KR20040106167A - Concrete composition for pavement of bridge surface and bridge pavement method using the same - Google Patents

Abstract

PURPOSE: A concrete composition for surfacing of bridge decks is provided, which has excellent watertightness, crack-resistance, easy application and construction cost savings by using concrete materials, silica fume, and optionally fly ash and PVA fiber. CONSTITUTION: The concrete composition of surfacing of bridge decks comprises 100pts.wt. of cement, 200-240pts.wt. of sand, 200-250pts.wt. of gravel, 5-15pts.wt. of silica fume for increase of watertightness. Also, auxiliary materials such as 20-30pts.wt. of fly ash for increase of strength and durability, 30-80pts.wt. of blast furnace slag, 0.05-2vol.%(based on the total composition) of PVA fiber for crack resistance, and admixture such as high performance water reducing agent for fluidity of concrete are optionally added to the concrete composition. The bridge decks are paved by cleaning the surface of bridge decks (S1), saturating the surface with water (S2), pouring ready mixed concrete comprising prepared composition to the surface (S3), smoothing the surface of concrete (S4), texturing (S5), applying a curing compound to the concrete surface (S6), covering a polyethylene film over the coated surface (S7), and curing (S8).

Description

Concrete composition for bridge paving and bridge paving method using same {CONCRETE COMPOSITION FOR PAVEMENT OF BRIDGE SURFACE AND BRIDGE PAVEMENT METHOD USING THE SAME}

The present invention relates to a bridge construction concrete composition and bridge construction method using the same for paving the surface of the bridge structure, more specifically, watertightness, chlorine ion permeability, crack resistance, etc. The present invention relates to a bridge construction concrete composition and bridge construction method using the same, while satisfying all the properties and at the same time excellent in economics and workability.

In general, a bridge is a generic term for expensive structures that are installed to pass through the upper part of rivers, coasts, roads, etc.The surface of these bridges is paved by paving to allow vehicles to pass smoothly. To form.

Such cross-section pavement is a part that directly transmits a traffic load, and should have a suitable strength and crack resistance, as well as being exposed to moisture, such as rainwater, and is required to have a waterproof performance, particularly in the penetration of chloride ions. It is required to have a low chlorine ion permeability in order to prevent the reinforcing bar by corrosion.

As such a pavement paving method, a conventional concrete paving method or ascon paving method has been known and widely used. Among them, the general concrete paving method is a method of finishing general concrete by wrapping it on the upper part of the bridge road surface. The material cost is low and economical, and it is possible to pour simultaneously with the bottom plate of the bridge. Cracking of concrete easily occurs due to vibrations along the passage, and high permeability has a problem that corrosion of reinforcing steel can easily occur due to penetration of harmful chemicals including chloride from the top.

On the other hand, ascon paving method is a method of forming a paving layer by laying asphalt asphalt (ASCON) mixed with asphalt and concrete on the bridge, this method has a good workability, low initial investment cost, excellent flatness, driving feeling On the other hand, it is necessary to repack periodically to prevent the inability to run due to plastic deformation and surface deterioration, which may cause traffic problems with excessive maintenance costs. Since it is installed on the upper surface of the existing concrete placed on the floor, there was a problem that separation of the pavement layer may occur due to the combination of different heterogeneous materials.

In addition, the concrete and asphalt concrete materials used in the conventional pavement methods as described above do not basically have a waterproofing ability, so the corrosion of the reinforcing bars due to chloride ions penetrated with rainwater, etc. may cause radical aging of the bridge deck. To avoid this, there was a disadvantage in that an additional waterproof layer should be installed between the paving layer and the floor concrete.

As a countermeasure for solving the problems of the prior arts, a method of paving a bridge using latex modified concrete in which synthetic rubber latex resin is added to conventional concrete has been developed and used. As the technology, the impervious bridge surface pavement modified concrete registered as Korean Patent Registration No. 10-013599 is representative.

According to the above patent, it is possible to prevent the penetration of chloride or moisture to prevent corrosion of the reinforcing steel in the concrete, and the cost of maintenance can be reduced, while this method has a low water-cement ratio (W). / C) is sensitive to plastic shrinkage cracking during initial curing according to the temperature during construction, and has a problem that may cause a decrease in strength due to the excessive amount of air due to the surfactant contained in the latex. In addition, the above method has a problem in economical efficiency by using expensive latex resin, and construction cost increases due to the use of a special equipment such as a mobile mixer, and the use of existing concrete pavement construction equipment during site construction. There was a problem.

Therefore, there is an urgent need for the development of a special concrete for bridge pavement with optimal performance that can replace the prior art while satisfying all the required characteristics in the use of bridge surface pavement. In consideration of all the problems with the technologies, the present invention has been completed as a result of an effort for research and development.

The present invention has been made to solve the problems of the prior art as described above, while the present invention satisfies all the characteristics required in particular in concrete used for the purpose of paving the surface of the bridge, at the same time economical and easy to construct The present invention provides a bridge paving concrete and a bridge paving method using the same.

That is, the present invention has a high water-tightness, does not easily pass moisture such as rain, and has low moisture permeability to chloride ions, so that there is no fear of shortening the lifespan due to corrosion of reinforcing bars, and high resistance against cracking caused by vibration caused by continuous vehicle passage. Its technical purpose is to provide special concrete for cross-linking paving and cross-linking paving method using the same, which has resistance and can be used for paving and renovation of bridge.

1 is a view showing a plastic shrinkage crack test apparatus used in Test Example 5.

2A and 2B are photographs showing the results tested by Test Example 5. FIG.

Figure 3 is a flow chart illustrating a process of the cross-section packaging method according to the present invention.

In order to achieve the above object, the present invention, in the special concrete composition for bridge pavement used for paving the surface of the bridge structure, in addition to silica, in addition to cement, sand, gravel which is a material constituting the concrete further comprises a silica fume It provides a cross-linked concrete composition for paving.

At this time, the cross-linked pavement concrete composition may be configured by incorporating silica fume alone, but in addition, may be formed by adding a fly ash or blast furnace slag.

In addition, it is preferable that the concrete composition for cross-section pavement according to the present invention further comprises a hydrophilic PVA fiber.

Furthermore, the present invention provides the most preferred compositional ratios for the composition of the cross-linked paving concrete with the above components, which is 200 to 240 parts by weight of sand, 200 to 250 parts by weight of gravel and 100 parts by weight of cement; Silica fume is characterized in that it is composed of 5 to 15 parts by weight.

At this time, the cross-linking concrete composition of the present invention may further comprise fly ash in a ratio of 20 to 30 parts by weight based on 100 parts by weight of cement or blast furnace slag in a ratio of 30 to 80 parts by weight with respect to 100 parts by weight of cement. It may be. In addition, the cross-linked concrete composition of the present invention is preferably further comprises a hydrophilic PVA fiber, wherein the PVA fiber is preferably contained in 0.05 to 2 v / v% relative to the total composition volume.

Hereinafter, the concrete composition for cross-linking pavement according to the present invention will be described in more detail together with the effects of the respective composition materials and the composition materials exerted in the entire composition.

First, the cross-linked pavement concrete composition according to the present invention is basically composed of cement, sand and gravel to be used by adding water as in a conventional concrete composition, characterized in that configured by adding silica fume to it.

The silica fume is an industrial by-product from an electric arc furnace used in the manufacture of silicon metal or silicon alloys. This silica fume contains more than 80% of amorphous silica, which is mainly composed of very fine and spherical particles (average particle diameter: 0.1 mu m). In addition, the chemical composition of the silica fume is 90% or more composed of amorphous SiO ₂ due to the large amount of silica, which causes a very effective pozzolanic reaction, which has a positive effect on the long-term strength increase of concrete.

In particular, the specific surface area of this silica fume is about 150,000 to 250,000 cm 2 / g, which is about twice the amount of cigarette smoke and about 50 times that of Portland cement. Thus, since the silica fume particles are filled between the cement paste and the aggregate because the particles are much finer than the cement particles, the waterproof effect is improved by the filling effect. It possesses water tightness and permeation resistance of chloride ions, which are important for paving concrete.

At this time, the content of the silica fume is preferably to be included in 5 to 15 parts by weight with respect to 100 parts by weight of cement, the reason for this is less than 5 chlorine ion permeability or waterproof than ordinary concrete without silica fume There is no significant difference in the effect, and if it exceeds 15, it does not show a significant improvement in performance compared to the content below that, because it is disadvantageous in terms of economics.

As described above, the present invention has excellent properties in strength and watertightness, etc., which are particularly required for cross-linked pavement concrete by including silica fume, but the silica fume used therein has a disadvantage in that the cost of the entire concrete composition is increased as a relatively expensive admixture. Therefore, when the fly ash or blast furnace slag is further added together with the silica fume, the economical efficiency and efficiency can be improved as compared to when the silica fume is mixed alone and used, and the construction properties are improved according to the characteristics of the fly ash or the blast furnace slag. You can expect

Here, the fly ash (fly ash) is a particle of a specific particle size range that is collected by the dust collector of coal ash contained in the waste gas discharged when the coal is used as a fine powder fuel in a combustion boiler such as a thermal power plant. It is a hydrated living material of portland cement, which is in the pore structure of cement paste and fixes the calcium hydroxide or alkali hydroxide mixture which precipitates with the infiltration water to fill the pores in the cement paste, thereby improving the permeability of concrete and permeability to erosive chemicals. By constraining, it contributes distinctly to increasing the strength and durability of concrete.

At this time, the content of the fly ash used with the silica fume is preferably to be included in 20 to 30 parts by weight based on 100 parts by weight of cement. If the fly ash content is less than 20 parts by weight, the effect of the addition of the fly ash is insignificant, and if it exceeds 30 parts by weight, the expression of the initial strength of the concrete is lowered and the amount of units required to maintain the slump increases This is because workability is poor.

On the other hand, blast furnace slag in addition to the fly ash may be used as the admixture in the form of particulates that can be used with the silica fume. The blast furnace slag is a pulverized granular crushed slag obtained by quenching molten slag generated at the same time as pig iron in a blast furnace with water in a blast furnace, and then pulverized. Depending on the purpose of use, gypsum may be added. When the blast furnace slag powder is mixed, the long-term strength is improved, and the anti-corrosion effect of the rebar is suppressed by improving water-tightness and inhibiting chloride ion penetration. The surface area of the blast furnace slag fine powder used in the present invention is 8,000 cm 2 / g or more.

At this time, the content of the blast furnace slag used with the silica fume is preferably included in 30 to 80 parts by weight with respect to 100 parts by weight of cement, which is ineffective when the content of the blast furnace slag is less than 30 parts by weight. When it exceeds 80 weight part, the expression of the initial stage strength of concrete will fall.

On the other hand, the use of silica fume in concrete increases the number of units to maintain the same slump, and therefore, to maintain the same water cement ratio without reducing the slump, a high performance water reducing agent or an admixture such as an AE agent is added to increase the fluidity of the concrete. Use it.

In addition, the concrete composition for cross-section pavement according to the present invention may be formed by further adding PVA fibers. This PVA fiber is used to increase the resistance to cracking caused by repeated passage vibration and plastic shrinkage, which is one of the important characteristics of cross-linked pavement concrete. Steel fiber and glass are used for this purpose. Fibers, carbon reinforcing fibers and synthetic fibers, but in the present invention is used in particular PVA fibers.

The PVA fibers are obtained from poly vinyl alcohol, which is characterized by being very effective in strong adhesion and dispersibility in concrete cured by OH-groups. The use of such PVA fibers in concrete can be expected in many ways, including high aspect ratios, improved tensile strength, good chemical compatibility with Portland cement, and harmlessness to the human body. The PVA fiber used in the present invention has a specific gravity of 1.30, an aspect ratio of 400 to 800, and a length of 6 mm to 12 mm.

In this case, the content of the PVA fiber is preferably to include a volume fraction of 0.05 ~ 2% (volume fraction) of the total composition containing the PVA fiber, which is lower than the above range, that is, the effect of the addition of the PVA fiber The effect of the crack resistance and the increase in tensile strength is insignificant, and if it is higher than this, the increase of the effect compared to the added amount is not remarkable.

Hereinafter, the present invention will be described in more detail with reference to the following examples, which are only presented to aid the understanding of the present invention, and the present invention is not limited thereto.

<Example 1>

Usually, 387 kg (100 parts) of Portland cement, 843 kg (218 parts) of sand, and 856 kg (221 parts) of gravel are mixed with 25 kg (6.5 parts) of silica fume, and 144 kg of mixed water is added to the mixture. To prepare a cross-linked pavement concrete composition according to the present invention.

Comparative Example 1

In the cross-linked pavement concrete according to the present invention in the same compounding ratio of Example 1, except that silica fume was not added to compare the change of physical properties of the concrete according to the addition of silica fume (but the amount of cement in Example 1 Cement amount and silica fume combined) to prepare a concrete composition.

Comparative Example 2

In order to compare the latex-modified concrete according to the prior art according to the present invention, according to a good mixing ratio of the latex-modified concrete, 85kg of mixed water is usually added to 390kg of Portland cement, 122kg of latex resin, 945kg of sand, and 676kg of gravel, and mixed with the latex-modified concrete. Concrete was prepared.

Table 1 below shows the compounding ratios of the components of Comparative Example 1 and 2 compared with Example 1 for the concrete composition for cross-section pavement according to the present invention.

Classification (kg) Example 1 Comparative Example 1 Comparative Example 2 cement 387 412 390 Silica fume 25 - - Latex - - 122 sand 843 843 945 Pebble 856 856 676 Mixed water 144 144 85

Test Example 1 Compressive Strength Test

The compressive strength test was performed to compare the compressive strength characteristics of Example 1 and Comparative Examples 1 and 2 of the present invention prepared according to the blending ratio as described above. The test method was carried out according to the test specimen fabrication and strength measurement method specified in KS F 2403, 2405, and the results are shown in Table 2 below.

Test Example 2 Flexural Strength Test

In order to compare the flexural strength characteristics of Example 1 and Comparative Examples 1 and 2 of the present invention prepared according to the blending ratio as described above, a flexural strength test was performed. The test method was carried out according to the test specimen fabrication and strength measurement method specified in Korean Industrial Standards KS F 2403 and KS F 2408 according to the concrete standard specification. The results are shown in Table 2 below.

Test Example 3 Chloride Ion Permeability Test

The composition prepared according to the compounding ratio of Example 1 and Comparative Examples 1 and 2 was measured permeability according to the method specified in ASTM C 1202 (chlorine ion permeation test method) and the results are shown in Table 2 below. In this case, the criterion for evaluating the permeability is very high when the Coulombs value is 4000 or more, the permeability is generally high when 2000 to 4000, the permeability is low when 1000 to 2000, and the permeability is very low when 100 to 1000. If less than 100, it is impermeable.

Comparison of physical properties between the present product and ordinary concrete and latex modified concrete division Age Example 1 Comparative Example 1 Comparative Example 2 Compressive strength (kgf / ㎠) 7 days 400 390 237 28 days 532 440 353 Flexural strength (kgf / ㎠) 7 days 56 51 55 28 days 81 69 62 Chloride Permeability (coulombs) 7 days 1200 3456 2600 28 days 654 2730 1400

As shown in Table 2, the cross-linked concrete composition according to the present invention was found to be superior to ordinary asphalt and latex modified concrete in terms of mechanical properties such as compressive strength and flexural strength. In particular, chlorine ion permeability has the most effect on the bridge life after the strength of concrete is secured, because rebar may be corroded by the penetration of deicing chloride such as calcium chloride used in winter. According to the Table 2, the product of the present invention was found to be superior in terms of chlorine ion permeability compared to ordinary concrete, and it was confirmed that it showed excellent chlorine ion permeability as compared to conventional latex modified concrete.

Example 2 PVA Fiber Added

In order to secure the crack resistance required for the cross-linked concrete composition, PVA fibers were incorporated into the composition in Example 1 and uniformly dispersed therein. The PVA fibers used were incorporated such that 6 mm in length comprised 0.07% of the total cross-linked pavement concrete composition volume.

Test Example 5 Plastic Shrinkage Test

In the case of the composition according to the present invention and the latex modified concrete of the prior art is characterized by being sensitive to plastic shrinkage cracking compared to conventional concrete due to the influence of the admixture and surfactant contained in each. This test is to examine the resistance to plastic shrinkage cracking. The test method was conducted according to the test method proposed by various researchers. As shown in Fig. 1, the test specimen mold was constrained at a distance of 76 mm from the center and both ends in a rectangular shape with a surface area of 560 × 365 mm so that the metal engraving caused a stress to induce cracks in the vicinity. The environmental conditions of this test were 28 ℃ ± 2 ℃, relative humidity 40%, wind speed 4.5 ~ 6m / sec. The crack width was measured using a microscope, and the crack length was placed along the crack using a thread, and then both ends of the thread were measured with a pin length. The crack area was calculated by multiplying the crack width by the crack length.

According to the test method described above, Example 2 and Comparative Example 2 (latex modified concrete) were formed and cured for 24 hours, and then subjected to a plastic crack test, and the results are shown in FIG. 2.

As a result of the test, cracks did not occur in the composition of the present invention incorporating PVA fibers as shown in FIG. 2A, whereas cracks occurred in the latex modified concrete according to Comparative Example 2 as shown in FIG. 2B. The maximum crack width at which the crack occurred was 0.2 mm and the width at which the crack occurred was 35.45 mm 2.

Next, a method of paving the bridge using the concrete composition for bridge construction pavement according to the present invention.

First, in order to pave the bridge using the concrete composition for bridge construction pavement according to the present invention, a surface cleaning operation for removing contaminants and aggregates exposed on the surface of the bridge must be preceded (S1). Such surface cleaning should be carried out within 48 hours prior to placing concrete. In addition, before the concrete is poured, the surface of the bridge is moistened with water and the surface is dried to prevent the water from being absorbed by the existing concrete (S2).

As described above, when the preparatory work on the bridge pavement is completed, the concrete for pavement pavement prepared by the present invention is poured on the existing concrete using the ready-mixed concrete and distributed using a shovel or a hand tool (S3). When the concrete is poured in this way, the flattening work using a vibrator, etc., and the surface finishing work through the electric finisher or manual work (S4). At this time, depending on the construction situation, the surface on which the concrete is poured may be texuring using Astroturf drag or the like (S5).

Next, after spraying the film curing agent on top of the finished concrete pouring surface (S6) and covered with a polyethylene film (S7) curing for a predetermined period of time, the bridge is finished using the bridge construction concrete composition for paving paving (S8) .

According to the present invention described in detail above, the production and construction methods of materials are generally used at the same time, while satisfying all the characteristics particularly required for the specialty concrete for bridge construction, that is, watertightness, adhesion, durability, and crack resistance. There is an effect that can be used almost as it is, the concrete composition for cross-section pavement excellent in economics and construction.

Claims (16)

In special concrete compositions for bridge paving, used for paving the surface of bridge structures, Concrete composition for cross-section pavement comprising cement, sand, gravel and silica fume. The method of claim 1, wherein the silica fume concrete composition for a pavement paving, characterized in that contained in 5 to 15 parts by weight based on 100 parts by weight of cement. The method of claim 1, wherein the cross-linking concrete composition for pavement concrete composition characterized in that it further comprises a fly ash. The method of claim 3, wherein the fly ash is a cross-linking concrete composition for pavement, characterized in that it comprises 20 to 30 parts by weight based on 100 parts by weight of cement. The method of claim 1, wherein the cross-linking concrete composition for pavement concrete composition characterized in that it further comprises a blast furnace slag. The method of claim 5, wherein the blast furnace slag is bridge concrete composition for pavement, characterized in that it comprises 30 to 80 parts by weight based on 100 parts by weight of cement. The method of claim 1, wherein the cross-linking concrete composition for pavement concrete composition characterized in that it further comprises a PVA fiber. The method of claim 7, wherein the PVA fiber is a cross-linking pavement concrete composition, characterized in that contained in 0.05 to 2% (volume fraction) of the total composition volume. In special concrete compositions for bridge paving, used for paving the surface of bridge structures, 200 to 240 parts by weight of sand, 200 to 250 parts by weight of gravel and 5 to 15 parts by weight of silica fume based on 100 parts by weight of cement, the concrete composition for packaging pavement. 10. The method of claim 9, wherein the concrete composition for paving pavement The concrete composition for pavement paving, characterized in that it further comprises 20 to 30 parts by weight based on 100 parts by weight of fly ash. 10. The method of claim 9, wherein the concrete composition for pavement bridges pavement concrete composition characterized in that it further comprises a blast furnace slag 30 to 80 parts by weight based on 100 parts by weight of cement. 12. The bridge construction concrete composition according to any one of claims 9 to 11, wherein the bridge construction concrete composition further comprises PVA fibers in a volume fraction of 0.05 to 2% of the total composition volume. 10. The method of claim 1 or claim 9, wherein the cross-linking pavement concrete composition, the cross-linking pavement concrete composition, characterized in that the admixture for increasing the fluidity of the concrete is further added. The concrete composition of claim 13, wherein the admixture is a high performance water reducing agent or an AE agent. In the method of paving the surface of the bridge using special concrete for bridge paving, Cleaning the surface of the bridge to be paved; Wetting the surface of the cleaned bridge with water and maintaining it in a dry saturated state; Placing a ready-mixed concrete made of the concrete composition for cross-section pavement according to claim 1 on the surface of the bridge; Finishing the poured concrete surface; Curing the poured concrete for a predetermined period; Bridge construction paving method using a concrete composition for bridge pavement, characterized in that comprises a. 16. The method of claim 15, wherein the curing of the poured concrete for a predetermined period of time is carried out with the coating curing agent applied to the upper surface of the poured concrete and curing with the polyethylene film covered.