JPH035350A - Cement-bitumen grout for track and its production - Google Patents

Abstract

PURPOSE:To improve seawater resistance by incorporating specified cement, a lime-based admixture, a bitumen emulsion, fine aggregate, a defoaming agent, a blowing agent and water. CONSTITUTION:A bitumen emulsion (A) having 40-70wt.% asphalt content, water (B) and a defoaming agent (C) such as metallic soap are charged to a cloud mixer fitted with turbine blades. Fine aggregate (D) of <=2.5mm diameter such as river sand, a lime-based expandable admixture (E), mineral cement (F) contg. a reduced amt. of tricalcium aluminate and having a lower tricalcium silicate content than the dicalcium silicate content or cement mixed with blast furnace slag or pozzolan material, a blowing agent (G) such as Al powder and the defoaming agent (H) are further added and kneaded. The components A, C, D, G and H are used by 100-250wt.%, 0.01-3wt.%, 100-250wt.%, 0.01-0.03wt.% and 0.01-3wt.% basing on the amt. of the component F, respectively.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cement bituminous grout material for tracks used as a filling material for slab tracks, ballast tracks, etc. in railways;
In particular, the present invention relates to a seawater-resistant cement-bituminous grout material for track, which is suitable for use in a saline environment, and a method for producing the same.

[Conventional technology]

In general, slab tracks for Shinkansen and conventional lines.

Cement-bituminous grout material (hereinafter referred to as CA mortar) is used as a filling material for paved tracks, filled bed tracks, etc.

For example, the CA mortar that has been commonly used for slab tracks until now is one that is mixed with cement, bitumen emulsion, fine aggregate, admixtures, water, etc. for use in warm regions when new tracks are constructed, and one for use in cold regions. In order to improve frost damage resistance, there is a mixture of the above materials with an antifoaming agent and an AE agent added thereto.

In addition, in order to quickly develop strength for cold-weather construction and repair work during route closures, super-fast-hardening cement or ordinary cement with a rapid-hardening admixture added instead of the above-mentioned ordinary hardening cement as both fillers. There are grout materials that use .

[Problem to be solved by the invention]

However, since none of the above CA mortars have seawater resistance taken into account, CA mortar deteriorates in submarine tunnels and bridges on the seashore due to salt accumulation and penetration due to seawater immersion and seawater spray. This caused a series of problems, such as many cases requiring early repair, requiring a great deal of effort and expense to maintain and repair the tracks, and causing serious problems with train operation.

In other words, the form of damage to CA mortar is that the hydrates of the cement and expandable admixture in the hardened body structure come into contact with seawater, causing tissue relaxation or destruction due to the expansion effect of the reaction product formed, or due to hydration. Part of the material will dissolve into the seawater and become porous, making it easier for seawater to penetrate and causing deformation such as accelerated deterioration.

In view of the above problems, an object of the present invention is to obtain a cement bituminous grout material for tracks that has seawater resistance, and to achieve long-term maintenance of tracks and prevention of repairs in saline environments.

Furthermore, it is an object of the present invention to improve construction efficiency by shortening the mixing time of the cement-bituminous grout material for tracks having the above-mentioned effects.

[Means to solve problems]

In order to achieve the above object, the present invention provides a cement for use in CA mortar, which is a mineral component cement that produces less reaction products and soluble hydrates that expand in volume upon contact with sulfates and chlorides in seawater. Alternatively, apply cement mixed with a borazone material that reacts with calcium hydroxide and fixes it.

In addition, the expansive admixture does not produce calcium sulfoaluminate (ettringite) through reaction with seawater components, but instead uses a lime-based expansive material that compensates for cement shrinkage by producing other types of hydroxide minerals. do.

Furthermore, antifoaming agents are used to densify the structure of the cured CA mortar and improve its watertightness, and high-viscosity bituminous emulsion is used to reduce material separation when it is not yet hardened and improve homogeneity. By changing the combination of materials constituting the CA mortar, a CA mortar with excellent seawater resistance can be obtained.

This will be explained in more detail below.

The cement-bituminous grout of the present invention can be applied to specific cements,
Expansive admixtures, bituminous emulsions, fine aggregates, water.

It consists of antifoaming agents and foaming agents.

As the cement, sulfate-resistant cement, moderate-heat cement, fly ash cement, blast furnace cement, or silica cement can be used, and sulfate-resistant cement and moderate-heat cement, which have high resistance to seawater, are particularly preferred. This forms the skeleton of the cured CA mortar and mainly contributes to ensuring strength.

The expandable admixture may be, for example, one mainly composed of lime, mixed with gypsum, inorganic salts, and a trace amount of a polymeric dispersant, which serves to compensate for shrinkage during hardening of the cement.

As a bituminous emulsion, for example, the penetration is 40/60 to 2007.
The main ingredients are about 500% straight asphalt and a surfactant, and if necessary, emulsification aids, dispersants, thickeners, protective colloids, etc. are used as appropriate and emulsified in water.

The asphalt content in the above emulsion is 40 to 70 wt%,
Particularly suitable is 55 to 65 wt%. At this time, anionic, cationic, and nonionic surfactants are used, and it is preferable to blend one or more of these surfactants.

In the bitumen emulsion, the surfactant is preferably blended in an amount of 0.1 to 5 wt% based on the asphalt content.

In addition, the CA mortar of the present invention uses medium-heat cement and lime-based admixtures, which have a coarser powder degree than the early-strengthening cements, C3A-based admixtures, or super-fast-hardening cements that have been commonly used in the past. , as a measure to prevent material separation 1
Preferably, the viscosity of the bitumen emulsion itself is increased by blending one or more types of thickening agents, protective colloids, etc.

Furthermore, such bituminous emulsions include natural rubber, synthetic rubber,
Synthetic resins and emulsions thereof can be mixed and used as necessary. This is effective in improving the elasticity, flexibility, impact resistance, frost damage resistance, etc. of the CA mortar cured body.

Since the required performance of bitumen emulsion differs depending on the use, it is preferable to change the blending ratio with respect to cement. For example, in the case of a slab track, 10
It is sufficient to mix 0 to 250 wt%.

As the fine aggregate, general river sand, mountain sand, silica sand, desalinated sea sand, etc. can be used, but those containing a large amount of salt must be absolutely avoided.

For example, river sand with a particle size of 2.5 mm or less is generally preferable for slab tracks, and 100 to 250 wt.
% is sufficient.

Fresh water is generally used. Examples include tap water, industrial water, groundwater, river water, lake water, etc. This is used to improve the mixability, workability, etc. of CA mortar, and it is preferable to reduce the amount added as much as possible.

Further, admixtures used together with the above-mentioned materials, such as antifoaming agents and foaming agents, AE agent 9 dispersants, thickeners, fibers, etc., can be used in combination.

Antifoaming agents include silicone-based and fatty acid-based antifoaming agents.

Alcohol-based, amine-based, amide-based, ether-based.

Metal soap etc. can be used. This is effective in reducing unnecessary air bubbles generated during kneading and improving the watertightness of the cured product. Usually 0.01 for cement
It is preferable to add up to 3 wt%.

As the blowing agent, for example, powders of aluminum, zinc, magnesium, silicon alloys, etc. can be used. Since this reacts with the alkaline content of cement hydrate to generate air bubbles, it has the function of expanding CA mortar that has not yet hardened by about 1 to 3% by volume and filling the voids with grout.

Usually, aluminum powder is 0.01 to 0.01 to cement.
It is preferable to add 0.03 wt%.

Examples of AE agents and dispersants include natural resin acid salts, polyoxyethylene alkyl ethers, lignin sulfonates, oxycarboxylate salts, naphthalene sulfonate salts, and the like.

This is effective in improving frost damage resistance by introducing minute closed cells and reducing added water by improving fluidity.

Examples of thickeners include carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, polyacrylates, polyvinyl alcohol, alginates, casein, gelatin, and animal proteins. This is effective in reducing material separation when the material is not yet cured and increasing the homogeneity of the structure of the cured product.

As for the fibers, short fibers of single materials such as glass, asbestos, carbon, polypropylene, and nylon or composite materials thereof can be used. The inclusion of fibers affects the bending strength of the cured product,
It is effective in improving impact strength and cracking resistance, and usually, alkali-resistant glass fiber has a strength of 1 to 5 w compared to cement.
t%, polypropylene fiber is 0.2 to cement
It is preferable to mix 1.5 wt%.

In addition, when kneading each of the above-mentioned materials, conventional C
A: The material input for mortar is generally bitumen emulsion.

Water, antifoaming agent, etc. first, then sand, expansive admixture.

Cement aluminum powder (approximately 10 minutes before injection), etc., and the same procedure may be applied to the CA mortar of the present invention.

Next, since the CA mortar of the present invention has problems such as requiring a long time to knead even with a conventional propeller blade type powerful mixer, a turbine blade type mixer was developed to carry out the kneading work. This allows kneading in a short time. In other words, the phenomenon of CA mortar jumping around during mixing is not observed at all, and although the swirling flow is gentle, cement nodules are rapidly sheared and destroyed, quickly disappearing, and each material is mixed well. Therefore, the kneading time can be significantly shortened.

〔Example] Examples of the present invention will be described below.

[Materials used]

(1) Cement: Early strength cement; Commercially available fineness = 4.350 dlg Specific gravity = 3.14 Sulfate-resistant cement; Commercially available fineness -3,300 cJ/g Specific gravity = 3.20 8 types of blast furnace cement; Commercially available powder degree = 3.700 ctA/g specific gravity = 3.05 moderate heat cement; commercial product fineness = 3.250 ci/g specific gravity = 3.21 (2) Expandable admixture calcium sulfoaluminate cement mineral powder; Commercial product AM Fineness - 5,800 cd/g Specific gravity = 2.89 Lime-based cement mineral powder; Invention product AP Fineness = 3.600 cii/g Specific gravity = 3.14 (3) Bitumen emulsion for mixing anionic cement ; Commercial product A: milk specific gravity = 1.015 Evaporation residue = 60 wt/χ Same needle density = 86 For mixing anionic cement; Invention product A' Emulsion specific gravity = 1.018 Evaporation residue = 63 wt/χ Same Needle density = 89 7 For mixing with ionic cement; Inventive product FA emulsion polymer density specific gravity = 1.013 Evaporation residue = 62 kt/χ (4) Fine aggregate river sand needle density = 95; Commercially available product Maximum particle size = 2.5 Garden FM = 1.40 Specific gravity = 2.62 (5) Water tap water (6) Aluminum powder J I 5K5906 Type 2; Commercial product AI component = 98.6wt/χ (7) Antifoaming agent Defoaming silicon; Commercially available product TSA730A Specific gravity = 1.01 (8) Fiber alkali-resistant glass fiber - Commercially available product Cem FIL chopped strand length = 12m Specific gravity = 2.71 Polypropylene fiber; Commercially available product P-chop, 3×5 Length = 5 mm Specific gravity = 0.91 [Mixer] (1) Medium-sized mixer Used in the laboratory test of the first embodiment. Universal AM-Qr type, capacity = 23.642. Uses beater blades.

(2) Large mixer The second embodiment was used for kneading and mixing tests based on on-site construction.

(a) ; Conventional product MA-1500 type capacity = 150
0 II! Propeller blade 1 Baffle plate 3 has maximum vertical rotation speed - 1100 rpm Motor 4 = 7.5 KW; Improved product of (a) above [Yes]) Capacity = 15001 Propeller blade 1 Baffle plate 3 has maximum tilt rotation speed = 11 Orpm Motor 4 = 9.0 (C); Invention product capacity - 15001° Turbine blade 2 Baffle plate 3 has vertical maximum rotation speed = 11 Orpm Motor 4 = 7.5KW The above items (a), (b), and (C) The shape of the blades of each mixer and the conceptual diagram of the OCA mortar spiral layer state during kneading are shown in the side view of FIG. 1 and the plan view of FIG. 2.

〔Test method〕

(1) Conforms to the J-Roth method of Flowtime JSCE rPC grout test method.

(2) Breathing rate Conforms to JSCE r Breathing rate test method for pouring mortar for prepacked concrete.

(3) Measure the height of the top surface of the sample taken in a graduated cylinder with an expansion rate of 250 cc and the diameter of the graduated cylinder with a caliper, and determine the expansion rate using the following formula.

Expansion rate (χ)・O,0OQ314 (He 1h4)
D"Here, Ho: Height of the top surface immediately after sample collection (mm)
Hza; Height of top surface after 24 hours (mm) D;
Inner diameter of measuring cylinder (mm) (4) Air content JIS A1116 rTest method using unit volume weight of unhardened concrete and weight of air content
Comply with.

(5) Cement powder generation rate Sample 52 is sieved through a 2.5 mm sieve, the weight of the remaining powder is divided by the weight of cement contained in the sample 52, and the percentage is taken as the raw powder generation rate.

(6) Degree of material separation A cylindrical specimen of 5 x 5 cm was divided into upper and lower halves on the 28th day of age, the difference in specific gravity of 172 was divided by the average specific gravity, and the percentage was taken as the degree of material separation.

(7) Compressive strength 2 Bending strength Compliant with JIS R5201r physical test method for cement. However, the loading speed is 0.5 m/sin.

(8) Seawater immersion test A 4 x 4 x 16C1 specimen is immersed in seawater (20±2°C) and various tests are conducted at the specified material age. The seawater should be replaced with fresh water once a week.

(9) Length change Conforms to the comparator method of JISA1129r "Length change test method for mortar and concrete".

0(I) Weight Change 4 X4 X16CI+ The weight change over time of the specimen is measured using a true vision balance (weight 0.1 g).

[First Example] Test examples of CA mortar from A to F shown in Table 1 and G,
Regarding Comparative Example H, the properties before hardening and the strength after hardening were investigated. The results are shown in Table 2. The formulation of the first example was used to find a CA mortar with excellent seawater resistance, and the formulation of the comparative example is that of the conventional slab track, with Blend G for warm regions and Blend H for cold regions. It has been used since.

As is clear from Table 2, the basic properties such as flow time, breathing rate, expansion rate, compressive strength, etc., which are required performances of slab track, are generally similar for each formulation of the first example compared to the formulation of the comparative example. It is equivalent, and has improved workability and ease of application to actual sites.
Good results were obtained in all aspects including strength.

Next, in order to examine the resistance to seawater, 4x4
A 16 cm specimen was immersed in natural seawater from 7 days old, and the changes in compressive strength, bending strength, length change, and weight change over time are shown in Figures 3 to 6, respectively. Further, Figs. 7 and 8 show the changes in compressive strength and bending strength over time when the material was immersed in natural seawater from 28 days old.

In addition, seawater immersion was performed at a young age of 7 days, when the hydration reaction of cement and the decomposition and solidification of bitumen emulsion have not sufficiently progressed, because the hardening structure is immature and the deterioration effect of seawater is severe. This is because we considered that the essence of CA mortar can be clearly understood.

First, as is clear from FIGS. 3 and 4, the resistance to seawater greatly differs depending on the combination of materials constituting CA mortar when the mixing ratio is the same.

The performance of each formulation will be evaluated while comparing the formulations shown in Table 1 below.

(1) Comparisons A, B, C, and D show almost no decrease in compressive and bending strength, while other formulations exhibit significant decreases in both strengths, and some break. The reason why the former group showed good seawater resistance is that, as can be seen from the formulation in Table 1, the types of cement and expandable admixture contributed. In other words, sulfate-resistant cement, moderate heat cement, and pozzolanic materials, which are relatively low in mineral components such as tricalcium aluminate and tricalcium silicate, which are conventionally considered to have excellent seawater resistance in general concrete, are mixed. Blast furnace cement falls under this category.

(2) When using early strength cement, ■ Mixture E and Mixture G
As is clear from the comparison of the two, in the former case, the deterioration caused by seawater was considerably reduced simply by not using a C3A-based admixture. This indicates that tissue relaxation and destruction due to the expansion effect of ettringite, which is produced by the reaction between calcium sulfoaluminate, the main component of the admixture, and sulfates in seawater, has been reduced. The material was verified to be hazardous.

Next, when comparing Formulation F and Formulation G, the seawater resistance of the former was significantly improved simply by adding an antifoaming agent. This can be said to be due to the effect of the disappearance and miniaturization of air bubbles in the CA mortar during kneading, which made the hardened structure somewhat denser and reduced the infiltration of seawater.

(3) In an example of the use of moderate heat cement, the formulation containing polymers and fibers has a somewhat superior resistance to seawater compared to formulation C which does not contain these substances. This is because the particle size of polymer is small at about 0.1 μm compared to the particle size of cement (about 20 μm) and the particle size of asphalt in bitumen emulsion (about a few μm), so it densifies the structure and makes the rubber It plays a role in alleviating the phenomenon of tissue destruction by imparting resin-like properties. Fibers have the effect of improving fiber properties such as bending strength, toughness, and crack resistance.

Furthermore, when looking at the state of seawater deterioration from a phenomenological standpoint, as is clear from FIG. 5, all of the formulations in which the above-mentioned deterioration was remarkable had a large change in length during the immersion period.

For example, Comparative Examples Blend G and Blend H are remarkable, followed by Blend F and Blend E.

Moreover, as is clear from FIG. 6, with these formulations, the structure of the cured product gradually swells and relaxes as the immersion progresses, increasing its weight, and eventually leading to destruction in some cases.

However, as can be seen by comparing Figures 3 and 4 and Figures 7 and 8, even in Comparative Examples Blend G and Blend H, hydration of the cement and decomposition of the bitumen emulsion have sufficiently progressed. In some cases, seawater deterioration can be considerably alleviated in the wood age. However, considering that many cases of deterioration have occurred on existing slab tracks, harmful causes must be eliminated.

In other words, from the test results above, cement.

The effectiveness of the present invention, which aims at modification by appropriately selecting the expandable admixture and bituminous emulsion, using an antifoaming agent, and further incorporating polymers and fibers as necessary, has been demonstrated.

[Second Example] The propeller blade mixer shown in FIG. 2(a) described above is usually used for mixing the CA mortars of Comparison G and Composition H of Comparative Examples shown in Table 1, which have been commonly used in the past. has been used and a large amount of construction work has been carried out.

For example, Blend G is carried out using the order of adding the materials and the mixer rotation speed shown in FIG. 9, and a good CA mortar can be obtained in a kneading time of about 5 minutes. However, in the case of the cement-bituminous grout material of the present invention, it took a long time to complete the mixing because the "leftover powder" of the cement did not disappear easily in the above-mentioned mixer.

In order to solve this problem, mixers were modified and newly manufactured as shown in Table 3 and the above-mentioned Figures 1 and 2, and a comparative test of the mixing performance of each mixer was conducted using Formulation C of the present invention. was carried out.

Table 4 shows the unhardened properties of the CA mortar and compressive strength after hardening for each mixer obtained in this test, and Table 5 shows the performance evaluation of the mixers.

As can be seen in Table 4, there are no significant differences in flow time or air volume during mixing (by sampling period) for each mixer, but mixing is completed with the disappearance of the cement "flour" as a guideline. There were considerable differences in the time required.

For example, as shown in Table 5, the No. 4 mixer of the comparative example uses a method in which the CA mortar is splashed by the centrifugal force of the propeller blade 1, so even though the turbulent swirl flow is quite strong, it does not hold and mix. It took about 15 minutes to finish. Also,
The Nα3 mixer, which is a modified version of the Nα4 mixer, has an expanded blade width.
Due to the increase in the number of rotations per rotation of the baffle plate 3, the stirring force became so strong that some of the CA mortar jumped out of the mixer.
Even so, it still took about 10 minutes to complete the kneading.

Contrary to the above, the Nα1 mixer and the Nα2 mixer of the second embodiment using the turbine blade type mixer according to the manufacturing method of the present invention, as shown in the swirling state of FIG. All of this is sucked into the center of the blade, and is repelled to the outside through the inside of the blade.
Since the blades and the baffle plate 3 had a special shape, there was no splashing phenomenon of the CA mortar, and the swirling flow was extremely soft. However, the mixing performance is significantly improved due to the structure in which all of the material always passes through the center, and there are many opportunities for shear failure and impact failure of the powder mass due to high-speed contact between the blades and the baffle plate 3. The time required is approximately 5 minutes, and the time required is approximately 173 minutes compared to the conventional mixer.
It was possible to shorten the time to

In addition, as shown in Table 4, the quality of the finished CA mortar is determined by flow time, air volume, breathing rate,
The expansion rate, compressive strength, etc. all meet the required standard values.

In other words, from the above test results, by mixing the cement-bituminous grout material of the present invention, which has excellent seawater resistance, with the new turbine blade mixer, the same construction efficiency and CA mortar quality as before can be ensured. I see that it is possible.

It should be noted that the manufacturing method of the present invention was applied to actual sites and very good results were obtained.

〔Effect of the invention〕

As explained in detail above, according to the present invention, cement,
In the cement bituminous grout material for track, which is made by adding lime-based admixture, bituminous emulsion, fine aggregate, antifoaming agent, foaming agent, water, etc., tricalcium aluminate is suppressed to a small amount and tricalcium silicate is added to the silicate. By appropriately combining the materials that make up CA mortar, such as using cement with a mineral component that is lower than that of dicardium acid, cement mixed with blast furnace slag or pozzolanic material, and lime-based expansive admixtures, it is possible to It is possible to obtain a cement-bituminous grout material for tracks that satisfies all the performance requirements for CA mortar and has excellent seawater resistance.

On the other hand, by using a special turbine blade type mixer, the mixing time of the CA mortar of the present invention is significantly shortened and construction efficiency is improved. Further, there are effects such as improvement in the quality of the cured product.

[Brief explanation of drawings]

Figure 1 is a vertical cross-sectional view showing the shape of the mixer blades and a conceptual diagram of the CA mortar swirl liquid state during kneading, Figure 2 is a cross-sectional view of the same, and Figure 3 is a 4 x 4 x 16 cm specimen at the age of 7. A graph showing the change over time in the compressive strength of the present example and the comparative example, which were determined by immersion in natural seawater from 20:00, and Figure 4 is a graph showing the change over time in the flexural strength of the present example and the comparative example in the same test. , FIG. 5 is a graph showing the change in length of the present example and the comparative example over time in the same test, and FIG. 6 is a graph showing the change in weight over time of the present example and the comparative example in the same test.
Figure 7 is a graph showing the time course of the compressive strength of the present example and comparative example, which were determined by immersing a 4 × 4 × 16 Ω specimen in natural seawater from the 28th day of age, and Figure 8 is a graph showing the change in compressive strength of this example in the same test. FIG. 9 is an explanatory diagram showing an example of the present manufacturing method. 2... Turbine blade 3... Baffle plate 4... Motor

Claims (1)

[Claims] 1. In a cement bituminous grout material for track, which is made by adding cement, lime-based admixture, bituminous emulsion, fine aggregate, antifoaming agent, foaming agent, water, etc., a small amount of tricalcium aluminate The invention is characterized by using mineral component cement containing less tricalcinium silicate than dicalcium silicate, cement mixed with blast furnace slag or pozzolanic material, lime-based expansive admixture, etc. Cement-bituminous grout for track. 2. Cement bituminous grout for tracks, characterized in that bituminous emulsion, water, antifoaming agent are added first, and then fine aggregate, admixtures, cement, foaming agent, etc. are added and kneaded using a turbine blade type grout mixer. Method of manufacturing wood.