JP6110749B2 - Crushed material - Google Patents

Description

  The present invention relates to a crushing medium that statically crushes a reinforced concrete structure, a block of rock, a rock mass, and the like by means of an expansion pressure of the medium, without using a blinking means such as blasting.

  Mainly in the construction and civil engineering fields, when a concrete structure or rock was torn down or removed, the surrounding environment was taken into consideration, and the hydration reactive expansive agent was swept into the structure, not dynamic means such as blasting or impact. Static crushing means that fills a plurality of small holes and causes expansion cracks is often employed. The hydration reaction expansive drug to be used requires a substance capable of expressing a high expansibility, and generally contains free quick lime as an active ingredient and an ettringite-forming substance, typically calcium sulfa aluminate, as an active ingredient. Broadly divided into things. The entity mainly uses the additive effect, but there are some cases where both are used together. Of these, hydration reaction expansive drugs containing free quick lime as an active ingredient may give a very high expansive force. However, in order to utilize this for static crushing, it is necessary to solve several problems. There is. That is, since the hydration reaction activity is extremely high, the hydration reaction proceeds rapidly immediately after water contact, and the reaction is completed in a very short time. Since the expansion is linked with the hydration reaction, it hardly expands after the hydration reaction. Thus, since the hydration reaction is too early, it is difficult to perform simultaneous filling and water injection into a plurality of drug injection holes at the location to be crushed. Can not. Further, quick lime itself does not have self-hardness even when in contact with water, and therefore, the expanded material overflows from the drug injection hole of the object to be crushed during expansion, and when the hydration reaction proceeds rapidly, there is a possibility that the lime is ejected and scattered from the hole. (The so-called “gun” phenomenon) This hydration reaction is an exothermic reaction and has a considerably large heat of hydration, so that the object to be crushed is likely to be stored at high temperature and heat, and as a result, the squirting phenomenon is more likely to occur. As a result, the momentum of the eruption increases, which causes a significant problem in work.

  In order to adjust the hydration reaction that is too early to an appropriate time, for example, a free lime-based crushing agent in combination with a retarder such as carboxylic acid or a salt thereof is known. (For example, refer to Patent Document 1.) However, if only a retarder is used in combination, the reaction activity over time is flattened and widened, and the maximum expansion pressure is likely to be lowered. was there. Since the expansion rate is increased by the use of an accelerator such as an inorganic salt of alkali metal, it is possible to adjust the development of expansion force in detail in combination with a retarder (see, for example, Patent Document 2). ) Hardly contributes to the improvement of the expansion force. In addition, in order to compensate for the lack of self-hardening, it is also known to mix a hydraulic substance such as cement with free lime and use it as a static crushing agent (see, for example, Patent Document 3). The expansion force per unit amount of the static crushing agent is reduced, and particularly when the hydraulic material is hardened during expansion, the expansion phase directly applies the expansion force to the object to be crushed. Propagation is hindered. Moreover, it is known to use polysaccharides, such as dextrin and starch, for suppression of the heat of hydration at the time of water contact. (For example, refer to Patent Document 4) However, since the use of polysaccharides suppresses heat generation, it is difficult to compensate for the activation force by heat. For this reason, when used in a low temperature environment, the expansion pressure was sluggish and cracks did not extend often.

JP-A-57-119850 Japanese Patent Laid-Open No. 01-79283 JP-A-57-187044 JP 2000-290635 A

  In view of the above circumstances, the present invention is capable of (1) maintaining high expansion pressure without lowering expansion pressure, and (2) suppressing the extreme hydration reaction and appropriately adjusting the expansion expression time, (3) When filled in holes, gaps, etc., there is no jet of chemicals after water contact, (4) high heat generation after water contact can be suppressed, and (5) good for crushed objects even in low temperature environments It is an object of the present invention to provide a crushed material that can easily cause a long crack extension.

  As a result of repeated investigations for solving the above problems, the present inventor has obtained a hydrated expansive substance containing a specific amount of phosphorus oxide as a chemical component, the main expansible component being free quick lime, dextrin, calcium By using a mixture of aluminate and retarder, it has a high expansion pressure that is not inferior to that of conventionally used free quicklime crushed material, and solves the problems (1) to (5) as a whole. Since the crushed material which can be obtained was obtained, it came to complete this invention. In particular, by using a specific dextrin, the hydration heat generation can be drastically suppressed, and the problems (3) to (4) can be solved more reliably.

That is, this invention is the crushing material represented by following [1]-[3].
[1] One or more kinds selected from the group consisting of 100 parts by mass of free quicklime and 0.056 to 0.17 parts by mass of phosphorus oxide, a dextrin, calcium aluminate, and a hydration reaction retarder The crushed material characterized by containing.
[2] The crushed material according to [1] above, wherein the hydrated and expansive substance contains 0.04 to 0.6 parts by mass of an alkali metal oxide with respect to 100 parts by mass of free lime.
[3] The crushed material according to [1] or [2], wherein the dextrin is dextrin having a cold water soluble content of 95 ± 1%.

  The crushed material of the present invention can (1) maintain a high expansion pressure without lowering the expansion pressure, and (2) suppress an extreme hydration reaction to appropriately adjust the expansion expression time. ) When filled into holes or gaps, no chemical eruption occurs after contact with water, (4) heat generation after contact with water can be suppressed, and (5) good crack elongation occurs in objects to be crushed even in low temperature environments. Therefore, it is a static crushing material with extremely few restrictions on use, and has a sufficiently high crushing force regardless of the use environment.

  The hydrated expansive substance that is an essential constituent of the crushed material of the present invention contains free quick lime as an active ingredient, and 0.056 to 0.17 mass of phosphorus oxide with respect to 100 mass parts of the free quick lime content. Part content. Free quicklime, which is an active ingredient of the hydrated expansive substance, is crystalline CaO. The content of free quick lime is not particularly limited as long as it is an amount capable of expressing an expansion force that causes expansion cracks in the hardened concrete, for example. Preferably, since there is a possibility that higher expansion force can be stably expressed, the content of free stone raw ash in the hydrated expansion material is set to 65% by mass or more. More preferably, the free stone raw ash content is 80% by mass or more.

The phosphorus oxide essential contained in the hydrated and expansive substance is preferably 0.056 to 0.17 mass relative to 100 parts by mass of free quicklime in the hydrated and expansive substance in the state of P ₂ O _5. Part contained. Preferably, 0.09 to 0.14 parts by mass are contained. The inclusion of phosphorus oxide has the effect of suppressing the rapid initial expansion pressure immediately after the water injection kneading, and although the initial expansion pressure is suppressed, the subsequent expansion pressure reaches a high level, and the maximum high expansion pressure itself is significantly reduced. Therefore, it is possible to shift the peak expansion pressure expression time. If the content of phosphorus oxide as a chemical component is less than 0.056 parts by mass, it is difficult to obtain the phosphorus oxide-containing action as described above, and if the content exceeds 0.17 parts by mass, the initial reaction is not achieved. Delaying causes an excessive decrease in the inflation pressure, which is not preferable.

Further, the particle size of the hydrated expansive substance is not particularly limited. Preferably, by setting the Blaine specific surface area to 3000 to 10000 cm ² / g, it is easy to obtain a reaction state and expansibility that are more appropriate. The production method of the hydrated expansive material used for the crushed material of the present invention preferably uses a raw material that is a source of formation of free quick lime, phosphorus oxide, etc., and free quick lime, phosphorus oxide, etc. have a desired production amount. The mixture thus prepared is baked, and a baked clinker in which at least free quick lime and phosphorus oxide are generated can be produced by pulverizing and classifying by any means. The raw materials that can be used are sometimes not limited, and examples thereof include natural ores such as limestone and industrially purified P ₂ O ₅ reagents, but are not limited to the description examples. In addition, the firing temperature is generally 1200 to 1500 ° C., and after the firing, it is recommended to carry out a slow cooling treatment such as natural cooling because free quick lime can be stably produced and grown. Any firing apparatus can be used as long as it can be fired at the temperature.

  Moreover, the hydrated expansive substance used in the crushed material of the present invention preferably further contains an alkali metal oxide in an amount of 0.065 to 1 part by mass with respect to 100 parts by mass of the free quicklime content. Examples of the alkali metal oxide include lithium oxide, sodium oxide, and potassium oxide, and two or more of them can be contained. By containing 0.065 to 1 part by mass of an alkali metal oxide, the expansion rate can be easily adjusted, which is advantageous for promoting the reaction.

  Moreover, the hydration-expandable substance used for the crushed material of the present invention may contain other components in addition to the above components, as long as the effects of the present invention are not substantially lost.

  Moreover, the crushed material of this invention contains 1 or more types chosen from the group of dextrin, calcium aluminate, and a hydration reaction retarder other than the said hydration expansive substance. Accordingly, it is possible to use only one of them, of course, to contain two types in any combination, or to use all three types. Preferably, it contains at least dextrin. Any dextrin may be used. By containing dextrin, an excessive temperature rise caused by the heat of hydration reaction can be suppressed without reducing the expansion pressure effective for crushing. It also contributes to preventing the gun phenomenon. The content in the case of containing dextrin is not limited, but is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the hydrated expansive substance. More preferably, the content is 0.5 to 3 parts by mass. When the content is within this range, the content effect is more strongly expressed without lowering the maximum expansion pressure.

  More preferably, the dextrin used has a cold water soluble content of 95 ± 1%. Here, the cold water-soluble component is a ratio in which dextrin is dissolved in distilled water at a temperature of 21 ° C., and is expressed as a mass percentage. Moreover, the notation of ± 1% indicates that the mass percentage value is within a range of 1 or around, for example, the cold water soluble component 95 ± 1% is substantially the cold water soluble component 94 to 96%. Means things. As the dextrin used in the present invention, any dextrin having a cold water soluble content of 95 ± 1% can be used. By containing dextrin with a cold water soluble content of 95 ± 1%, the rate of temperature rise due to hydration exothermicity of the hydration-expandable substance when in contact with water can be considerably reduced, and the initial hydration reaction is also moderated. Extreme reactions that cause the gun phenomenon can be sufficiently suppressed.

Calcium aluminate that can be used in the crushed material of the present invention is a general term for hydration active substances containing CaO and Al ₂ O ₃ as main chemical components, and as a compound, solid solution, glassy material, etc. A mixture of these can be exemplified. More specifically, for example, _{12CaO · 7Al 2 O 3, CaO} · Al 2 O 3, 3CaO · Al 2 O 3, CaO · 2Al 2 O 3, CaO · 6Al 2 O 3 , and the like. In addition to CaO and Al ₂ O ₃ , other chemical components are also broadly defined as calcium aluminate, and other chemical components alone or reacted with either CaO or Al ₂ O ₃ or both. It may be a product. Specifically, as calcium aluminate containing other chemical components in addition to CaO and Al ₂ O ₃ , for example, 4CaO · 3Al ₂ O ₃ · SO ₃ , 11CaO · 7Al ₂ O ₃ · CaF ₂ , Na ₂ O · Examples include 8CaO.3Al ₂ O ₃ . In addition, calcium aluminate having a molar ratio of CaO and Al ₂ O ₃ other than those illustrated may be used, and the value of the molar ratio of CaO and Al ₂ O ₃ is not particularly limited. By containing calcium aluminate, the expansion pressure can be expressed at an earlier stage, and since self-hardening can be imparted, there is also an action of suppressing the ejection of medicine after filling water injection. The content in the case of containing calcium aluminate is not limited, but is preferably 5 parts by mass or less, more preferably 0.2 to 3 parts by mass with respect to 100 parts by mass of the hydrated expansive substance in the crushed material. By doing this, the above-mentioned action at the time of water contact is more easily obtained.

  In addition, the crushed material of the present invention contains a hydration reaction retarder, so that the initial rapid hydration reaction can be suppressed and the reaction time and reaction rate can be adjusted to be slow as a whole. This is an effective measure when you want to secure a long pot life. The hydration reaction retarder used can be any setting retarder that can be used for mortar and concrete. Specific examples include carboxylic acids such as citric acid and tartaric acid and salts thereof. In addition, lignin sulfonic acid or naphthalene sulfonic acid type polymers that have a delayed setting action can be used. Preferably, an organic retarder (including a polymer) is suitable because the reaction retarding action generally works with a small amount of use and it is not necessary to adjust the content of free quick lime. The content in the case of containing a hydration reaction retarder is not limited, but is preferably 0.1 to 1.5 parts by mass with respect to 100 parts by mass of the hydrated expansive substance. With this content, it becomes easier to obtain a proper reaction delaying action while ensuring a desired expansion force. In addition, also when using any 2 or more types among dextrin, a calcium aluminate, and a hydration reaction retarder, suitable content in the case of using single type about each can be applied.

  The crushed material of the present invention can contain components other than the hydrated expansive substance, dextrin, calcium aluminate and hydration reaction retarder as long as the effects of the present invention are not lost.

  The crushed material of the present invention is hydrated and expanded by water contact. The method of use is not particularly limited, but for example, this crushing object is filled with this crushing material in a crack, gap or core, and water is poured, or a desired crushing jig is filled in advance and the jig is broken. It can be used by being inserted into a core or the like provided at a planned site. In addition, since the crushed material of the present invention has almost no self-hardness, it is desirable to use a hydraulic substance such as cement together in order to prevent leakage at the time of expansion from the filling location depending on the filling direction. Cement that can be used is not particularly limited, and examples thereof include normal, early strong, super early strong, moderate heat, low heat, etc. Portland cement, mixed cement such as blast furnace cement and silica cement, and special cement such as eco-cement. . The amount of cement used is not limited. Preferably, 45 parts by mass of cement is set as the upper limit for 100 parts by mass of the crushed material of the present invention in order to ensure a sufficient expansion pressure that can be crushed.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to the described examples.

A composition using raw materials selected from CaO (commercial reagent), P ₂ O ₅ (commercial reagent) and Na ₂ O (commercial reagent) is heated in an electric furnace at a maximum temperature of about 1400 ° C. (± 50 ° C.) for 1 hour. Firing was performed to produce a fired product having the component contents shown in Table 1. The fired product was naturally cooled in the furnace from the highest temperature to about 500 ° C., and then taken out of the furnace. The cooled fired product was pulverized with a ball mill, and an expandable powder having a fineness of about 3200 cm ² / g was produced using a separator. The product phase of the fired product was confirmed by powder X-ray diffraction, and the component content was examined by chemical analysis.

  The produced expandable powder, dextrin A (cold water soluble content 45%; commercial reagent), dextrin B (cold water soluble content 95%; commercial reagent), dextrin C (cold water soluble content 90%; commercial reagent), dextrin Using a material selected from D (cold water soluble content 98%; commercially available reagent), citric acid (commercially available reagent), and alumina cement (manufactured by Kerneos Co., Ltd., product name “SECAL 51”), the blending amounts shown in Table 2 are obtained. The mixture was dry-mixed with a Henschel mixer for about 3 minutes to produce a crushed material.

  30 parts by mass of water was poured into the produced crushed material with respect to 100 parts by mass of the crushed material, and kneaded with a Hobart mixer for about 1 minute. Immediately after kneading, a cylindrical steel mold (with an inner diameter of 42 mm, a thickness of 3 mm, and a height of 155 mm) filled with one end face was filled with the kneaded material, and after filling, the other open end face was closed with a steel material with a thickness of 3 mm. . This sealed form is immersed in constant temperature brine at about 5 ° C for 8 hours or 16 hours, and the amount of expansion of the steel pipe is measured with a strain gauge affixed to the surface of the steel pipe by a method according to the restrained expansion pressure test, and converted into expansion pressure. Thus, the expansion pressure at 5 ° C. was measured. The results are shown in Table 3.

  Also, in the vicinity of the center of one end face of a cylindrical hardened body (outer diameter 130 mm, height 160 mm) made of mortar consisting of 100 parts by weight of ordinary Portland cement, 200 parts by weight of fine aggregate (No. 6 silica sand) and 15 parts by weight of water. A hole having a diameter of 42 mm and a depth of 125 mm was drilled with a core drill. Under a 10 ° C environment, the hole was filled with a kneaded material of crushed material and water obtained by the same composition and method as described above, and a thermocouple was installed at the center of the hole where the hole was drilled. The maximum temperature due to the temperature rise of the packing and the temperature arrival time were measured. In addition, the injection of the filler did not occur at all using any of the crushed materials of the present invention. The above measurement / evaluation results are shown in Table 3.

  From the results in Table 3, the crushed material of the present invention can express a high expansion pressure that can be sufficiently utilized for crushing in a shorter time, and also has a low calorific value, a relatively long maximum temperature reaching time, and a rapid increase. It can be seen that the fever is considerably suppressed.

Claims (3)

Contains 100 parts by weight of free quicklime, 0.056 to 0.17 parts by mass of phosphorus oxide, and one or more selected from the group of dextrin, calcium aluminate, and hydration retarder A crushed material characterized by that. The crushed material according to claim 1, wherein the hydrated expansive substance contains 0.065 to 1 part by mass of an alkali metal oxide with respect to 100 parts by mass of free lime. The crushed material according to claim 1 or 2, wherein the dextrin is a dextrin having a cold water soluble content of 95 ± 1%.