KR102250270B1 - Composition of the watertight asphalt paving overlay for bridges and concrete roadways - Google Patents

Abstract

The present invention relates to a watertight asphalt concrete pavement composition for bridges and concrete roads, which is a modified watertight asphalt mixture preventing corrosion caused by infiltration of rainwater and chloride without forming a separate waterproofing layer on road structures, especially bridges and road tops made of cement concrete or steel, and securing commonality by grafting an asphalt binder modified with a viscoelastic polymer, thereby enabling water-tightening of a surface layer of decks of steel and concrete bridges. According to the present invention, a composition for forming an asphalt surface layer on a deck of a bridge and road made of cement concrete or steel comprises: 5 to 10 parts by weight of a modified asphalt binder; 80 to 94.5 parts by weight of aggregate for a dense asphalt mixture for the surface layer; and 0.5 to 10 parts by weight of thermally expandable microspheres.

Description

Composition of the watertight asphalt paving overlay for bridges and concrete roads}

The present invention relates to a watertight asphalt concrete pavement composition for bridges and concrete roads, and more specifically, to road structures, especially bridges and road tops made of cement concrete or steel, without a separate waterproofing layer, generated by infiltration of rainwater and chloride Watertight asphalt concrete pavement composition for bridges and concrete roads that can watertightize the surface layer of steel and concrete bridge tops with a watertight modified asphalt mixture that prevents corrosion and secures commonality by grafting asphalt binder modified with viscoelastic polymer is about

In general, the surface layer of road structures, especially bridges, is made of asphalt concrete or cement concrete. Compared to the cement concrete surface layer, the initial construction cost of the asphalt surface layer is economical, easy to construct, and has excellent ride comfort and driving performance, so the preference of bridge road users is very high. It has many high advantages.

However, since most of the asphalt mixture for the surface layer has a porosity of 4 to 6%, the penetration of rainwater and chloride is possible, so a separate waterproofing layer must be installed to prevent damage to the structure of the lower layer of the road, especially the bridge. In addition, although the contraction and expansion rate of the bridge structure is higher than that of the road structure of the earthworks along with vibration caused by heavy vehicles, in comparison, the thermodynamic durability of the asphalt binder constituting the asphalt surface layer is not sufficient, so cracks, plastic deformation, and destruction of potholes are possible. Because it occurs frequently, the durability life of the surface layer is shortened and the lifetime maintenance cost is increased.

In consideration of this, on roads with high traffic volume or frequent passage of heavy vehicles, the pavement layer is strengthened using modified asphalt mixtures and mastic asphalt mixtures to prevent damage and traffic loads caused by environmental loads such as rainwater and chloride. It is possible to reduce plastic deformation and cracking caused by

The modified asphalt mixture and mastic asphalt form a price about 1.3 to 2 times higher than that of a general asphalt mixture for the surface layer, and as the general asphalt mixture, asphalt or polymer waterproofing film, latex-modified concrete, etc. are the main materials. The waterproofing process must be performed separately. In the waterproofing process, there was a problem that the waterproofing of the coating film had to be preceded in the repair process when the surface layer of the asphalt concrete of the bridge was damaged independently of its own durability performance.

KR 10-0699035 KR 10-0994195 KR 10-0661864 KR 10-0629902

In order to solve this problem, the present invention mixes a straight asphalt binder modified with a viscoelastic polymer to a road structure, particularly a bridge made of cement concrete or steel, and an aggregate for a surface layer, and then thermally expandable microspheres. Watertight asphalt concrete pavement for bridges and concrete roads that satisfy both the properties and performance of existing waterproofing members without the need for a separate waterproofing layer by adding water-tightness to the asphalt surface layer of the steel and concrete bridge tops, and realize the convenience and economy of construction composition for the purpose.

The present invention relates to a composition for forming an asphalt surface layer on the top plate of a bridge and road made of cement concrete or steel, 5 to 10 parts by weight of a modified asphalt binder, 80 to 94.5 parts by weight of aggregate for a dense asphalt mixture for the surface layer, The composition of the watertight asphalt concrete pavement for roads and bridges is characterized by containing 0.5 to 10 parts by weight of thermally expandable microspheres.

The modified asphalt binder is characterized in that 5 to 20 parts by weight of the rubber-based viscoelastic polymer is contained in 80 to 95 parts by weight of straight asphalt.

The thermally expandable microsphere is in the form of a ring having a diameter of 75 to 600 μm, and is made of a thermoplastic resin having a thermal expansion coefficient of 40 to 110 ppm/° C. The thermoplastic resin is polyethylene, polypropylene, vinyl chloride resin, polystyrene acrylic, poly It is characterized in that it consists of a mixture of any one or more of methyl methacrylate, ABS (Acrylonitrile Butadiene Styrene), and vinyl acetate.

The thermally expandable microsphere is in the form of a ring having a diameter of 75 to 600 μm, and is made of a thermosetting resin having a thermal expansion coefficient of 40 to 110 ppm/° C. The thermosetting resin is phenol, urea, melamine, epoxy, polyurethane, unsaturated poly It is characterized in that it consists of a mixture of any one or more of esters and polyimides.

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The present invention has the following effects.

first ; Heat-expandable microspheres are added as fine powder to the compaction aggregate for the surface layer so that the heated asphalt mixture maintains a porosity of 1 to 3% and becomes watertight through the compaction process. It has the effect of preventing corrosion of the bridge by rainwater and chloride and reducing maintenance costs by performing physical properties and performance.

second ; The straight asphalt binder is based on a binder modified with a rubber-based viscoelastic polymer mixture, and the surface layer of asphalt has high adhesion to the bridge, and improves flexural strength, compressive strength, abrasion resistance, high and low temperature elasticity, shrinkage of bridge structures due to temperature change, Absorbs behaviors such as expansion sufficiently and prevents the fracture patterns of cracks and plastic deformation that can be caused by vibration and stress caused by heavy vehicles, thereby increasing the durability of the asphalt surface layer and reducing the life cycle repair cost of the asphalt surface layer for bridges There is an effect that can be done.

1 is a view schematically showing a state in which an asphalt surface layer is formed on the upper plate of a bridge using the watertight asphalt concrete pavement composition of a bridge and a concrete road according to the present invention.
2 is a view illustrating thermally expanded microspheres applied to the watertight asphalt concrete pavement composition for bridges and concrete roads according to the present invention.
Figure 3 is a view illustrating a thermal stabilization process of thermal expansion microspheres applied to the watertight asphalt concrete pavement composition of the bridge and concrete road according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail. In the description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

The present invention comprises 5 to 10 parts by weight of a modified asphalt binder and 80 to 94.5 parts by weight of aggregate for a dense asphalt mixture for a surface layer, and 0.5 thermally expandable microspheres to form an asphalt surface layer on the top plate of a bridge and road made of cement concrete or steel. It is to make the asphalt surface layer watertight by the composition containing to 10 parts by weight.

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The modified asphalt binder is made by mixing straight asphalt and a rubber-based elastomer mixture, the rubber-based elastomer mixture is SBS (styrene-butadiene-styrene), SBR (styrene-butadiene-rubber), CRM (crumb rubber modifiers), SIS (styrene-isoprene-styrene) and a mixture of any one or more of rubber-based elastomers such as water-soluble polychloroprene.

This modified asphalt binder reduces the risk of cracking, plastic deformation, and potholes occurring in the surface layer of asphalt when the durability of the surface asphalt concrete is improved along with the watertightness provided. Therefore, the rubber-based viscoelastic polymer can be used with straight asphalt at a heating temperature of 180 to 200 °C. However, it is preferable to mix and use 5 to 20 parts by weight of the rubber-based viscoelastic polymer in 80 to 95 parts by weight of the straight asphalt, which is excellently modified in viscoelasticity when mixing the rubber-based elastomer, so that the bonding strength between the asphalt binder and the aggregate is increased, and at high temperature Remarkably improved plastic deformation due to the thermal stability of the binder

The aggregate for the surface layer dense asphalt mixture is contained in the composition of the watertight asphalt concrete pavement for bridges of the present invention, and the aggregate size suggested in the 'Heated asphalt mixture mixing design guideline' of the Ministry of Land, Infrastructure and Transport is 13 to 20 mm dense asphalt. Based on the particle size distribution of the mixture aggregate, the formulation is designed as shown in Table 1 below to have a porosity of 1 to 3%.

Asphalt Mixture Aggregate Size Standard Table for Standard Density

Nominal size of body WC-1 WC-2 WC-3 WC-4 tightness tightness tightness tightness 13 13F 20 20F barrel
and
quality
amount
back
minute
rate
(%) 25mm - - 100 100 20mm 100 100 90-100 95-100 13mm 90-100 95-100 72-90 75-90 10mm 76-90 84-92 56-80 67-84 5mm 44-74 55~70 35~65 45~65 2.5mm 28-58 35-50 23-49 35-50 0.60mm 11-32 18-30 10-28 18-30 0.30mm 5-21 10-21 5-19 10-21 0.15mm 3-15 6-16 3-13 6-16 0.08mm 2-10 4-8 2-8 4-8

The thermal expansion microspheres (microspheres) are made of micro-particles and are characterized in that they are made into a ring shape in which one or more synthetic resins having a thermal expansion coefficient different from that of straight asphalt in a solid or semi-solid form are encapsulated therein.

Thermal expansion microspheres contained in the fine powder have a lower coefficient of thermal expansion than straight asphalt 120 ppm/℃, and a higher thermal expansion coefficient than 10 to 30 ppm/℃ of aggregate (rock) Among thermoplastic and thermosetting resins of 40 to 110 ppm/℃ It is composed of any one or more complexes. The microspheres with a diameter of 75 to 600 μm have an increased surface area, so that in a heating process of 180 to 200° C., flowability of 1000 cP or less is expressed in a general asphalt mixture in about 60 seconds, so that it is evenly distributed with the straight asphalt binder and fine powder. When mixed, it is coated on the surface of the blended aggregates, filling the gaps between the aggregates, the modified asphalt mixture of 1-3% porosity is watertightened, and the asphalt surface layer is thermally stabilized to accommodate binder expansion.

The thermoplastic resin is a mixture of any one or more of polyethylene, polypropylene, vinyl chloride resin, polystyrene acrylic, polymethyl methacrylate, ABS (Acrylonitrile Butadiene Styrene), and vinyl acetate, and the thermosetting resin is a mixture of It contains a mixture of any one or more of phenol, urea, melamine, epoxy, polyurethane, unsaturated polyester, and polyimide having fluidity.

The construction process for forming the asphalt surface layer on the upper surface of the bridge and concrete road using the composition of the watertight asphalt concrete pavement as described above is as follows.

(a) cleaning the surface of the concrete top plate or the steel top plate;

(b) forming an asphalt-based adhesive layer by applying emulsified asphalt for tack coating on the cleaned upper surface;

(c) 5 to 10 parts by weight of the asphalt binder modified on the upper surface of the emulsified asphalt on which the asphalt-based adhesive layer is formed, 80 to 94.5 parts by weight of aggregate for the surface layer dense asphalt mixture, and 0.5 to 10 parts by weight of thermally expandable microspheres. Forming a watertight asphalt surface layer by the composition made; pavement or repair of roads and bridges with an elastic waterproof layer is made.

The tack coating emulsified asphalt used in the above construction process is a general asphalt paving material stipulated in the guidelines for the production and construction of asphalt mixtures of the Ministry of Land, Infrastructure and Transport (2014, 01). When applied together with the watertight asphalt concrete of the present invention, it is a waterproof quality indicator for major bridges. It satisfies a tensile adhesive strength of 0.6 MPa or more and a shear adhesive strength of 0.15 MPa or more.

According to the experimental results, ^{emulsified asphalt for tack coating and watertight asphalt concrete of 0.4 to 0.5 L/m 2} for tack coating can secure the best adhesion, but in the field, the roughness of the floor surface, moisture state, cleaning state, etc. Considering various conditions, 0.3 to 0.8 L/m ² of emulsified asphalt for tack coating can be applied.

Hereinafter, the present invention will be described in detail by way of Examples.

The straight asphalt mentioned in Table 2 below is a material classified according to the ‘KS M 2201, Straight Asphalt’ classification in a form in which a rubber elastomer is mixed or not.

Content selection by microsphere (%) division
Kinds comparative example
One comparative example
2 Example
One Example
2 Example
3 Example
4 Example
5 Example 6 straight asphalt
(Pen.60-80) 6 5 5.5 straight asphalt
(Pen.20-40) 6 5 6 6 5 polyethylene 0.3 0.2 0.5 polypropylene 0.5 0.3 vinyl chloride resin 0.5 0.5 polymethyl methacrylate 0.5 0.5 0.5 phenolic resin 0.5 ABS 4 3 3 3 polyurethane resin 0.5 0.5 SBS 0.4 0.5 aggregate 94 94 89.6 90.5 91 92.9 92.8 91

It is preferable to use the straight asphalt having a penetration of about 60 to 80, and when using a straight asphalt having a penetration of 20 to 40, when the amount of rubber-based elastic polymer is reduced in order to secure compaction performance, low temperature It can be difficult to improve the brittleness in

The straight asphalt may be used in an amount of 5 to 10 parts by weight in 100 parts by weight of the asphalt mixture, and when the content is out of the range of 5 to 10 parts by weight, the physical strength of the asphalt mixture may decrease.

The modified asphalt binder of the present invention is any of rubber-based elastomers such as SBS (styrene-butadiene-styrene), SBR (styrene-butadiene-rubber), CRM (crumb rubber modifiers), SIS (styrene-isoprene-styrene), water-soluble polychloroprene, etc. One or more mixtures are mixed with the straight asphalt.

The elastomer can improve the resistance to cracks, plastic deformation, portholes, etc. of the surface layer asphalt concrete with water tightness imparted by improving tensile strength, thermal stability, elastic recovery, etc. of straight asphalt.

The rubber-based elastomer belonging to the modified asphalt binder may be used in an amount of 5 to 20 parts by weight per 100 parts by weight of the straight asphalt. At this time, if the amount is less than 5 parts by weight, it is difficult to expect improvement in performance due to modification, and if it exceeds 20 parts by weight, the viscous behavior region of the asphalt binder may be reduced and adhesive strength may be reduced.

The thermal expansion coefficient of the thermal expansion microspheres of the present invention is lower than the thermal expansion coefficient of straight asphalt (120 ppm/℃), and the thermal expansion coefficient of the aggregate (rock) is higher than that of the aggregate (rock) thermal expansion coefficient (10 to 30 ppm/℃), 40 to 110 ppm/℃ thermoplastic , is composed of any one or more composites of thermosetting resins.

The thermal expansion microspheres of the present invention have a lower thermal expansion coefficient than 120 ppm/℃ for straight asphalt, and a higher thermal expansion coefficient for aggregate (rock) (10 to 30 ppm/℃, higher thermal expansion coefficient than 40 to 110 ppm/℃ among thermoplastic and thermosetting resins. It consists of one or more complexes.

The amount of the thermally expandable microspheres may be used in an amount of 0.5 to 10 parts by weight for the total composition, and more specifically, 1 to 6 parts by weight to express watertightness and physical strength.

Polyethylene, polypropylene, vinyl chloride resin, polystyrene acrylic, polymethyl methacrylate, ABS (Acrylonitrile Butadiene Styrene) as the thermoplastic thermally expandable microsphere filler. Vinyl acetate and the like have a melting point of 100° C. or higher, so they have excellent strength enhancement, adhesion and plastic deformation resistance, and are excellent in economy and versatility. In particular, vinyl chloride resin can improve chemical resistance and abrasion resistance and impart rigidity. At this time, when the amount is less than 1.0 parts by weight, the effect is insignificant, and when it exceeds 6.0 parts by weight, negative effects such as reduced compaction performance and stripping of the mixture due to lack of binder may occur.

As the thermosetting thermally expandable microsphere filler, phenol, urea, melamine, epoxy, polyurethane, unsaturated polyester, polyimide resin, etc. can simultaneously improve plastic deformation resistance at high temperature and crack resistance at low temperature, and compaction of asphalt pavement performance can be improved. It can be used in 0.3 to 2.0 parts by weight, and when less than 0.3 parts by weight, it is difficult to obtain the desired effect, and when it exceeds 2.0 parts by weight, economic efficiency may be deteriorated.

The composition according to the change in the microsphere content was prepared as an asphalt concrete specimen with a thickness of about 60 mm using aggregate that satisfies WC-2 (13 mm), the standard for surface layer dense asphalt concrete aggregate particle size suggested by the Ministry of Land, Infrastructure and Transport, and then the porosity, resistance Water permeability, deformation strength, indirect tensile strength, toughness, etc. were measured, and a 50 mm thick asphalt concrete layer was prepared and dynamic stability was measured and shown in Table 3 below.

division porosity
(%) water permeability deformation strength
(Mpa) dynamic stability
(times/mm) Indirect Tensile Strength (ITS) -20℃ 25℃ Comparative Example 1 4.1 pitched 3.8 1,224 3.8 0.76 Comparative Example 2 4.5 pitched 4.2 1,860 4.1 0.88 Experimental Example 1 2.3 not pitched 4.3 2,299 4.9 1.03 Experimental Example 2 2.0 not pitched 4.3 2001 4.7 1.01 Experimental Example 3 2.5 not pitched 4.5 2,317 4.8 1.17 Experimental Example 4 2.1 not pitched 4.7 2,599 4.3 1.34 Experimental Example 5 2.3 not pitched 4.7 2,541 4.2 1.33 Experimental Example 6 2.1 not pitched 5.0 2,763 5.0 1.28

In Table 3, waterproof performance was evaluated by applying water permeable resistance to the surface of the test piece at a pressure of 0.3 MPa for 3 hours to check whether or not water penetrated the lower part of the test piece. In Comparative Examples 1 and 2, permeability occurred, whereas in Experimental Examples 1 to 6, permeability did not occur, and the microspheres contributed to watertightness in the asphalt mixture.

Deformation strength and dynamic stability are indicators that show resistance to plastic deformation caused by traffic loads applied to actual roads by applying static and dynamic loads simulating wheel loads to the test piece. The higher the number, the higher the resistance to plastic deformation. Experimental Examples 1 to 6 show improved resistance compared to Comparative Examples 1 and 2, which means that plastic deformation due to traffic load at high temperature is reduced.

Indirect tensile strength is a method of measuring the indirect tensile strength occurring on the side of the specimen by applying a vertical load to the cylindrical specimen. The indirect tensile strength at low and room temperature (-20˚C, 25˚C) is It is an index to judge the crack resistance of Experimental Examples 1 to 6 confirmed significantly improved results compared to Comparative Examples 1 and 2, which resist cracking of asphalt concrete according to temperature change through thermal expansion microspheres and thermal stability during the thermal behavior of the asphalt mixture.

In the above, the present invention has been described with reference to the above embodiments, but it is needless to say that various modifications are possible within the scope of the technical idea of the present asphalt and the present invention.

Claims (6)

In the composition for forming an asphalt surface layer on the top plate of a bridge and road composed of cement concrete or steel,
5 to 10 parts by weight of a modified asphalt binder containing 5 to 20 parts by weight of the rubber-based viscoelastic polymer in 80 to 95 parts by weight of the straight asphalt;
80 to 94.5 parts by weight of aggregate for a dense asphalt mixture for the surface layer;
0.5 to 10 parts by weight of thermally expandable microspheres are contained, and the thermally expandable microspheres are in the form of a ring having a diameter of 75 to 600 μm, and a thermal expansion coefficient of 40 to 110 ppm/° C. of a thermoplastic resin or a thermosetting resin. Watertight asphalt concrete pavement composition for bridges and concrete roads, characterized in that.
delete The method of claim 1,
The thermoplastic resin is polyethylene, polypropylene, vinyl chloride resin, polystyrene acrylic, polymethyl methacrylate, BS (Acrylonitrile Butadiene Styrene), watertight asphalt concrete of bridges and concrete roads, characterized in that it consists of a mixture of any one or more of vinyl acetate package composition.
The method of claim 1,
The thermosetting resin is a watertight asphalt concrete pavement composition for bridges and concrete roads, characterized in that it consists of a mixture of any one or more of phenol, urea, melamine, epoxy, polyurethane, unsaturated polyester, and polyimide.
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