KR101292175B1 - high range water reducing admixure having polycarboxylic acid group for enhancing watertightness and strength of concrete - Google Patents

Abstract

The present invention relates to a polycarboxylic acid-based high performance sensitizer composition that enhances the water tightness and strength of concrete, and more particularly, by reducing the fluidity by allowing the polycarboxylic acid polymer to include a water-tightness enhancer made of silicate, siliculate, and stearic acid salt. The present invention relates to a high performance water reducing agent capable of obtaining a water-free water-reducing effect and providing a tight structure to concrete to enhance watertightness and strength.

Description

High performance water reducing admixure having polycarboxylic acid group for enhancing watertightness and strength of concrete}

The present invention relates to a polycarboxylic acid-based high performance sensitizer composition that enhances the water tightness and strength of concrete, and more particularly, by reducing the fluidity by allowing the polycarboxylic acid polymer to include a water-tightness enhancer made of silicate, siliculate, and stearic acid salt. The present invention relates to a high performance water reducing agent capable of obtaining a water-free water-reducing effect and providing a tight structure to concrete to enhance watertightness and strength.

Concrete is a porous construction material in which there are small capillary pores of 10 nm to 10 μm in size from large bubbles having a diameter of 0.1 to 50 mm, and fine particles having a width of 0.3 mm or less produced by drying and shrinking under an external environment. There are a myriad of cracks. These voids and cracks become a passageway through which external moisture and deteriorated materials penetrate, causing a decrease in durability of the concrete structure.

Conventional techniques for improving watertightness to such concrete include a powder or liquid penetration method and a method of adding a watertightness enhancer to the concrete.

Powder or liquid infiltration method forms insoluble gel rapidly under alkaline conditions when active ingredient penetrates into concrete through capillary movement by osmotic phenomenon, making it difficult to uniformly penetrate the waterproofing agent composition, making it waterproof throughout the structure. There is a problem that it does not give performance and watertight performance.

In addition, in the case of adding a water-tightness enhancer to concrete, Korean Patent Application No. 2001-63881 (method of improving the waterproofness of concrete or ready-mixed concrete using zinc fluoride aqueous solution) by applying a zinc fluoride aqueous solution alone in the fluorinated salt The waterproof effect is excellent, but the compressive strength enhancement effect of the concrete is weak, and in particular has a problem that the fluidity is significantly reduced.

In addition, Korean Patent Application Nos. 2002-42799 and 2003-76689 aim to increase the watertightness to improve the waterproofing function of concrete and reduce the cracking to increase the strength. Patent application No. 2002-42799 improves the waterproofing effect by applying the zinc fluoride aqueous solution alone in the fluorinated salts, improves the compressive strength of concrete and decreases the fluidity. Patent application No. 2003-76689 further improves the watertightness and crack reduction effect, including only silica fluoride salts made of magnesium fluoride and zinc fluoride, reticulated silica, and water. However, these technologies require the input by a separate facility other than the conventional chemical admixture for concrete, and there is a problem in that the cost is large.

Chemical admixtures for concrete are classified into lignin-based (ligninsulfonate), naphthalene-based (naphthalene sulfonic acid formalin condensate), melamine-based (melamine sulfonic acid formalin condensate), and polycarboxylic acid-based (polycarbonate) according to their chemical composition. It is used.

Lignin-based, melamine-based, and naphthalene-based chemical admixtures have excellent susceptibility and fluidity, making it possible to manufacture high strength, high flow, and high durability concrete, but have a disadvantage of large slump. On the other hand, the polycarboxylic acid-based chemical admixture not only exhibits excellent sensitivity compared to conventional chemical admixtures, but also has low slump loss and excellent kneading performance.

Generally, the mechanism related to the improvement of dispersibility of particles due to the addition of concrete chemical admixtures is due to the electrostatic repulsion of the main chain, the three-dimensional effect by the side chain, and the effect of the penetration pressure obtained by simultaneously operating the aforementioned two effects. have. This mechanism corresponds to the functional mechanism of the lignin-based, naphthalene-based, melamine-based and polycarboxylic acid-based chemical admixtures. However, in the case of lignin-based, naphthalene-based and melamine-based chemical admixtures, the sensitizing effect due to the static repulsive force is dominant, and the sensitizing effect due to the three-dimensional effect is below the expected performance, and it is known that a sudden slump loss occurs. On the other hand, the polycarboxylic acid system acts up to the electrostatic repulsive force, the steric effect and the penetrating pressure effect acting as a synergistic effect by the two effects above, resulting in high sensitivity, workability and low slump loss.

For this reason, research and development related to polycarboxylic acid-based chemical admixtures are currently being actively conducted, and in order to solve water-resistance, which is a problem of concrete mentioned above in addition to the small water slump loss of the polycarboxylic acid-based chemical admixture, The development of a polycarboxylic acid-based high performance sensitizer is required.

Accordingly, the present invention is to provide a high performance water reducing agent that can provide concrete with excellent durability by improving the water-resistance effect while securing fluidity as a property of the polycarboxylic acid system and at the same time improving the watertightness of the concrete.

In order to achieve the above object, the present invention is a polycarboxylic acid-based high performance sensitizer composition to enhance the water-tightness and strength, characterized in that it comprises a water-tightness enhancer, a curing accelerator and a surfactant, including a polycarboxylic acid-based polymer, silicate and silicic salts It is done.

The polycarboxylic acid-based polymer of the present invention exhibits a high susceptibility to improve the dispersibility of the cement particles to reduce the amount of water used by 18% by weight or more. It has the property to develop working intensity. In addition, the fluidity deterioration rarely occurs with time, and an appropriate amount of air can be continuously entrained to provide a good workability to the cement composition, but can also have a feature of forming concrete having high strength. In particular, the polycarboxylic acid-based polymer is preferably a number average molecular weight in the range of 15,000 to 300,000, when the number average molecular weight is less than 15,000 is a problem that is not adsorbed by the fine powder and the porous material present in the aggregate does not express the proper physical properties If it exceeds 300,000, it may be a problem that does not effectively disperse the cement may be limited to the above range.

On the other hand, the blending ratio of the high performance water reducing agent of the present invention is appropriate to include 10 to 150 parts by weight of the water-tightness enhancer, 0.1 to 5 parts by weight of the curing accelerator, 0.1 to 1 parts by weight of surfactant based on 100 parts by weight of the polycarboxylic acid-based polymer.

When the content of the polycarboxylic acid-based polymer exceeds the above range, the susceptibility of cement becomes excessive to cause the material separation of concrete, and when the content of the polycarboxylic acid-based polymer exceeds the above range, the performance as a chemical admixture for concrete decreases. there is a problem.

Meanwhile, in the present invention, the polycarboxylic acid-based polymer can be blended to ensure fluidity while reducing the amount of water used. However, the polycarboxylic acid-based polymer alone cannot express the watertightness and strength due to sufficient sealing of concrete. In the present invention, the water-tightness and strength of concrete are further reinforced by incorporating a water-tightness enhancer including a silicate and a silicate salt into the polycarboxylic acid-based polymer.

The silicate produces calcium silicate hydrate through the reaction with calcium hydroxide produced during the cement hydration reaction on the surface of the concrete structure, and the resulting calcium silicate hydrate is filled in the micropores on the surface of the concrete structure, thus providing a dense surface structure. The watertightness and strength of the will be strengthened.

Such silicates are appropriate to use a mixture of one or more of sodium silicate, potassium silicate, lithium silicate.

By the way, the sodium hydroxide (NaOH) is produced in the production reaction of calcium silicate hydrate, so the sodium hydroxide is solubilized in water, there is a problem that is dissolved again and dissolved in the presence of water. Therefore, it reacts with sodium hydroxide to insolubilize, and adds a fluorinated salt that chemically reacts with concrete components such as silicate to fill micropores, thereby making the concrete structure completely closed. In other words, silicic fluoride reacts with calcium hydroxide produced during cement hydration in concrete structures to create insoluble fine particles to fill the micropores on the surface of the concrete structure, thereby improving the watertightness and strength of the concrete structure.

It is appropriate to use such a mixture of one or two or more of zinc fluoride, copper fluoride, magnesium fluoride, nickel fluoride, lithium fluoride, iron fluoride, and cobalt fluoride.

That is, the water-tightness enhancer of the present invention is to improve the water-tightness and strength of the concrete structure by complementing the silicate and silicate salts, including silicate and silicate salts.

In addition, the water tightness enhancer of the present invention may further include stearates such as aluminum stearate and zinc stearate. Based on the interaction between the silicate and the fluoride salts mentioned above, the micropores of the concrete structure are filled, and stearic acid salt is further added to prevent condensation delay and strength degradation caused by the movement of moisture in the concrete. That is, by adding stearate to silicate and silicate salt to the water-tightness enhancer of the present invention, the high performance water-reducing agent of the present invention can provide a tight structure in concrete, prevent water condensation delay, and improve watertightness and strength.

In conclusion, the watertightness enhancer, which is one component of the present invention, acts as a binder to increase the bonding force between the silicon (Si) and oxygen (O) atoms between the silicates so that the silicates form strong crosslinks (Si-O-Si). As a result, the internal structure of the concrete is made more compact, thereby imparting watertight performance and increasing the strength of the concrete. In addition, low- or high-calcium aluminum sulfate (calcium sulfur aluminate, mCaO · nSiO 2 · mH 2 O, wherein m and n are integers of 3 to 10), insoluble silicate gel (calcium silicate hydrate gel), metal fluorides are produced in concrete It is to increase the water-tightness of the concrete by forming a dense structure by the filling action against the micropores and cracks of several micrometers to several tens of micrometers present. In addition, it is possible to increase the strength through the pozzolanic effect to promote the production of calcium silicate hydrogel (C-S-H gel) that reacts with the calcium hydroxide produced by the hydration of the cement dominates the ultimate strength of the cement.

The content of the water-tightness enhancer is limited to 10 to 150 parts by weight of the water-tightness enhancer with respect to 100 parts by weight of the polycarboxylic acid-based polymer. This is because the inhibition of the hydration reaction and the neutralization of concrete can be promoted, and when the content of the water-tightness enhancer is less than 10 parts by weight, the effect of strengthening the water-tightness is insufficient.

In order to facilitate the penetration of the water-tightness enhancer including the above-mentioned silicates, silicate salts and stearates into the concrete structure, it is reasonable that the surfactant is formulated in the present invention. That is, the silicate, silicate salts and stearates are not only to stably mix with the polycarboxylic acid-based polymer, but also to facilitate penetration into concrete structures. The surfactant is an anionic sodium dodecylbenzenesulfonate, higher alcohol sodium sulfate, and olefinic acid. Sodium, non-ionic polyoxyethylene nonyl phenol ether, polyoxyethylene higher alcohol ether may be a mixture of one or two or more, but in the present invention preferably the molecular formula of C5H8SO2LiF (C2F4) n (where n is 3 to 8) It is reasonable to use a fluorine-based surfactant that is an integer) or (C 2 H 4 O) nHF (C 2 F 4) m (wherein m is an integer of 3 to 8). This is because such a fluorine-based surfactant is more preferable in improving the stability of the mixture by lowering the viscosity of the mixture of the present invention, that is, the high performance water reducing agent to 50 to 100 cps. The content of such a surfactant is appropriate to be limited to 0.1 to 1 parts by weight based on 100 parts by weight of the polycarboxylic acid-based polymer. Such a limitation cannot be expected to improve the permeability when formulated at less than 0.1 part by weight, and if it exceeds 1 part by weight, it is reasonable to use it in such a way that the contribution to the permeability improvement is almost the same as when formulated below.

In addition, in the present invention, it is reasonable to further mix an inorganic or organic curing accelerator in order to prevent a decrease in strength caused by delaying cement hardening. These curing accelerators may be selected from sodium carbonate, potassium carbonate, calcium carbonate, sodium nitrate, potassium nitrate, calcium nitrate, sodium nitrite, potassium nitrite, calcium nitrite, sodium sulfate, potassium sulfate, calcium sulfate, monoethanolamine (MEA) and triethanolamine (TEA) or It is preferable to use a mixture of two or more, and it is reasonable that the formulation is blended in the range of 0.1 to 5 parts by weight of the curing accelerator relative to 100 parts by weight of the polycarboxylic acid polymer. If the blending amount exceeds 5 parts by weight, a retardation action occurs, and the surface strength is lowered. If the amount is less than 0.1 part by weight, the effect of hardening promotion is insignificant.

In addition, the high-performance water reducing agent of the present invention includes 10 to 400 parts by weight of water-tightness enhancer, 0.1 to 5 parts by weight of curing accelerator, 0.1 to 1 part by weight of surfactant, and ammonia, calcium phosphate, sodium phosphate, and hydroxide based on 100 parts by weight of polycarboxylic acid-based polymer. It is preferable to further add 0.1 to 1 parts by weight of a mixture of one or two or more of the aqueous potassium solution, and it is preferable that the pH of the entire high performance water reducing agent is limited to 9 to 12 by further adding a Ph regulator.

The high-performance sensitizer of the present invention can obtain excellent water-resistance effect while preventing fluidity deterioration by the polycarboxylic acid-based polymer, and can secure water-tightness by the water-tightness enhancer including silicate, silicate salt, and stearic acid salt, and thus excellent durability. There is an advantage in providing concrete.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

Examples 1 to 17 and Comparative Examples 1 to 3 prepared a water reducing agent by uniformly mixing the components shown in Tables 1 and 2 below, slump, compressive strength, permeability, porosity, length change ratio, Resistance to freeze thaw was measured.

-. Concrete preparation: The unit was manufactured by applying the slump 180 ± 10mm unit quantity according to the KS F 2560 concrete mixing admixture for KS F 2560. The amount of admixture was 0.7% of the amount of cement.

-. Slump, compressive strength, length change ratio, and resistance to freezing and thawing: Tested according to Korean Industrial Standard KS F 2560 Test Method for Chemical Admixtures for Concrete.

-. Permeability: Tested according to Korean Industrial Standard KS F 2451 Construction Cement Waterproofing Test Method.

-. Porosity: The porosity of concrete was carried out by mercury intrusion porosimetry under vacuum pressure of 50㎛Hg, vacuum time of 5 minutes, mercury injection pressure of 0.49psia.

Yes Polycarboxylic acid system (weight part) Watertightness increase (parts by weight) Curing accelerator (part by weight) Surfactant (parts by weight) Slump (mm) Compressive strength (MPa) Permeability (g) Porosity (%) Length change ratio (%) % Resistance to freezing and thawing 0 min 60 minutes 3 days 7 days 28th Example 1 10 5 One 0.5 180 135 10.8 22.8 28.4 14.5 50.2 98.1 90.1 Example 2 10 One 〃 180 140 10.9 23.5 29.0 8.5 48.6 97.3 91.3 Example 3 15 One 〃 180 140 10.6 23.6 29.2 5.2 46.5 96.8 94.0 Example 4 15 5 0 〃 180 145 14.5 25.9 33.7 11.2 46.5 96.5 93.2 Example 5 One 〃 185 145 15.2 26.7 34.2 11.3 46.4 96.4 93.3 Example 6 2 〃 180 150 15.9 27.3 35.1 11.1 46.5 96.4 93.1 Example 7 10 0 〃 185 150 14.3 25.7 33.8 6.2 43.3 95.8 94.4 Example 8 One 〃 180 155 15.2 25.9 34.0 6.4 43.2 95.7 94.4 Example 9 2 〃 180 150 15.8 26.8 35.4 6.2 43.2 95.8 94.6 Example 10 15 0 〃 180 155 14.5 26.0 33.8 2.1 41.8 95.2 95.8 Example 11 One 〃 180 155 15.1 26.9 34.3 2.2 42.0 95.2 95.7 Example 12 2 〃 180 150 15.7 27.2 35.5 2.2 41.9 95.1 95.9

Yes Polycarboxylic acid system (weight part) Watertightness increase (parts by weight) Curing accelerator (part by weight) Surfactant (parts by weight) Slump (mm) Compressive strength (MPa) Permeability (g) Porosity (%) Length change ratio (%) % Resistance to freezing and thawing 0 min 60 minutes 3 days 7 days 28th Example 13 20 5 One 0.5 185 165 19.3 32.6 39.6 10.4 45.3 95.5 96.2 Example 14 10 One 〃 180 170 19.3 32.9 40.2 5.7 42.1 94.8 97.0 Example 15 15 One 〃 180 170 19.2 33.1 41.7 1.9 40.3 94.3 97.7 Example 16 15 One 〃 185 169 18.3 31.6 39.5 2.4 43.3 95.5 96.0 Example 17 15 One 〃 180 170 19.0 32.7 40.1 2.0 41.1 95.0 96.8 Comparative Example 1 10 - - - 180 135 10.6 21.9 27.5 18.2 53.3 98.5 89.2 Comparative Example 2 15 - - - 180 145 14.9 25.6 32.3 16.3 51.2 97.1 92.1 Comparative Example 3 20 - - - 185 165 19.1 31.2 38.8 14.8 49.6 96.2 94.4

As shown in Table 1 and Table 2, when only the polycarboxylic acid-based polymer is blended as the water-tightness enhancer in the case of Comparative Examples 1 to 3, the slump value, compressive strength and freeze-thawing are increased as the blending amount is increased from 10 parts by weight to 20 parts by weight. It can be seen that the resistance to, and the permeability, porosity and length change ratio is small.

However, when comparing the comparative example and the example, as in the comparative example, the water-tightness enhancer including silicate, silicate salt, and stearic acid salt is further added to the polycarboxylic acid polymer as in the example, compared to the case where only the polycarboxylic acid polymer is blended. In this case, it can be seen that the resistance to slump, compressive strength and freeze-thawing increases, and the permeability, porosity and length change ratio decrease. That is, it can be seen that the basic physical properties are further improved.

As mentioned above, since the combination of silicate, silicate and stearic acid salts the concrete structure, it is more improved in basic physical properties such as compressive strength, resistance to freezing and thawing, permeability, porosity and length change ratio. The effect is expressed.

On the other hand, Examples 15 to 17 are blended with 20 parts by weight of the polycarboxylic acid-based polymer to 15 parts by weight of the water-tightness enhancer, Example 15 as a water-tightness enhancer includes all the silicate, silica fluoride and stearic acid salt, Example 16 Only the silicate is included, and Example 17 includes the silicate and the silicate salt.

That is, as shown in Table 3 below, Example 15 is a sample formulated with 10 parts by weight of silicate, 3 parts by weight of silicate salt and 2 parts by weight of stearic acid salt, and Example 16 is a sample containing only 15 parts by weight of silicate. 17 is a sample in which only 10 parts by weight of silicate and 5 parts by weight of silicate salt are combined.

Yes Polycarboxylic acid polymer (part by weight) Watertightness enhancer (parts by weight) Curing accelerator (part by weight) Surfactant (parts by weight) Silicate Fluoride flame Stearate Example 15 20 10 3 2 One 0.5 Example 16 15 - - One 〃 Example 17 10 5 - One 〃

First, when comparing Example 16 with Example 17, Example 17 is almost the same slump than Example 16 in the experimental results, but the resistance to compressive strength and freeze-thawing increases, and the permeability, porosity and length change ratio are smaller. Able to know. The reason is that the silicate produces calcium silicate hydrate during the cement hydration reaction of the concrete structure, and the calcium silicate hydrate thus formed is filled in the micropores to strengthen the strength of the concrete structure. As a result of eluting problem, as in Example 17, the silicic acid salt is further added to react with sodium hydroxide to insolubilize, and also react with calcium hydroxide to generate insoluble fine particles to fill the micropores of the concrete structure. As a result, the watertightness, strength, and the like in the concrete structure are considered to complement each other.

In comparison with Example 15 and Example 17, the slump value of Example 15 is almost the same as that of Example 17 in the experimental results, but the resistance to compressive strength and freeze-thawing increases, and the permeability, porosity, and length change ratio become smaller. It can be seen that.

That is, using all of the silicate, silicate salt, and stearate as the water-tightness enhancer as in Example 15 is to improve the basic physical properties than when using only silicate, silicate salt as the water-tightness enhancer as in Example 17. This is a water-tightness enhancer that includes all silicate, silicate and stearate salts to fill the micropores of concrete structures based on the interaction of silicate and silicate salts. It is believed to double the basic physical properties of concrete by preventing condensation delay and strength degradation.

As a result, as shown in the above experimental example, the polycarboxylic acid-based polymer can improve the strength by reducing the amount of water used without lowering the fluidity of concrete (improving), and in addition, complementing each other with silicate, silicate and stearate In order to improve the water-tightness and strength, as a result, when the high-performance water reducing agent of the present invention is used, the workability is facilitated, and the watertightness and strength of the concrete structure after construction are improved.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

Claims (9)

10 to 150 parts by weight of a water tightness enhancer including silicate and silicide salts, 0.1 to 5 parts by weight of curing accelerator, and 0.1 to 1 parts by weight of surfactant based on 100 parts by weight of polycarboxylic acid-based polymer Polycarboxylic acid-based high performance reducer composition to enhance the.
delete The method of claim 1,
The polycarboxylic acid-based polymer has a number average molecular weight of 15,000 to 300,000 polycarboxylic acid-based high performance water reducing agent composition to enhance the water-tightness and strength.
The method of claim 1,
The silicate is a polycarboxylic acid-based high performance sensitizer composition for enhancing water-tightness and strength, characterized in that consisting of a mixture of one or two or more of sodium silicate, potassium silicate, lithium silicate.
The method of claim 1,
The silica fluoride salt is a polysilicon strengthening water tightness and strength, characterized in that consisting of a mixture of one or two of zinc fluoride, copper fluoride, magnesium fluoride, nickel fluoride, lithium fluoride, iron fluoride, cobalt fluoride Carbonic acid type high performance reducer composition.
The method of claim 1,
The polycarboxylic acid-based high performance water sensitizer composition for enhancing the water-tightness and strength, characterized in that stearic acid salt is added to the water-tightness enhancer in addition to the silicate, silicate salt.
The method of claim 1,
The curing accelerator is one of sodium carbonate, potassium carbonate, calcium carbonate, sodium nitrate, potassium nitrate, calcium nitrate, sodium nitrite, potassium nitrite, calcium nitrite, sodium sulfate, potassium sulfate, calcium sulfate, MEA (monoethanolamine) and TEA (triethanolamine) A polycarboxylic acid-based high performance sensitizer composition for enhancing the watertightness and strength, characterized in that composed of two or more mixtures.
The method of claim 1,
The surfactant is a fluorinated surfactant which is C5H8SO2LiF (C2F4) n (wherein n is an integer of 3 to 8) or (C2H4O) nHF (C2F4) m (wherein m is an integer of 3 to 8), the entire formulation The polycarboxylic acid-based high performance sensitizer composition to enhance the water tightness and strength, characterized in that the viscosity of 50 to 100cps.
The method of claim 1,
0.1 to 1 part by weight of a mixture of one or two or more of ammonia, calcium phosphate, sodium phosphate, and potassium hydroxide aqueous solution is further added, and the pH of the entire compound is 9 to 12, wherein the polycarboxylic acid system enhances water tightness and strength. High performance reducer composition.