KR100806637B1 - High strength non-shrink grout composition with steel corrosion protection - Google Patents

Abstract

The present invention relates to a high strength non-contraction grout mortar composition having corrosion resistance of steel materials. The present invention is 1 to 2 parts by weight of dispersant, 0.06 to 0.1 parts by weight of coagulant control agent, 0.1 to 0.4 parts by weight of aluminum hydroxide as a flame-resistant mixture, based on 100 parts by weight of cement-based powder composition in which portland cement, calcium aluminosulfate and gypsum are mixed. It provides a grout material composition, characterized in that 5 to 10 parts by weight of blast furnace slag fine powder, 0.3 to 1.4 parts by weight of steel corrosion inhibitor and 105 to 125 parts by weight of sand having a maximum particle diameter of 3 mm or less.

The composition of the present invention provides a salt resistance effect by inhibiting chlorine ion penetration into the interior, and by performing physiochemical effects to prevent corrosion of steel even under conditions of high salt content. By multiplying, it is possible to greatly increase the corrosion protection performance of the steel by the grout material.

Description

Hi-Strength and Non-Shrinkage Grout Composition have a Non-Corrosion Ability of Steel}

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the steel corrosion prevention mechanism of nitrite.

The present invention relates to a high-strength non-shrink grout mortar composition having corrosion resistance of steel materials, and more specifically, high flow, high strength, non-existent grout material used in the filling of mechanical foundations, bridge shoes, and various steel structures. The present invention relates to a grout composition in which resistance to salt penetration is added in addition to shrinkage performance and steel corrosion protection is added.

The non-shrink grout material used for the bridge system of road and railway bridges and the machine foundation filling and injection work of various factories, flood gates, power plants, etc. stably transmits the loads, impacts, and vibrations of steel structures and machines to the sphere. It is an important construction material that protects against various deterioration factors from the outside. The major quality characteristics of most of the non-shrink grouts used so far are high flow, high strength, and no shrinkage, and most of them have similar quality performance.

With the recent increase in the development and use of the ocean, the construction work of landfills, ports, power plants, various bridges, coastal roads, and plant factories has been actively progressed. There is a trend.

Various concrete design and anticorrosive coating are applied to concrete structures and hardware used in the ocean to increase the resistance to salt damage. Especially, grout used for basic filling and fixing of major machinery and steels is more corrosion resistant than steel. It is necessary to secure high flame resistance for prevention.

In addition, major roads and bridges located in the inland area, not on the coast, are spraying a large amount of snow remover to ensure traffic safety in winter. An ice making agent, represented by calcium chloride, flows through drains or leaks under the bridge slab. It is a major cause of threat to the safety of bridges by severe corrosion. Accordingly, in order to supplement these problems, development and use of highly flame-resistant non-shrink grout material added to high salt, high strength, non-shrinkage performance in addition to high salt resistance, unlike any other conventional grout material is more necessary than ever.

In the conventional non-shrink grout material, development of high-strength type grout material has been mainly made to obtain high strength. In Japanese Patent Laid-Opens 53-16410 and 52-150434, binders were used a lot to express compressive strength of 700 kgf / cm ² or more on the 7th day of age, and iron powder was used to improve the filling properties and fluidity by self weight. The grout material manufactured by the above method has a high binder content, so there is a high risk of cracking due to initial dry shrinkage and self-shrinkage.In addition, the use of iron raw materials damages the appearance due to rust caused by the oxidation of iron powder when exposed over a long period of time. It can induce expansion crack by steel corrosion on the surface.

In Korea Patent Publication No. 1993-0009342, 1997-026999, cement is made of finer grains for the production of ultra-high-strength grout material with 7-day strength of 1000 kgf / cm ² or more and adjusted to have specific particle size distribution to prevent fluidity deterioration. Was used. These technologies can obtain the desired strength required, but the economy is low due to the particle size adjustment, the high heat generation occurs due to the development of ultra-high strength in the early age, high risk of temperature cracking during casting due to the absence of mass, realistically age 1 There is a problem that there is almost no construction of grout material that requires a compressive strength of 700 kgf / cm ² or more per day. In addition, the domestic patent registration number 10-0481976-0000 to prepare a high toughness non-shrink grout material composition containing powder waste tire and powder resin. Powder waste tires and powder resins, which are elastic materials, provide high toughness in addition to the existing high flow, high strength, and non-shrinkable properties. Such a composition is limited in high strength expression, and the water-soluble powder resin is dissolved to integrate with cement hydrate. Powder tire itself is an organic polymer material, which is heterogeneous with cement mortar, and has poor interface adhesion with cement paste. There is a high risk of rubber powder.

As described above, the conventional techniques for manufacturing non-shrink grout materials have been developed for the purpose of increasing the strength of the grout material itself. However, even though the site where the grout material is used has a high risk of corrosion due to the high contact with salt or snow remover, The grout material itself has not yet been given the anti-corrosion performance. In particular, even high-strength non-shrink grouts are frequently cracked and damaged during the initial casting period or during the period of use.

The present invention has the same shrinkage, high flow, and high strength as conventional grout products, but also prevents corrosion and salt penetration of steel in the salty coastal environment or the site where salt damage is expected due to the use of ice making agent in winter. It is an object of the present invention to provide a highly flame resistant grout material composition to which the corrosion resistance of the steel developed is added.

The invention also chayeom performance inhibiting the penetration of the salt are physically via excellent binder and honhapjae and at the same time chemically chloride ions (Cl ^-) by the corrosion inhibitors to block the reaction of by passivating the steel surface significantly the steel corrosion An object of the present invention is to provide a grout composition that can be prevented.

The present invention to achieve the above technical problem,

1 to 2 parts by weight of dispersant, 0.06 to 0.1 parts by weight of coagulant control agent, 0.1 to 0.4 parts by weight of aluminum hydroxide as flame-resistant mixture, and blast furnace slag based on 100 parts by weight of cement-based powder composition mixed with portland cement, calcium aluminosulfate and gypsum 5 to 10 parts by weight of fine powder, 0.3 to 1.4 parts by weight of steel corrosion inhibitor, and 105 to 125 parts by weight of sand having a maximum particle diameter of 3 mm or less are provided.

In the present invention, the cement-based powder composition is preferably composed of 16 to 23 parts by weight and 12 to 17 parts by weight of C ₄ A ₃ S with respect to 100 parts by weight of portland cement.

In addition, the steel corrosion inhibitor in the present invention is preferably a bipolar inorganic salt is calcium nitrite or sodium nitrite.

Hereinafter, the present invention will be described in more detail.

Portland cement used in the present invention can obtain a high strength by using any cement, such as ordinary portland cement, medium heat portant cement, crude steel portland cement.

Calcium aluminosulfate used in the present invention is calcium hydroxide [Ca (OH) ₂ ] which is a hydrate of gypsum and cement to which mineral composition is added as 4CaO.3Al ₂ O ₃ .CaSO ₄ (hereinafter referred to as C ₄ A ₃ S); The reaction produces ethrinzite (3CaO.Al ₂ O ₃ .3CaSO ₄ .32H ₂ O) to express the compressive strength of the grout material early. The continuous supply of sulfate (SO ₃ ^2- ) also prevents the highly expandable ethrinzite from being decomposed into monosulfate (3CaO · Al ₂ O ₃ · CaSO ₄ · 12H ₂ O) with a small hydrate crystal size. It will prevent shrinkage. In the composition of cement powder of grout material, the composition ratios of portland cement, C ₄ A ₃ S and gypsum are particularly important for adjusting the strength development timing and expansion rate. In more detail, when the gypsum content ratio is higher than that of C ₄ A ₃ S, the hardening of the grout material becomes the initial hardening due to the excessive production of ethrinzite, and the strength is initially expressed. There is a risk of increased expandability and overexpansion over long term.

Accordingly, in the present invention, the use of C ₄ A ₃ S 16 to 23 parts by weight and gypsum 12 to 17 parts by weight relative to 100 parts by weight of portland cement continuously compensates for shrinkage without causing high-strength expression and overexpansion. It is preferable at the point which can obtain stable expansion performance.

The gypsum used in the present invention may be a mixture of 20 to 40 parts by weight of alpha-type hemihydrate gypsum (α-CaSO ₄ 1 / 2H ₂ O) to 100 parts by weight of natural anhydrous gypsum (CaSO ₄ ). The solubility of gypsum appears in the order of alpha-type hemihydrate gypsum〉 isugi gypsum〉 anhydrite-free gypsum. Alpha-type hemihydrate gypsum has high solubility. The castle will be degraded. When only anhydrous gypsum is used in gypsum, workability and long-term strength expression effect are good, but it is inferior to the initial dry shrinkage compensation performance and the initial high strength expression performance. When using gypsum in the same composition ratio as the present invention, strength expression and shrinkage compensation can be stably obtained without deterioration of workability.

In the present invention, an aluminum hydroxide powder [Al (OH) ₃ ] and a blast furnace slag powder having a powder degree of 5000 cm ² / g or more were used as the flameproof mixture. The mechanism of action of each component used is described in detail as follows.

Aluminum hydroxide, which is easily soluble in alkali, functions to block salt penetration by immobilizing salts present inside or chloride ions penetrating from the outside with Friedel's salt (C ₃ A · CaCl ₂ · 12H ₂ O) salts. . The aluminum hydroxide component reacts with calcium hydroxide of cement to produce calcium aluminum-hydrooxide (C ₃ AH ₆ ), and the produced calcium aluminum hydrate is a porous hydrate having a large specific surface area, and has an adsorptivity to water-soluble chlorine ions. It acts to immobilize this large chlorine ion.

_{2Al (OH) 3 + 3 Ca} (OH) 2 → 3CaO · Al2O 3 · 6H 2 O (C 3 AH 6)

CaCl ₂ · 6H ₂ O (soluble salts) + C ₃ AH ₆ ) → C ₃ ACaCl ₂ 12H ₂ O (Friedel salt)

In addition, the high-purity slag-based mineral having excellent activity used in the present invention is characterized by the elution of Ca ²⁺ , Mg ²⁺ , AlO ₄ ^4- , SiO ₄ ^4- ions contained in the slag-based mineral in the glass phase. Calcium silicate (CSH _n ) and calcium aluminate (CAH _n ) generation through the reaction with cement hydrates to promote the hydration reaction, and serves to help adsorption and block penetration of salt ions penetrated inside. In addition, the slag aluminum mineral contributes to the improvement of water resistance and densification of hydration hardening tissue through the following ethrinzite formation reactions.

_{2Al (OH) 3 + 3Ca (} OH) 2 + 3CaSO 4 · 2H 2 O + 19 H 2 O →

3CaOAl ₂ O ₃ + 3CaSO ₄ 32H ₂ O (ethrinzite)

If the amount of aluminum hydroxide is used too much, the fluidity of the grout material is reduced by the gelation reaction.

In the present invention, the metal nitrite salt may be used as the anode type inorganic salt as corrosion inhibitor of steel. As the metal nitrite salt, both calcium nitrite and sodium nitrite can be used, and calcium-based is more suitable for affinity with cement. Nitrite ions (NO ₂ ⁻ ) in the inorganic rust inhibitor are reacted with ferrous ions (Fe ²⁺ ) as shown in FIG. 1 to react hydroxy ions (OH ⁻ ) with chloride ions (Cl ⁻ ) by chemical action. Will be blocked. The movement of ferrous ions oxidized at the anode part is hindered, and as a stable ferric oxide (Fe ₂ O ₃ ) is attached to the surface to form a passive film on the steel surface to act to protect the steel in the grout material from corrosion.

2Fe → Fe ²⁺ + 4 e ^-

_{2H 2 O + O 2 + 4} e - → 4OH - → 2OH - + 2OH -

_{^{2OH - + 1/2 O 2 + 2}} e - → H 2 O

^{_{2NO 2 - + O 2 + 2}} e - → 2NO

_{^{2 Fe 2+ + 3/2 O 2 +}} 4 e - → Fe 2 O 3 + 4 e -

When the amount of nitrite used is 0.3 parts by weight or less based on 100 parts by weight of the cement-based powder composition, the corrosion resistance of the steel is greatly reduced. When the amount of nitrite is 1.4 parts by weight or more, the setting time is faster and the fluidity is lowered.

  The admixture used in the present invention is a mixture containing a proper amount of a dispersant and a coagulation delay agent, and as described above, 1 to 2 parts by weight of the admixture is added to 100 parts by weight of the cement-based powder composition. In this case, when the amount of admixture is less than 1 part by weight, it is difficult to secure fluidity and short pot life. When the amount of admixture is more than 2 parts by weight, the fluidity is so high that material separation such as sedimentation of sand occurs and a large amount of bleeding water occurs. Happens. Here, as the dispersant among the components of the admixture, naphthalin sulfonic acid high condensate, melanin sulfonic acid formaldehyde high condensate, lignin sulfonic acid high condensate may be used. The coagulation delay agent may be citric acid, gluconic acid, boric acid or metal salts and various sugars thereof. The addition of the coagulation delay agent is effective in improving fluidity and pot life during the summer.

  Sand is mixed from 105 to 125 parts by weight with respect to 100 parts by weight of the cement-based powder composition, wherein the particle size of the sand is preferably not more than 3mm.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples.

Examples 1 to 4 (Comparative Examples 1 to 3)

  As shown in Table 1, the mixing ratio of the cement-based powder composition in which calcium aluminosulfate and gypsum was mixed in the portland cement was changed. Fluidity, compressive strength, bleeding rate, expansion rate, and condensation characteristics were performed on the grout material manufactured by using the same parts by weight. At this time, the test method was carried out according to the hydraulic cement shrinkage grout test method of KS F 4044, the Korean industrial standard. Table 3 is a test result of the grout material tested by the formulation of Table 2.

division Cement-based powder composition (parts by weight) cement* C ₄ A ₃ S Anhydrous gypsum Half gypsum Example 1 100 17 10 5 Example 2 100 21 10 5 Example 3 100 19 12 3 Example 4 100 19 11 6 Comparative Example 1 100 10 9 6 Comparative Example 2 100 26 9 6 Comparative Example 3 100 19 15 0

        Note) * Cement: Normal Portland Cement

division Grout Material Composition (parts by weight) Cement Powder Composition * Admixtures ** Aluminum hydroxide Blast furnace slag powder *** Corrosion Resistant **** sand Example 1 100 1.5 0.2 6 0.7 112 Example 2 100 1.5 0.2 6 0.7 112 Example 3 100 1.5 0.2 6 0.7 112 Example 4 100 1.5 0.2 6 0.7 112 Comparative Example 1 100 1.5 0.2 6 0.7 112 Comparative Example 2 100 1.5 0.2 6 0.7 112 Comparative Example 3 100 1.5 0.2 6 0.7 112

  Note * Cement-based powder composition: Composition ratio according to Table 1

     ** Admixture: 8 parts by weight of a gluconic acid retardant is mixed with 100 parts by weight of a high concentration of naphthalinsulfonic acid-based condensate as a dispersant.

*** Blast furnace slag fine powder: 5000cm ² / g or more

**** Preservatives: calcium nitrite (Ca (NO ₂ ) ₂ )

division Descent time (seconds) Bleeding Rate (%) Initial setting (hr: min) Inflation height (%) Compressive strength (kgf / cm ² ) 3 days 7 days 28 days 1 day 3 days 7 days 28 days Example 1 44 0 3: 40 0.08 0.05 0.04 273 435 544 678 Example 2 42 0 4: 30 0.11 0.08 0.07 265 451 568 708 Example 3 43 0 4: 10 0.06 0.04 0.04 251 439 542 683 Example 4 47 0 3: 40 0.09 0.07 0.06 292 487 573 661 Comparative Example 1 72 0 1: 50 0.27 0.36 0.42 332 514 587 634 Comparative Example 2 45 0 4: 50 0.02 -0.01 -0.03 214 418 521 611 Comparative Example 3 41 0 4: 20 0.01 0.01 -0.02 222 423 517 628

As can be seen from Table 3, the grout material composition prepared according to the present invention can ensure the dripping time by the cone test within 60 seconds in the workability, high compressive strength expression and 28 days at age It showed stable dimensional stability without shrinkage or excessive expansion. However, when the ratio of cement-based powder composition is not suitable, fluidity and strength expression are decreased, shrinkage or excessive expansion occurs.

Examples 5 to 10 (Comparative Examples 4 to 8)

  As shown in Table 4 below, the composition ratio of aluminum hydroxide and blast furnace slag fine powder and steel corrosion inhibitors, which are flame-resistant mixtures, was prepared in a cement powder composition in which portland cement, calcium aluminosulfate, and gypsum were mixed according to the present invention. Table 5 tested the steel corrosion resistance and salt penetration resistance in addition to the basic fluidity, compressive strength, expansion ratio, and condensation characteristics for the grout materials prepared in Table 4. The evaluation method was tested for the basic physical properties of the grout material according to the hydraulic cement shrinkage grout test method of KS F 4044, the Korean industrial standard, and the salt penetration resistance was immersed in 2.5% sodium chloride solution for 2 months according to KS F 4930. The depth of salt penetration due to discoloration was measured by silver nitrate. On the other hand, steel corrosion protection performance was evaluated by the test method of accelerated corrosion by autoclave of KS F 2561 Concrete Anticorrosive Admixture Annex 2.

division Grout Material Composition (parts by weight) Cement Powder Composition * Admixture * Aluminum hydroxide Blast Furnace Slag Fine Powder * Corrosion Resistant * sand Example 5 100 1.5 0.1 6 0.7 112 Example 6 100 1.5 0.3 6 0.7 112 Example 7 100 1.5 0.2 5 0.7 112 Example 8 100 1.5 0.2 8 0.7 112 Example 9 100 1.5 0.2 6 0.3 112 Example 10 100 1.5 0.2 6 1.0 112 Comparative Example 4 100 1.5 0.2 6 1.6 112 Comparative Example 5 100 1.5 0 0 0.7 112 Comparative Example 6 100 1.5 0.5 6 0 112 Comparative Example 7 100 1.5 0 0 0 112 Comparative Example 8 Commercial Grout Products

  Note * Cement-based powder composition: Composition ratio according to Example 2 of Table 1

     ** Admixture: 8 parts by weight of a gluconic acid retardant is mixed with 100 parts by weight of a high concentration of naphthalinsulfonic acid-based condensate as a dispersant.

     *** Water use ratio is mixed with grout material 1 at 0.16 weight ratio of water

division Descent time (seconds) Initial setting (hr: min) Inflation height (%) Compressive strength (kgf / cm ² ) Salinity penetration depth (mm) Antirust rate ¹⁾ (%) 3 days 7 days 28 days 1 day 3 days 7 days 28 days Example 5 42 3: 50 0.06 0.03 0.02 265 445 551 699 4.3 99.0 Example 6 46 4: 00 0.07 0.06 0.04 285 467 562 688 3.4 98.3 Example 7 45 4: 10 0.05 0.04 0.03 248 451 558 707 3.7 99.2 Example 8 44 4: 30 0.03 0.02 0.02 232 434 538 714 3.0 98.8 Example 9 43 4: 05 0.04 0.03 0.03 261 448 573 696 3.1 97.4 Example 10 45 4: 15 0.03 0.02 0.02 254 450 538 684 3.3 100 Comparative Example 4 68 3: 30 0.02 0.02 0.01 228 434 521 662 3.2 100 Comparative Example 5 44 4: 00 0.04 0.03 0.03 248 462 554 702 8.3 98.5 Comparative Example 6 72 3: 40 0.06 0.05 0.04 267 487 550 687 2.8 42 Comparative Example 7 41 4: 10 0.05 0.04 0.04 276 471 583 714 10.2 34 Comparative Example 8 46 4: 30 0.03 0.03 0.02 238 449 531 662 9.8 27

1) anti-corrosive rate: the test method of the corrosion promoting test method according to an autoclave of KS F 2561, wherein a total chloride content material grout is Cl ^- was added to 4kg / m ³ in an amount of reference. The anti-corrosion rate was calculated by the same salt content (4kg / m ³ ) in the general mortar (cement: sand = 1: 2.5, water / cement ratio = 0.5) and then the corrosion promotion test was performed. The rust prevention rate was calculated from the corrosion area ratio of the steel bars in the grout material prepared in each example and the comparative example with respect to the corrosion area of the steel bars in the general mortar.

As can be seen in Table 5, the grout composition of the present invention is 95% or more of the rust prevention rate of the steel even at a high salt content of about 3 times higher than 1.2 kg / m ³ of the corrosion resistance of the steel bar in the grout. It shows good results, and the result of measuring the depth of penetration of chloride ions penetrated into the grout material after immersion in the saline solution is also shown to be small. In addition to the conventional high flow, high strength, and non-shrinkage characteristics, it has excellent salt resistance. Appeared.

The high-strength non-shrink grout composition having the corrosion resistance of steel according to the present invention, unlike the conventional non-shrink grout material, has a high strength, high flow rate, non-shrinkage property, and grout material in a corrosive environment due to salty areas, chlorine ions, and snow removing agent. It is a new concept of high durability grout material composition developed to prevent corrosion of steels. The composition of the present invention provides a salt resistance effect by inhibiting chlorine ion penetration into the interior, and by performing physiochemical effects to prevent corrosion of steel even under conditions of high salt content. By multiplying, it is possible to greatly increase the corrosion protection performance of the steel by the grout material.

The prior art mainly aims at high strength and early strength through the type of cement used, clinker mineral composition, and particle size adjustment. There was no. Particularly, the high strength and early strength expression of grout material is likely to cause problems such as cracking and temperature cracking in the mass member, and such cracking is caused by the penetration of calcium chloride by snow removal agent and salt penetration in the ocean. As a result, there is a high risk that steels in the grout members are exposed from corrosion.

Claims (3)

(Correction) 1 to 2 parts by weight of dispersant, 0.06 to 0.1 part by weight of coagulant control agent, 0.1 to 0.4 parts by weight of aluminum hydroxide as flame-resistant mixture, based on 100 parts by weight of cement-based powder composition mixed with portland cement, calcium aluminosulfate and gypsum. , 5 to 10 parts by weight of blast furnace slag fine powder, 0.3 to 1.4 parts by weight of steel corrosion inhibitor and 105 to 125 parts by weight of sand having a maximum particle diameter of 3 mm or less . (Correction) The method according to claim 1, The cement-based powder composition is a grout material composition, characterized in that consisting of 16 to 23 parts by weight of C ₄ A ₃ S and 12 to 17 parts by weight of gypsum based on 100 parts by weight of portland cement. (Correction) The method according to claim 1, The steel corrosion inhibitor is a grout material composition, characterized in that the bipolar inorganic salt is calcium nitrite or sodium nitrite.

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