JPH0313603A - Asphalt paving composite - Google Patents

Abstract

PURPOSE:To form a paving surface excellent in durability, antifluidity, wear- resistance and crack resistance by mixing a specified quantity of at least one kind among rubber, thermoplastic resin and elastomer and rubber powder in asphalt. CONSTITUTION:A binder is prepared by mixing 1-10wt. parts, preferably 4-7wt. parts at least one kind among rubber, thermoplastic resin and elastomer and 0.5-5wt. parts, preferably 0.5-3wt. parts rubber powder in 100wt. parts asphalt. An asphalt paving composite containing the above binder and aggregate is manufactured. It is possible to form a multipurpose and high quality paving surface which has large toughness, and tenacity not only to asphalt concrete of dense or fine-grain size but also to asphalt concrete of rough grain size and, low brittle temperature and can stand comparison with the others in respect of the temperature-viscosity curve of the binder.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to asphalt pavement compositions, and in particular to improved asphalt pavement compositions comprising heated asphalt mixtures or heated asphalt stabilization mixtures for use in road surfaces, base layers, or roadbeds. The present invention relates to an asphalt paving composition suitable for paving vehicle roads, runways, taxiways, parking lots, etc., using an asphalt-based paving binder.

[Prior Art] In recent years, the wear and tear on the pavement surface of asphalt pavement has increased significantly due to the increase in the size of traffic vehicles, increased wheel loads, increased traffic volume, wear caused by spikes and chains in winter, etc. There is. Wear and tear on the pavement surface causes unevenness and cracks on the pavement surface, which causes water puddles to form during rain, causing serious problems for safe driving such as decreased slip resistance and difficulty in steering. The problem of harm to third parties due to splashes cannot be ignored and has become a major social problem.

Conventionally, in order to prevent wear and tear on the pavement surface, roads in warm regions and heavy traffic areas use aggregate particles with high flow resistance, such as dense-grained asphalt concrete, for the surface layer, and rubber-containing asphalt as a binder. Modified asphalts such as those typified by are used. On the other hand, on roads in snowy and cold regions, aggregate grains with high wear resistance, such as fine-grained gap asphalt concrete or fine-grained gap asphalt concrete, are used for the surface layer.

On the other hand, there are pavements that contain a large amount of coarse aggregate and have a porous structure, as typified by open-grained asphalt concrete. This pavement is used for the following purposes.

■ Permeable pavement: In other words, with the recent progress of urbanization, various pavements and structures block water from the ground surface, causing a rapid decrease in permeated groundwater, resulting in ground subsidence and deterioration of tree growth conditions. , ecological changes in soil organisms, and river flooding caused by localized heavy rains, and other adverse effects have occurred, so permeable pavement is being used to improve these problems.

■ Drainage pavement: In other words, it is used for the purpose of preventing water from being splashed by vehicles, but unlike ■ above, roadbed,
In order to suppress softening caused by rainwater intrusion into the roadbed and roadway body,
An impermeable membrane is applied to the roadbed or base layer, and a porous structure is formed on top of the membrane.It is used as a drainage pavement that drains rainwater that has passed through the pavement into roadside gutters, etc.

■ Sound-absorbing pavement: This material absorbs so-called vehicle noise, such as the sound generated by the interaction between the road surface layer and tires and engine noise, into the pavement, which has a porous structure, to reduce vehicle noise and improve the comfort of roadside residents. It has been adopted as a sound-absorbing pavement for the purpose of ensuring a safe driving environment for living and drivers.

[Problem to be solved by the invention] Asphalt concrete, which is used to prevent wear and tear on the pavement surface mentioned above, is not sufficiently effective against flow, especially in warm regions and heavy traffic areas. This is the actual situation.

On the other hand, although pavements with a porous structure using open-grained asphalt concrete have excellent structural advantages as shown in ■ to ■, they are better than pavements made of normal dense-grained or fine-grained asphalt concrete. , generally durable,
Flow resistance, abrasion resistance, etc. are significantly inferior. Paving materials with a porous structure include straight asphalt and various rubber-containing asphalts.More recently, straight asphalt mixtures containing 0.1 to 10 parts by weight of vegetable fibers have been used for roadways, especially heavy traffic roads. durability,
It is being used on a trial basis to improve wear resistance, etc.
It is still far from meeting the required standards and has not yet reached the stage of practical application.

The present invention solves the above-mentioned conventional problems and has sufficient durability not only for dense or fine-grained asphalt concrete with low porosity, but also for open-grained asphalt concrete with high porosity that provides a porous pavement structure. The purpose of the present invention is to provide a high-performance asphalt pavement composition that exhibits properties such as hardness, flow resistance, and abrasion resistance.

[Means for solving the problem] The asphalt pavement composition of the present invention has asphalt 10
A binder made by blending 1 to 10 parts by weight of at least one selected from the group consisting of rubber, thermoplastic resin, and elastomer and 0.5 to 5 parts by weight of rubber powder to 0 parts by weight, and aggregate; It is characterized by containing.

The present invention will be explained in detail below.

In the present invention, the rubber, thermoplastic resin, and elastomer to be blended with asphalt include, for example, SBR, BR
,NR,IR,I IR,CR.

Examples include one or more of EPDM, SBS, SIS, EVA, EEA, and recycled rubber. These rubbers,
If the blending ratio of the thermoplastic resin and/or elastomer is less than 1 part by weight per 100 parts by weight of asphalt, a sufficient modifying effect according to the present invention cannot be obtained, and if it exceeds 1 part by weight, the kinematic viscosity of the binder increases excessively. However, the workability of asphalt pavement (kneading ability, spreading ability, rolling ability) decreases. Therefore, the blending ratio of rubber, thermoplastic resin and/or elastomer is 1 to 1 to 100 parts by weight of asphalt.
0 parts by weight, preferably 4 to 7 parts by weight.

Further, there is no particular restriction on the rubber material of the rubber powder used in the present invention, but the particle size is preferably 100 mesh or less, particularly 10 to 60 mesh, from the viewpoint of improving asphalt dispersibility and binder properties. The blending ratio of such rubber powder is 100% asphalt.
If it is less than 0.5 parts by weight, a sufficient modifying effect according to the present invention will not be obtained, and if it exceeds 5 parts by weight, the kinematic viscosity of the binder will increase excessively and the workability of asphalt pavement will deteriorate. Therefore, the mixing ratio of rubber powder is 0.5 to 5 parts by weight per 100 parts by weight of asphalt! Parts by weight, preferably 0.5 to 3 parts by weight.

The asphalt pavement composition of the present invention uses as a binder a mixture of rubber, a thermoplastic resin and/or an elastomer, and a rubber powder uniformly dispersed and dissolved in asphalt at the above-mentioned mixing ratio; It is a combination of.

There is no particular restriction on the aggregate to be mixed, and aggregates used in ordinary asphalt pavement compositions such as crushed stone, sand, and stone powder can be used. Further, there are no particular restrictions on the particle size distribution or blending ratio, and particle size distributions and blending ratios such as dense-grained, fine-density, or open-grained asphalt concrete can be adopted depending on the purpose.

In addition, the asphalt pavement composition of the present invention contains asphalt, rubber, thermoplastic resin and/or elastomer, and rubber powder in the binder, as well as, if necessary, for the purpose of improving spreadability to aggregate. It may also contain various additives such as aromatic mineral oil or naphthenic mineral oil, and anti-peeling agents.

The asphalt pavement composition of the present invention is prepared by adding and mixing rubber, thermoplastic resin and/or elastomer, rubber powder, and various additives as necessary to a predetermined amount of asphalt to prepare a binder. It can be easily manufactured by adding and mixing a predetermined amount of aggregate with a particle size distribution.

[Function] By blending a specific amount of at least one of rubber, thermoplastic resin, and elastomer, and rubber powder into asphalt, the asphalt binder is significantly modified. In other words, the binder properties are completely different from those of conventional straight asphalt and modified asphalt materials, and the toughness and tenacity are significantly higher. Also, the Fraas embrittlement point is significantly lower, and the temperature-viscosity curve of the binder, which is a measure of work properties, is not commercially available. A significantly better modification effect can be obtained, with properties almost equivalent to those of the modified asphalt material.

Therefore, the asphalt pavement composition of the present invention using such an asphalt binder provides a pavement surface with excellent durability, flow resistance, abrasion resistance, crack resistance, resistance to low temperature brittleness, etc. .

[Example] The present invention will be described in more detail with reference to Examples below.

Examples 1 to 3, Comparative Example 1.2 An asphalt binder was prepared, its properties were investigated,
The results are shown in Table 1. In addition, penetration, softening point, elongation,
The Fraas embrittlement point, toughness, and tenacity were measured in accordance with the asphalt pavement guidelines, and the viscosity at 60°C was measured by the Japan Petroleum Institute method.

Comparative Examples 3 and 4 The various properties of commercially available modified asphalt materials A and B were investigated, and the results are shown in Table 1.

The modified asphalt material A is a commercially available modified asphalt material obtained by modifying asphalt itself for the purpose of flow resistance, and the modified asphalt material B is a commercially available modified asphalt material based on SBR latex.

Table 2 Table 1 *St As ao7ao Nistrade Asphalt 11078GSBS: Styrene Butadiene Block Copolymer 515: Styrene Isoprene Block Copolymer NR: Natural Rubber Recycled Rubber Chips:
Average particle size 2 Fin size Rubber powder: Average particle size 400 mesh From Table 1, the following is clear.

Generally, as a binder for asphalt pavement assemblies, a kinematic viscosity of 300 Cst or less at 200°C is an indicator of the workability of cross-tracking at high temperatures;
When Cst or less is considered as an index of workability during rolling, Examples 1 to 3 fully satisfy these conditions.

On the other hand, 6 is an indicator of the flow resistance of the binder.
There is an absolute viscosity (Poise) at 0°C. Regarding the absolute viscosity at 60°C, the straight asphalt 60/80 of Comparative Example 1 is about 2000 Poise, but the values of Examples 1 to 3 exceed 4000 Poise, and the conventional modified asphalt material (Comparative Example 3.4) It has an extremely large absolute viscosity at 60°C, which is even higher than that of In general, binders with high viscosity tend to have a high mixing temperature during the production of paving compositions, but as mentioned above, the binders of Examples 1 to 3 have a kinematic viscosity of 300°C even at 200°C.
Cst or less, commercially available modified asphalt material (Comparative Example 3.
4), and the mixing temperature can be set to the same level as these for asphalt plants used to manufacture pavement compositions, without the need for any special methods, equipment, or equipment. It is not necessary and can be handled in the same way as commercially available modified asphalt materials.

Furthermore, the characteristics of the physical properties of Examples 1 to 3 are toughness, tenacity, and Fraas's sophistication point. Toughness and tenacity indicate the gripping power and adhesive strength of the binder to the aggregate, and Examples 1 to 3, especially Example 1
This is accompanied by a much larger value than that of the commercially available modified asphalt material (Comparative Example 3.4). Further, the Fraas embrittlement point indicates the degree of brittleness of the binder at low temperatures, and in Examples 1 to 3, particularly in Example 1, the value is extremely high. -The Fraas embrittlement point of the binder used numerically is rarely found to be -20°C or lower. Therefore, the binder according to the present invention is
It can be said that it has excellent resistance to brittleness at low temperatures. In this way, the binder of Examples 1 to 3, and especially Example 1, achieved extremely high absolute viscosity at 60°C, toughness, tenacity, and improvement of brittleness at low temperatures (reduction of Fraas embrittlement point) at the same time and to a high degree. ing.

In Comparative Example 2, only rubber powder was added to straight asphalt 60/80. Although the softening point increases with the addition of rubber powder, the increase in the softening point with rubber powder alone is relatively small.

In addition, although the kinematic viscosity at 200°C is 300Cst or less, the kinematic viscosity at 140°C is 3500Cst, and a significant increase in viscosity is observed as the temperature decreases, making compaction work difficult. .

Example 4.5. Comparative Examples 5 to 8 Binder of Example 1 The binder of Comparative Example 1 and the binder of Comparative Example 3 were used in the proportions shown in Table 3 or 4 to produce dense-grained asphalt concrete with the aggregate particle size distribution shown in Table 2. (13), open-grained asphalt concrete (
An asphalt pavement composition was prepared in 13), and the properties of the tamped mixture were tested. The aggregates used were No. 6 crushed stone, No. 7 crushed stone, coarse sand, fine sand, and limestone powder. Among the characteristic tests, Marshall stability and dynamic stability were measured in accordance with the asphalt pavement guidelines, and spike wear amount and brittleness point by bending test were measured by the Road Association's pavement test method.

The results are shown in Tables 3 and 4.

Table 3 (Dense Grained Asphalt Concrete (13) - Properties of Mixture Compacted 75 Times) The following is clear from Table 3 above.

Dynamic stability obtained in wheel tracking test (times/
m m ) indicates the number of passes required for a test wheel equivalent to the wheel load of a large vehicle to deform the pavement specimen by in at a test temperature of 60°C, and is a method for evaluating the flow resistance of an asphalt mixture. As such, it is a very common and reliable test.

When the flow resistance of the asphalt pavement composition according to the present invention (Example 4) was evaluated using this test method, it was found that the flow resistance was 8000 (
times/mm), which is an extremely large value in Example 4 when compared with that of the straight asphalt material (Comparative Example 5) and the commercially available modified asphalt material (Comparative Example 6). I can say that. This dynamic stability value of aooo (times/mm) or more means the maximum value that can be measured in a wheel tracking test is 6000 (times/mm).
m m ), the dynamic stability may be interpreted as a value close to infinity.

On the other hand, the amount of spike wear in Example 4 was reduced by 30% or more compared to the straight asphalt mixture (Comparative Example 5), indicating excellent wear resistance.

Furthermore, when the embrittlement point at low temperatures was determined by a bending test, it was +1°C in the case of Example 4, which was about 6°C different from that in Comparative Example 5, and the brittleness was significantly improved. Therefore, it is considered to be extremely effective in preventing crank occurrence at low temperatures.

Table 4 (Open-grained asphalt concrete (13) - Mixture properties after ramming 50 times)
．． 5% addition The following is clear from Table 4 above.

Open grain asphalt concrete shown in Table 4 (13)
The properties of the mixture also have the same tendency as the dense-grained asphalt concrete (13) shown in Table 3, but the important point to pay particular attention to here is the difference in dynamic stability, which indicates flow resistance. That is, in Example 5, 3000 (times/m m
), but in the case of Comparative Examples 7 and 8, both Example 5
(The dynamic stability, which is an indicator of the flow resistance of heavy traffic roads, is generally 1500 to 300.
0 (times/mm) is required. ). This indicates that in the case of the asphalt pavement composition of the present invention, even mixtures with difficult to obtain strength, such as open-grained asphalt concrete (13) with a large porosity, can withstand the surface layer of heavy traffic roads. clearly shown.

[Effects of the Invention] As detailed above, according to the asphalt pavement composition of the present invention, not only dense-grained or fine-grained asphalt concrete with low porosity but also open-grained asphalt with high porosity that provides a porous structure can be used. As a concrete, it provides a multi-purpose, high-quality paved surface with outstanding properties such as durability, flow resistance, abrasion resistance, crack resistance, and low-temperature brittleness resistance.

Claims (1)

[Claims] (1) A binder made by blending 1 to 10 parts by weight of at least one selected from the group consisting of rubber, thermoplastic resin, and elastomer and 0.5 to 5 parts by weight of rubber powder to 100 parts by weight of asphalt. An asphalt pavement composition characterized in that it contains , and aggregate.