JPS59158803A - Repairing of pavement - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pavement repair method, and particularly to an in-situ repair method for existing asphalt pavement where ruts have occurred.

Flow ruts, which are generally caused by concentrated loads on wheels during traffic use, are more likely to occur in the summer when the temperature of asphalt pavement increases. Flow ruts occur due to flow deformation that occurs when an asphalt mixture that has been softened by high temperatures is subjected to pressure.There are many factors that can be cited for this.
A major factor in this is the influence of excess asphalt.

As a method to completely prevent such asphalt ruts from forming, many attempts have been made to prevent their occurrence in advance using various modified binders, but it has not been possible to completely prevent this. not present. -As a method of repairing the existing asphalt pavement, which has recently developed ruts, is it possible to scrape up the asphalt (ti11) and add crushed stone to it? : Some studies have begun to consider a method of adding mixture, leveling and compacting, but there are problems such as workability and economic efficiency.
K: Yes, but no fully satisfactory method has been developed.

Therefore, the present inventors conducted extensive studies to establish an in-situ repair method that can provide asphalt pavement with excellent workability, economic efficiency, and excellent flow resistance at high temperatures. We have arrived at the remarkable invention.

That is, the present invention provides an in-situ repair method for asphalt pavement, which involves scraping up asphalt pavement, mixing it with artificial lightweight fine aggregate having a water absorption capacity of 7 to 1 I, leveling it, and compacting it. It is something.

The additives used in the present invention belong to the category of artificial lightweight fine aggregates and have a water absorption of 7% or more, but those with an FDR value of 1.75 or less, which will be described later, are particularly effectively used. Specific examples of such artificial lightweight fine aggregates include fine aggregates commercially available under the names of Mesalite, Pilton, Asanolite, and the like. Such artificial lightweight fine aggregates with a water absorption of 7 or more exhibit sufficient effects when used in small amounts.

The amount added is 1 to 1 per raked asphalt pavement.
0% by weight, particularly preferably 2 to 7% by weight.

Artificial lightweight fine aggregate with a water absorption of 7 cm or more exhibits a sufficient effect by itself, but it can be used in combination with other additives as appropriate. In particular, when a fine mineral powder having a flow test value of 70 or more is used in combination, even more remarkable effects can be obtained. Mineral fine powder with a flow test value of 70 or higher has superior asphalt absorbency compared to limestone powder, etc., which is normally used as filler for pavement, and also has superior adhesive strength and gripping power when turned into filler bitumen. . These fine mineral powders are difficult to disperse uniformly in an asphalt mixture by themselves, but can be sufficiently uniformly dispersed by mixing or adhering them to the above-mentioned artificial lightweight fine aggregate.

Methods for attaching fine mineral powder to artificial lightweight fine aggregate include dispersing the fine mineral powder in water or an aqueous solution of glue material, sprinkling it on the artificial lightweight fine aggregate, and then drying it. There is a method in which lightweight fine aggregate is coated with water or an aqueous solution of a glue substance, sprinkled with fine mineral powder, and then dried.

Mineral fine powder is 20 parts by weight for 100 parts by weight of artificial lightweight fine aggregate.
It is preferable to use 100 parts by weight.

Examples of fine mineral powder preferably used in the present invention include diatomaceous earth, kaolin, precipitated calcium carbonate, and slaked lime.

In this way, the existing asphalt pavement where ruts have occurred is completely heated and scraped up, and the above-mentioned artificial lightweight aggregate or the above-mentioned mineral fine powder mixed or attached thereto is added and mixed to the asphalt mixture and laid. Apply by leveling and compacting.

This makes it possible to obtain asphalt pavement that is easy to construct, inexpensive, and has excellent flow resistance at high temperatures. Next, the effect of improving flow resistance at high temperatures according to the present invention will be explained in more detail.

Existing surface asphalt mixtures in which flow ruts have occurred vary depending on the traffic load conditions, but generally wheel tracking tests (asphalt pavement guidelines method, ground pressure 6.
4 K9/CR&, test temperature 60°C) dynamic stability should be less than 500 cycles/depression, and the overall compression deformation of the pavement should be less than 3%, which is a condition where excess asphalt is likely to occur. It has become. This kind of asphalt pavement is scraped up and artificial lightweight aggregate with a water absorption of 7% or more is mixed (or, if desired, a complete mixture of fine mineral powder or an attached additive with a siflow test value of 70 or more is added to this). This improves the high-temperature stability of asphalt mixtures with reduced dynamic stability, and easily achieves the dynamic stability of 1,500 cycles/body or more, which is the target for flow-resistant asphalt mixtures in the Asphalt Paving Guidelines. This can be achieved.

The present invention will be explained below based on Examples.

Example Dense-grained asphalt asphalt (20) and fine-grained asphalt (one patch of asphalt mixture) as defined in the asphalt pavement guidelines, by adding artificial lightweight aggregate or a mixture of fine mineral powder to this, The high-temperature stability effect of asphalt mixtures was investigated.The synthetic particle sizes and mixture properties of dense-grained Ascon (20) and fine-grained Ascon (13) are shown in Table 2, and the artificial lightweight fine aggregate is shown in Table 1. It has the properties shown.

As for the asphalt mixture in which all the additives are added, the excess asphalt is likely to breathe and flow ruts are likely to occur. Section 5 and i'i
Q meter Asun-Dalt h) - 11, 0 two gods and again.

, this mixture: /r-150~160℃) Ji'i,
9+2, put it in the sample frame for wheel dragging,
Marsyel specimen density (prepared according to the asphalt pavement guidelines method)'X boiling and tamping 75 times each)
1st degree Nitaru-sama D-Raconbacter 1 Kasaiichi 41 Meru 1,
After this/(Mini) the thickness of the specimen (2.5cm)
Add a specified amount of 'cj - scraped, cooled if] and mix with a small scoop, 4)] Tighten [61st] to make a specimen for wheel trot type 1. Fine-grained Ascon (1:3F') shown in Table 2, which is applied as a wear-resistant mixture in the ground, also lost M in the S1 asphalt test. For comparison, we also conducted a case in which an additive whose water absorption amount was outside the range of the present invention was used.

, Wheel tracking test method ζ′, 1: Asphalt pavement guidelines method, test temperature 60℃, ground pressure 6.4 h /
crri toshi/ko.

The dynamic stability results of these wheel tracking tests are shown in Table 3. In Table 3, (seconds) and ■ are comparative examples outside the present invention.

The void ratio of the compacted specimen of the asphalt mixture of -(, -1.0%) with the dense grain size Ascon (20) shown in Table 3 is 1.7 and the asphalt pavement required silk 1. 'j)% value for Marshall test 3.0 ~
6.0 The lower limit of article 1.3 due to the running of the load type. It is a mixture that causes fluid ruts to occur immediately.
This was carried out with the assumption that improvements would be made by in-situ regeneration Tfi: of the road surface where flow ruts had occurred on the existing pavement. In addition, the dynamic stability of fine-grained Ascon (13F) for wear resistance in a wheel tracking test under the conditions of a test temperature of 60°C and a ground pressure of 6.4 Kr/csi is generally impossible to measure due to the large amount of deformation.

As a result of the above, it has been shown that asphalt mixtures containing artificial lightweight aggregate or mineral fine powder mixed therein are excellent in stability at high temperatures. Because there is a concern that the fracture strain at low temperatures will decrease due to high temperature stability, these studies were also attempted.The test conditions and test results for the 5-Mo are shown in Table 4.

As a result, the reduction in fracture strain at low τjlu due to high temperature stability was not observed within the range of 1 to 10 wt u'% of additives, resulting in no problem.

1: 1-----------1
---: 1 1 1, ----- 1,000-year-old man-1: 1: ■ 1 1 1 Note) The testing machine and method for fine aggregate hardness (FDR) are described in the Japan Society of Civil Engineers paper report Azumaya 250 (June 1976). month)7)
, 133-136, "Proposal of test method for toughness of fine aggregate for roads".

■ Hardness tester An iron cylinder with an inner diameter of 20 cm and a depth of 34 cIn and a bottom is mounted on the horizontal rotating shaft at an angle of 30 degrees. Attach an iron lid that can be tightened so that there are no gaps in the cylinder.

■Sample (i) Dry sample 2.5, 1.2, 0.6
, Sieved with a 0.3-meter mesh sieve, with particle size groups of 2.5-1.2, 1.2-0.6, and 0.6-0.3: r, (1300±11 Mix all three of these and use as a sample for hardness testing.

(ii) (Determine the unit volume weight of the sample D using the light weight method.

(iii) The amount of sample used for hardness test is 1740i
Let the amount be .

(Unit volume weight
, t.

(11) Sample and 4300±202 spheres (approximately 25 in diameter made of ceramics).

Each piece weighs 30.0 to 31.5 gr) and is placed in the cylinder of a total hardness tester and the lid is tightened, followed by rotation at 30 r, p, m for 60 minutes.

(i:i) Take out the sample from the cylinder and pass it through a mesh sieve 2.5
, 1.2, 0.6.

ll5A 11 at 03.0.15 and 0.074mm
Sift according to 02.

■ How to determine hardness The hardness is calculated using the following formula. .

Here FDR-hardness FD-sample mesh sieve 2. et al., 1.2, 0.6,
0.3.

Sum of weight percentages passing through 0.15 and 0.074 mm (FD before test is 200) Note) ■ Asphalt amount of dense grain Ascon (20) before addition is 6.1% (QAG' + 0.5%) It is.

■The conditions for the bending test are as follows ('r) Specimen dimensions: 2 widths: 5 cm, thickness: 5α, length: 3
0 mouth (lj) test temperature knee 10℃

Claims (1)

[Claims] An in-situ repair method for pavement, which is characterized by scraping up asphalt pavement, adding and mixing artificial lightweight fine aggregate with a water absorption of 7% or more, leveling it, and compacting it.