KR102545413B1 - Mortar composition and concrete composition using organic-inorganic hybrid water-repellent - Google Patents

Abstract

A mortar composition and a concrete composition using an organic/inorganic composite water repellent are disclosed. The mortar composition of the present invention includes cement, fine aggregate, inorganic metal salt-based powdery water repellent and organic silicone-based liquid water-repellent agent in the repair mortar composition used for repair work on deteriorated concrete structures. In addition, the concrete composition of the present invention includes cement, fine aggregate, coarse aggregate, inorganic metal salt-based powder water repellent, and organic silicon-based liquid water repellent in the concrete composition for expressing water repellent performance in concrete.

Description

Mortar composition and concrete composition using organic-inorganic composite water repellent

The present invention relates to a mortar composition and a concrete composition using an organic/inorganic composite water repellent, and more particularly, in a mortar/concrete composition, compression while securing water repellency for preventing deterioration factors such as moisture from penetrating into concrete It relates to an organic-inorganic composite water repellent that can overcome the limit of strength reduction.

Reinforced concrete is the most widely used construction material for buildings and civil structures. However, since concrete has a porous structure with many pores inside, it is easy for various deterioration factors such as CO ₂ and Cl ^- to penetrate from the outside. The concentration of chlorine ion is higher than the limit state, so it has a serious durability deterioration problem that the yield strength is lowered due to the occurrence of concrete cracks due to the corrosion of the reinforcing bars. In particular, when a deterioration factor such as Cl ^- penetrates into concrete, the penetration rate of diffusion into the inside is relatively slow, but when it is dissolved by moisture and moves, the penetration rate increases rapidly.

Therefore, in order to protect porous concrete, a method of applying a surface impregnating agent or a water repellent to the surface of concrete is widely used, and unlike the coating method, such a surface application and impregnation method has less problems in that the film peels off or peels off, and recently the range of use has been reduced. is expanding However, when the deterioration progresses due to cracks or peeling of the concrete itself, the impregnated surface layer is damaged and the expected durability cannot be secured.

In consideration of this aspect, recently, studies have been conducted to improve the durability of concrete by incorporating various water repellent materials into concrete or mortar to exhibit water repellency even in cracks even when peeling or cracking of the concrete itself proceeds. In this regard, in the case of incorporating a silicone-based liquid water repellent, which is an organic material, it is possible to secure very high water repellency and has the advantage of improving workability, but there is a disadvantage in that a lot of air is entrained and the compressive strength is greatly reduced. On the other hand, in the case of mixing inorganic metal salt-based water repellent powder, it reduces the amount of air and despite being a hydrophobic material, the decrease in compressive strength due to the fine powder is relatively small compared to the water-based water repellent agent, but the workability is lowered and the water repellency performance is reduced. The downside is that it's not that big. Of these, the decrease in compressive strength is the biggest problem. In fact, when organic silicone-based water repellents are mixed, the water-repellent performance is excellent and workability is increased, but the compressive strength shows a decrease of about 30 to 40%. Although this decreased and the expression of water repellency was shown, the experimental results confirmed that the compressive strength was also reduced by about 10 to 20%.

Until now, research is being conducted to overcome the limitation of lowering the compressive strength while securing water repellency by using the advantages and disadvantages of each material by simultaneously using an organic silicon-based liquid (aqueous) water repellent and an inorganic metal salt-based powder water repellent. not.

Therefore, in order to solve the existing problems such as an increase in air volume and a decrease in compressive strength while securing the water repellent performance required in a mortar/concrete composition, the present invention mixes an organic silicon-based liquid water repellent with an inorganic metal salt-based powdered water repellent. We would like to propose an organic-inorganic composite water repellent that complements the advantages and disadvantages.

Related prior art documents include Japanese Patent Registration No. 4555066 (Title of Invention: Concrete Structure Repair Method, Publication Date: September 29, 2010).

An object of the present invention is a mortar composition using an organic/inorganic composite water repellent that can solve problems such as an increase in air volume and a decrease in compressive strength while ensuring water repellency to prevent deterioration factors such as moisture from penetrating into the inside of concrete. and to provide a concrete composition.

The above object is, according to the present invention, in the repair mortar composition used for the repair work for the degraded concrete structure, whether or not it is characterized in that it includes cement, fine aggregate, inorganic metal salt-based powdered water repellent and organic silicone-based liquid water repellent This is achieved by a mortar composition using a pre-existing composite water repellent agent.

In addition, the above object is, according to the present invention, in the concrete composition for expressing water repellency inside concrete, including cement, fine aggregate, coarse aggregate, inorganic metal salt-based powdery water repellent and organic silicone-based liquid water-repellent agent Characterized in that It is achieved by a concrete composition using an organic/inorganic composite water repellent.

Here, the inorganic metal salt-based water repellent in powder form is provided as a stearate powder-type water repellent agent, and the organic silicone-based liquid water repellent agent is preferably provided as a silane-siloxane water-based water repellent agent.

Preferably, the stearate powder water repellent agent includes calcium stearate and zinc stearate, and the calcium stearate and zinc stearate may be mixed in a weight ratio of 9.5 to 8.5: 0.5 to 1.5.

Preferably, the solid content of the silane-siloxane aqueous water repellent agent may be 40 to 60% by weight.

Preferably, the inorganic metal salt-based powdery water repellent and the organic silicone-based liquid water-repellent agent may be mixed in a weight ratio of 3 to 6: 1, wherein the weight ratio of the organic silicon-based liquid water-repellent agent may be based on the weight of the solid content.

Preferably, the organic/inorganic composite water repellent including the inorganic metal salt-based powder water repellent and the organic silicon-based liquid water repellent may be mixed in an amount of 1 to 3 parts by weight based on 100 parts by weight of the cement.

Preferably, the inorganic metal salt-based powder water repellent agent is mixed with the cement by dry mixing, and the organic silicon-based liquid water repellent agent may be mixed with the fine aggregate after preparing the cement paste.

In the present invention, in a mortar/concrete composition, an organic silicone-based liquid water repellent and an inorganic metal salt-based powdered water repellent are mixed and used, but the organic silicone-based liquid water repellent and the inorganic metal salt-based powdered water repellent are respectively preferred components and mixing ratios thereof. By presenting it, it is possible to solve problems such as an increase in the amount of air and a decrease in compressive strength, which occur in conventional water repellents, while securing water repellency to prevent the penetration of deterioration factors into the inside of concrete.

1 is a graph showing the compressive strength test results for test specimens according to Examples 1 to 4 and Comparative Examples 1 to 3 of the present invention.
2 shows SEM images of mortar test specimens without water repellent and organic silicone liquid water repellents, and FIG. 3 shows SEM & EDS analysis results of test specimens mixed with organic silicone liquid water repellents.
Figure 4 is a graph showing the amount of water absorption per unit area over time of the test specimens according to Examples 1 to 4 and Comparative Examples 1 to 3 of the present invention.
5 shows a 500-fold magnified SEM image of the surface of a mortar test specimen without water repellent and a test specimen mixed with an inorganic metal salt-based powdery water repellent, and FIG. 6 is a mortar specimen without water repellent and a test specimen mixed with an inorganic metal salt-based powdery water repellent SEM images of the surface of are magnified 10,000 times.
7 is a graph showing the amount of electric charge passing through the test specimens according to Examples 1 to 4 and Comparative Examples 1 to 3 of the present invention.

In order to fully understand the present invention and its operational advantages and objectives achieved by the practice of the present invention, reference should be made to the accompanying drawings illustrating preferred embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, the present invention will be described in detail by describing preferred embodiments of the present invention with reference to the accompanying drawings. However, in describing the present invention, descriptions of already known functions or configurations will be omitted to clarify the gist of the present invention.

The mortar composition using the organic-inorganic composite water repellent of the present invention is a repair mortar composition used for repair work for a degraded concrete structure, and includes cement, fine aggregate, and an organic-inorganic composite water repellent, wherein the organic-inorganic composite water repellent is an inorganic metal salt. A powder-type water repellent and an organic silicon-based liquid water repellent are provided.

In addition, the concrete composition using the organic-inorganic composite water repellent of the present invention is a concrete composition for expressing water-repellent performance inside concrete, and includes cement, fine aggregate, coarse aggregate, and an organic-inorganic composite water repellent, wherein the organic-inorganic composite water repellent is An inorganic metal salt-based powder water repellent and an organic silicone-based liquid water repellent are provided.

That is, the mortar composition of the present invention and the concrete composition of the present invention are characterized by mixing an inorganic metal salt-based powder water repellent and an organic-inorganic composite water repellent provided as an organic silicon-based liquid water repellent when mixing mortar or concrete. At this time, it is preferable that the inorganic metal salt-based water repellent is mixed with cement by dry mixing, and the organic silicon-based liquid water repellent is mixed with fine aggregate or fine aggregate and coarse aggregate after preparing the cement paste.

In the present invention, the inorganic metal salt-based water repellent agent is provided as a stearate powder-type water repellent agent, and the organic silicon-based liquid water repellent agent is provided as a silane-siloxane water-based water repellent agent. In particular, in the present invention, the stearate powder water repellent agent includes calcium stearate and zinc stearate, but calcium stearate and zinc stearate have a weight ratio of 9.5 to 8.5: 0.5 to 1.5 (more preferably is preferably mixed in a 9:1 weight ratio), and the solid content of the silane-siloxane aqueous water repellent agent is preferably 40 to 60% by weight (most preferably 50% by weight).

The inorganic metal salt-based water repellent (stearate powder-type water repellent) and the organic silicon-based liquid water repellent (silane-siloxane water-based water repellent) having the above components have sufficient water repellent performance required while increasing the amount of air generated from existing water repellents, In order to solve problems such as deterioration in compressive strength, it is preferable to mix in a weight ratio of 3 to 6: 1 (more preferably 5: 1 weight ratio). The results will be described later. At this time, the weight ratio of the organic silicone-based liquid water repellent (silane-siloxane water-based water repellent) is based on the weight of the solid content excluding the mixing water.

In addition, the organic-inorganic composite water repellents including inorganic metal salt-based powder water repellents and organic silicon-based liquid water repellents as described above show a relatively large decrease in compressive strength and change in water repellent performance according to the experimental results, based on 100 parts by weight of cement. It is preferably blended in ~3 parts by weight (more preferably 2 parts by weight).

On the other hand, in the present invention, the cement is preferably provided as one type of normal Portland cement having a fineness of 2,800 cm ² /g or more. For reference, fine aggregate and coarse aggregate can be used according to general specifications for mortar or concrete.

Hereinafter, the configuration and operational effects of the present invention will be described in more detail by explaining preferred embodiments of the present invention and the experimental results thereof. However, this is presented as a preferred example of the present invention, and the present invention is not limited or limited by the embodiments disclosed below.

1. Experiment outline

<Materials used>

In this experiment, normal Portland cement of type 1 was used, and fine aggregate was used standard sand conforming to KS L ISO 679 standard.

The characteristics of the silane-siloxane modified water repellent, which is an organic silicone-based liquid water repellent used in this experiment, and the characteristics of calcium stearate and zinc stearate, which are inorganic metal salt-based powder water repellents, are shown in [Table 1] and [Table 2], respectively. Silicon-based silane-silonic acid has a milky white color and alkalinity, and since the solid content is 50%, it is a material that needs to be corrected for the mixing number. Stearate is a fine powder having a lower density than that of cement, and has neutral or weak alkalinity.

<Experiment plan>

[Table 3] shows the mortar formulation according to Comparative Examples 1 to 3 and Examples 1 to 4 used in this experiment.

In this experiment, Examples 1 to 4 are cement mortars using both the organic-inorganic composite water repellent according to the present invention, that is, the inorganic metal salt-based powdery water-repellent agent (stearate powder-type water-repellent agent) and the organic silicon-based liquid water-repellent agent (silane-siloxane water-based water-repellent agent). Test specimens made of the composition, wherein the inorganic metal salt-based powder water repellent and the organic silicone-based liquid water repellent were 3: 1 weight ratio in Example 1 (P3L1) and 4: 1 weight ratio in Example 2 (P4L1). 3 (P5L1) has a weight ratio of 5: 1 and Example 4 (P6L1) has a weight ratio of 6: 1.

On the other hand, Comparative Example 1 (OPC) is a test specimen made of a cement mortar composition using only one type of ordinary Portland cement without mixing any water repellent, and Comparative Example 2 (Powder) is an inorganic metal salt-based powdery water repellent (stearate powder) as a water repellent. Comparative Example 3 (Liquid) is a test specimen made of a cement mortar composition using only organic silicon-based liquid water repellent (silane-siloxane water-based water repellent) as a water repellent.

Flow, air volume, and compressive strength tests were conducted to evaluate the physical performance of the mortar mixed with the organic-inorganic composite water repellent, and water absorption and chloride permeation resistance tests were conducted to evaluate the water repellent performance. The organic-inorganic composite water repellent used in the experiment was added 2 parts by weight compared to 100 parts by weight of cement, which showed a relatively large decrease in compressive strength and change in water repellency as a result of existing literature and preliminary experiments. Calcium stearate (Ca): zinc stearate (Zn) = 9: 1 weight ratio was applied, which had excellent performance and showed the lowest decrease in compressive strength. In addition, the amount of compounding water was adjusted considering that the solid content of the organic silicone-based liquid water repellent agent was 50%. The mixing ratio of the organic-inorganic composite water repellent was adjusted by adjusting the amount of the organic silicon-based liquid water repellent (silane-siloxane water-based water repellent), which greatly reduces the compressive strength, in consideration of the decrease in compressive strength.

2. Experimental method

<Construction Performance Evaluation of Unhardened Mortar>

The air volume test was conducted in accordance with KS F 2421. The flow experiment was conducted based on KS L 5105, and 200±5mm and 7±% were set as target performance ranges based on water-binder ratio (W/C) of 50% and water-repellent-free mortar to measure flow and air volume. conducted.

<Compressive strength>

After demolding the test body manufactured based on KS L ISO 679, air-drying was performed. The compressive strength was measured using a 30Ton UTM at 3, 7, 14, and 28 days of age, and the average value was calculated as the compressive strength after measuring the compressive strength of three specimens for each level. The compressive strength test was performed by making a 50x50x50 cubic mold.

<Absorbency>

After 28 days of air-curing, epoxy was coated on the side of the cured specimen and dried in the air for 24 hours. After measuring the weight of the specimen after drying, the specimen was immersed in water to a depth of about 10 mm, and the weight of the specimen was measured over time for 10, 30, 60, and 360 minutes to derive the water absorption rate and water absorption coefficient per area. The experiment was conducted based on KS F 2609, and since the absorption coefficient calculated through four or more measured values has a linear relationship, the experiment was terminated at 360 minutes.

<Chloride permeation resistance (RCPT)>

The procedure for the chloride penetration resistance test (RCPT = Rapid Chloride Permeabillity Test) is as follows. First, a Ø100 × 200 circular specimen cured for 28 days in an air-dry state was cut from the center to the pouring surface and the bottom surface to a thickness of 50 mm, respectively, and then epoxy coating was performed on the side of the cut specimen to conduct the experiment in one direction. Time Cured at room temperature. After the epoxy cured specimen was placed in a desiccator and a vacuum was maintained at a pressure of 133 Pa or less for 3 hours, distilled water was filled in the desiccator to the extent that all specimens were submerged and immersed for 18 ± 2 hours. After immersion, the specimen is put into a chloride permeation resistance cell to assemble, and then 3.0% sodium chloride and 0.3N sodium hydroxide are put into the assembled cell. The cell was connected to a constant voltage power supply, 60v was supplied for 6 hours, and the current value was recorded every 30 minutes from the beginning to derive the amount of charge passed through [Equation 1] below.

In the above [Equation 1], Q is the amount of charge (C) passing through, and I ₀ is the current (A) immediately after applying the voltage. I _t represents the current (A) after t minutes have elapsed after applying the voltage. Chloride permeation resistance test was conducted based on KS F 2711.

3. Experimental Results and Analysis

<Changes in flow and air volume according to the amount of water repellent mixed in>

[Table 4] below shows the flow and air amount test results for the mortars according to Examples 1 to 4 and Comparative Examples 1 to 3 of the present invention. All test specimens (Comparative Examples 1 and 2 and Examples 1 to 4) except for the test specimen of Comparative Example 3 (Liquid) incorporating an organic silicone-based liquid water repellent (silane-siloxane water-based water repellent) flow set as the target performance range in this study 200±15mm and air volume 7±1% were met. In the case of organic silicone-based liquid water repellent, it is judged to have excellent workability by entraining a lot of air to the inside when mixed. However, the test specimen of Comparative Example 2 (Powder) incorporating an inorganic metal salt-based powder water repellent (stearate powder water repellent) confirmed a decrease in the amount of air when the amount of metal salt was increased, indicating that the pores inside the mortar were reduced when the metal salt-based stearate was added. considered to be charging.

<Relationship between water repellent mixing amount and compressive strength>

1 is a graph showing the compressive strength test results for test specimens according to Examples 1 to 4 and Comparative Examples 1 to 3 of the present invention.

In all test specimens, the compressive strength increased over time, and the compressive strength of the water repellent-free specimen (Comparative Example 1) was 30 and 36 MPa, respectively, on the 3rd and 7th days, respectively, showing high compressive strength. In the case of test specimens incorporating a water repellent (Comparative Examples 2 and 3 and Examples 1 to 4), overall strength enhancement increased significantly after 14 days of age.

In the case of inorganic metal salt-based powdered water repellent (Comparative Example 2), the compressive strength was low until the age of 14 days, but after the age of 28 days, the compressive strength was 39.5 MPa, which was 97.5% higher than that of the mortar without mixing. The organic silicone-based liquid water repellent (Comparative Example 3) had a compressive strength of 24 MPa at the age of 28 days, and a 42% decrease in compressive strength compared to the mortar without mixing was confirmed.

The test specimens (Examples 1 to 4) incorporating the organic-inorganic composite water repellent showed a higher compressive strength than the specimen (Comparative Example 3) incorporating the organic silicone-based liquid water repellent regardless of age, at about 38 MPa at the age of 28 days. High compressive strength was shown compared to the specimen of Comparative Example 3. Specifically, Example 1 (P5L1) showed a decrease in compressive strength of about 2.5% compared to Comparative Example 2 (Powder), which was a test body incorporating an inorganic metal salt-based powdery water repellent at 38.5 MPa, and in the case of Example 4 (P6L1) . It is judged that stearate is filled as a filler inside, and in the case of Example 4 (P6L1), it is considered that it does not affect the decrease in compressive strength because the amount of the silicone-based liquid water repellent mixed in is very small.

2 shows SEM images of mortar test specimens without water repellent and organic silicone liquid water repellents, and FIG. 3 shows SEM & EDS analysis results of test specimens mixed with organic silicone liquid water repellents.

As shown in FIGS. 2 and 3, microcracks were confirmed on the surface of the test body mixed with the organic silicon-based liquid water repellent compared to the mortar test body without the water repellent agent, and the joint surface of the fine aggregate and the cement paste was judged to be the cause of the decrease in compressive strength. (ITZ) As a result of the analysis, it was measured that Si was about 6 times higher than the mortar test specimen without water repellent in the ITZ (The Interfacial Transition Zone) part. It is considered that the compressive strength is greatly reduced by these two causes.

<Change in water absorption per unit area according to water repellent incorporation>

Figure 4 is a graph showing the amount of water absorption per unit area over time of the test specimens according to Examples 1 to 4 and Comparative Examples 1 to 3 of the present invention.

Referring to FIG. 4, it was found that the water repellency performance of all test specimens except Comparative Example 1 (OPC), which is a mortar test specimen without water repellent agent, was excellent. Specifically, in the case of Comparative Example 1 (OPC), the water absorption per area continuously increased over time, and after 6 hours, the water absorption per area was 1.394 kg/m ² . In the case of Comparative Example 2 (Powder), which is a test sample incorporating an inorganic metal salt-based water repellent, it is 0.12kg/m ² , which is 92% less than that of Comparative Example 1 (OPC), and in the case of Comparative Example 3 (Liquid), which is a test sample using an organic silicone-based liquid water repellent, water has been shown not to absorb

And, in the case of the test specimen incorporating the organic-inorganic composite water repellent, the water absorption per area was found to be large in the order of Example 4 (P6L1) > Example 3 (P5L1) > Example 2 (P4L1) > Example 1 (P3L1). , This is judged to be the result of the decrease in the amount of the organic silicon-based liquid water repellent (silane-siloxane water-based water repellent) with excellent water repellency according to the mixing ratio. Example 4 (P6L1), which had the lowest water repellency among the test specimens incorporating the organic-inorganic composite water repellent, showed 0.072kg/m ² , which is 95% less than that of Comparative Example 1, which is a mortar test specimen without water repellent, and is an inorganic metal salt-based powdery water repellent. It was confirmed that it was 40% less than that of Comparative Example 2 (Powder), which was a test body incorporating . All of the test specimens (Examples 1 to 4) incorporating the organic-inorganic composite water repellent showed higher water repellency than the test specimen (Comparative Example 2) incorporating the inorganic metal salt-based powdery water repellent.

[Table 5] below shows the water absorption coefficient over time of the test specimens according to Examples 1 to 4 and Comparative Examples 1 to 3 of the present invention.

Referring to [Table 5] above, it was found that the water absorption coefficient also converged to 0 regardless of the passage of time except for Comparative Example 1 (OPC), which is a mortar test material without water repellent. Specifically, Comparative Example 2 (Powder), a test sample incorporating an inorganic metal salt-based powdery water repellent, showed a constant water absorption coefficient of about 0.06, and in Comparative Example 3 (Liquid), a test sample incorporating an organic silicone-based liquid water repellent, water The absorption coefficient was found to be zero.

In addition, the water absorption coefficient of the test specimens (Examples 1 to 4) incorporating the organic-inorganic composite water repellent also showed the same tendency as the water absorption per area, and in the case of Example 4 (P6L1), the water absorption coefficient was different from other examples. About 0.03 showed some absorption performance. Therefore, the ratio of Example 3 (P5L1) (the mixing ratio of the inorganic metal salt-based powdery water repellent and the organic silicon-based liquid water repellent) is determined to be the minimum of the organic-inorganic composite water repellent agent.

5 shows a 500-fold magnified SEM image of the surface of a mortar test specimen without water repellent and a test specimen mixed with an inorganic metal salt-based powdery water repellent, and FIG. 6 is a mortar specimen without water repellent and a test specimen mixed with an inorganic metal salt-based powdery water repellent SEM images of the surface of are magnified 10,000 times.

Referring to FIGS. 5 and 6, unlike the surface of the mortar test specimen without water repellent agent, it was confirmed that the waxy material was coated over the entire surface of the test specimen incorporating the inorganic metal salt-based powdery water repellent agent, which was magnified 10,000 times. , it was confirmed that a waxy material was coated on the surface of the cement hydration product. It is judged that the coating layer formed on the surface of the cement hydrate has a water-repellent effect both inside and outside, and the size of the water-repellent power is adjusted by the mixing ratio of the organic silicon-based liquid water-repellent (silane-siloxane water-based water-repellent) test specimen with strong water-repellency, and inorganic metal salt-based It is considered that the water repellency decreases as the mixing ratio of the powder type water repellent increases.

<Results of chloride permeation resistance test>

7 is a graph showing the amount of electric charge passing through the test specimens according to Examples 1 to 4 and Comparative Examples 1 to 3 of the present invention.

Referring to FIG. 7, compared to Comparative Example 1 (OPC), which is a mortar test specimen without water repellent agent, it was found that the amount of charge passing through all test specimens decreased according to the incorporation of water repellent agent. In the case of Comparative Example 2 (Powder), which is a test sample containing inorganic metal salt-based powdered water repellent, and Comparative Example 3 (Liquid), which is a test sample containing organic silicone-based liquid water repellent, about 7007 and 5864 coulombs, which are 48% and 56% lower than those of Comparative Example 1 (OPC), respectively. appear.

And, in the case of Examples 1 to 4, which are organic-inorganic composite water repellent mixed test specimens, the average was about 7300 coulomb, which was about 45% lower than that of Comparative Example 1 (OPC). In particular, in the case of Example 1 (P3L1), about 6807 coulombs were found, which is 3% lower than that of Comparative Example 2 (Powder). However, in the case of Examples 1 to 4, which are organic-inorganic composite water repellent mixed test specimens, the same water absorption coefficient as Comparative Example 3 (Liquid), which is an organic silicone liquid water repellent mixed test specimen, was expected to have a low passing charge amount, but Example 2 (P4L1) and In the case of the specimen of Example 3 (P5L1), a higher than expected amount of charge was confirmed, with about 7020 and 7699 coulombs, which were 20% and 30% higher than those of Comparative Example 3 (Liquid).

[Table 6] below shows the average chloride penetration depth shown by spraying a silver nitrate solution after the chloride penetration resistance test was completed for the test specimens according to Examples 1 to 4 and Comparative Examples 1 to 3 of the present invention.

Referring to [Table 6] above, the chloride penetration depth also showed that the test specimens incorporating the water repellent generally showed a low chloride penetration depth. In the case of Comparative Example 3 (Liquid), a test sample mixed with an organic silicone-based liquid water repellent, the lowest penetration depth was 21.77 mm, and in the case of Comparative Example 2 (Powder), a test sample mixed with an inorganic metal salt-based powder water repellent, the penetration depth was 26.47, about 5 mm higher than that. showed

In addition, in the case of Examples 1 to 4, which are organic-inorganic composite water repellent mixture test specimens, Example 2 (P4L1) and Example 3 (P5L1) showed relatively high penetration depths of 26.42 and 27.25 mm, respectively, which was due to the water repellent material. It is judged to be caused by the micropores inside the test body and the chemical reaction inside, and it is considered that additional research is needed.

4. Conclusion

In order to solve problems such as increase in air volume and decrease in compressive strength when organic silicon-based liquid water repellent (silane-siloxane water-based water repellent) is mixed with cement-based materials, organic-inorganic composite water repellents (inorganic metal salt-based powder water repellent and organic silicon-based liquid water repellent) have been developed. The following conclusions were obtained as a result of evaluating the physical performance and water repellency of the mortar with mixed).

1) In the case of Comparative Example 3 (Liquid), a test chain containing organic silicone-based liquid water repellent, the mortar compressive strength at 28 days of age is 42% compared to Comparative Example 1 (OPC), a test chain without water repellent. It is believed that hydrophobic substances such as silane-siloxane in the transition zone (ITZ) of fine aggregate delayed the cement hydration reaction. However, in the case of Comparative Example 2 (Powder), which is an inorganic metal salt-based powder water repellent mixed test body, and Example 3 (P5L1) and Example 4 (P6L1) among test bodies mixed with an inorganic metal salt-based powdery water repellent agent, the 28-day compressive strength is comparable to that of Comparative Example 1 Compared to (OPC), there was almost no decrease in compressive strength at about 97%.

2) Due to the excellent water repellency of the organic silicone liquid water repellent (silane-siloxane water repellent), the organic/inorganic composite water repellent test specimens (Examples 1 to 4) incorporating the organic silicone liquid water repellent have a water absorption coefficient and water absorption area of almost zero. In particular, in the scope of this experiment, it was confirmed that the water repellency of the mortar was very good at a mixing ratio of 5: 1 or less between the inorganic metal salt-based powder water repellent and the organic silicon-based liquid water repellent.

3) Comparative Example 3 (Liquid), an organic silicone-based liquid water repellent mixing test, increased the amount of air and flow accompanied by entrained air only when mixed inside, but Comparative Example 2 (Powder), an inorganic metal salt-based powder water repellent mixing test, stea It is determined that the rate reduces the amount of air by filling the micropores. In addition, Examples 1 to 4 in which the organic/inorganic composite water repellent was incorporated had an effect of reducing the flow by about 10% and the amount of air by about 50% compared to Comparative Example 3 (Liquid).

4) The amount of passing charge representing the chloride penetration resistance of the organic-inorganic composite water repellent mixed test specimens (Examples 1 to 4) was an average of 7300 coulomb, which was about 45% lower than that of 13,432 coulomb of Comparative Example 1 (OPC), which is organic It is judged by the water-repellent performance of the silicone-based liquid water-repellent agent and the filling effect of the inorganic metal salt-based powder-type water-repellent agent.

5) Summarizing the above experiments, the organic-inorganic composite water repellent according to Example 3 (P5L1), in which an inorganic metal salt-based powdery water repellent and an organic silicon-based liquid water repellent were mixed at a ratio of 5: 1, prevents a decrease in compressive strength and secures water repellent performance. considered the most reasonable and effective.

In conclusion, according to the examples of the present invention and the test results thereof, in the mortar/concrete composition, an organic silicone-based liquid water repellent and an inorganic metal salt-based powdered water repellent are mixed and used, but the organic silicone liquid water repellent is a silane-siloxane water-based water repellent. Inorganic metal salt-based powder water repellent is applied as a stearate powder water repellent mixture of calcium stearate and zinc stearate, inorganic metal salt powder water repellent and organic silicone liquid water repellent agent at a weight ratio of 3 to 6: 1 (most Preferably, by mixing at a weight ratio of 5: 1, it is possible to solve problems such as an increase in the amount of air and a decrease in compressive strength, which occur in existing water repellents, while ensuring water repellency to prevent deterioration factors from penetrating into the inside of concrete. .

The present invention is not limited to the above-described embodiments, and it is obvious to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, it should be said that such modifications or variations fall within the scope of the claims of the present invention.

Claims (10)

In the repair mortar composition used for repair work on a degraded concrete structure,
It includes cement, fine aggregate, inorganic metal salt-based powder water repellent and organic silicon-based liquid water repellent,
The inorganic metal salt-based water repellent in powder form is provided as a stearate powder-type water repellent, and the organic silicone-based liquid water repellent is provided as a silane-siloxane aqueous water repellent,
The stearate powder water repellent agent includes calcium stearate and zinc stearate, wherein the calcium stearate and the zinc stearate are mixed in a weight ratio of 9: 1,
The inorganic metal salt-based powdered water repellent and the organic silicone-based liquid water repellent are mixed in a weight ratio of 5: 1, and the weight ratio of the organic silicone-based liquid water repellent is based on the weight of the solid content,
The organic-inorganic composite water repellent including the inorganic metal salt-based powder water repellent and the organic silicon-based liquid water repellent is blended in 2 parts by weight based on 100 parts by weight of the cement.
delete delete According to claim 1,
Mortar composition using an organic-inorganic composite water repellent, characterized in that the solid content of the silane-siloxane water-based water repellent is 40 to 60% by weight.
delete delete According to claim 1,
The inorganic metal salt-based powdery water repellent is mixed with the cement by dry mixing,
The organic silicon-based liquid water repellent is a mortar composition using an organic/inorganic composite water repellent, characterized in that mixed with the fine aggregate after preparing the cement paste.
In the concrete composition for expressing water repellency in concrete,
Including cement, fine aggregate, coarse aggregate, inorganic metal salt-based powder water repellent and organic silicon-based liquid water repellent,
The inorganic metal salt-based water repellent in powder form is provided as a stearate powder-type water repellent, and the organic silicone-based liquid water repellent is provided as a silane-siloxane aqueous water repellent,
The stearate powder water repellent agent includes calcium stearate and zinc stearate, wherein the calcium stearate and the zinc stearate are mixed in a weight ratio of 9: 1,
The inorganic metal salt-based powdered water repellent and the organic silicone-based liquid water repellent are mixed in a weight ratio of 5: 1, and the weight ratio of the organic silicone-based liquid water repellent is based on the weight of the solid content,
The inorganic metal salt-based powder water repellent and the organic-inorganic composite water repellent including the organic silicon-based liquid water repellent are mixed in 2 parts by weight based on 100 parts by weight of the cement. Concrete composition using organic-inorganic composite water repellent. delete delete

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