KR101084789B1 - Concrete binder composition for reinfored laitance - Google Patents

Abstract

PURPOSE: A concrete binder composition for reinforcing laitance is reduce the generation of cracks and moisture penetration by improving the reactivity of the composition with respect to laitance. CONSTITUTION: A concrete binder composition for reinforcing laitance includes 45-49.9 weight% of nano slag powder, 45-49.9 weight% of an alkaline stimulator, and 0.1-10 weight% of water. The fineness of the nano slag powder is more than or equal to 30,000cm^2/g. The alkaline stimulator is one or more selected from calcium hydroxide, potassium hydroxide, calcium silicate, and sodium carbonate. The content ratio of the nano slag powder and the alkaline stimulator is 1:1.

Description

Concrete binder composition for reinforcement

The present invention relates to a latent reinforced concrete binder composition, and more particularly, to a latent reinforced concrete binder composition which exhibits excellent strength expression in compressive strength and flexural strength by utilizing nano-grade blast furnace slag and alkali stimulant.

The construction of building structures is on the rise due to the continuous industrial development and expansion of housing supply rate. However, there are many deterioration factors in performance due to the increase in size, height, and heightening of construction. In order to improve this, development of accurate construction method and adaptation of loading place to secure required performance of building structure at construction site should be preceded. Among these, in order to secure the reliability of the concrete structure, it is very important to secure the construction quality and structural strength of the joint part, which is the weakest part of the concrete, which is an integral structure.

In general, the method of joining the surface of the existing concrete is very important because the difference in adhesion with the concrete being poured after the existing concrete is generated. In order to remove the weak layer of the lattices and the surface, a method of spraying compressed air at high pressure in the early stage of concrete hardening is used, and reinforcing bars may be required depending on the point of joining. In principle, the minimum shear force and the compression angle should be used. Considering this principle, it should be selected as the location where work can be done by considering the construction of the rebar and the overall construction order.

In general, the position of the seam is provided at right angles to the direction of the member at the portion where the shear force is small. At the same time, consideration should be given to the positions where the work of the construction joints is possible, and the workability of the formwork or reinforcing bars, and the overall tool division and construction order. In addition, in order to improve the precision of the joint construction, after removing the latencies of the joints to be connected, it is necessary to secure the bonding strength with the newly poured concrete by washing with water and using the high pressure cleaner.

However, in the domestic construction site, it is difficult to remove the latencies generated in the hard concrete because it is connected after at least 3 days to the precast concrete surface. This can be a direct cause of leakage and a drop in strength, as it can be continued without water accumulation.

In addition, the conventional method of removing the latency is to remove it through grinding work using the latent remover and shot blast. The latent remover delays the hardening of the concrete surface 2-5 mm. It must be sprayed before curing can proceed. Secondary work is required to remove the latencies by hydraulic pressure within a certain time after the injection, and in the case of the shot blast, there are various problems such as the need for safety equipment along with expensive equipment.

In particular, cracks (interlayer cracks, which are an indicator of lack of integrity) that occur in the joint section of the concrete structure reduce the strength of the structure and may cause leakage or deterioration of durability. .

However, due to the lack of skilled workers and manpower, interest, lack of air, and lack of quality due to evasion of 3D occupations, it is not easy to input manpower. It is very difficult to remove and the safety accidents caused by rebars are still present.

In order to solve the above problems, the present invention can penetrate into the already cured concrete without the addition of additional equipment or manpower, which is a conventional method of removing the lattices, and has excellent adhesive performance but does not have a chemical effect on concrete. It is an object of the present invention to provide a nano-class composition to provide a latent strengthening adhesive composition capable of coping with durability, such as structural strength and leakage.

In order to achieve the above object, the present invention

45 to 49.9% by weight of nano slag powder having a powder degree of 30,000 cm 2 / g or more;

45-49.9 weight percent of an alkaline stimulant;

It provides a latent reinforced concrete binder composition comprising 0.1 to 10% by weight of water.

The alkali stimulant is preferably at least one selected from the group consisting of calcium hydroxide, potassium hydroxide, calcium silicate, and sodium carbonate.

The content ratio of the nano slag powder and the alkali stimulant is preferably 1: 1.

It is preferable that the content of water is 0.1 to 2.0% by weight.

The alkali stimulant is a mixture of calcium hydroxide and potassium silicate or a mixture of potassium hydroxide and potassium silicate, and the composition ratio of the mixture is preferably 1: 1.

According to the present invention, effective field application through spraying of the composition is reduced because the cracking and moisture penetration are reduced by improving the reactivity with the latency and improving the adhesion of the release-treated surface as an alternative method for the removal of the latency in the existing site. It is possible and economical by shortening the air can be achieved.

In addition, there is a disadvantage that the application of the conventional latex remover should be made before concrete hardening, the composition of the present invention has the advantage that it can be applied regardless of the application point by adjusting the alkali stimulant of the composition in consideration of the point of concrete pouring.

1 shows a process for removing a latency layer according to the prior art.
2a and 2b show the results of the blast furnace slag 1 and 3 XRD analysis, respectively, according to the prior art.
Figure 3 shows the quenched nano slag XRD analysis results according to an embodiment of the present invention.
Figure 4 shows the result of the latency XRD analysis according to the prior art.
Figure 5 shows the results of XRD analysis of the latency and calcium hydroxide according to an embodiment of the present invention.
Figure 6 shows the results of XRD analysis of the latency and potassium hydroxide according to an embodiment of the present invention.
7 shows EDS analysis results according to the prior art.
8 shows EDS analysis results of calcium hydroxide according to an embodiment of the present invention.
Figure 9 shows the results of EDS analysis of calcium hydroxide and potassium silicate according to an embodiment of the present invention.
Figure 10 shows the results of EDS analysis of potassium hydroxide according to an embodiment of the present invention.
11 shows EDS analysis results of potassium hydroxide and potassium silicate according to an embodiment of the present invention.
Figure 12 shows the compressive strength of each age of the test piece after 3 days in accordance with an embodiment of the present invention.
Figure 13 shows the bending strength for each age of the test piece after 3 days according to an embodiment of the present invention.
Figure 14 shows the compressive strength for each age of the splice test body after 7 days according to an embodiment of the present invention.
Figure 15 shows the bending strength of each age of the test piece after 7 days according to an embodiment of the present invention.

The present invention is 45 to 49.9% by weight of nano-slag powder having a powder degree of 30,000 cm 2 / g or more; 45-49.9 weight percent of an alkaline stimulant; It provides a latent reinforced concrete binder composition comprising 0.1 to 10% by weight of water.

The present invention relates to the development of nano-adhesives for horizontal jointing of concrete vertical structures, and the effect of delaying coagulation through the application of the primary latex remover of the conventional latex remover (requires input before hardening of the old concrete) and the secondary Unlike the redundant structure, which consists of two stages of removing the lattices through water pressure washing and wire brush, no additional work is required through the first application.

The present invention can be applied irrespective of the application time by adjusting the alkali stimulant of the composition in consideration of the timing of pouring new concrete, unlike the point of time when the input of the existing latex remover has a time limit to be made before the hardening of the old concrete.

In the present invention, the nano-slag is filled with high fine powder of 30,000 cm ² / g or more in the pores of the lattices to enhance the hardness and strength of the lattices itself, and progress the integration as the new pour concrete and curing proceed simultaneously It is a fine powder latent hydraulic material, which improves the activity compared to one or three types of existing blast furnace slag.

Here also the nano slag powder is preferably a 30,000cm ² / g to 40,000cm ² / g. The general blast furnace slag fine powder has a powder degree of 4,000 to 6,000 cm 2 / g, while the nano slag fine powder of the present invention shows a very high fine powder. When the fine powder of nano slag exceeds 30,000cm ² / g, and the flow characteristics and activity index is observed a phenomenon that is radically improved performance, 40,000cm ² / g or higher, from the increase in the cost of manufacture, and high Unfavorable as the cohesion between particles is observed due to the powderiness.

If the nano slag powder is less than 30,000cm ² / g is not fine because the degree of fine powder is not filled in the voids of the latency do not enhance the hardness and strength of the latency.

Figure 2a shows the blast furnace slag 1 XRD analysis results according to the prior art, Figure 2b shows the blast furnace slag 3 XRD analysis results according to the prior art, Figure 3 is a quenching nano slag according to an embodiment of the present invention XRD analysis results are shown. Referring to Figures 2a, 2b and 3, the activity of the material can be confirmed, in the case of nano slag is measured to increase at least 100 to 200cps or more compared to blast furnace slag 1 and 3 species to confirm the performance improvement according to the nano slag Can be.

The content of the nano slag powder is preferably 45 to 49.9% by weight. When the content of the nano slag powder is less than 45% by weight, it is not preferable because the effect of improving the latent hardness and strength is inadequate, and when it exceeds 49.9% by weight, the content of the alkaline stimulant, which is another component of the composition, is lowered. I can't.

Alkali stimulants are used for curing the latencies and inducing the alkali activation reaction of the nano slag, and all kinds of alkaline stimulants are used, for example, but not limited to, calcium hydroxide, potassium hydroxide, calcium silicate, and sodium carbonate. It is preferably one or more selected from the group consisting of.

The content of the alkaline stimulant is preferably 45 to 49.9% by weight. If the content of alkali stimulant is less than 45% by weight, it is not preferable because the effect of improving the hardness and strength is insufficient, and if it exceeds 49.9% by weight, the content of nano slag powder, which is another component of the composition, is lowered. I can't.

The content of the nano slag powder and the alkali stimulant may be selectively used within a predetermined range, and the content ratio (weight ratio) of the nano slag powder and the alkali stimulant is preferably 1: 1. The content ratio of nanoslag and alkali stimulant is about 1: 0.3 ~ 0.5 in general manufacturing of non-plastic cement concrete, but it reacts with unhydrated cement and latent hydraulic material contained in the latency to enhance the latency. 1: 1 is most preferred as it satisfies both the alkali stimulation reactions of the mixed nanoslag and requires more than the strength of the mother. Nevertheless, the ratio can be changed depending on the time of introduction of the composition and the strength of the mother.

It is preferable that the content of water is 0.1 to 2.0% by weight. If the water content is less than 0.1% by weight, alkali stimulants and nanoslags may not be melted and mixed easily, resulting in unhydrated nanoslags. It is not desirable because there is. In addition, when the content of water exceeds 0.2% by weight, the nanoslag and alkali stimulant may be diluted, which may bring advantages in construction, but is not preferable because it may express strength below the strength with the mother.

The alkali stimulant is a mixture of calcium hydroxide and potassium silicate or a mixture of potassium hydroxide and potassium silicate, and the mixing ratio can be arbitrarily selected and used. Specifically It is preferable that the composition ratio of the said mixture is 1: 1. Both calcium hydroxide and potassium silicate are alkaline stimulants suitable for nanoslag and have similar strength expression when mixed. Both alkali stimulants exhibit similar pH (alkalinity) of 11.5 to 13.5. There is no big problem in the range, but in order to control the intensity expression time point is 1: 1 is most preferred.

The present invention increases the strength of the lattices themselves generated during concrete splice, and the hardness is low enough to be removed by spraying water with an injector such as latencies as a binder composition for integrating new concrete. In addition, the penetration of more than 30,000 cm ² / g nanoscale blast furnace slag (a latent hydraulic material such as blast furnace slag and fly ash) between the layers of large porosity enhances hardness by filling the pores, and long-term hydration product by alkali stimulant Creates. In addition, the tightness of the structure can be improved by fully integrating the new concrete by controlling the rate of hydration reaction with the new concrete.

According to the present invention, it is possible to secure an effective on-site application and economical air shortening by stimulant injection as an alternative method of removing the latency in the field application.

Example

Latency  making

For the production of the latency, concrete mixed using the forced mixing mixer specified in KS F 2403: Test Method for Constructing the Strength Test of Concrete was used, and the W / C ratio was determined to be 50% to sufficiently generate the latency. Produced as shown in Table 1, the latent physicochemical analysis was carried out experimental analysis after drying only the latent portion.

Example 1

495 g of nano slag powder, 495 g of calcium hydroxide, and 10 g of water having a powder degree of 35,000 cm ² / g were mixed to prepare a latent reinforced concrete binder composition.

Example 2

A latent reinforced concrete binder composition was prepared by mixing 247.5 g of calcium hydroxide with a mixture of 495 g of nanoslag powder having a powder degree of 35,000 cm ² / g, 247.5 g of liquid potassium silicate, and 10 g of water.

Example 3

495 g of nano slag powder, 495 g of potassium hydroxide, and 10 g of water having a powder degree of 35,000 cm ² / g were mixed to prepare a latent reinforced concrete binder composition.

Example 4

A latent reinforced concrete binder composition was prepared by mixing 2495 g of potassium hydroxide with a mixture of 495 g of nanoslag powder having a powder level of 35,000 cm ² / g, 247.5 g of liquid potassium silicate, and 10 g of water.

Comparative Example 1

OPC was prepared under the most favorable conditions produced by assuming that the condition does not occur in the center of the test body by placing at once in the mixing conditions according to the composition shown in Table 1 below.

Comparative Example 2

The composition was prepared under the same formulation conditions as in Comparative Example 1, followed by dividing into three and seven days, and OPC was prepared under vulnerable conditions without separate removal according to the latencies.

Evaluation and Results

XRD  Analysis

The main component of the latency is calcium carbonate (CaCO ₃ ) and is composed of a small amount of magnesium oxide (MgO) and sodium oxide (Na ₂ O). When Example 1 was injected into the latency, the peak point of the latency was increased to 30 cps or more, and even when Example 3 was injected, the peak point was increased by 20 cps or more. It is observed that the maximum peak point is increased through Examples 1 and 3 of the present invention, and it is determined that the performance improvement by the injection of the present composition is possible.

The component of the latency is composed mostly of CaO component and Ca (OH) ₂ , by using the composition of the present invention is expected to be able to induce a curing reaction through the latency stimulation effect.

EDS  Analysis

In the case of spraying Example 1, it was observed that O ions decreased and Ca ions, Si ions, and K ions increased compared to Comparative Example 1, thus affecting the development of strength through the filling of voids on the cold joint surface. Example 2 and Example 4 was found to have a high content of O ions. This is judged by oxygen adsorption of liquid potassium silicate, which indicates the content of oxygen ions and does not significantly affect the curing reaction.

When spraying Example 3 K ions, ie, C ₃ A; The high content of aluminate component showed the best initial strength, but it seems to be the reason for the decrease in long-term strength. In the case of Example 4, the high content of Si ions appears to affect the increase in long-term strength.

In addition, the case of dissolving and spraying calcium hydroxide + nano slag in water (Example 1) and the case of dissolving and spraying potassium hydroxide in water + liquid potassium silicate + nano slag (Example 4) compared to Examples 2 and 3 It was found that the content of ingredients affecting the strength was high.

7 shows EDS analysis results in the case of no stimulant according to Comparative Example 1, and FIG. 8 shows EDS analysis results according to Example 1 of the present invention. 9 illustrates EDS analysis results according to Example 2 of the present invention. 10 shows EDS analysis results according to Example 3 of the present invention. 11 shows EDS analysis results according to Example 4 of the present invention.

Compressive and Flexural Strength Analysis

In consideration of the general period of stitching, the decision was made at two levels of stitching after 3 days and stitching after 7 days. The mechanical properties of alkaline joint stimulator + nano slag on the cold joint surface were analyzed by determining the level of OPC that did not connect the reference specimen and OPC-ear which was connected without spraying the stimulant and nano slag. In addition, in order to reduce the error of the experiment in the hard concrete test, the average of the results of the three specimens was measured.

FIG. 12 shows the compressive strength by age of the test specimen after 3 days, FIG. 13 shows the bending strength by age of the test specimen after 3 days, and FIG. 14 shows the compressive strength by age of the test specimen after 7 days. FIG. 15 shows the bending strength for each age of the splice test specimen after 7 days.

Given that the condition of the OPC is the strength of concrete that does not remove the current progress, the condition indicated by the OPC is the most favorable condition that does not occur, that is, impossible in reality. The conditions according to the invention using slag and alkali stimulants exceed OPC's following under conditions of compressive and flexural strengths. At one minute, as the OPC exceeds the OPC, the concrete binding composition of the present invention, which utilizes nanoslag and alkali stimulants, may compensate for such strength weakness.

The present invention is to improve the quality of the cold joint surface by the alkali curing reaction and to improve the adhesive strength of old and new concrete, through the physicochemical analysis and mechanical properties analysis through concrete experiments to confirm the following results.

First, the results of physicochemical analysis confirmed that the main component of the latency is composed of the CaO component and the Ca (OH) ₂ component. It was confirmed.

In addition, in the experiment using potassium silicate and nano slag as a solvent, it was confirmed from the surface texture observation that the viscosity of the potassium silicate and the nano slag was hardened to assist the aggregation of the particles, resulting in a dense structure and strong adhesion. It is expected to improve the bond strength and induce the alkali curing reaction of the new concrete of the joint surface.

Finally, as a result of the concrete strength test, the compressive strength and flexural strength test results were superior to those of the non-irritant test specimens when water was sprayed with a mixture of nano-slag with alkali stimulants such as calcium hydroxide, potassium hydroxide and potassium silicate. It showed the expression and was excellent in the hardening reaction induction effect of the Cold Joint surface.

Claims (5)

45 to 49.9% by weight of nano slag powder having a powder degree of 30,000 cm 2 / g or more;
45-49.9 weight percent of an alkaline stimulant;
A latent reinforced concrete binder composition comprising 0.1 to 10% by weight of water,
The alkali stimulant is a mixture of calcium hydroxide and potassium silicate or a mixture of potassium hydroxide and potassium silicate, the composition ratio of the mixture is 1: 1, characterized in that the reinforced concrete binder composition.
delete The method of claim 1,
Latency reinforced concrete binder composition, characterized in that the content ratio of the nano slag powder and the alkali stimulant is 1: 1.
The method of claim 1,
Latency reinforced concrete binder composition, characterized in that the water content of 0.1 to 2% by weight.
delete

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