KR101176823B1 - Latex modified concrete composition used polyfiber and polymer powder - Google Patents

Abstract

PURPOSE: A latex modified concrete using powdered resin and poly fiber is provided to enhance strength, crack resistance, and bonding strength of concrete by using powdered resin, poly fiber and liquid latex at the same time. CONSTITUTION: A latex modified concrete comprises 15-20 wt% of cement based binding material, 40-45 wt% of fine aggregate, 30-35 weight% of coarse aggregate, 5-10 weight% of water, and 1-3 weight of liquid latex. The cement based binding material is composed of 60-96 weight% of normal Portland cement, 1-10 weight% of expansion material, 1-20 weight% of slag powder, 0.1-5 weight% of powdered resin, 0.01-2.0 weight% of poly fiber, and 1-3 weight% of water reducing agent. The powdered resin includes one of vinyl acetate, methyl methacrylate-butyl acrylate and styrene butyl acrylate. The poly fiber is polyvinyl alcohol.

Description

Latex modified concrete composition used polyfiber and polymer powder

The present invention relates to a concrete composition, and more particularly, to a latex modified concrete composition for cross-packaging using concrete powder resin and polyfiber (polymerized fiber).

In general, normal concrete (Normal Concrete) has been used to manufacture various concrete structures. In the case of the ordinary concrete, there is an advantage that the workability is good, while the water permeability has a problem that the concrete is deteriorated due to the penetration of chloride or water.

In order to solve the above problems, latex modified concrete (Latex Modified Concrete) has been developed and used to form a watertight structure by adding SBR (Styrene-Butadiene Rubber) latex to general concrete in the early 2000s.

However, in the case of latex modified concrete, latex film is formed on the concrete surface when the latex film is cracked due to the difference between the condensation of organic material latex and the cement material which is inorganic material, and the amount of latex is excessive. Due to the latex material cost of the construction cost was inevitable.

In addition, high performance concrete (HPC: High Performance Concrete) has been introduced in 2006 by adding a large amount of mineral admixture and poly-based fiber to the binder to make the concrete watertight, thereby reducing salt penetration rate, freezing thawing and peeling resistance. Expected to extend the service life of the bridge by using the above concrete, but high material cost due to deterioration of adhesion performance with bridge slab concrete, excessive resistance of cracks due to excessive use of inorganic mixed materials, and the use of expensive silica fume not produced in Korea. It is emerging.

Recently, in order to improve construction performance, quality deviation, and construction cost reduction, the development of concrete composition with powder resin and fiber in binder is being studied, but it is true that there is a problem in that adhesion performance and salt penetration resistance are not exhibited.

Application No. 10-2006-0022695 (name of the invention: surface packaging method with excellent waterproof performance and fatigue resistance; published September 19, 2006)

The present invention has been made to solve the problems of the prior art as described above, the object of the invention is to improve the strength, crack resistance performance, adhesion strength of concrete by using a powder resin, polyfiber (polyfiber) and liquid latex at the same time It is to provide a concrete composition that can reduce the production cost and quality deviation of concrete by reducing the effect and the use of expensive latex.

The present invention is a powder resin and polyfiber comprising 15 to 20 wt% cement-based binder, 40 to 45 wt% of fine aggregate, 30 to 35 wt% of coarse aggregate, 5 to 10 wt% of water, and 1 to 3 wt% of liquid latex. To provide a latex modified concrete composition using.

Hereinafter, the present invention will be described in detail.

The cement-based binder is usually 60 to 96% by weight of Portland cement, 1 to 10% by weight of expansion material, 1 to 20% by weight of slag powder, 0.1 to 5% by weight of powder resin, 0.01 to 2.0% by weight of polyfiber and water reducing agent 1 to It is preferable that it consists of 3 weight%.

When the ordinary portland cement is less than 60% by weight, concrete strength expression, adhesion, and durability are lowered due to the lack of a binder, and coarse concrete is produced, resulting in a problem in that the surface finish is lowered. Since the specific surface area of the binder is increased, a large amount of unit is required, and there is a problem of lowering workability and crack resistance, and it is preferably 60 to 96% by weight based on 100% by weight of the cement-based binder.

The expansion material uses a gypsum-based expansion material, if less than 1% by weight there is a risk of cracking caused by the shrinkage of the concrete, if more than 10% by weight may occur due to expansion cracking, there is a problem of lowering the strength of the cement-based It is preferable that it is 1-10 weight% with respect to 100 weight% of binders.

The slag powder uses a blast furnace slag powder having a latent hydrophobicity, there is a problem that the performance of the fine blast furnace slag powder is less than 1% by weight, the initial strength is not expressed in the case of more than 20% by weight There is a problem that can not be 1 to 20% by weight based on 100% by weight cement-based binder.

The powder resin is preferably vinyl acetate (Vinyl acetate), methyl methacrylate (methyl methacrylate) (butyl acrylate), styrene butyl acrylate (styrene butyl acrylate). More preferably, vinyl acetate type is preferable.

The powdered resin is a polymer solid material having excellent elasticity, high aging stability and weather resistance, and high viscosity, and has high adhesive strength. 35 to 40% by weight of vinyl acetate monomer (VAM) based on 100% by weight of liquid resin, polyvinyl alcohol (PVA: Polyvinyl alcohol) 0.5 ~ 2 wt%, 2-phenoxyethanol (2-Phenoxyethanol; Ethylene Glycol Monophenyl Ether) 1 ~ 5 wt% It is preferable to use what was made.

When the powdered resin is less than 0.1% by weight, there is a problem that the adhesion strength and chlorine ion permeation resistance performance is lowered, and when the powdered resin is more than 5% by weight, the strength expression is lowered 0.1 to 5 with respect to 100% by weight of the cement binder It is preferable that it is weight%.

This has got the acid resistance, alkali resistance, dispersibility is excellent and due to the rough surface of the fiber cement and the adhesion ^{performance, wherein} the poly-fiber (Polyfiber) is polyvinyl alcohol (Polyvinyl alcohol) The hydroxy group in the fiber itself (OH) for use It is excellent and has high tensile strength, excellent modulus of elasticity, low elongation and high weatherability of fiber car. In addition, due to the large number of fibers per unit volume, it is possible to improve the mechanical properties of concrete such as increasing the tensile strength, flexural toughness and crack resistance of cement composites, and increasing the resistance to impact and breakage and repeated fatigue loads through fiber crosslinking. Very effective.

When the polyfiber is less than 0.01% by weight, bending strength, tensile strength, and crack resistance are deteriorated, and in the case of more than 2.0% by weight, the strength of the fiber and agglomeration of concrete when mixing concrete cement-based binder It is preferable that it is 0.01 to 2.0 weight% with respect to 100 weight%.

The water reducing agent is preferably used to select any one of the naphthalene-based, melamine-based or polycarboxylic acid-based reducing agent, when less than 1% by weight is lowered in workability due to slump lowering, when more than 3% by weight Since there is a problem of strength deterioration due to material separation, it is preferable that the content is 1-3 wt% based on 100 wt% of the cement-based binder.

The cement-based binder is preferably used in 15 to 20% by weight based on the total concrete composition of the present invention. If it is less than 15% by weight, the strength and adhesion deterioration, chloride penetration resistance, freeze-thawing resistance, etc. are lowered, and when it exceeds 20% by weight, workability and cracking resistance are lowered.

The fine aggregate is preferably used in 40 to 45% by weight relative to the total composition of the concrete of the present invention. If less than 40% by weight, a problem occurs that the strength performance and surface finish of the concrete is lowered, in the case of more than 45% by weight material separation and strength performance is reduced.

The coarse aggregate is preferably used in 30 to 35% by weight relative to the total composition of the concrete of the present invention. If less than 30% by weight, the strength performance and workability is lowered, there is a problem that the unit quantity is increased, and when more than 35% by weight, the rough concrete is produced to cause a problem that the surface finish is lowered.

When the water is less than 5% by weight, workability and finishing performance is lowered, and when the water content is greater than 10% by weight, there is a problem that the risk of material separation and bleeding and the strength performance is lowered. It is preferable to use it at -10 weight%.

The liquid latex is 45 to 50% by weight of the latex solids 55 to 50% by weight of water, latex solids are styrene (Styrene) 60 to 70% by weight, butadiene (Butadiene) consisting of 30 to 40% by weight of SB (Styrene-Butadiene) Preference is given to using latex.

The liquid latex is preferably used in 1 to 3% by weight with respect to the total composition of the present invention, less than 1% by weight of the waterproof performance and adhesion is reduced, in the case of more than 3% by weight of concrete finishing performance deterioration And material separation risks.

By providing a concrete composition in which powder resin, polyfiber, and liquid latex are mixed according to the present invention, the concrete is prevented from being deteriorated by preventing the penetration of chloride or water, as well as the effect of inhibiting cracking due to freeze-thawing resistance and shrinkage reduction. It has the effect of improving long-term strength and adhesion strength.

In addition, by significantly reducing the use of expensive latex, it is possible to reduce the effect of cost reduction and the quality deviation of concrete.

1 is a photograph of a polyvinyl alcohol fiber.
FIG. 2 is a photograph of a binder in which powder resin and polyfiber are mixed.
Figure 3 is a graph showing the results of measuring the length change rate for each compounding case.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are not intended to limit the scope of the present invention, and ordinary changes by those skilled in the art are possible within the scope of the technical idea of the present invention.

≪ Example 1 >

Strength Measurement of Concrete Using Vinyl Acetate Powder Resin

The properties of the vinyl acetate powder resin of the present invention are shown in Table 1 below.

The vinyl acetate powder resin (VA resin), the methyl methacrylate acrylate powder resin (MMA resin), and the styrene butyl acrylate powder resin (ST resin) of the present invention were each used in an amount of 2.5% by weight based on 100% by weight cement. Other components were prepared in the concrete as shown in Table 2 below to measure the 28-day compressive strength, flexural strength, adhesion strength, slump of concrete as follows.

General concrete without the resin was prepared as a control.

The results are shown in Table 2 below.

Slump measurement

According to KS F 2402 "Test method of concrete slump", slump cone with 20cm inside diameter, 10cm inside diameter, 30cm height and 1.5mm thickness is filled with 25 rods of concrete 1/3 times, and the slump cone is vertically After lifting, the difference from the specimen height in the center of the concrete was measured in 5 mm units.

Compressive strength measurement

Place the specimen in accordance with KS F 2405 `` Concrete Compressive Strength Test Method '' so that the central axis of the specimen coincides with the center of the platen, and then press the test plate directly to the end face of the specimen and load it at a constant speed so as not to impact the specimen. The compressive strength was measured.

Flexural strength measurement

In accordance with KS F 2408, Test Method of Flexural Strength of Concrete, when the specimen is filled with concrete, the upper and lower sides of the specimen are placed in the center of the bearing butterfly with the upper and lower sides of the specimen, and the upper presser is brought into contact with the third point. The flexural strength was measured by breaking between the three points of the direction center line.

Bond strength measurement

In accordance with KS F 2386 "Test Method for Tensile Adhesion of Road Pavement Attachment Surface", the test specimen shall be placed on the base plate of 300mm × 300mm × 100mm in 50mm thickness. After 28 days of age, the specimen was penetrated with a Φ 100 mm core taker to cut a portion of the base plate, and a tensile adhesive plate was installed on the specimen. The tensile adhesive plate installed was mounted on a tensile tester, and the test piece was drawn and tested while applying hydraulic pressure at a speed of 0.1 MPa / s.

As can be seen in Table 2 below, it was found that the use of vinyl acetate powder resin improved the flexural strength and the adhesion strength than other methyl methacrylate acrylate powder resins and styrene butyl acrylate powder resins.

shape Average particle size pH importance White powder 74 μm 9.1 480 g / ℓ

<Example 2>

Measurement of crack resistance performance of concrete using polyvinyl alcohol fiber

Roughness of the surface of the polyvinyl alcohol fiber of the present invention is shown in Figure 1, the performance is shown in Table 3 below.

Using vinyl acetate fiber (VA fiber), cellulose fiber, polypropylene fiber (PP fiber) of the present invention 1% by weight relative to 100% by weight of cement as a binder, and other components as shown in Table 4 to produce concrete The 28-day compressive strength, flexural strength, bond strength, slump and crack width of concrete were measured as follows.

General concrete without the fiber was prepared as a control.

The results are shown in Table 4 below.

Slump measurement

According to KS F 2402 "Test method of concrete slump", slump cone with 20cm inside diameter, 10cm inside diameter, 30cm height and 1.5mm thickness is filled with 25 rods of concrete 1/3 times, and the slump cone is vertically After lifting, the difference from the specimen height in the center of the concrete was measured in 5 mm units.

Compressive strength measurement

Place the specimen in accordance with KS F 2405 `` Concrete Compressive Strength Test Method '' so that the central axis of the specimen coincides with the center of the platen, and then press the test plate directly to the end face of the specimen and load it at a constant speed so as not to impact the specimen. The compressive strength was measured.

Flexural strength measurement

In accordance with KS F 2408, Test Method of Flexural Strength of Concrete, when the specimen is filled with concrete, the upper and lower sides of the specimen are placed in the center of the bearing butterfly with the upper and lower sides of the specimen, and the upper presser is brought into contact with the third point. The flexural strength was measured by breaking between the three points of the direction center line.

Crack width measurement

According to ASTM C 1581 "Method of Evaluation of Crack Initiation Resistance of Concrete", a standard steel ring has an inner diameter of 12.7 mm ± 0.4 mm, an outer diameter of 305 mm, and a height of 152 mm. After the concrete test specimen was placed between the inner and outer rings and cured, the outer steel was demolded. The specimens were kept constant at a temperature of 21 ° C. ± 1.7 ° C. and a relative humidity of 50 ± 4%, and were examined for crack incidence due to dry aging for 56 days.

As can be seen in Table 4 below, it was found that the concrete using polyvinyl alcohol fibers showed the smallest crack width.

division Polyvinyl Alcohol (PVA) Fiber Fiber length (mm) 6-9 Diameter (μm) 16 importance 1.25 Tensile Strength (MPa) 800-1,500 Modulus of elasticity (MPa) 1.1 ~ 3.7 × 10 ⁴

<Example 3>

To prepare a latex modified concrete composition using a cement-based binder containing 2.5% by weight of the powder resin and 1% by weight of the polymer fiber in the composition as shown in Table 5.

&Lt; Comparative Example 1 &

Existing latex modified concrete was prepared in the composition shown in Table 5 below.

Comparative Example 2

To prepare a concrete using a cement-based binder containing 2.5% by weight of the powder resin and 1% by weight of the polymer fiber in the composition as shown in Table 5.

&Lt; Test Example 1 >

For Example 3 and Comparative Examples 1 and 2, the slump, air volume, compressive strength, flexural strength, and adhesive strength were measured according to the following test methods.

The results are shown in Table 6 below.

Slump measurement

According to KS F 2402 "Test method of concrete slump", slump cone with 20cm inside diameter, 10cm inside diameter, 30cm height and 1.5mm thickness is filled with 25 rods of concrete 1/3 times, and the slump cone is vertically After lifting, the difference from the specimen height in the center of the concrete was measured in 5 mm units.

Air volume measurement

According to SF 2421 `` Testing method of air volume of concrete not hardened by pressure method '', compact the concrete 25 times every 1/3 times and tap the sides of the container 10 times with a wooden hammer. After tightening all the valves, all the valves were closed, and the air pressure was increased by the air hand pump to increase the pressure in the air chamber above the initial pressure.

Compressive strength measurement

Place the specimen in accordance with KS F 2405 `` Concrete Compressive Strength Test Method '' so that the central axis of the specimen coincides with the center of the platen, and then press the test plate directly to the end face of the specimen and load it at a constant speed so as not to impact the specimen. The compressive strength was measured.

Flexural strength measurement

In accordance with KS F 2408, Test Method of Flexural Strength of Concrete, when the specimen is filled with concrete, the upper and lower sides of the specimen are placed in the center of the bearing butterfly with the upper and lower sides of the specimen, and the upper presser is brought into contact with the third point. The flexural strength was measured by breaking between the three points of the direction center line.

Bond strength measurement

In accordance with KS F 2386 "Test Method for Tensile Adhesion of Road Pavement Attachment Surface", a test piece was cast to a thickness of 50 mm on a base plate of 300 mm x 300 mm x 100 mm. After 28 days of age, the specimen was penetrated with a Φ 100 mm core taker to cut a portion of the base plate, and a tensile adhesive plate was installed on the specimen. The tensile adhesive plate installed was mounted on a tensile tester, and the test piece was drawn and tested while applying hydraulic pressure at a speed of 0.1 MPa / s.

As can be seen in Table 6 below, the concrete using the composition of the present invention of Example 3 is higher compression in the same formulation than the concrete using the conventional latex modified concrete of Comparative Example 1, powdered resin of Comparative Example 2 and fibers It can be seen that the strength, the bending strength and the bond strength are shown.

&Lt; Test Example 2 &

The length change rate of the concrete with time for Example 3 and Comparative Examples 1 and 2 was maintained according to KS F 2424 "Testing method for changing the length of mortar and concrete" after the specimen was manufactured to maintain the ambient temperature at 20 ° C and 60% humidity. After measuring the change in the length of the specimen using LVDT having a sensitivity of 0.001mm under the condition of maintaining temperature and humidity, the rate of change of length was calculated by the following formula.

The results are shown in Table 7 and FIG. 3.

As can be seen in Table 7 and FIG. 3 below, the degree of concrete dry shrinkage with time of the concrete of the present invention of Example 3 was found to be lower than that of Comparative Examples 1 and 2. FIG.

From this fact, it can be seen that the reduction of the dry shrinkage of Example 3 has an excellent effect of suppressing the occurrence of concrete cracking.

<Test Example 3>

In Example 3 and Comparative Examples 1 and 2, the chlorine ion permeation resistance performance of the concrete by the electrical conductivity specified in KS F2711 was measured.

The results are shown in Table 7 below.

As can be seen in Table 7 below, the permeation resistance of chlorine ions is very high when the passing charge is 4000 or more, and the permeation resistance is poor. The permeability of chlorine ions is low level, 100 to 1000, the permeability of chlorine ions is very low, and the chlorine ion permeation level is less than 100, the concrete composition of the present invention of Example 3 powder Since resin, fiber, and latex are used at the same time, chlorine ion permeation is equivalent to the conventional latex modified concrete of Comparative Example 1, and the waterproof performance was higher than that of the concrete using the powder resin of Comparative Example 2.

Claims (5)

delete In the latex modified concrete composition comprising 15 to 20% by weight of cement-based binder, 40 to 45% by weight of fine aggregate, 30 to 35% by weight of coarse aggregate, 5 to 10% by weight of water and 1 to 3% by weight of liquid latex.
The cement-based binder is usually 60 to 96% by weight of the Portland cement, 1 to 10% by weight of the expansion material, 1 to 20% by weight of the slag powder, 0.1 to 5% by weight of the powder resin, polyfiber 0.01 ~ Latex modified concrete composition using a powdered resin and polyfiber, characterized in that composed of 2.0% by weight and 1 to 3% by weight of a reducing agent.
The method of claim 2,
The powdered resin is a vinyl resin (Vinyl acetate), methyl methacrylate (methyl methacrylate-butyl acrylate), styrene butyl acrylate (styrene butyl acrylate) comprising a powdered resin and polyfiber Used latex modified concrete composition.
The method of claim 2,
The polyfiber is a polyvinyl alcohol (Polyvinyl alcohol), characterized in that the latex modified concrete composition using a powder resin and polyfiber.
The method of claim 2,
The powdered resin is 35 to 40% by weight of vinyl acetate monomer, 0.5 to 2% by weight of polyvinyl alcohol, and 2-phenoxyethanol to 1 to 100% by weight of liquid resin. A latex modified concrete composition using a powdered resin and polyfiber, characterized in that the solid content of the liquid resin prepared by mixing 5% by weight and 55 to 60% by weight of water.

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