KR101048669B1 - Repair mortar and tunnel repair method using the same - Google Patents

Abstract

The present invention provides a repair mortar that can be quickly and soundly repaired in a short time in the repair work of tunnel perforated concrete using industrial by-products.

In the mixing of the repair mortar expressing a compressive strength of 6 N / mm 2 or more for 3 hours, an ultrafine cement having a powder level of 5000 to 8000 m 2 / g is used as the cement-based binder, and 50% by volume or less of fine aggregate is absorbed by 5%. Replace with artificial lightweight aggregate sand with a dry density of 1.4 to 2.0 g / cm3 and replace less than 50% by weight of ultrafine cement with fly ash and water binder ratio of 37 to 44% (fly ash is added to the binder) These mixtures are kneaded, pre-flow 200 to 300 mm, condensation start time is 45 minutes or later, and condensation termination time is 80 minutes or less.

Tunnel repair, repair mortar, compressive strength, ultra fine cement, artificial lightweight aggregate.

Description

Repairing mortar and a process for repairing tunnel using the same}

1 is a view showing a preflow test result of the repair mortar according to the present invention.

Figure 2 shows the results of a J lot packed flow test of a repair mortar according to the present invention.

3 is a view showing the test results regarding the setting time of the repair mortar according to the present invention.

4 is a view showing test results regarding the compressive strength of the repair mortar according to the present invention.

5 is a view showing the relationship between the starting time and the three-hour compressive strength of the repair mortar according to the present invention.

6 is a diagram showing the relationship between the binder material ratio (B / W) and the compressive strength of the repair mortar according to the present invention.

7 is a view showing the change in length of the repair mortar according to the present invention.

8 is a view showing the test results of the adhesion strength to the various primers of the repair mortar according to the present invention.

Fig. 9 is a diagram showing the change in the amount of wear caused by the elapsed time of the repair mortar according to the present invention in comparison with that of the normal strength mortar.

The present invention relates to a repair mortar and a tunnel repair method using the same.

Deterioration such as abrasion, scouring, and cracking occurs over years in general tunnels, waterway tunnels, and raceways, and as a maintenance work, a mobile center mold is usually installed. The inner volume method which injects and charges mortar with a grout pump is implemented. At this time, it is desired to be able to construct as quickly as possible in the night construction or the dryer with low traffic volume. In particular, hydroelectric power plants have many repair structures that have passed more than 50 years after construction. To cope with this, industrial by-products should be effectively repaired while considering the conservation of the global environment and the use of resource-circulating materials.

Repair work of waterway tunnel is carried out at construction environment temperature of less than 10 degrees Celsius or less of dryer of almost November to February, but charges maintenance mortar with grout pump using mobile center mold (steel assembly mold) for shortening air Afterwards, rapid construction is required to demould three hours after pouring. To this end, use of a maintenance mortar with high fluidity and fastness is indispensable. In general, increasing the fluidity of the high flow mortar composition having a fast hardness slows curing. In the low temperature environment of about 10 ° C, the strength development of the cement is further delayed. On the other hand, when the fastness is increased, the time for maintaining the flow is shortened, so that sufficient pot life required for construction cannot be secured.

Japanese Unexamined Patent Application Publication No. Hei 7-17794 describes a highly rigid high-flow cement composition having high fluidity and rapid rigidity by maintaining fluidity for a predetermined time without adding a coagulation retardant. Such a composition aims at maintaining fluidity for 10 minutes or more and expressing an intensity of 1 N / mm 2 or more within 3 hours.

Japanese Laid-Open Patent Publication No. 2001-146458 discloses a high-flow fast cement compound that can be condensed and demolded immediately by adding a fluidizing agent to a mortar having a fast hardening, thereby obtaining high fluidity during pouring, and then immediately condensing and demolding. It is. This formulation is usually a kneading of the polland cement mortar, followed by 30 minutes of elapsed time, followed by post-adding of a mixture of a fastener, a glidant and a retardant.

In Japanese Unexamined Patent Publication (Kokai) No. 7-17794, as shown in the examples thereof, even if its fluidity indicates a flow of 200 mm within 10 minutes, if the flow exceeds 10 minutes, the flow becomes less than 200 mm. Therefore, it is difficult to employ a pot life (waiting time) of 10 minutes or more from kneading, and must be poured immediately after kneading, and the highest compressive strength after 3 hours is only 1.68 N / mm 2. Therefore, it is difficult to say that the injection time into the mold cannot be sufficiently taken and that the strength at the time of demolding is not sufficient, so that it is difficult to apply to the repair of the vent mortar of the tunnel.

In Japanese Unexamined Patent Application Publication No. 2001-146458, for example, a quickener, a fluidizing agent, and a retardant are added after 30 minutes have passed after mortar kneading. It is not suitable for injection construction into the mold. In addition, although the setting time is shown only as an evaluation of fastness in an Example, since important intensity data are not shown in the evaluation of fastness, also in this point, it is difficult to apply to repair of a tunnel hole mortar.

Accordingly, the present invention has a problem of developing a repair mortar that has a high fluidity suitable for repairing a tunnel air mortar and exhibits a high strength that can maintain its high fluidity for at least 10 minutes and can be demolded after casting. In addition, by using industrial by-products, such as fly ash or blast furnace slag, and artificial lightweight aggregate manufactured from the coarse ash powder and shale as raw materials as much as possible to constitute the repair mortar Let's make it a task. The object of the present invention is to allow repair of the repaired concrete of a waterway tunnel and a raceway, as well as a general tunnel, with good constructionability and high quality.

As a repair mortar which solved the said subject, According to this invention, in the mixing | blending of repair mortar which expresses compressive strength 6N / mm <2> or more of the age of 3 years, the powder degree as a cement type binder is 5000-8000 cm <2>. Substituting less than 50% by volume of fine aggregate cement / g of fine aggregates with artificial light weight aggregates with absorption rate of 5% or more and dry density of 1.4 to 2.0g / cm3, and replacing less than 50% by weight of ultrafine cement with fly ash With a water binder ratio of 37 to 44%, preferably 39 to 41% (fly ash is incorporated into the binder), these blends are kneaded to give a preflow of 200 to 300 mm, preferably 240 to 300 mm, and the settling start time. A repair mortar is provided after 45 minutes and the condensation termination time is within 80 minutes. The repair mortar may have a compressive strength of 40 N / mm 2 or more, preferably 45 N / mm 2 or more for 28 days, and the artificial lightweight aggregate is preferably a fine grain having a particle diameter of 5 mm or less. As the fine aggregate, one or two of silica sand and blast furnace slag yarn are used. In addition, the measurement of the preflow, the condensation start time and the condensation end time can satisfy the above-mentioned values even when all are measured under conditions of a temperature of 10 ° C. and a relative humidity of 80%.

In addition, with respect to the above-mentioned formulation, as a blending material, the calcium aluminate-based fast hard material 480Kg / m 3 or less, calcium aluminate-based expander 60 Kg / m 3 or less, the powder also 8000 cm 2 / g or more ultra-fine particle activating material 150Kg / m 3 or less The repair mortar which mix | blended 1 type or 2 or more types is provided.

Further, for the above-mentioned compounding, as a admixture, for repairing, further comprising one or two or more of an antifoaming agent of 1 Kg / m 3 or less, a dispersant of 12 Kg / m 3 or less, a strength accelerator of 1 Kg / m 3 or less, and a retardant of 1 Kg / m 3 or less. Provide mortar.

In addition, according to the present invention, in the inner space method of a tunnel in which a mold is provided on an inner wall of a general tunnel or a water channel tunnel, and a repair mortar is filled in the space between the inner wall and the mold, the repair mortar is used as the repair mortar. Provide the tunnel repair method to be installed.

The inventors of the present invention have repeatedly conducted various test studies regarding the problem of deterioration of the hollow concrete of the tunnel, but the mobile steel mold is installed inside the hollow concrete and the high flow mortar is filled to demould in a short time. Considering that the inner frame method of using the center mold changing the filling range is excellent in terms of short-term construction and repair quality, various studies have been conducted to obtain a repair mortar suitable for the inner frame method. As a result, it was possible to develop a repair mortar at this time, which is capable of fully deriving the advantages of the internal protection method while using industrial by-product materials as much as possible. The repair mortar is set to 39 to 41% of water / binder ratio by using ultra fine cement, fly ash, lightweight artificial aggregate sand, silica sand and / or blast furnace slag, and has a compressive strength of 6 N / mm 2 or more for three hours. , Preflow 240 to 300mm, condensation start time 45 minutes or more, condensation termination time 80 minutes or less to express.

Below, the matter specified in the maintenance mortar which concerns on this invention is demonstrated.

[Super fine grain cement]

It is cement which refined cement particle | grains, and actually refers to the cement whose powder degree was raised to 5000-8000 cm <2> / g by regrinding the normal polland cement of powder degree 2800-3500cm <2> / g. Since the ultrafine cement is a fine particle, the hydration reaction with water is fast, and since the structure of the cement matrix is densified, the initial strength is higher and the long-term strength is also increased than the normal cement. In the present invention, the ultra-fine particle cement is used in a blend of 150 Kg / m 3 or less, preferably 10 to 120 Kg / m 3, more preferably 300 to 600 Kg / m 3, thereby promoting the fast hardness and high strength of the auxiliary mortar. When the amount of the ultrafine cement is less than 10 Kg / m 3, this effect cannot be sufficiently exhibited and the strength is also insufficient. On the other hand, in the formulation exceeding 150 Kg / m 3, the compressive strength of 6 N / mm 2 may not be secured for 3 hours.

[Fly ash]

Fly ash is an industrial by-product from coal-fired power plants. It is mainly used as a raw material for cement and as a substitute for cement in concrete production at ready mixed concrete factories and construction sites, but not all of the fly ash generation is used here. The unused portion is processed for landfilling and the like. In the present invention, such an unused fly ash is used in a large amount as much as possible, so that it can be effectively used as a repair mortar for tunneling perforated concrete. Fly ash does not react directly with water, but hardens by reacting with calcium hydroxide produced by the reaction of ultrafine cement and water. That is, in the auxiliary mortar of the present invention, it is used as a latent hydraulic material which functions as a binder together with ultrafine particle cement. In addition, fly ash has a property of slower strength development and stronger chemical resistance than foolland cement, thereby increasing long-term strength. Fly ash also contributes to densifying the structure of the cement matrix and acts on the high mobility and viscosity of the secondary mortar. The fly ash powder used in the present invention is about 2500 to 4500 cm 2 / g. In the auxiliary mortar of the present invention, 50% by weight or less of the ultrafine cement is replaced with a fly ash. Specifically, it is preferable to use in the formulation of 400 Kg / m 3 or less, preferably 300 Kg / m 3 or less. In formulation exceeding 400Kg / m <3>, it may become difficult to ensure intensity | strength 6N / mm <2> or more for 3 hours.

[Artificial lightweight aggregate company]

The artificial lightweight aggregate used in the present invention has an absorption rate of 5% or more, a dry density of 1.4 to 2.0 g / cm 3, an average particle diameter of 5 mm or less, and a proportion (assembly rate) of 7% of granules having a particle diameter of 5 mm or more is present. Hereinafter, it is preferable that it is 5% or less preferably. Artificial lightweight aggregates having these characteristics are more porous than natural fine aggregates, and since water contains in their pores, mixing them with mortar can improve fluidity, and the internal curing effect at an early age by containing water. Is expressed, and shrinkage at the time of curing can be reduced to suppress the occurrence of cracking.

Such artificial lightweight aggregate, for example, by mixing the coarse powder (a) of the coal-fired power plant by-product and the fine powder of shale (b) in the ratio of (a): (b) in the weight ratio of 4: 6 to 6: 4 After granulation, the resultant was calcined at about 1100 to 1200 ° C. in a rotary kiln and quenched in water from about 100 to 200 ° C. in the course of its cooling, and the resulting fired product was pulverized and classified to fine aggregate of 5 mm or less. It can obtain by fractionating.

When the cutting density of the artificial lightweight aggregate yarn is less than 1.4 g / cm 3, the crushing load is less than 1000 N. When the density exceeds 2.0 g / cm 3, it is difficult to secure a sufficient absorption rate. The cutting density of the lightweight aggregate yarn is preferably 1.4 to 2.0 g / cm 3, preferably 1.40 to 1.90 g / cm 3. As for the water absorption rate, the shrinkage reduction effect due to the fluidity and the internal curing effect is not sufficiently exhibited at 5% or less. It is preferable that a water absorption is 20% or less. A water absorption higher than this becomes excessively porous and hardly contributes to strength improvement.

In the present invention, up to 50% by volume of fine aggregate is replaced with such artificial lightweight aggregate yarn. Replacing fine aggregates with artificial lightweight aggregates in excess of 50% by volume is not very desirable because there is a risk of stably controlling the fluidity and strength characteristics of the auxiliary mortar. The replacement rate of artificial lightweight aggregate sand to fine aggregate is preferably 40% by volume or less, more preferably 30% by volume or less.

[Aggregate Aggregate]

The fine aggregate used in the present invention is preferably one or two of silica sand and blast furnace slag. By using silica sand and / or blast furnace slag yarn having an appropriate particle size distribution, the fluidity and density of the repair mortar can be improved. Blast furnace slag is recycled blast furnace slag as aggregate, and can be used in the present invention as an alternative material of silica sand. The blending of fine aggregate depends on the water binder ratio and the blending amount of the artificial lightweight aggregate yarn, but is preferably in the range of 800 to 1,800 Kg / m 3, preferably in the range of 1,000 to 1500 Kg / m 3. The greater the amount of blast furnace slag replacement for silica sand, the more effective utilization of industrial by-products becomes possible.

[Water binder ratio]

The repair mortar according to the present invention is kneaded with a water binder ratio of 37 to 44%, preferably 39 to 41%. In calculating the water binder ratio, the binder is expressed as a percentage of water / (ultrafine cement + fly ash) as the total amount of the ultrafine cement and the fly ash. If the water binder ratio is less than 37%, it is difficult to stably secure 200 mm of the preflow of the repair mortar, and if it exceeds 44%, it is difficult to increase the strength to the intended place, and material separation is likely to occur.

As such, the repair mortar of the present invention uses ultra-fine cement having a powder level of 5000 to 8000 cm 2 / g as cement-based binder, and has 50% by volume or less of fine aggregates having an absorption rate of 5% or more and a dry density of 1.4 to 2.0g /. Pre-flow 200-300mm, preferably by kneading these basic formulations by substituting artificial light weight aggregate of 3cm3 and replacing 50% by weight or less of ultrafine cement with fly ash and adopting the basic formulation with water binder ratio of 37-43%. Preferably it exhibits an initial hardening characteristic with good fluidity of 240 to 300 mm, with a compressive strength of 6 N / mm 2 or more of 3 hours, a condensation start time later than 45 minutes, and a condensation termination time within 80 minutes. Moreover, the compressive strength of 40 N / mm <2> or more of 28 days can be ensured.

According to the repair mortar of such a basic compounding, the inner-winding method of a tunnel can be performed with favorable constructability also in the low temperature environment of 10 +/- 5 degreeC. In other words, in the inner space method of a tunnel in which a mold (for example, a center mold) is provided on the inner wall of a general tunnel or a water channel tunnel, and the repair mortar is filled in the space between the inner wall and the mold, the mold is demolished when the filling point is hardened. When moving the mold to the next filling point, the repair mortar of the present invention satisfactorily self-fills to the narrow filling point, and furthermore, since curing does not start within 45 minutes from kneading, the kneaded material is started to be injected. Inner tunnel construction method that is limited in construction time and time, because it can have sufficient margin until 3 hours and shows strength of 6N / mm2 or more that can be demolded after 3 hours. It can greatly contribute to the improvement of construction method.

Therefore, according to this invention, in the inner-winding method of the tunnel which forms a mold in the inner wall of a general tunnel or a waterway tunnel, and fills the space of the said inner wall and a mold with a repair mortar, the repair mortar of the said basic compound is used. The inner tunnel construction method can be provided. According to the tunnel inner construction method, it is possible to realize a good workability not existing in the related art and to ensure a good repair quality.

The repair mortar which concerns on this invention mix | blends a more suitable admixture and admixture with the repair mortar of the said "basic formulation", and provides the thing which further improved the characteristic. The admixture and admixture used are as follows.

using Admixture

[Calcium Aluminate-based Fast Hard Material]

Calcium aluminate hardwood is used in combination with gypsum to react instantaneously with water to produce Ettringite hydrate. For this reason, the compressive strength which expresses in several days to several tens of days can usually be obtained in several hours in a poleland cement. Also in the repair of this invention, the expression level of initial stage intensity | strength can be adjusted by mix | blending such a calcium aluminate type | mold hardwood material (gypsum added). The blending source of the calcium aluminate-based fast hard material may be 480 Kg / m 3 or less, particularly 150 to 480 Kg / m 3.

[Calcium Aluminate Expansion Material]

When the calcium aluminate-based expanding material is blended, the cement matrix structure in the initial stage of the hydration reaction is densified to expand the cement hardened body, thereby compensating for self shrinkage of the cement and preventing dry shrinkage in the long term. Also in the repair mortar of this invention, when mix | blending this calcium aluminate type expansion material, the dry shrinkage of a repair point is suppressed, and the repair which has stable quality over a long term can be performed. As a compounding quantity of the calcium aluminate type expansion material with respect to the repair mortar of this invention, the range of 15-60Kg / m <3> is suitable.

[Super fine activation material]

The ultrafine activator is made of anhydrous gypsum of ultrafine particles having a powder degree of 8000 cm 2 / g or more. When the ultrafine activating material is blended into the repair mortar of the present invention, it is possible to prevent the ultrafine cement and calcium aluminate-based rapid economy from coming into contact with water and being quickly frozen. For this reason, the pot life required for a construction work can be ensured stably. After a certain time has elapsed, the ultrafine activator reacts chemically with the ultrafine cement and calcium aluminate-based economics, contributing to securing the initial strength, and effectively acting on the densification of the tissue. However, unreacted anhydrous gypsum that did not react initially causes a reaction over a long period of time. As a compounding quantity of the ultrafine activating material with respect to the repair mortar of this invention, the range of 30-150 Kg / m <3> is suitable.

[Silica fume]

Part of the fly ash can be replaced by silica fume. When silica fume is used, the amount thereof is added to the amount of the binder to calculate the water / binder ratio.

All of these admixtures can be said to be one of the binders influencing the strength of the repair mortar. For this reason, in calculating the water-bonding ratio in the case of using such a mixed material, such a mixed material is also counted as the binder. Among these admixtures, the calcium aluminate fasteners, calcium aluminate expanders, and ultrafine active fires can be premixed with the ultrafine cement in powder form and used as a cement binder. In the calculation of the water / binder ratio, the cement-based binder mixed with such admixtures is added to the amount of the binder as it is, and if the fly ash is added, the fly ash thereof is also added to the amount of the binder.

Water binder ratio of admixture mixture: The water binder ratio at the time of mixing such admixtures is preferably 37 to 44%, preferably 39 to 41%, as described in the basic formulation.

Admixture Used

Depending on the construction environment, it may be necessary to appropriately adjust the fluidity and strength characteristics of the repair mortar. In such a case, it is preferable to knead the repair mortar by adding the following admixture.

[Defoamer]

When the amount of air increases due to the generation of entrained air, it is added to suppress it, and one or two or more of polyester-based, silicone-based, ethyl alcohol and ethylene glycol can be used, and those available on the market can be used. Can be. As addition amount, 1 Kg / m <3> is normally enough.

[Dispersant]

It is used to increase the durability of mortar by securing the fluidity of mortar without increasing the quantity of unit and improving the watertightness and resistance to freezing and thawing. In addition, the viscosity and fluidity of the fresh mortar are added at the same time, and used to have a fluidity requiring no compression. As a dispersing agent, the high performance sensitizer available on the market can be used, and the 1 type (s) or 2 or more types of the high performance sensitizers of polycarboxylic acid type, naphthalene type, melamine type, and lignin type can be used. As an addition amount, the objective can be achieved at 12 Kg / m <3> or less normally.

[Strength accelerator]

It is used when it is necessary to promote strength expression after 3 hours of mortar. Examples of the strength promoter include sodium sulfate (Na ₂ SO ₄ ), sodium nitrate (NaNO ₃ ), sodium cyanide (NaSCN), lithium carbonate (LlCO ₃ ), calcium nitrate (CaNO ₃ ), and the like. It is possible. As the addition amount, the object can be achieved at 1 Kg / m 3 or less.

[Delayed retardant]

Depending on the temperature and construction conditions at the time of construction, it may be necessary to lengthen the pot life until pouring while kneading. In this case, a retarder capable of delaying the hydration reaction of the fast-hardening ultrafine cement and calcium aluminate-based expanding agent is used. Examples of the retardant to be used include sodium gluconate, citric acid, tartaric acid and boric acid, and these may be used alone or in combination. As addition amount, 1 Kg / m <3> is enough.

It shows in Table 1 with reference to the compounding example of the improved formulation which mix | blends a admixture and a admixture.

The high-performance repair mortar according to the present invention is characterized by high flow, fast hardness, high strength, and high durability by using coal ash, coal ash artificial aggregate and blast furnace slag aggregate of industrial by-products as the main raw materials. It is particularly suitable for the internal law of the law. It can also be used as a repair material for roads and other structures. The repair mortar of the present invention is excellent in the balance of fluidity, fastness, high strength and high durability, compared with general repair mortar, and thus it is economical because a high quality repair performance is obtained based on good workability.

Examples are described below.

[Example]

Table 2 shows the kinds and physical properties of the raw materials used in this example. These raw materials were kneaded with the formulations shown in Table 3, and the results of the flash test of each mortar obtained were listed in Table 3. The test assumed that the inner-area method was performed inside a channel tunnel in a drier, and it set on the conditions of 10 degreeC of air temperature, and 80% of a relative humidity.

As the cement as a binder, an ultrafine particle mixed cement obtained by mixing a superfine particle cement with a calcium aluminate fastening material, a calcium aluminate expanded material and an ultrafine activating material in advance was used. The mixing ratio of each material of the ultrafine particle mixed cement used in the present embodiment is 9.5% by weight of the ultrafine particle cement, 67.0% by weight of the calcium aluminate fastening material, 8.0% by weight of the calcium aluminate expansion material, and 15.0% by weight of the ultrafine activating material. In the blending example of Table 3, when the blending ratio of each material in the ultra-fine particle mixed cement is expressed on a unit weight basis per 1 m 3 of mortar, the ultra-fine particle cement 28 to 57 Kg / m 3, the calcium aluminate-based fast hard material 201 to 402 Kg / m 3, Calcium aluminate-based expander 25 to 51 Kg / m 3, ultrafine activator 45 to 90 Kg / m 3.

As shown in Table 3, in the combination examples 1 to 6, the combination had 41% water binder ratio (W / B), the unit binder content was 600 Kg / m 3, and 0 to 300 Kg / m 3 of the ultra fine particle mixed cement. Alternate levels were replaced by fly ash. In addition, the equivalent of 30% by volume of the total aggregate volume was replaced with artificial lightweight aggregate sand (JS in Table 2).

In actual practice, since it is difficult to quantitatively measure the unit quantity at the time of construction, the change in properties when only the unit quantity is added or subtracted in the compounding examples 7 to 12 was investigated. In other words, in the blending of the fly ash content of 100, 150, and 200 Kg / m 3, the water binder ratio was set to 39% and 44%, and their properties were examined.

[Test Items and Test Methods]

The result of the fresh test of each compounding example is shown in Table 3 and FIGS. 4 to 6 show the results of the compression test, FIG. 7 shows the relationship between the age and the rate of change of length, FIG. 8 shows the results of the adhesion strength test for the primer, and FIG. 9 shows the relationship between elapsed time and wear depth. The test result which shows is shown.

Their test method is as follows.

Preflow test: In accordance with JIS R 52O1 (flow test of the physics test method of cement), the free flow value without dropping motion was measured.

J14 Lot Test: Conforms to JSCE-F541 (Fluidity Test of Filling Mortar).

Measurement of air volume and unit volume mass: It was in accordance with JIS A 1128 (test method by pressure of air volume).

Measurement of solidification time: According to JIS A 1147 (consolidation time test method of concrete).

Measurement of compressive strength: According to JIS A11O8 (the method of testing the compressive strength of concrete), the measurement age was 3 hours, 7 days and 28 days, and the curing conditions were 10 ° C. and 80% R.H.

Length change test: According to JIS A 1129-1 (Length change test method-compilator method), the size of a test body shall be 40x40x160mm, and after compacting concrete, it seals and cures for 1 day, and immediately 10 Cured at 60 占 폚 RH.

Adhesion test: According to JIS A 6909 (Adhesion strength test of building finishing porcelain), it carried out using the 600 * 30O * 60mm JIS flat plate. After the roughing of the upper surface of the packaging plate, the test specimens were coated with various primers in a standard amount and poured a 10 mm thick repair mortar, and the adhesion strength was measured at 14 days and 28 days. Curing conditions were 10 degreeC * 80% R.H. The primer was made into six types of uncoated (water wet), two kinds of ethylene vinyl acetate type, two kinds of acrylic polymer, and one kind of epoxy resin type. The test sample was sampled 6 at each age, and evaluated by the average value of four test samples except the maximum value and the minimum value.

Abrasion test: It carried out according to method A (rotational disk) of ASTM C 779 "Method for testing the wear resistance of the concrete surface". The test body was made into a flat plate of 300 × 300 × 50 mm, and air-cured at 20 ° C. 60% RH for 1 week after soaking in 10 ° C. water for 28 days, 0 minutes, 30 minutes, 60 minutes, 90 minutes, Abrasion tests up to 120 minutes were performed. In the method of measuring the amount of wear, a chip for fixing the leg of the measuring plate was attached to four corners of the test body, and a measuring plate was installed. The depth from the upper surface to the upper surface of the test body was averaged using a digital gauge with respect to 24 wear surfaces. .

〔Test result〕

As shown in Table 3 and the test results of FIGS. 1 to 9, it can be seen that the repair mortar according to the present invention exhibits specific characteristics different from the conventional ones.

1. As shown in Fig. 1, the preflow shows 258 to 289 mm even if the amount of fly ash is increased. In the case where the water binder content was changed at 100 Kg / m 3 and 150 Kg / m 3 of the fly ash content, the preflow tends to increase when the content of the fly ash content is increased, but it is 257 to 302 mm at the water binder content 39 to 44%. Indicates.

2. As shown in Table 3, with respect to the amount of air, the range was 1.4 to 2.8% in all combinations, and the influence of the amount of fly ash incorporation and water binder ratio was hardly seen.

3. Although FIG. 2 shows the result of the filling fluidity of the J lot by the amount of fly ash incorporation, in the repair mortar in which the fly ash is mixed, the flow time of J lot tends to be slowed down by increasing the amount of fly ash incorporation. It is about 22 to 55 seconds. In addition, when the water binder ratio decreases, the dripping time tends to be slow, and the water mortar ratio of 39% of the water binder is 2.5 times slower than that of the water binder ratio 44%.

4. Although the result of a condensation test is shown in FIG. 3, starting time is 48 to 62 minutes, termination time is 65 to 76 minutes, and about 15 minutes from start to finish in all the mixing. In the practical application of the repair mortar to the inner-area method, since it takes about 20 minutes to infuse the grout pump while kneading, securing a pot life of 30 minutes or more is necessary, but the mortar of this example has a starting time of 48 minutes. Since the above is shown, pot life can be fully secured.

5. Fig. 4 shows the compressive strength. Although the compressive strength of 3 hours tends to fall by increasing the amount of fly ash incorporation, it is 6 N / mm <2> or more other than the fly ash content of 300 Kg / m <3> (combination example 6). The compressive strength of 28 days tends to decrease greatly with increasing fly ash incorporation, and ranges from about 25.3 to 67.3 N / mm 2. All the maintenance mortars except the fly ash content of 300 Kg / m 3 (compound example 6) are 40 N / mm 2 or more.

6. In Fig. 5, the relationship between the start time and the intensity of 3 hours is shown. As the fly ash increases, the start time is faster, but the 3 hour compressive strength tends to be smaller. The difference in starting time due to the amount of fly ash incorporated is about 15 minutes at maximum. The start time can be adjusted by adjusting the amount of fly ash mixed with the amount of cement.

7. Fig. 6 shows changes in compressive strength due to the difference in the number of binders (B / W, not W / B). With respect to the fly ash content of 100 Kg / m 3 (compound example 3), 150 Kg / m 3 (compound example 4) and 200 Kg / m 3 (compound example 5), the compressive strength at 3 hours of age was less influenced by the difference in binder ratio. And in any binder ratio, 6N / mm 2 or more. The compressive strength of 28 days tends to increase as the number of binders increases, but all of them exceed 40 N / mm 2. In the repair mortar according to the present invention, the compressive strength with respect to the change in the water-binding material ratio due to the mixing amount of the fly ash and the unit quantity is found to satisfy the set target value when the mixing amount of the fly ash is 200 Kg / m 3 or less. Can be. Therefore, as the allowable range of the water binder ratio by the addition and subtraction of the unit quantity, even if the water binder ratio is about ± 3% (unit quantity ± 18 Kg / m 3) in the plan combination, the quality of its compressive strength can be ensured.

8. Although an example of the test result of a rate of change is shown in FIG. 7, the length is almost stable from 60 days of age, and it is the range of 7.9x10 <^-4> -8.8 * 10 <^-4> at age 91. Moreover, there is no big difference in the length change by the fly ash mixing amount.

9. The adhesion strength to the various primers is shown in FIG. The adhesion strength of 14 days is largely exceeding 1.5 N / mm <2> except an epoxy resin primer. The adhesion strength of 28 days is 2.1-3.4 N / mm <2>. Except for epoxy resin primers, the adhesion strength tends to slightly increase by the application of the primers. Paying attention to the primer component, the adhesive strength of the acrylic polymer is high. In the acrylic polymer, the adhesion strength of the A primer is slightly larger than that of the M primer, and has good compatibility with the repair mortar of the present invention.

10. The results of the wear test are shown in FIG. The abrasion test was performed in the elapsed time with respect to the present invention mortar of the compounding example 3 and high-strength mortar (W / C: 43%, unit cement amount 570 Kg / m), S / C: 2.58, using natural sand). The amount of wear is shown in contrast to both. As shown in Fig. 9, both wear depths increase linearly with elapsed time, but both wear depths in the elapsed time of 120 minutes are about 2 mm, and both show an equivalent slope. There is no significant difference and you can think of it as nearly equal.

The present invention provides a repair mortar that can be quickly and soundly repaired in a short time in the repair work of tunnel perforated concrete using industrial by-products.

Claims (9)

In the formulation of a repair mortar expressing a compressive strength of 6 N / mm 2 or more for 3 hours, ultrafine cement having a powder level of 5000 to 8000 cm 2 / g is used as the cement binder, and 50 vol% or less of fine aggregate is absorbed by 5 By replacing artificial lightweight aggregate sand having a dry density of 1.4 to 2.0 g / cm3 or more, replacing 50% by weight or less of ultrafine cement with fly ash, and mixing the blend with a water binder ratio of 37 to 44%. Obtained but having a value measured under conditions of a temperature of 10 ° C. and a relative humidity of 80%, preflow of 200 to 300 mm, condensation start time after 45 minutes, and condensation termination time within 80 minutes. The repair mortar of claim 1, wherein the compressive strength of 28 days is 40 N / mm 2 or more. The repair mortar according to claim 1 or 2, wherein the average particle diameter of the artificial lightweight aggregate yarn is 5 mm or less. The mortar for repair according to claim 1, wherein the fine aggregate consists of one or two of silica sand and blast furnace slag yarn. delete 2. The ultrafine particle activator according to claim 1, wherein the admixture includes at least 480 Kg / m 3 of calcium aluminate-based fastener, 60 Kg / m 3 of calcium aluminate-based expander, and at most 150 Kg / m 3 of ultrafine particle activator made of anhydrous gypsum having a powder of 8000 cm 2 / g or more. A repair mortar characterized by further compounding two or more species. The mortar for repair according to claim 6, wherein the admixture is mixed in advance into the ultrafine cement in powder form, and the mixed powder forms a cement binder. 8. The mixed material according to claim 1, further comprising one or two or more of an antifoaming agent of 1 Kg / m 3 or less, a dispersant of 12 Kg / m 3 or less, a strength accelerator of 1 Kg / m 3 or less, and a retardant of 1 Kg / m 3 or less. Characteristic for repair mortar. In the inner space method of a tunnel in which a mold is provided on an inner wall of a general tunnel or a water channel tunnel and a mortar for repair is filled in the space between the inner wall and the mold, the repair mortar according to claim 1 or 6 as the repair mortar. Tunnel repair method characterized by using mortar.

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