KR101693333B1 - Low heating high strength concrete composite - Google Patents

Abstract

The present invention relates to a water reducing agent for low-heat type high-strength concrete consisting of 50 to 70 wt% of a retention system and 30 to 50 wt% of a water reducing system as a polycarboxylic acid system, 30 to 50 wt% of TEA (Tri-Ethanol- And 45 to 55 wt% of blast furnace slag fine powder, 25 to 35 wt% of ordinary portland cement, and 15 to 25 wt% of fly ash, which are composed of 50 to 70 wt% of PA (Polyphenol-Amine) 450 to 550 kg / m < 3 > of the binder (B) Water (W) 135-175 kg / m3; Fine aggregate (S) 700 to 770 kg / m3; Coarse aggregate (G) 850 to 940 kg / m3; Water reducing agent for low-heat type high-strength concrete, 4.05 to 8.25 kg / m3; (W / B) of 27 to 35% and a fine aggregate ratio (S / a) of 42 to 48%, and the low heat generation type high strength concrete The water reducing agent for high strength concrete is mixed with 0.9 to 1.4 parts by weight with respect to 100 parts by weight of the binder (B), and the alkali ion activator for the low heat generating type high strength concrete is mixed with 0.1 part by weight with respect to 100 parts by weight of the binder (B) ≪ / RTI >

Description

TECHNICAL FIELD [0001] The present invention relates to a low-temperature high strength concrete composition,

The present invention relates to a low-heat type high-strength concrete composition comprising a water reducing agent for low-heat type high-strength concrete and an alkali ion activator for low-heat type high-strength concrete. More particularly, The present invention relates to a low heat generating high strength concrete composition comprising a water reducing agent and an alkali ion activator suitable for a low heat generating type high strength concrete composition in which blast furnace slag cement and fly ash are mixed.

Since high strength concrete is designed with a large amount of binder and low water binder ratio compared with general concrete, high performance AE water reducing agent excellent in water reducing effect is used. However, in the case of high-strength concrete using a blast furnace slag cement containing 60 wt% of blast furnace slag cement, which is not usually Portland cement, a high-performance AE water reducing agent is not enough. This is because it is necessary to consider the maintenance of the slump flow over time as well as the effect of reducing the unit water quantity due to the characteristics of the binder having a low cement content.

In addition, in the case of ordinary concrete using ordinary Portland cement as a binder, the alkali environment of the concrete is formed by the calcium hydroxide generated in the hydration process, and the pozzolanic reaction or the latent hydraulic reaction of the fly ash or blast furnace slag incorporated into the admixture under the thus- . However, since the amount of cement is relatively small in the concrete used as the second blast furnace slag cement binder containing 60 wt% of blast furnace slag powder, which is not usually Portland cement, the alkaline environment that causes the reaction of the admixture is not smoothly formed do. Therefore, development of an appropriate alkali activator is required.

Registered Patent No. 1140561 entitled " Carbon Dioxide-Reducing Hydrocarbon Ultra-Ultra Exothermic Concrete Composition ", 2012. 05. 02. Registered Patent No. 1359277 entitled " High Strength Low Exothermic Concrete Composed of Excellent Initial Strength and Concrete Structure Obtained Therefrom ", 2014. 02. 07.

The present invention relates to a water reducing agent and an alkali ion activator suitable for a low-heat type high strength concrete composition which is used by mixing a blast furnace slag cement mixed with blast furnace slag fine powder of 60 wt% And it is an object of the present invention to provide a heat generating type high strength concrete composition.

In order to solve the above-described problems, the present invention provides a water reducing agent for low-heat type high strength concrete comprising 50 to 70 wt% of a retention system and 30 to 50 wt% of a water reducing system as a polycarboxylic acid system.

The present invention also provides an alkaline ion activator for low-heat type high-strength concrete comprising 30 to 50 wt% of TEA (Tri-Ethanol-Amine) and 50 to 70 wt% of PA (Polyphenol-Amine).

Further, the present invention is characterized in that the binder (B) consisting of 45 to 55 wt% of blast furnace slag fine powder, 25 to 35 wt% of ordinary Portland cement and 15 to 25 wt% of fly ash, 450 to 550 kg / Water (W) 135-175 kg / m3; Fine aggregate (S) 700 to 770 kg / m3; Coarse aggregate (G) 850 to 940 kg / m3; (W / B) of 27 to 35% and a fine aggregate ratio (S / a) of 42 to 48%, and a water reducing agent for low-heat type high-strength concrete (4.05 to 8.25 kg / And the low-heat-generating type high strength concrete water reducing agent is incorporated in an amount of 0.9 to 1.4 parts by weight based on 100 parts by weight of the binder (B).

The low heat generating type concrete composition further comprises the low heat generating high strength concrete alkali ion activator, wherein the low heat generating type high strength concrete alkali ion activator is mixed with 0.1 part by weight of 100 parts by weight of the binder (B) .

The binder (B) may be characterized by comprising 75 to 85 wt% of a blast furnace slag cement having 60 wt% of the portland cement replaced with a blast furnace slag fine powder, and 15 to 25 wt% of fly ash.

The water reducing agent for low heat generating type high strength concrete, the alkali ion activator for low heat generating type high strength concrete and the low heat generating type high strength concrete composition containing the same according to the present invention have the following effects.

1. A water reducing agent is provided for a low-heat type high-strength concrete composition in which a blend of blast furnace slag cement mixed with blast furnace slag fine powder of about 60 wt% is mixed with fly ash.

2. An alkali ion activator is provided for a low-heat type high-strength concrete composition in which a blend of blast furnace slag cement mixed with blast furnace slag fine powder of about 60 wt% is mixed with fly ash.

3. By using cement and fly ash containing blast furnace slag fine powder of about 60wt% as a binder, it is eco-friendly by reducing the amount of cement, and it has excellent low-heat-generating property and high strength- Resistance to chloride ion penetration is also provided as compared with conventional high strength concrete.

Hereinafter, a water reducing agent for a low-heat type high strength concrete, an alkali ion activator for low heat generating type high strength concrete, and a low heat generating type high strength concrete composition containing the same will be described in detail.

The water reducing agent for low-heat type high-strength concrete according to the present invention is characterized by comprising a polycarboxylic acid system comprising 50 to 70 wt% of a retention system and 30 to 50 wt% of a water-reducing system.

The alkaline ion activator for low-heat type high-strength concrete according to the present invention is characterized by being composed of 30-50 wt% of TEA (Tri-Ethanol-Amine) and 50-70 wt% of PA (Polyphenol-Amine).

The low heat generating type high strength concrete composition according to the present invention comprises 450 to 550 kg / m 3 of a binder (B) comprising 45 to 55 wt% of blast furnace slag fine powder, 25 to 35 wt% of ordinary Portland cement and 15 to 25 wt% of fly ash; Water (W) 135-175 kg / m3; Fine aggregate (S) 700 to 770 kg / m3; Coarse aggregate (G) 850 to 940 kg / m3; (W / B) of 27 to 35% and a fine aggregate ratio (S / a) of 42 to 48%, and a water reducing agent for low-heat type high-strength concrete (4.05 to 8.25 kg / The water reducing agent is incorporated in an amount of 0.9 to 1.4 parts by weight based on 100 parts by weight of the binder (B).

Further, the low heat generating type concrete composition according to the present invention may further comprise the alkali ion activator for the low-heat type high strength concrete, wherein the TEA is an alkali ion activator for low heat type high strength concrete, (B) is mixed with 0.1 part by weight to 100 parts by weight of the binder (B) so that 0.05 to 0.07 part by weight of the PA is mixed with 100 parts by weight of the binder (B) have.

The binder (B) means a mixture of blast furnace slag cement mixed with blast furnace slag fine powder of about 60 wt% and fly ash as an admixture. The present invention has developed an optimum water reducing agent and an alkali ion activator based on the assumption that 20 wt% of the binder is replaced with fly ash using a blast furnace slag cement containing 60 wt% or more of blast furnace slag fine powder as a binder, It is another object of the present invention to provide a low-heat-generating high-strength concrete composition containing the same.

(W / B) is 27% and the target compressive strength is 50 MPa when the target compressive strength is 40 MPa, and the water binding ratio (W / B) is 27 to 35% (W / B) of 31% and a water binding ratio (W / B) of 27% when the target compressive strength is 60 MPa.

In order to derive a water reducing agent suitable for a low-heat type high-strength concrete composition containing the binder (B), considering the effect of water reduction for high strength development, it also considers the maintenance effect that the workability after concrete production can be maintained at a certain level shall. For this purpose, it is necessary to use the polycarboxylic acid - based water reducing agent and to derive the optimal blending ratio of the water reducing system and the holding system. For this purpose, the performance of the polycarboxylic acid-based water reducers with the concrete formulation shown in [Table 1] was changed to 3: 7, 5: 5 and 7: 3 respectively. The results are shown in [Table 2].

[Table 1]

FA: Fly ash, G: Coarse aggregate, S: Fine aggregate, AD (W / B: water binding ratio, S / a: fine aggregate ratio, W: water, Pc: blast furnace slag cement containing 60wt% : Water reducing agent)

[Table 2]

As shown in Table 2, as the mixing ratio of the water-reducing type as the water reducing agent increases, the unit water quality reduction effect is improved, but the workability maintenance performance is weakened and the reverse tendency is observed when the mixing ratio of the holding type is increased have. In addition, when the mixing ratio of water - soluble type is high, the hydration promoting effect due to unit water reduction appears at the early stage of strength development, but in the long term, the strength enhancement due to early age hydration promotion is slightly decreased. In the case of high water level, the hydration delay effect was observed at the beginning of the ages, but the moderate increase in strength was observed in the long - term ages. In view of the above results, it can be deduced that the water reducing agent in the present invention is preferably a polycarboxylic acid-based water reducing agent consisting of 50 to 70 wt% of a retention agent and 30 to 50 wt% of a water reducing agent, 0.9 to 1.4 parts by weight based on the weight of the composition.

In the case of the low-heat type high-strength concrete composition containing the binder (B), unlike general high-strength concrete using Portland cement as a binder, the composition of the alkali environment is poor during the aging process, It is preferable that an alkaline ion activator is added for smooth progress of the pozzolanic reaction or the latent hydration reaction. In view of such a special point, in the present invention, a modified amine-based PA (Polyphenol-Amine) is additionally used in addition to the amine-based TEA (Tri-Ethanol-Amine) used as an alkaline ion activator, Respectively.

Specifically, the mortar part was selected from the concrete mixture shown in [Table 1], and the mortar test was carried out. The fine aggregate used was the standard silica as shown in the KS L ISO 679 test method. First, a primary test was conducted to evaluate the strength development according to the kind of the alkali ion activator and the method of use, and the method of using the alkaline ion activator was selected based on the results of the primary test to determine the strength development and simple hydration A secondary test was conducted to measure the exothermic characteristics.

In the first test, strength development according to the type of alkaline ion activator was first evaluated by the method shown in [Table 3] below. In Table 3, the reference formulation is a formulation employing a general high-performance AE water reducing agent. In addition to the conventional amine-based TEA (Tri-Ethanol-Amine), the modified amine type isophenol amine (IA) and polyphenol- Two types were used. The use of an alkaline ion activator is applied in a weight ratio to binder.

[Table 3]

[Graph 1] below is a graph of the results of [Table 3].

[Graph 1]

[Table 3] and [Graph 1] show that the use of an alkaline ion activator has a higher mortar strength than that of the reference formulation. Compared with the case of using alkaline ion activator, TEA is effective for accelerating the strength in the early age, and the strength increasing effect is increasing and decreasing as the usage is increased. But the strength enhancement effect in long - term age is excellent. Especially, as the amount of use increases, the effect of strengthening in long - term age is excellent. However, when the amount of PA is increased excessively in the early ages, the intensity of PA is delayed. When the amount of PA is increased excessively, the delay in the development of strength of early ages is considered to be very large. IA shows a trend similar to that of PA. As the usage increases, the strength at the early age decreases but the strength at the long term age increases. However, it was lower than that of PA. These results suggest that it is preferable to use an appropriate mixture of TEA, a conventional amine activator, and PA, a modified amine activator, rather than using any one of the alkaline ion activators alone.

Based on the results of the first test, the results of the secondary tests for selecting the method of using the alkali ion activator and measuring the strength and mortality characteristics of the mortar are shown in [Table 4] and [Graph 2] below.

[Table 4]

[Graph 2]

As shown in [Table 4] and [Graph 2], the secondary test was conducted by using a mixture of TEA having excellent initial strength development and PA having excellent long-term strength development based on the results of the first test . The results showed that the initial strength increased as the amount of TEA increased, and the longer the strength increased as the amount of PA increased. In the early age, the strength decreased when the amount of PA used increased regardless of the amount of TEA used. Therefore, it is desirable to adjust the amount of PA to be 0.05 parts by weight or less with respect to the binder (B) in order to secure an adequate compressive strength at an early age. In summary, it is preferable that the alkaline ion activator for low-heat type high-strength concrete of the present invention is composed of 30-50 wt% of TEA (Tri-Ethanol-Amine) and 50-70 wt% of PA (Polyphenol-Amine) . The alkali ion activator for low-heat type high-strength concrete according to the present invention is incorporated in an amount of 0.1 part by weight based on 100 parts by weight of the binder (B), whereby 0.03 to 0.05 part by weight of the TEA is mixed with 100 parts by weight of the binder (B) It is preferable that 0.05 to 0.07 part by weight of the PA is incorporated relative to 100 parts by weight of the binder (B).

In order to verify the performance of the concrete composition including the optimum water reducing agent and the alkaline ion activating agent for the binder (B) derived through the above process, various performance evaluations were carried out with the concrete formulation shown in Table 5 .

[Table 5]

In Table 5, general means that Portland cement (OPC) and blast furnace slag fine powder (BFS) are used as binders. SC is blast furnace slag cement (SC) mixed with 40wt% blast furnace slag cement (SC) (Pc) used as a binder, and Pc means a blast furnace slag cement (Pc) mixed with 60 wt% of blast furnace slag fine powder (BFS) and fly ash as a binder (FA) . In the following, AD means an admixture.

First, only the mortar portion of the concrete composition as shown in Table 5 was sampled to measure the hydration heat generation temperature. As a test method, a sealed container having an internal space of 100 mm × 100 mm × 100 mm was made using a heat insulator having a thickness of 50 mm as shown in [Reference 1], and mortar was put into the sealed container. As for the admixture, the conventionally used high-performance AE water reducing agent was applied to the 'general' formulation in Table 5. In the 'SC' formulation, a polycarboxylic acid system was used as the low heat generating type In a low-heat type high-strength concrete constructed by mixing 0.03 parts by weight of tri-ethanol-amine (TEA) with 100 parts by weight of binder and 0.05 part by weight of PA (polyphenol- (Hereinafter referred to as an 'improved admixture') was applied to the mixture of the alkaline ion activator and the conventional high-performance AE water reducing agent and the improved admixture were applied to the 'Pc' mixing, respectively.

[Reference Figure 1]

The results of hydration heating temperature measurement are shown in [Graph 3] below.

[Graph 3]

[Graph 3] shows that the 'regular' formulation using the existing high performance AE water repellent agent has the highest hydration heat temperature and the hydration heat temperature is lowest when the 'Pc' formulation is used with the improved admixture. Especially, when the modified admixture was used in the 'Pc' formulation, the hydration heat of the 'Pc' formulation was lower than that of the conventional high performance AE water reducing agent by about 2 ° C., The reason for this is that the water reducing agent contained in the admixture immediately induces the hydration delay immediately after the production, but the hydration is accelerated by the alkali ion activator contained in the admixture after a certain time.

Next, basic properties such as slump flow, amount of change in unit water, and compressive strength were measured for the concrete composition as shown in Table 5. As for the admixture, the conventional high-performance AE water reducing agent was applied for the 'general' formulation in Table 5, the improved admixture was applied for the 'SC' formulation, and the conventional high-performance AE water reducing agent and the improved admixture for the 'Pc' A high-performance AE water reducing agent was mixed with an admixture containing an amine-based (TEA: Tri-Ethanol-Amine) alkaline ion activating agent. The measurement results of basic physical properties are shown in Table 6 below. The variation amount of unit water to secure the same fluidity and the width of drop in slump flow with elapsed time are shown in [Graph 4] The characteristics are shown in [Graph 5]. TEA (Tri-Ethanol-Amine) is added to conventional high performance AE water reducing agent, functional (PA) is an improved admixture and amine type (TEA) is a conventional high performance AE water reducing agent in the basic types in [Table 6] and [Graph 4] Respectively. ≪ / RTI >

[Table 6]

[Graph 4]

[Graph 5]

The results shown in [Table 6], [Graph 4] and [Graph 5] show that the use of an improved admixture suitable for the 'Pc' formulation is not only superior in the water reducing effect but also in the flow properties of the concrete composition considering the workability. Was the best. Considering the characteristics of the low-heat-generating concrete used to control temperature cracking caused by the early age hydration heat, it is known that the initial hydration progress is retarded, but the hydration progresses continuously in the long- 'The use of an improved admixture was found to be able to satisfy both low heat and high strength properties. As a result, it can be confirmed that the low-heat-generating high-strength concrete composition according to the present invention has excellent properties in terms of quality control in the field construction as a low heat-generating high-strength concrete.

Finally, chloride penetration resistance of the concrete composition as shown in Table 5 was measured. Specifically, the test was conducted in accordance with the NT-Build method as shown in [Reference Fig. 2]. As a result, the chloride ion diffusion rate in each of the measured blends is shown in [Graph 6]. In the graph 6, the basic type is a conventional high performance AE water reducing agent, the functional silver is an improved admixture, and the amine type (TEA) is a conventional high performance AE water reducing agent and TEA (Tri-Ethanol-Amine).

[Reference Figure 2]

[Graph 6]

[Graph 6] shows that the chloride ion diffusion rate is the fastest when the conventional high performance AE water reducing agent is applied to the 'general' formulation, and the chloride ion diffusion rate of the 'Pc' or 'SC' , And the rate of chloride ion diffusion was slowest in the case of using an improved admixture for 'Pc' formulation. This confirms that the low-heat type high-strength concrete composition according to the present invention is a material suitable for securing durability against salting.

The low-heat type high-strength concrete composition according to the present invention has been described with specific examples. As a result, it can be confirmed that the low-inventive high-strength concrete composition according to the present invention is excellent in physical properties such as low heat generation property, strength development in terms of compressive strength, and resistance to penetration of chloride divorce during hydration.

Claims (5)

delete delete delete (B) consisting of 45 to 55 wt% of blast furnace slag powder, 25 to 35 wt% of ordinary Portland cement and 15 to 25 wt% of fly ash, 450 to 550 kg / m3;
Water (W) 135-175 kg / m3;
Fine aggregate (S) 700 to 770 kg / m3;
Coarse aggregate (G) 850 to 940 kg / m3;
A water reducing agent consisting of 50 to 70 wt% of a retention system and 30 to 50 wt% of a water reducing system as a polycarboxylic acid system; 4.05 to 8.25 kg / And
An alkaline ion activator composed of 30 to 50 wt% of TEA (Tri-Ethanol-Amine) and 50 to 70 wt% of PA (Polyphenol-Amine); And,
(W / B) of 27 to 35% and fine aggregate ratio (S / a) of 42 to 48%
The water reducing agent is incorporated in an amount of 0.9 to 1.4 parts by weight based on 100 parts by weight of the binder (B)
Wherein the alkali ion activator is incorporated in an amount of 0.1 part by weight based on 100 parts by weight of the binder (B).
5. The method of claim 4,
Wherein the binder (B) is composed of 75 to 85 wt% of a blast furnace slag cement wherein 60 wt% of the portland cement is substituted with blast furnace slag fine powder, and 15 to 25 wt% of fly ash.