JPH06173210A - Base reinforcing method - Google Patents

Abstract

PURPOSE:To improve executing ability by low-pressure injecting and permeating a hardenable resin system fluid or its cement mixture into a repair paving material, or mixing the above fluid or cement mixture with the base material of a new paving material. CONSTITUTION:An asphalt layer and a cement stabilized layer are core-bored up to the upper part of a base layer. Next an injecting pipe is inserted into the base layer to inject resin system fluid composed of the resin latex of polyurethane and hardening agent under low pressure, and then a normal temperature repairing asphalt mixture is charged in a core hole. In the case where only an asphalt layer is replaced, after the asphaly layer is peeled off, the above resin system fluid is scattered from the upper part of the base layer and permeated. In the case where the base is newly provided, the above resin system fluid is used independently or together with the cement instead of the cement or asphalt emulsion added to the base. Thus the supporting force of the base layer can be quickly reinforced, and influence to environment can be sharply reduced, and the base layer can be simply executed and saved in required labor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for repairing and newly constructing a roadbed layer of a pavement, particularly when it is necessary to effectively use in-situ materials and low-quality aggregates, and is labor-saving. To
In addition, the present invention relates to a roadbed strengthening method that is applied when the construction is carried out quickly and the burden on the surrounding residents and road users such as construction congestion and noise is minimized.

[0002]

2. Description of the Related Art The following construction methods are mainly used as related arts, but each has many problems. The conventional method is as follows.

(1) Replacement method and new construction The replacement construction method is to provide a pavement with a new material, requires a large-scale construction system, and has a long construction period. In particular, in urban areas, traffic congestion due to construction may occur. There are many complaints from roadside residents about noise. In addition, a large amount of roadbed materials, asphalt concrete waste materials, ground by-products such as construction by-products (hereinafter referred to as generated materials) are involved, and it is difficult to treat them. Furthermore, since a large amount of new material is input, this is not a resource-saving construction method, and not only the economic burden of transporting the generated material and new material, but also a great deal of discomfort for roadside residents. Will be things. Also, when a new pavement is constructed, there are almost the same problems.

(2) Road Reclaiming Roadbed Method The roadbed material at the current position and the asphalt mass obtained by crushing the asphalt layer are mixed with cement powder or bituminous emulsion at the current position to regenerate the pavement. Although it is advantageous in that it reduces the amount of generated material, the construction machine is large and the construction system is large, and noise and dust are often generated, and the burden on roadside residents is great. Becomes Furthermore, it is difficult to form the required stable layer due to the capacity of the mixer, the asphalt layer crusher, and the compaction ability of the compaction roller, so it is usually necessary to reproduce a roadbed with a thickness of about 30 cm. The whole roadbed cannot be regenerated except for light traffic routes. Therefore, it is not applied to the full-scale heavy traffic pavement repair work, and the applicable range is narrow.

(3) Conventional injection method Conventionally, in the construction of dams and tunnels, many injection methods have been used in which a chemical solution or a suspension is used for stopping water and stabilizing the ground. However, the scale of construction machinery is generally large, and it is not suitable for use in repairing road construction. Also, it is often injected at high pressure ( ^{2 to 20} kgf / cm ² ),
The strengthened ground strength is not so strong. Therefore,
It was difficult to apply it to the roadbed of roads that require a high bearing force because of the small top loading pressure (about 0.1 kgf / cm ² ).
Therefore, such a pouring method is not applied to the roadbed. In addition, as a method for partially repairing concrete floor slabs, etc., there is a construction method using an injecting agent such as cement-based suspension, but this construction method fills a large existing cavity,
Since it is expected to adhere to a concrete floor slab, and many of the injectants used have high viscosity, they cannot be applied as the method for strengthening the roadbed described in the present invention.

[0006]

As described above, when the pavement is repaired or newly installed, a large amount of the generated material is generated particularly by the replacement method and the disposal becomes difficult and a large amount of new material is generated. There is no choice but to put in the materials, which will be questioned from a recycling perspective. There is also a problem that the applicable range is narrow even in the roadbed reclaiming method. Furthermore, the construction requires a large number of personnel, and the traffic congestion and noise generated by the construction will cause a great loss not only to road users but also to the surrounding residents. Further, since the construction thickness of the roadbed layer is regulated from the viewpoint of rolling compaction and the like, there is a limit in shortening the construction period. Construction methods that use injection are not applied to strengthen roadbeds due to the characteristics of the injection material. The roadbed reinforced construction method (hereinafter referred to as the present construction method) according to the present invention effectively utilizes the material at the current position and the low-quality aggregate and repairs or newly installs the pavement in a resource saving manner. Furthermore, this method
A series of steps such as material leveling and rolling in general construction can be greatly omitted, and quick construction is possible, for example, construction of a thick roadbed layer is possible at a time, and as a result, It is possible to shorten the construction period. That is, the occurrence of construction congestion can be minimized. In addition, since each process does not require a large number of personnel and noise generation can be reduced, it is possible to minimize the burden on road users and local residents.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a roadbed reinforcing material (hereinafter referred to as the present reinforcing material) mainly composed of a curable resin fluid or a mixed fluid obtained by mixing cement with the cement, through an injection pipe. It is possible to save the resources and labor of the roadbed layer by injecting it into the bed at a low pressure, infiltrating it from the surface of the roadbed layer, or by kneading and simultaneously kneading the roadbed layer like the stabilization treatment method or the roadbed roadbed method. It is a construction method that can be strengthened quickly.

The reinforcing material has voids in the roadbed (voids between particles).
Is satisfied and the voids between particles are reduced, and at the same time, curing is performed to enhance the adhesive force between particles. As a result, the bearing capacity of the entire roadbed is increased. Due to the effect of this reinforcement, in the case of repair, if it has the same cross-sectional thickness as before repair, it can be configured to further support heavy traffic, and it is possible to use low quality aggregate that could not be used before. Become.

The construction method used in the present invention will be described in detail below. Method of injecting this reinforcing material from the injection pipe This method requires increasing the traffic volume without changing the road height, especially when it is necessary to release the traffic at an early stage and to suppress the generated material as much as possible. It is applied when improving the bearing capacity of the roadbed in order to cope with the above (hereinafter, referred to as this injection method).

[0010] In outline, in this injection method, a hole is drilled in the asphalt layer and cement stabilization layer to the upper part of the roadbed layer by core boring or the like, and the injection pipe is inserted into the roadbed layer. After that, the low-viscosity main reinforcing material is press-fitted through the injection pipe. At this time, it is more effective to use a pressure as high as possible, but since the upper asphalt layer or the like may be destroyed by the pressure from below, it is injected at a pressure of about 1 kgf / cm ² or less. After injecting a predetermined amount, the injection pipe is pulled out, and the core hole is filled with asphalt mixture for room temperature repair or the like.

In this injection method, when there is a spatial margin not only from the pavement surface above but also on the side road part of the road, the injection pipe is inserted transversely from the side road part into the roadway roadbed layer, The reinforcement can also be injected. According to this method, it is possible to inject the reinforcing agent without restricting traffic on the road. That is, the roadbed layer can be strengthened while the vehicle is passing normally, and it is possible to minimize construction congestion and noise due to traffic regulation, which is a problem particularly in urban areas.

According to this pouring method, the asphalt layer such as the surface layer and the base layer is crushed, the existing roadbed material (generating material) is carried out, the new material is carried in, and a series of steps in the general replacement method can be omitted. It is possible to significantly shorten the process and save labor. After that, particularly when the rubbing or the like of the surface layer portion of the pavement is remarkable, the surface layer may be cut by about 5 cm and overlayed. The curing time of the present reinforcing material depends on the type of the present reinforcing material used, the water content of the injection channel, the temperature, etc., but it is several hours to several days. Therefore, it is possible to inject this reinforcing material during traffic regulation such as night construction, to exert necessary strength when the regulation is released, and to increase the bearing capacity of the roadbed without almost destroying the asphalt layer. Further, it is possible to have a cross-sectional structure that can cope with heavy traffic with almost no generation material.

Furthermore, the present injection method can significantly improve the maximum finish thickness of each roadbed layer. That is, at present, the finished thickness per layer of a layer usually made of crushed stone or the like is about 30 to 50 cm, which is mainly controlled by the ability of the compaction machine. That is, when compacting a thickness of about 50 cm or more, it is difficult to obtain the required compaction degree in the lower part of the layer, so the finishing thickness per layer is specified, and the process shortens in large-scale construction. It is considered to be an obstacle to Here, after the completion of the compaction, it is possible to increase the strength of the entire roadbed by injecting the reinforcing material into the thick layer having a low degree of compaction. The upper part of the layer is considered to have a specified density strength due to the compaction,
In the lower part, compaction degree, density, strength, etc. are insufficient due to lack of compaction energy. The reinforcing material is injected into that portion to increase the strength of the entire layer. In this case, the injection range of the reinforcing material is determined in consideration of the total thickness of the layer, the degree of compaction at that portion, and the required strength of the entire roadbed. In this case, since the compaction degree of the injection layer is lower than usual, this reinforcement can be injected even with higher viscosity (about 200 cps or less) than the normal type, and the one that emphasizes the reinforcement effect is used. It

Method of infiltrating the reinforcing material from the upper surface of the roadbed The rubbing of the asphalt layer extends to the entire asphalt layer, but there is no problem in the roadbed layer, and this roadbed reinforcement method is used even when only the asphalt layer is replaced. Can be applied. This is a construction method that does not use an injection pipe, but strips off the asphalt layer, then spreads and permeates this reinforcement from above the subbase layer with a sprayer-like spraying device to non-destructively strengthen the subbase layer. (Hereinafter, referred to as this infiltration method). At this time, it is also an effective means to give vibration to the roadbed by a vibrating roller or the like to promote penetration of the reinforcing material. The viscosity of the reinforcing material is about 100 cps or less, though it depends on the grain condition of the roadbed material to be reinforced.

The reinforced roadbed layer exhibits the required strength after curing for several hours to several days, and the construction of the upper layer can be performed.
Therefore, the steps such as excavation, unloading, and loading of the roadbed layer, and further laying and leveling, rolling compaction, etc. are omitted, the construction period is shortened, and not only many personnel are required in the infiltration process, but also skilled workers are required. This is a labor-saving construction method because it is not necessary. Further, similar to the construction method, there are many advantages such as a small amount of generated material.

Method of Mixing This Reinforcement Material with Roadbed Material It is also possible to use this reinforcement material in combination with an on-road roadbed regeneration construction method or a road stabilization treatment method (hereinafter referred to as this mixing construction method). In this case, the reinforcing material is used alone or in combination with the cement instead of the cement or asphalt emulsion added to the subbase during mixing. By using this reinforcing material, it is possible to easily and early form a high-strength roadbed layer as compared with the conventional stabilization treatment, and it is possible to eliminate the generation of dust that occurs when cement or the like is used. In addition, the addition of the reinforcing material makes the roadbed material easy to compact, and a large compacting effect can be obtained even in the same compactor. Furthermore, the strength of the roadbed can be increased even with a relatively small degree of compaction due to the consolidation effect of the present reinforcing material. From these two effects, a thicker roadbed can be strengthened, and the support force of the roadbed can be increased more efficiently. Further, when the existing structural strength of the pavement is sufficient, the total thickness of the pavement can be reduced. Similar to the construction method, the present mixing construction method can provide a more stable and high-strength roadbed in addition to the advantages that the generation material is scarce and the construction period is short.

In the reinforcing material used in this mixing method, the amount of water added to the main agent and the curing agent is determined in consideration of the amount of water in the roadbed and the mixing property. Generally, the present reinforcing material, which is mainly composed of a main agent and a curing agent, is used without adding water. The viscosity of this reinforcing material is determined in consideration of the characteristics of the roadbed material, the performance of the mixing machine, the required strength, etc.
cPs or less. At this time, if it is difficult to obtain strength due to a large amount of water in the roadbed, or if there is a problem with the mixability, add about 3% of cement to the roadbed material to build a stable roadbed layer. be able to. The method of adding cement includes a method of adding it simultaneously with the reinforcing material at the time of mixing, and a method of adding it to the reinforcing material itself in advance.

The materials used in the present invention will be described in detail below. The reinforcing material used in the present invention is, for example, a fluid obtained by mixing a curing agent such as an MDI-based or TDI-based water-soluble isocyanate with a resin latex such as an acrylic-based, SBR-based, NBR-based, or polyurethane-based resin latex or room-temperature curing. Obtained from a type epoxy resin-based fluid. It is preferable to use an epoxy resin system for particularly large reinforcement. When low viscosity is required due to the characteristics of the roadbed material to be infiltrated or injected, the viscosity is reduced by diluting with water, but the stability of the reinforcement (prevention of separation, etc.) is achieved by adding cement, especially thin cement paste. ) Can be increased. The water-cement ratio of this cement paste is determined by the required strength, penetration and injection method, gel time, characteristics of the roadbed material to be reinforced, etc.
Approximately 1000% is used. When it is necessary to further improve the stability and fluidity of the reinforcing material depending on the types of the curable resin and cement, it is preferable to add a latex such as an acrylic latex.

The gel time, the curing time and the injection pressure in the case of injection of the present reinforcing material used in the present roadbed reinforcing method are determined in consideration of the construction form, the grain size of the roadbed material to be strengthened and the like. For example, when the injection method is applied to a roadbed material having a small maximum particle size and a good particle size distribution, it is injected with a pressure of about 0.5 kgf / cm ² with a gel time of about 20 to 40 minutes. The gel time is set to a few seconds to a few minutes when the particle size is coarse and the injected or permeated reinforcement material may be immediately washed away laterally or downward. In this case, the injection pressure is determined in consideration of the mounting pressure and the like. However, there is no risk of the reinforcement being washed away from the roadbed material, and when filling all the voids in the roadbed with the reinforcement material, or in the case of the infiltration method, the mixing method, etc. It is also possible to set the gel time to a degree or more.

[0020]

EXAMPLES The present invention will be described in detail with reference to examples. [Example 1] To crushed stone (M-40, median particle size), 3% by weight of ordinary Portland cement and 6% by weight of water (equivalent to the optimum water content ratio with respect to crushed stone + cement) were added, and sufficiently kneaded and mixed. I do. Then, 3.5 parts by weight of the main reinforcing material (normal temperature curing type epoxy resin-based fluid) in which the main component and the curing agent (the product names are DT-377 and I-1199) were mixed in advance at a ratio of 1: 1 (weight ratio). % (Against crushed stone + cement)
Add and mix well. The mixture was divided into 3 layers, packed in a mold for uniaxial compression test, and crushed 25 times for each layer with a 2.5 Kg rammer (crushed stone is JIS A-1.
According to No. 210, the replacement of aggregate of 25 mm or more is performed). The tamped specimen is in a good state without any phenomena such as separation or softening, and is in a state that it can be immediately demolded. Place this sample in a sealed state for 1 day, 3 days,
And a uniaxial compression test was carried out after 7 days of curing (the test method includes uniaxial compression test method of stable treatment mixture for 3 and 7 days including 1 day of underwater curing) Pavement Test Manual Handbook (edited by Japan Road Association) According to). As shown in Table 1 below, the results showed good results exceeding the standard (30.0 Kgf / cm ² ) when the cement stabilization treatment was applied to the upper layer roadbed even in the 1-day strength.

[0021]

[Table 1]

[Embodiment 2] By the composition shown in Embodiment 1,
Specimens were prepared in accordance with the CBR test method specified in JIS A 1211. The prepared test piece was kept in a sealed state, and CBR value was measured after 1, 3, 6, and 9 hours (JIS A1211). As shown in the table below, the test results show a CBR of 44% after 1 hour of curing and a value of 450% or more after 3 hours. This indicates that at the site, the construction of the next layer can be started in a short time after the construction. The results are shown in Table 2.

[0023]

[Table 2]

[Embodiment 3] With the formulation shown in Embodiment 1,
The uniaxial compressive strength of 1-day curing was measured by setting the number of times of tamping to 10, 15 and 25 times. As shown in the figure below, even when the compaction number is 10 times, which is less than half of the regular (25 times), the compressive strength of 1-day curing is 35 kg.
Since it exhibits f / cm ² or more and can exert 70% or more of the strength obtained by regular tamping, it has sufficient strength even in the lower part of a thick roadbed layer where the roller compaction effect is not sufficient. And stability can be demonstrated. The results are shown in Table 3.

[0025]

[Table 3]

[Comparative Example] To a crushed stone (M-40), 3% by weight of ordinary Portland cement and 6% by weight of water (based on crushed stone + cement) were added and mixed, and a sample was prepared in the same manner as in Example 3. Created. As shown in the table below, the uniaxial compressive strength for 1-day curing is significantly inferior to the case where the present reinforcing material is mixed, and particularly the strength is significantly reduced when the tamping number is reduced.

[0027]

[Table 4]

[Embodiment 4] In order to verify the effect of the present reinforcing material by the injection method, the following experiment was conducted. Crushed stone (M-40, median particle size) in the optimum water content ratio is 5
A specimen was prepared by compacting in a transparent acrylic mold of 0 × 30 × 30 (width × depth × height). The compaction degree of the specimen at this time is about 95%. An injection pipe having a diameter of 3 cm and an inner diameter of 2 cm was driven into the center of the test piece and connected to a pressure tank storing the reinforcing material. An epoxy-based curable resin was used as the reinforcing material, water was added to improve the injection property, and acrylic latex was added to improve the stability of the mixed reinforcing material. The initial viscosity of the mixed reinforcement is about 30 cPs (normal temperature),
The pot life is about 20 minutes. The injection into the test piece was performed at an injection pressure of 0.5 Kgf / cm ² for about 8 minutes. According to the observation after the injection, it is considered that the reinforcing material was injected into the test piece almost uniformly, the start of the solidification was confirmed in about 30 minutes after the injection, and the practical strength was reached in about 3 hours.

[Example 5] In the same manner as in Example 4, the following experiment was conducted in order to confirm the reinforcing effect of the crushed stone material in which the present reinforcing material was injected. The mold for producing the uniaxially compressed specimen was modified so that the reinforced stone (M-40, median grain size) compacted in the mold could be injected with the reinforcing material from the side. The specimen was prepared according to the specimen preparation procedure for the uniaxial compression test. After the specimen was prepared, the reinforcement was injected through the pressure tank. The injection pressure was 0.5 Kgf / cm ^2, and the injection time was about 3 minutes. As in the case of Example 4, the reinforcing material here is one in which the viscosity is lowered by adding water to an epoxy-based curable resin, and acrylic latex is added to increase the stability. The initial viscosity of this reinforcing material is about 30 cPs, and the pot life is about 20 minutes (normal temperature). After completion of the injection, the test piece was sealed and after curing (in air for 6 days and in water for 1 day), a uniaxial compression test was performed. As a result, a result exceeding 30 Kgf / cm ² which is the standard of the cement stabilized roadbed material was obtained.

[0030]

Industrial Applicability The present invention, when repairing an existing pavement or constructing a new pavement, by using this roadbed reinforcement material in combination with the roadbed equivalent layer of the pavement, the bearing capacity of the roadbed layer can be improved. The present invention enables a simple, economical and labor-saving method for strengthening a roadbed and its structure, which strengthens the roadway at an early stage and has very little impact on the local environment.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a curing time and a CBR value of a specimen prepared by using the present reinforcement material (combined with cement).

FIG. 2 is a diagram showing the relationship between the number of times of tamping and the uniaxial compressive strength after 1-day curing of the test piece to which the present reinforcement material (also cement is used together) and the test piece to which only cement is applied.

Continuation of the front page (72) Kohei Kawabata 1-19-11 Kyobashi, Chuo-ku, Tokyo Inside Nippon Tappido Co., Ltd.

Claims (1)

[Claims] 1. When repairing an existing pavement body or when constructing a new pavement body, mainly a curable resin fluid or a mixed fluid obtained by mixing cement with the roadbed layer of the pavement body is mainly used. A method for strengthening a roadbed, which comprises injecting a roadbed reinforcing material at a low pressure through an injection pipe, infiltrating it from the upper part, or mixing it with the roadbed material at the current position to strengthen the bearing capacity of the roadbed layer.