KR102310892B1 - Low viscosity ultra high performance concrete composition using property stabilizer composed of glycol ether compound - Google Patents

Abstract

The present invention relates to a physical property stabilizer made of a glycol ether-based compound capable of reducing the viscosity of ultra-high-performance concrete having both high strength with a compressive strength of 150 MPa or more and high toughness with a tensile strength of 5 MPa or more, and a low-viscosity ultra-high-performance concrete composition using the same.
In the present invention, the problem of high viscosity of ultra-high-performance concrete was solved by applying a glycol ether-based compound as a physical property stabilizer. The glycol ether-based compound is adsorbed on the surface of the used binder to reduce the surface tension of the material and ultimately produce the effect of smoothing the surface, thereby reducing the viscosity of ultra-high-performance concrete.
The present invention is an ultra-high-performance concrete composition modified from an ultra-high-strength concrete composition in which the amount of unit binder is larger than that of general concrete and the water-binder ratio is low, and the 28-day compressive strength is expressed as 150 MPa or more. The water reducing agent is 1.5 to 3.5 compared to the binder Added by wt%, a physical property stabilizer composed of a glycol ether-based compound having a degree of polymerization of 100 to 200 is added in an amount of 0.1 to 1.0 wt% compared to the water reducing agent. It provides a low-viscosity ultra-high-performance concrete composition" characterized in that the above physical properties are satisfied together.

Description

Low viscosity ultra high performance concrete composition using property stabilizer composed of glycol ether compound

The present invention relates to a low-viscosity ultra-high-performance concrete composition in which a physical property stabilizer made of a glycol ether-based compound is applied to ultra-high-performance concrete having both a compressive strength of 150 MPa or higher and a tensile strength of 5 MPa or higher.

Ultra High Performance Concrete (UHPC) is a next-generation concrete characterized by ultra-high strength with a compressive strength of 150 MPa or more and high toughness with a tensile strength of 5 MPa or more. is used worldwide. Not only France, but also the United States, Japan, Germany, etc. recognize ultra-high-performance concrete as a new material for next-generation construction, and a lot of research and development is being carried out. is coming to When ultra-high-performance concrete is applied to a structure, the use of reinforcing materials such as reinforcing bars can be minimized, and the cross section can be slimmed to reduce weight, thereby increasing the designer's degree of freedom in designing the structure. Therefore, in the future, concrete structures are expected to evolve into economical structures with innovative designs using ultra-high-performance concrete.

The principle of mixing design of ultra-high performance concrete is as follows.

① Improved homogeneity by removing coarse aggregates

② Optimization of particle size distribution and improvement of dense density by steam pressure during curing

③ Improvement of Micro Structures by Heat Treatment

④ Toughness is improved by using small size steel fiber

According to this mixing design principle, ultra-high-performance concrete achieves homogeneity improvement using only fine aggregate, optimization of material particle size based on the closest packing theory, improvement of density of hydration products through high-temperature steam curing, and maximization of flexural tensile performance due to the use of a large amount of steel fiber. do.

The amount of binder used per 1m3 of this ultra-high-performance concrete is increased compared to that of general concrete. The binder is a material with the highest specific surface area among materials used in concrete. If the amount used increases, the specific surface area of the concrete increases, which increases the surface tension and thus increases the viscosity of the concrete. However, for ultra-high-performance concrete, the water-binder ratio must be low in order to express ultra-high strength of 150 MPa or more. When the viscosity of the concrete composition is high, the workability (filling property, conveying property, etc.) is lowered, which causes defects in construction and reduced durability.

1. 10-0873514 "Binder material for ultra-high strength concrete and manufacturing method of concrete using the same" 2. 10-1073393 "Steel fiber for ultra-high-performance fiber-reinforced concrete" 3. 10-1207038 "Ultra-high-performance fiber-reinforced cement composite containing fine glass powder and manufacturing method therefor" 4. 10-1209282 "Ultra-high-performance fiber-reinforced concrete and its manufacturing method" 5. 10-1230256 "Ultra-high-performance fiber-reinforced cement composite and manufacturing method thereof" 6. 10-1292173 "Ultra-high-performance fiber-reinforced concrete composition using hybrid steel fibers and manufacturing method thereof" 7. 10-1486269 "Method for manufacturing steel fiber teeth with improved adhesion strength and fiber-reinforced concrete including the same" 8. 10-1705242 "Manufacturing method of ultra-high-performance fiber-reinforced concrete with improved workability" 9. 10-1751479 "Ultra-high-performance fiber-reinforced concrete and its manufacturing method" 10. 10-1856690 "Manufacturing method of ultra-high performance concrete using UHPC premix cement mixture"

The present invention provides a physical property stabilizer for reducing the viscosity of an ultra-high-performance concrete composition, which increases the viscosity by mixing a large amount of unit binder and a small amount of unit amount for ultra-high strength expression, and an ultra-high-performance concrete composition using this property stabilizer The purpose There is this.

Therefore, in the present invention, the problem of high viscosity of ultra-high-performance concrete was solved by applying a glycol ether-based compound as a physical property stabilizer. Glycol ether-based compounds are adsorbed on the surface of the used binder to reduce the surface tension of the material and ultimately produce the effect of smoothing the surface, thereby reducing the viscosity of ultra-high performance concrete. Thus, the overall physical properties of concrete are stably secured.

The present invention is an ultra-high-performance concrete composition modified from an ultra-high-strength concrete composition that has a larger amount of unit binder compared to general concrete and a low water-binding material ratio, resulting in a 28-day compressive strength of 150 MPa or more. Added by wt%, a physical property stabilizer composed of a glycol ether-based compound having a degree of polymerization of 100 to 200 is added in an amount of 0.1 to 1.0 wt% compared to the water reducing agent. It provides a low-viscosity ultra-high-performance concrete composition" characterized in that the above physical properties are satisfied together.

In addition, the present invention is "the physical property stabilizer is added 0.1 to 0.3wt% compared to the water reducing agent, the viscosity in an unconsolidated state is 60,000 cps or less, slump flow 240 to 245 mm, compressive strength at 28 days of age of 190 MPa or more, and flexural strength at 28 days of age of 50 MPa or more It provides a low-viscosity ultra-high-performance concrete composition that satisfies the physical properties together.

The glycol ether-based compound is at least one of propylene glycol monomethyl ether acetate, polyethylene bisphenol-A ether, and polyethylene glycol trimethylnonyl ether. composition can be applied.

By using a physical property stabilizer made of a glycol ether-based compound that has not been used as a concrete additive before, it reduces the viscosity of ultra-high-strength concrete that exhibits a compressive strength of 150 MPa or more at 28 days to improve workability and is added to improve toughness. It is possible to prevent the 'Fiber Ball' phenomenon in which the steel fibers are not dispersed efficiently and agglomerated with each other.

The present invention is an ultra-high-performance concrete composition modified from an ultra-high-strength concrete composition that has a larger amount of unit binder compared to general concrete and a low water-binding material ratio, resulting in a 28-day compressive strength of 150 MPa or more. Added by wt%, a physical property stabilizer composed of a glycol ether-based compound having a degree of polymerization of 100 to 200 is added in an amount of 0.1 to 1.0 wt% compared to the water reducing agent. It provides a low-viscosity ultra-high-performance concrete composition" characterized in that the above physical properties are satisfied together.

The glycol ether-based compound is a sticky and sweet colorless liquid, absorbs moisture well, and when oxidized, becomes glycolic acid, glyoxal, oxalic acid, and the like. It is produced by synthesizing ethylene chlorohydrin by reacting dilute chlorine water with ethylene, and hydrolyzing it by heating it in an autoclave with an aqueous sodium carbonate solution. It is mainly used as a synthetic raw material for tetron, but is also used as a raw material for manufacturing alkyd resins, cold-resistant cooling liquids, pharmaceuticals and cosmetics.

The glycol ether-based compound applied as a physical property stabilizer in the present invention is propylene glycol monomethyl ether acetate, polyethylene bisphenol-A ether, and polyethylene glycol trimethylnonyl ether. ether) may be one or more materials selected from the group consisting of. The three compounds listed above have excellent viscosity reduction and dispersion effects by reducing the surface tension of the materials. have.

The principle of reducing the viscosity of the concrete composition by adsorbing the physical property stabilizer to the cement to modify the cement surface and reducing the interfacial tension is schematically shown in [Reference Fig. 1] below.

[Reference 1]

In the present invention, as the glycol ether-based compound, a polymerization degree of 100 to 200 is used. When the degree of polymerization of the glycol ether-based compound is less than 100, there is no effect of improving the workability of concrete using crushed sand as a physical property stabilizer. .

When adding 0.1~1.0wt% of the above physical property stabilizer compared to the water reducing agent, a low-viscosity ultra-high-performance concrete composition that satisfies the physical properties of a viscosity of 60,000 cps or less in an unconsolidated state and a compressive strength of 150 MPa or more at 28 days of age is derived. The water-reducing agent is an admixture applied to improve fluidity under a low water-binder ratio, and is added in an amount of 1.5 to 3.5 wt% compared to the binder. The water reducing agent may be selected and applied from one of the general product groups classified as 'high performance water reducing agents'. The following test data are derived by applying a polycarbonic acid-based water reducing agent, but do not exclude a lignin-based water reducing agent in the present invention.

That is, when 0.1 to 1.0 wt % of the physical property stabilizer is added compared to the water reducing agent under the general mixing conditions of the ultra-high performance concrete composition, the effect of reducing the viscosity appears. However, when the addition amount of the physical property stabilizer is as above, a loss section occurs in terms of compressive strength and flexural strength of the ultra-high performance concrete composition.

Accordingly, as the physical property stabilizer is limited to being added in the range of 0.1 to 0.3wt% compared to the water reducing agent, the viscosity in a non-solidified state is 60,000cps or less, the slump flow is 240 to 245mm with rheological properties in the range of 28 days, and the compressive strength is 190MPa. Above, it is possible to show physical properties of over 50 MPa in flexural strength at 28 days of age.

On the other hand, the ultra-high performance concrete composition may generate entrapped air as the viscosity increases due to the low water-binding material ratio, and an antifoaming agent is added in 0.5 to 1.0 wt% compared to the water reducing agent to remove the trapped air inside the ultra high performance concrete composition. , preferably 0.5 to 0.7 wt% may be added. The antifoaming agent may be one or more selected from alcohol-based, mineral-based, polyether-based, silicone-based, and emulsion-based.

Hereinafter, the present invention will be described in detail with specific test examples.

[Table 1] below shows the formulation of the ultra-high-performance concrete composition example. The amount of binder (total amount of cement, silica fume and silica fine powder) was specified as 1,200 kg/m3.

[Table 1]

C : Class 3 crude steel cement or Class 1 cement S/F : Silica fume

SP: fine silica powder CSA: expansion material

S: fine aggregate

The formulation shown in [Table 1] above can be said to be an example of the formulation used for general ultra-high performance concrete. The water-binder ratio was set to 20 wt%, and 2% of the total volume of the steel fiber was added. The water reducing agent (polycarboxylic acid-based) was added at 3.0 wt % compared to the binder, and the physical property stabilizer was added at 0, 0.1, 0.3, 0.5, 0.7, 1.0 wt %, respectively, compared to the water reducing agent, and each physical property was tested. Polyethylene glycol trimethylnonyl ether was applied as the physical property stabilizer.

L ISO 679 "Cement strength test method" was applied as the test method. The materials were mixed using a mortar mixer, and the mixing method was 2 minutes of dry bibim after the powder material was added, water and water reducing agent were added, and then mixing was performed for a total of 4 minutes at low speed for 2 minutes and at high speed for 2 minutes. After mixing at a low speed for an additional 1 minute, the viscosity was measured. Viscosity measurement was performed using Brookfield's 'DV-Ⅲ ULTRA' equipment.

A test specimen for measuring compressive strength and flexural strength was fabricated in a size of 40 × 40 × 160 mm, cured at 20 ± 2 °C for 48 hours, and then steam cured at 90 °C for 48 hours. Compressive strength and flexural strength were measured based on the age of 28 days after curing.

[Table 2]

[Table 2] above shows comparative examples corresponding to conventional ultra-high performance concrete and examples of the present invention. First, looking at Example 1 and Comparative Example 1, it can be seen that in the case of Example 1, overall physical properties were improved. Viscosity was improved by about 15.8%, and _{both flow and T 20} were improved. In the case of Example 2, compared to Comparative Example 1, the viscosity was improved by 19.7%, respectively, and the flow and T ₂₀ were also improved. The compressive strength of Examples 1 and 2 was found to be expressed at an equivalent or higher level compared to Comparative Example 1.

In the case of Comparative Example 1, the viscosity was measured as high as 70,000 cps or more, indicating that the dispersion of the steel fibers was not efficient and a 'Fiber Ball' phenomenon occurred (see [Reference Photo 1] below).

[Reference photo 1]

However, in Examples 1 to 5 in which the physical property stabilizer was added, the viscosity was 60,000 cps or less, and the 'Fiber Ball' phenomenon did not appear and all were evenly dispersed (see [Reference Photo 2] below). Therefore, it is judged that it is necessary to manage the viscosity of ultra-high-performance concrete below 60,000cps to consider the dispersion of steel fibers.

[Reference photo 2]

In Examples 3, 4, and 5, compared with Comparative Example 1, the viscosity and non-hardening properties were improved, but the compressive strength and the flexural strength were decreased. Therefore, it can be seen that the optimum amount of the physical property stabilizer for overall improvement of the physical properties of ultra-high performance concrete is 0.1 to 0.3 wt% compared to the water reducing agent.

Although the present invention has been described in relation to the preferred embodiment as mentioned above, various modifications and variations are possible without departing from the gist of the present invention, and can be used in various fields. Accordingly, the claims of the present invention include modifications and variations that fall within the true scope of the preceding invention.

Claims (3)

delete As an ultra-high-performance concrete composition modified from an ultra-high-strength concrete composition that has a larger amount of unit binder compared to general concrete and a lower water-binding material ratio, which exhibits a compressive strength of over 150 MPa at 28 days of age,
1.5 to 3.5 wt% of the water reducing agent is added compared to the binder,
A physical property stabilizer composed of a glycol ether-based compound having a degree of polymerization of 100 to 200 is added in an amount of 0.1 to 0.3 wt% compared to the water reducing agent,
Low-viscosity ultra-high-performance concrete composition, characterized in that the physical properties of 60,000 cps or less in unconsolidated state, slump flow 240-245 mm, compressive strength at 28 days of age of 190 MPa or more, and flexural strength of at least 50 MPa at 28 days of age are satisfied.
In claim 2,
The glycol ether-based compound is at least one of propylene glycol monomethyl ether acetate, polyethylene bisphenol-A ether, and polyethylene glycol trimethylnonyl ether. Low-viscosity ultra-high-performance concrete composition, characterized in that the composition.