrafine powder, or a specific aggregate, a mortar composition having a good fluidity even at a low water cement ratio and a high strength of the cured product is disclosed.

As a mortar composition used for a radiation shielding member such as a reactor shielding wall (RSW) of a reactor containment building, a back-stripping construction member of a radiation shielding wall, etc., Patent Document 3 is excellent in corrosion resistance and has no material separation. A weight mortar containing cement and corrosion-resistant alloy powder having a unit volume mass of 7 t / m 3 or more with good fluidity is disclosed.

  As crushed sand obtained by rubbing particles of crushed sand and treating these particles by friction between particles, Patent Document 4 is a fresh concrete composed of at least cement, fine aggregate, coarse aggregate, and water. As the fine aggregate, there is disclosed a fresh concrete characterized in that it contains 70% by volume or more of ground sand obtained by rubbing ground sand particles and spheroidizing these particles by friction between the particles.

JP-A-6-293549 JP 2005-119885 A JP 2002-321196 A JP 2004-083336 A

In response to improvements in construction materials and construction methods, and the rise of buildings due to progress, and labor savings in construction work due to a lack of skilled workers, a method for joining precast reinforced concrete members on site has been put into practical use. These properties are well-balanced in a high-performance area, such as fluidity that can be filled into a joint sleeve for joining members, low shrinkage that can tightly integrate construction sites, and strength properties that provide high strength of the cured product. A grout material is also required.
The present invention exhibits excellent fluidity, non-shrinkage, and hardened body strength in various injection methods in the field of civil engineering and construction, especially for joints for joining rebars in construction methods for joining precast reinforced concrete members in the field. An object of the present invention is to provide a hydraulic composition excellent in fluidity that can be suitably filled into a sleeve, non-shrinkage capable of firmly integrating construction sites, and strength properties of a cured product.

As a result of various studies to solve the above problems, the present inventor has obtained a hydraulic composition capable of obtaining good flow characteristics and high strength characteristics using a hydraulic component, polishing sand, chromite sand and an antifoaming agent. And the present invention was completed.

That is, the present invention is a hydraulic composition containing a hydraulic component, a fine aggregate and an antifoaming agent,
The fine aggregate is a hydraulic composition characterized in that it includes abrasive sand obtained by rubbing sand particles or polishing sand using a polishing member, and chromite sand.

The preferable aspect of the hydraulic composition of this invention is shown, These can be combined multiplely.
1) The mass ratio of polishing sand to chromite sand (polishing sand / chromite sand) is 95/5 to 5/95.
2) The total mass of polishing sand and chromite sand is 70% by mass or more with respect to 100% by mass of fine aggregate.
3) The fine aggregate contains fine sand, and the content of fine sand with respect to 100% by mass of fine aggregate is less than 30% by mass.
4) The hydraulic composition further includes at least one component selected from an expanding agent, a fluidizing agent, and a thickener.
5) The hydraulic composition is used for filling the joint sleeve gap of the deformed reinforcing bar for joining concrete members.
6) A hydraulic mortar composition obtained by kneading a hydraulic composition and water.
7) A cured product of a hydraulic mortar composition obtained by curing a blend of a hydraulic composition and water.

The hydraulic composition of the present invention includes a hydraulic component, polishing sand, and chromite sand, so that it can stand out from the flowability of mortar, and can provide a high-strength, non-shrinkable cured body. It can be used as a grout material that exhibits excellent characteristics in various injection methods in the field.
Furthermore, the hydraulic composition of the present invention can obtain a mortar having excellent characteristics of fluidity as well as material separation resistance by blending fine sand, resulting in a high strength, non-shrinkable cured body. Obtainable.
In particular, it has excellent performance as a grout material that fills the gaps of the joint sleeves of deformed reinforcing bars for joining precast reinforced concrete members.

The hydraulic component is not particularly limited, but normal Portland cement, early strength Portland cement, super early strength Portland cement, medium heat Portland cement, low heat Portland cement, white Portland cement such as Portland cement, blast furnace cement, fly Mixed cements such as ash cement and silica cement, alumina cement and the like can be used.
In particular, when it is necessary to develop good strength in a short time for shortening the construction period, it is preferable to use early-strength Portland cement or ultra-early-strength Portland cement.

  In the hydraulic composition of the present invention, the fine aggregate is preferably 30 to 300 parts by mass, more preferably 40 to 250 parts by mass, more preferably 50 to 220 parts by mass, particularly preferably 100 parts by mass of the hydraulic component. Is blended in an amount of 60 to 200 parts by mass.

The fine aggregate according to the present invention includes abrasive sand and chromite sand. The ratio of the total mass of polishing sand and chromite sand in 100% by mass of fine aggregate is preferably 70% by mass or more, more preferably 74% by mass or more, more preferably 77% by mass or more, and particularly preferably 80%. That's it.

The blending ratio of the polishing sand and chromite sand according to the present invention (mass ratio = polishing sand / chromite sand) is a mass ratio from the flow characteristics of the mortar and the strength characteristics of the cured body, preferably 95/5 to 5/95, More preferably 90/10 to 5/95, more preferably 85/15 to 10/90, and particularly preferably in the range of 80/20 to 15/85, mortar having excellent fluidity and excellent strength are obtained. A cured product having the same can be obtained.

The abrasive sand according to the present invention is obtained by rubbing sand particles, or by sanding a sand surface with a polishing member. For example, sand having a particle size of 5 mm or less (crushed sand, natural sand, crushed stone Waste) and water into a stirrer such as a drum type aggregate grinder (for example, Sand Gulliver: manufactured by Ube Techno Engineering Co., Ltd.), and sand particles, or sand and a polishing member. Abraded, polished sand surface and further dried.
As the polishing sand, trade name: Gulliver sand manufactured by Toyohyo Kogyo Co., Ltd., Tohoku Stone Industrial Co., Ltd., etc. can be used.

  The polishing sand according to the present invention preferably has a particle size of 3.5 mm or less, and in 100% by weight of the polishing sand, polishing sand having a particle size of 0.15 to 2 mm is preferably 60% by weight or more, More preferably, a mortar having excellent fluidity can be obtained by using a material containing 65% by mass or more, particularly preferably 70% by mass or more.

  In particular, the sand is preferably 70% by weight or more, more preferably 75% by weight or more, more preferably 80% by weight or more, and particularly preferably 85% by weight or more. By using a sand containing 0.15 mm or less, preferably 20% by mass or less, more preferably 18% by mass or less, more preferably 16% by mass or less, and particularly preferably 15% by mass or less. In particular, a mortar having excellent fluidity can be obtained.

  As the chromite sand according to the present invention, natural fresh sand and / or sand used in a foundry can be used.

In particular, it is preferable to use a chromite sand having a particle size of 2 mm or less. In 100% by mass of the chromite sand, a chromite sand having a particle size of 0.075 to 0.6 mm is preferably 60% by mass or more, and more preferably. By using a material containing 65% by mass or more, particularly preferably 70% by mass or more, an excellent fluid mortar can be obtained.
Further, the chromite sand is preferably 70% by mass or more, more preferably 80% by mass or more, more preferably 85% by mass or more, and particularly preferably 90% by mass or more, with a chromite sand having a particle size of 0.6 mm or less, and A chromite sand having a particle size of 0.075 mm or less is preferably 20% by mass or less, more preferably 18% by mass or less, more preferably 15% by mass or less, and particularly preferably 10% by mass or less. In particular, it is preferable because a mortar excellent in fluidity can be obtained.

  It is preferable to use a chromite sand having a specific gravity of 4.3 to 4.8 in order to obtain a mortar particularly excellent in fluidity.

In the fine aggregate according to the present invention, fine sand having a particle size of 2 mm or less can be used in addition to abrasive sand and chromite sand.
As fine sand, fine-grained silica sand and limestone crushed sand generated in the process of producing crushed stone and crushed sand such as silica sand and limestone sand can be suitably used, and by adding these fine sand, the viscosity of mortar can be increased. The material separation resistance can be greatly improved while being minimized.
In particular, the fine sand preferably has a fine particle size of 0.6 mm or less, preferably 70% by mass or more, more preferably 80% by mass or more, more preferably 85% by mass or more, and particularly preferably 90% by mass or more, and Fine sand having a particle size of 0.075 mm or less is preferably 20% by mass or less, more preferably 18% by mass or less, more preferably 15% by mass or less, and particularly preferably 10% by mass or less. Thus, the material separation resistance can be further improved without particularly increasing the viscosity of the mortar.
The amount of fine sand is preferably less than 30% by mass, more preferably less than 26% by mass, more preferably less than 23% by mass, and particularly preferably less than 20% by mass in 100% by mass of fine aggregate. As a result, a decrease in fluidity accompanying an increase in the viscosity of the mortar can be minimized, and good material separation resistance can be imparted.
When the blending amount of fine sand exceeds 30% by mass, the increase in the viscosity of the mortar increases, so that the amount of kneading water for obtaining a predetermined fluidity increases, resulting in a decrease in the strength of the cured body. Absent.

Used sand discharged after using chromite sand in a foundry includes used sand containing only chromite, and containing sand containing chromite and silica sand. In the present invention, any of these used sands can be suitably used.
Regarding the fine aggregate used in the present invention, when using sand containing chromite and silica sand, the mass% of the fine sand containing silica sand in the used sand is preferably less than 30 mass% in 100 mass% of the fine aggregate. More preferably, it is less than 26% by mass, more preferably less than 23% by mass, and particularly preferably less than 20% by mass.

In the hydraulic composition of the present invention, it is preferable to add an antifoaming agent in order to obtain a cured body having a dense structure and excellent strength.
As the antifoaming agent, known materials such as synthetic materials such as silicon-based, alcohol-based and polyether-based materials, mineral oil-based materials derived from petroleum refining, and plant-derived natural materials can be used. In particular, a polyether-based antifoaming agent can be preferably used.
The amount of the antifoaming agent added can be one or more in a range not impairing the properties of the present invention, and is preferably 0.005 to 2 parts by mass with respect to 100 parts by mass of the hydraulic component. Preferably it is 0.01-1.5 mass parts, More preferably, it is 0.025-1 mass part, It is preferable to contain 0.05-0.5 mass part especially.
It is preferable to add an antifoaming agent in the above range because the defoaming effect is good, the fluidity of the mortar composition and the effect of improving the strength of the cured product are high, and the strength of the cured product is particularly remarkable.

In addition to the fine aggregate, the hydraulic composition contains at least one component such as an expanding material, gypsum, a fluidizing agent, a thickening agent, and a setting speed adjusting agent as long as the characteristics of the present invention are not impaired. Seeds can be blended.

The expansion material according to the present invention compensates for the volume change that occurs during the curing process of the mortar composition, and is effective in improving the adhesion to the joint sleeve and the deformed reinforcing bar.
As the expansion material, it is preferable to use a metal expansion material such as aluminum powder or iron powder, an inorganic expansion material such as calcium sulfoaluminate or lime, and in particular, a combination of a metal expansion material and a lime expansion material. And preferably used.

As the metal-based expansion material, use of aluminum powder is particularly preferable because of its low specific gravity and high reactivity. As the aluminum powder, those conforming to the second type of JIS K-5906 “Aluminum powder for coating” can be preferably used.
The amount of the metal-based expansion material added is preferably 0.0001 to 0.01 parts by mass, more preferably 0.0002 to 0.005 parts by mass, and more preferably 0.0003 to 100 parts by mass of the hydraulic component. It is preferable to use in the range of ˜0.004 parts by mass, particularly 0.0005 to 0.003 parts by mass.

Examples of the inorganic expansion material include Auin as the calcium sulfoaluminate system, and quick lime, quick lime-gypsum system, calcined dolomite, and the like as the lime system, and at least one selected from these can be used. As the lime system, quick lime and quick lime-gypsum system are particularly preferable.
The added amount of the inorganic expansion material is preferably 1 to 40 parts by mass, more preferably 1.5 to 30 parts by mass, more preferably 2 to 25 parts by mass, and particularly 3 to 3 parts by mass with respect to 100 parts by mass of the hydraulic component. It is preferable to use 20 parts by mass.

The hydraulic composition may contain gypsum as necessary.
As the gypsum, gypsum such as anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum can be used as one kind or a mixture of two or more kinds regardless of the kind.

The hydraulic composition of the present invention is added with a fluidizing agent that has a water reducing effect in order to ensure appropriate fluidity while suppressing material separation, increase the strength of the cured product, and reduce drying shrinkage. It is preferable to do.
As a fluidizing agent, commercially available products such as formaldehyde condensate of melamine sulfonic acid, casein, calcium caseinate, polyether-based, polycarboxylic acid-based, polycarboxylic acid polyether-based, which have a water-reducing effect, are classified into the types. Can be used regardless.
According to the hydraulic component to be used, one or two or more fluidizing agents can be appropriately added as long as the characteristics are not impaired, and preferably 0.001 to 5 mass with respect to 100 parts by mass of the hydraulic component. Parts, more preferably 0.005 to 4 parts by mass, more preferably 0.01 to 3.5 parts by mass, particularly preferably 0.1 to 3 parts by mass.

A thickener is added in order to adjust the fluidity | liquidity of a mortar composition and to suppress material separation.
As the thickener, cellulose-based, protein-based, latex-based, water-soluble polymer-based and the like can be used, and cellulose-based is particularly preferable.
One or two or more thickeners can be added within a range that does not impair the characteristics of the present invention, and preferably 0.001 to 2 parts by mass with respect to 100 parts by mass of the hydraulic component. Preferably it is 0.002-1.5 mass parts, More preferably, it is 0.0025-1 mass part, Especially the range of 0.005-0.5 mass part is preferable.

The hydraulic composition of the present invention can adjust properties such as fluidity, pot life, and material separation of the mortar composition by adjusting the amount of water added.
The hydraulic composition of the present invention is kneaded with water so that 1) the J funnel flow value does not impair the filling property, preferably 35 seconds or less, more preferably 34 seconds or less, more preferably 32 seconds or less, Particularly preferably, it is 30 seconds or less,
Moreover, in order not to impair the material separation resistance, the lower limit of the J funnel flow value is preferably 10 seconds or more, more preferably 12 seconds or more, particularly preferably 15 seconds or more,
2) A mortar composition having a mortar flow value of preferably 250 mm or more, more preferably 260 mm or more,
By curing the resulting mortar,
3) Compressive strength (age of 28 days) is preferably 105N / mm ² or more, more preferably it is possible to obtain a 110N / mm ² or more cured body.

The addition amount of water can be added within a range that does not impair the flow characteristics and strength characteristics of the present invention, and is preferably 6 to 36 parts by mass, more preferably 6.5 to 33 parts by mass with respect to 100 parts by mass of the hydraulic composition. More preferably, it is added in the range of 7 to 30 parts by mass, particularly preferably 7.5 to 27 parts by mass.

INDUSTRIAL APPLICABILITY The hydraulic composition of the present invention can obtain a mortar composition excellent in fluidity and a mortar hardened body having high strength and no shrinkage, and is widely used as a grout material in the field of civil engineering and construction, particularly a precast reinforced concrete member. It can be suitably used as a grout material that fills the gap of the joint sleeve of the deformed reinforcing bar for joining.

  Hereinafter, the present invention will be described in more detail based on examples. However, the present invention is not limited by the following examples.

(Characteristic evaluation method)
1) J funnel (s): indicates a falling value by Civil Engineers Filling Mortar test method (draft) (JSCE · F542-1993) _{J 14} funnel.
2) Flow value (mm): A cone defined in the condensation test of JIS R 5201, an upper end inner diameter of 75 mm, a lower end inner diameter of 85 mm, and a height of 40 mm (internal volume of about 200 ml) are placed on a 5 mm thick sheet glass and kneaded. After filling the concrete composition, the cone is pulled up. After the spread has stopped, the diameters in two perpendicular directions are measured, and the average value is taken as the flow value.
3) Compressive strength (N / mm ² ): Specimen φ5 × 10 cm, according to JIS A-1108.

The following materials were used.
1) Hydraulic component:
Portland cement (Ube Hayashi Portland cement, Blaine specific surface area 4500 cm ² / g).
2) Polishing sand:
· Gulliver sand (manufactured by Toyohyo Kogyo), dried and selected using a sieve of 150 μm to 2 mm, the particle size (sieving) is shown in Table 3.
3) Chromite sand:
Table 3 shows the chromite sand (Okazaki Huttenus Albertus, specific gravity 4.5) and particle size (sieving).
4) Fine sand:
・ Silica sand (manufactured by Ashiya) and particle size (sieving) are shown in Table 3.
5) Admixture:
-Inorganic expansion material: Lime-based expansion material (manufactured by Taiheiyo Materials Co., Ltd.).
Metal-based expansion material: aluminum powder (containing a particle size of 44 μm or less, 60% by mass or more, manufactured by Daiwa Metal Powder Industry Co., Ltd., a mixture of ALC Fine and K-250).
-Fluidizer: A polycarboxylic acid fluidizer (manufactured by Kao Corporation).
-Antifoaming agent: A polyether type antifoaming agent (manufactured by San Nopco).
-Thickener: Methylcellulose thickener (manufactured by Ube Industries).

  The particle size shown in Table 3 was measured using a sieve.

[Examples 1-6 and Comparative Examples 1-6]
The components shown in Table 1 and Table 2 were mixed using an Eirich mixer to obtain hydraulic compositions composed of cement, fine aggregate and admixture shown in Table 1 and Table 2.

  Under conditions of a temperature of 20 ° C. and a relative humidity of 65%, 11.2 parts by mass of water with respect to 100 parts by mass of the hydraulic composition (Example 1 is 11.8 parts by mass, Example 6 is 12.0 parts by mass) And kneaded using a Hobart mixer for 1 minute at low speed and further for 2 minutes at high speed.

  Tables 1 and 2 show the results of evaluating the J funnel and flow value of the obtained kneaded product and the compressive strength of the cured product of the kneaded product.

1) Example 2, Comparative Example 2 and Comparative Example 3 in which an antifoaming agent was blended showed a tendency that the fluidity was excellent as compared with Comparative Examples 4 to 6 in which no antifoaming agent was blended, and particularly cured. In the compressive strength of the body, the improvement in strength due to the blending of the antifoaming agent is remarkable.
2) When only chromite sand was used for the fine aggregate of the hydraulic composition (Comparative Example 1), although the fluidity evaluation results were excellent in numerical values, the material separation was remarkable and good mortar was not obtained.
When only abrasive sand was used as the fine aggregate (Comparative Example 2), although the cured body strength was good, the J funnel flow value was large, the flow value was small, and good fluidity was not obtained.
In Comparative Example 3 in which chromite sand and silica sand were used for the fine aggregate, the fluidity was good, but sufficient strength could not be obtained for the compressive strength of the cured product.
3) In Example 4 in which abrasive sand and chromite sand were used as the fine aggregate of the hydraulic composition, excellent fluidity was obtained, and the strength of the cured body was 105 N / mm ² or more at 28 days of age. Is obtained.
4) In Examples 1 to 3 using abrasive sand, chromite sand, and silica sand as fine aggregates, stable good fluidity was obtained and excellent cured body strength was obtained.
Furthermore, in Example 5 and Example 6 which increased the amount of kneading | mixing water by the mixing | blending of the hydraulic composition of Example 1, the further outstanding fluidity | liquidity was obtained and the result that workability improved more was obtained. Furthermore, although it is considered that the kneadability of the mortar was further improved, the strength of the cured product was the same as that of Example 1 despite the increase in the amount of kneading water.

The hydraulic composition of the present invention includes a hydraulic component, polishing sand, and chromite sand, so that it can stand out from the flowability of mortar, and can provide a high-strength, non-shrinkable cured body. It can be used as a grout material that exhibits excellent characteristics in various injection methods in the field.
Furthermore, the hydraulic composition of the present invention can obtain a mortar having excellent characteristics of fluidity as well as material separation resistance by blending fine sand, resulting in a high strength, non-shrinkable cured body. Obtainable.
In particular, it has excellent performance as a grout material that fills the gaps of the joint sleeves of deformed reinforcing bars for joining precast reinforced concrete members.

Claims (6)

A hydraulic composition containing a hydraulic component, a fine aggregate, and an antifoaming agent,
The fine aggregate includes abrasive sand obtained by rubbing particles of sand or sand using a polishing member, and chromite sand,
The mass ratio of the polishing sand to the chromite sand (polishing sand / chromite sand) is 95/5 to 5/95,
A hydraulic composition, characterized in that the total mass of polishing sand and chromite sand is 70% by mass or more with respect to 100% by mass of the fine aggregate . The hydraulic composition according to claim 1 , wherein the fine aggregate includes fine sand, and a content ratio of the fine sand with respect to 100 mass% of the fine aggregate is less than 30 mass%. The hydraulic composition according to claim 1 or 2 , wherein the hydraulic composition further contains at least one component selected from an expanding agent, a fluidizing agent, and a thickening agent. The hydraulic composition according to any one of claims 1 to 3 , wherein the hydraulic composition is used for filling a joint sleeve gap of a deformed reinforcing bar for joining concrete members. A hydraulic mortar composition obtained by kneading the hydraulic composition according to any one of claims 1 to 4 and water. The hardened | cured material of the hydraulic mortar composition obtained by hardening the hydraulic composition of any one of Claims 1-4 , and water.