JPH0436747B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of statically crushing a brittle object by filling an expansion agent into a loading hole drilled in a brittle object such as concrete or rock and utilizing the expansion pressure, and an expandable tablet used in the method. be. Conventionally, as a crushing agent for statically crushing brittle objects, an expansive substance containing quicklime and a hydraulic substance as main ingredients has been proposed, as described in, for example, Japanese Patent Application Laid-open No. 56-67059. Several types are produced industrially as crushing agents. This crushing agent is mainly in powder form, and the method for using it is to mix the powdered crushing agent with water in a container in advance to form an aqueous slurry, and then fill it into a loading hole drilled in the object to be crushed. has been put into practical use. However, such crushing agents and crushing methods have the following drawbacks. (1) When the crushing agent and water are mixed, a hydration reaction immediately occurs with quicklime, the main component, and the fluidity of the aqueous slurry decreases, so it must be quickly injected into the loading hole. Injection becomes difficult. (2) Commercially available crushing agents have applicable temperature ranges.
If you use it above the upper limit, or even if you use it within the applicable temperature range, the diameter of the loading hole will be 50 mm.
If the diameter exceeds φ, the filled crushing agent will explosively protrude outside the loading hole (this is called the protrusion phenomenon or the gun phenomenon. Hereinafter referred to as the protrusion phenomenon), and not only will the crushing effect not be obtained, but the work will be interrupted. Above is extremely dangerous. Furthermore, even when used within the applicable temperature range and with a charging hole diameter of 50 mm or less, there are times when the temperature of the material to be crushed is high due to large changes in temperature, the influence of solar heat, etc., or when the material is mixed with water. A protrusion phenomenon often occurs when the temperature is high. (3) The time it takes for the crushing effect to occur varies depending on conditions such as temperature, but it takes a very long time of 12 to 24 hours, and the workability is poor (this is especially true if the material is an expandable material that accelerates the onset of expansion pressure). phenomenon is more likely to occur). For this reason, as a method to prevent the protrusion phenomenon, Japanese Patent Application Laid-Open Nos. 48-25337 and 49-21924 disclose that after filling the loading hole with a crushing agent slurry, the upper part of the slurry is filled with mortar or instruments. Methods have been proposed in which the container is sealed tightly, but these methods have the drawbacks of poor workability and high cost. The present invention aims to improve these drawbacks and provide a crushing method and crushing agent that effectively, safely, and quickly perform static crushing of rocks, concrete, etc. by utilizing the expansion force of the expanding agent. That is, the present invention provides the following features: (1) When statically crushing a brittle object such as concrete using the expansion pressure accompanying the hydration reaction of an expansion agent, calcium oxide and boric acid, which is a substance that retards the hydration reaction of calcium oxide, are used. or a static crushing method characterized by filling a loading hole with a three-dimensional expandable tablet formed by compression molding an expanding agent mainly consisting of an inorganic salt of boric acid, and then injecting water; (2) oxidation; The volume is 0.05 cm ³ made by compression molding an expanding agent mainly composed of calcium and boric acid, which is a substance that retards the hydration reaction, or an inorganic salt of boric acid.
(3) The static crushable expandable tablet according to item (2) above, which is molded into a three-dimensional shape of 10 cm ^{3 or} less, and (3) the expandable tablet molded into a three-dimensional shape has a bulk specific gravity of 2.0 to 3.2. (4) The expandable tablet for static crushing according to item (2) above, wherein the calcium oxide is hard-burned lime. By molding such a specific ingredient into a tablet and using it, there is no need to make it into an aqueous slurry beforehand and fill it into the loading hole, unlike conventional powder crushing agents, which improves the fluidity of the aqueous slurry. This eliminates the operational disadvantage of not being able to inject into the loading hole due to a drop in the pressure, and furthermore, since the occurrence of protrusion is suppressed, it is possible to use an expansion agent that develops expansion pressure quickly, and the time required for crushing is therefore greatly reduced. It has the characteristic that it can be shortened. Next, embodiments of the present invention will be described in detail with reference to the drawings. In Fig. 1, reference numeral 1 denotes a material to be crushed such as concrete, into which loading holes 2 of a constant length and diameter are bored at regular intervals, and inflatable tablets are inserted into the loading holes 2. 3 is injected from the opening 4 of the loading hole 2 to hydrate and expand the expandable tablet, thereby crushing the object 1 to be crushed. In the figure, 5 is the hole bottom. According to the method of the present invention, the expansible tablets filled in the material to be crushed release water vapor generated during the hydration reaction (exothermic reaction) into the atmosphere through the gaps between the expansible tablets. It prevents the water vapor pressure inside the tablet from increasing, the filled expandable tablet does not protrude outside the hole even if the loading hole diameter is 50 mmφ or more, and the expansion pressure can be used effectively.
It is possible to prevent dangers caused by protrusion phenomena, thereby further increasing work safety. In addition, unlike conventional powder crushing agents, there is no need to mix the crushing agent and water in a container in advance and immediately fill the filling hole with the mixture. Instead, only water is injected into the expanding agent filled in the loading hole. This will make your work easier. Next, the expandable tablet of the present invention will be explained in detail. The expansible tablet of the present invention is characterized in that calcium oxide is used as an expansible component, and boric acid or an inorganic salt of boric acid is mixed therein as a hydration reaction retardant, and then the tablet is molded into a three-dimensional shape. By making the expandable tablet into a three-dimensional shape, water can be injected after the expandable tablet is first filled, unlike powdered crushing agents that cannot be properly filled into the loading hole unless it is made into an aqueous slurry. As a result, the disadvantage of using a powdered crushing agent, where the fluidity of the slurry decreases during mixing with water and cannot be injected into the loading hole, can be eliminated, and workability is improved. Improved. In addition, the protrusion phenomenon can be prevented by using calcium oxide and a substance that retards the hydration reaction as a crushing agent formed into a three-dimensional shape.
When used in powder form, the expansion pressure develops quickly, but an extrusion phenomenon occurs, making it possible to utilize an expansive component that could not be used. It has the feature that the required time for the development of inflation pressure can be greatly shortened.
From the perspective of the components that make up the crushing agent, in the case of powdered crushing agents, a hydraulic substance is used for quicklime (expandable component) (quicklime alone will turn into powder and it is difficult to obtain effective expansion pressure. ), a method is used in which the hydration reaction of quicklime is caused from the time when the hydraulic substance first solidifies and has a certain degree of strength, so the time for the expansion pressure to develop depends to some extent on the time for the hydraulic substance to develop strength. It was difficult to develop inflation pressure within a few hours. When quicklime is used as an intumescent component,
In the method of the present invention, it is not necessarily necessary to add a hydraulic substance, and a combination of quicklime and boric acid or an inorganic salt of boric acid, which is a substance that retards the hydration reaction, may be used. It is possible to make fast expanding tablets. Calcium oxide used in the present invention is an expansive component, and specifically, calcined dolomite can be used in addition to quicklime, and preferably has a CaO content of 30% or more.
When the CaO content is less than 30%, the expansion pressure necessary to crush the object cannot be obtained. As for the firing degree, hard firing makes it easier to control the hydration reaction, and among these, hard firing quicklime is particularly preferable. The particle size must be determined in consideration of ease of mixing with the hydration reaction retarding substance and molding into a three-dimensional shape. Next, the hydration reaction retardant substance used in the present invention is:
A substance that has the effect of delaying the hydration reaction of calcium oxide, and is an inorganic salt of boric acid such as boric acid, lithium borate, or calcium borate. If the tablet is not boric acid or an inorganic salt of boric acid, the protrusion phenomenon cannot be completely suppressed even if the expandable tablet is formed into a three-dimensional shape, which is not preferable. Such a hydration reaction retarder must be homogeneously mixed with a calcium oxide material before molding, and then compressed into a uniform three-dimensional expandable tablet. If calcium oxide and a hydration retarder are mixed together and used without forming into a three-dimensional shape, it is necessary to make an aqueous slurry and fill it into the charging hole. Problems may arise if the filling becomes difficult or a protrusion phenomenon occurs after filling. The performance of the expandable material of the present invention (the time required for the expansion pressure to develop) is determined not only by the hydration retardant material, but also by the properties of the calcium oxide material and the expandable tablet formed into a three-dimensional shape. The selection of a hydration retardant must be made in consideration of these conditions. Boric acid and an inorganic salt of boric acid are preferred because the shape of the expandable tablet does not easily collapse for a relatively long time when injected, the ejection phenomenon is less likely to occur, and the expansion pressure of calcium oxide can be used effectively. Specific examples include boric acid, lithium, sodium, magnesium, and calcium borates. The mixing ratio of calcium oxide to the hydration retarder cannot be unconditionally determined because the performance of the hydration retarder varies depending on the hydration retarder. If the proportion of the hydration retardant is small, the protrusion phenomenon is likely to occur, for example, when quicklime is used alone, while if the amount of the hydration retardant is too large, it will take a long time for the expansion pressure to develop, which is undesirable. . A molding machine such as a tablet press can be used to uniformly mix the hydration retarding substance and calcium oxide in powder form and then compression mold them to form an expandable tablet. In this case, in order to particularly improve moldability, it is preferable to mix a moistening agent such as a molding aid (mold release agent) with the swelling agent of the powder tablet in advance. The shape of the expandable tablet allows water injected from the opening of the loading hole to easily penetrate to the bottom of the loading hole, and the filled expandable tablet absorbs water vapor generated by the hydration reaction that begins when water is injected into the expandable tablet. Preferably, the material can easily be released into the atmosphere through the particles of each expandable tablet before it expands, such as cylinders, rectangles, disks, polyhedrons, or rounded corners and spheres of these. desirable. The volume of the expandable tablet should be 0.05 to 10 cm if the diameter of the loading hole is 30 to 100 mmφ, considering the ease of filling into the loading hole and the filling density of the holes filled in the loading hole. has the greatest crushing effect. If the volume of the expansible tablet is less than 0.05 cm ³ , the protrusion phenomenon tends to occur, and if the volume exceeds 10 cm ³ , the protrusion phenomenon will not occur, but the crushing effect will be reduced and the crushing time will also tend to be delayed. The bulk specific gravity of the expandable tablet is such that the tablet is hard to break when handled, and after being filled into the loading hole, water is injected to start the hydration and expansion reaction, and the water vapor generated in the initial reaction is absorbed into the expandable tablet. The tablet must have such hardness that it does not lose its shape until it is released into the atmosphere, and a bulk specific gravity of 2.0 to 3.2 is most preferable. If the bulk specific gravity is less than 2.0, the shape may be broken during handling, or the expansion pressure may be insufficient during expansion, making it difficult for the material to be crushed to be completely crushed. On the other hand, those with a bulk specific gravity exceeding 3.2 are undesirable because they are difficult to manufacture and the penetration of water into the interior of the expandable tablet is too slow. According to the method of the present invention, the expandable tablets filled in the material to be crushed release the water vapor generated during the hydration reaction into the atmosphere through the gaps between the expandable tablets, thereby increasing the water vapor pressure inside the loading hole. Even if the loading hole is set to 50 mmφ or more, the filled expandable tablet will not protrude outside the hole, and the expansion pressure of the expandable tablet can be effectively used. This eliminates the need to mix the crushing agent and water in a container in advance and then immediately fill the filling hole with the mixture. This eliminates the need to inject only water into the expansible tablets filled in the loading hole, which improves work efficiency and improves work efficiency. It is possible to carry out crushing work with great economical effects, and to prevent dangers due to protrusion, it is possible to further improve work safety. In addition, since the expanding agent can be used in large holes with a charging hole diameter of 50 mmφ or more during crushing operations, a larger amount of expanding agent can be used per hole. Since it can be made larger, it is possible to reduce the number of holes required for crushing, which has the effect of making crushing work more efficient and economical. In addition, because no protrusion phenomenon occurs, conventional crushing agents
What used to require 12 to 24 hours now only takes 1 to 3 hours, significantly reducing the time required to break the deadline. The present invention will be specifically described below using Examples. Examples 1 to 5 Crushing experiments were conducted using expandable tablets having the components, shapes, volumes, and bulk specific gravity shown in Table 1. The object to be crushed was a cylindrical unreinforced concrete with an outer diameter of 300 mmφ and a height of 300 mm, in which a hole with a hole diameter of 60 mmφ and a depth of 270 mm was bored. The results are shown in Table 1. Comparative Example 1 A crushing experiment was conducted using expandable tablets having the ingredients, shape, volume, and bulk specific gravity shown in Table 1. The same method as in Example 1 was carried out using concrete having the same shape as that used in Example 1 as the material to be crushed. The results are shown in Table 1. The results shown in Table 1 are examples in which an inorganic salt of boric acid was used as a hydration-retarding substance, and cracks were observed to occur in a short period of time in all of the Examples of the present invention. On the other hand, with the expandable tablet having a large volume (Comparative Example 1), no protrusion phenomenon occurred, but no cracking was observed 3 hours after the start of the experiment.

【table】

[Table] * Crushing results observed 1 hour after the start of the experiment ** Some pieces lost their shape during handling, so the example was carried out with that part removed.

[Brief explanation of drawings]

FIG. 1 is a sectional view of one embodiment of the method for crushing concrete, etc. according to the present invention. 1... Material to be crushed such as concrete, 2... Loading hole, 3... Expandable tablet, 4... Hole opening of drilling hole 2, 5
...Bottom of drilling hole 2.

Claims (1)

[Claims] 1. When statically crushing brittle objects such as concrete using the expansion pressure accompanying the hydration reaction of an expanding agent, calcium oxide and boric acid or boric acid, which is a biological substance that retards the hydration reaction, A static crushing method characterized by filling a loading hole with a three-dimensional expandable tablet formed by compression molding an expanding agent mainly consisting of an inorganic salt of an acid, and then injecting water. 2 A volume of 0.05 cm ³ or more formed by compression molding an expanding agent mainly composed of calcium oxide and boric acid, which is a substance that retards the hydration reaction of calcium oxide, or an inorganic salt of boric acid,
Expandable tablets for static crushing that are formed into a three-dimensional shape of 10 cm ³ or less. 3 The bulk specific gravity of the expandable tablet formed into a three-dimensional shape is
The expandable tablet for static crushing according to claim 2, which has a particle size of 2.0 to 3.2. 4. The expandable tablet for static crushing according to claim 2, wherein the calcium oxide is hard calcined lime.