JPH0440512B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Application of the Invention] The present invention relates to a limited crushing method suitable for brittle objects, particularly thin brittle objects such as concrete slabs. [Prior art and its drawbacks] Conventionally, when attempting to limitedly crush the surface of a brittle object such as mortar, concrete or rock using an expansive slurry, an appropriate number of holes are drilled in the brittle object and then the inside of the brittle object is crushed. A method is used in which slurry is injected into the tank and expansion pressure is applied. At that time, in order to enhance the crushing effect, the holes are drilled diagonally or variously devised in the hole pattern. However, even if such a method is applied to a thin and brittle object in which the drilling depth cannot be sufficiently deep, a sufficient effect cannot be obtained considering the complexity of the drilling operation. [Object of the present invention] As a result of various studies on limited crushing methods for thin brittle objects using expandable slurry, the present inventor adjusted quicklime with high hydration activity as an expansion component to the slit grooves made in a lattice pattern. The present invention was completed by discovering that it can be easily destroyed by injecting a slurry prepared by the process. [Structure of the present invention] That is, the present invention has slit grooves with a width of 30 mm or less arranged in a lattice shape, and the interval between the slit grooves is 200 to 600 mm, and quicklime with a crystal diameter of less than 10 μm is placed therein. This is a limited crushing method for thin and brittle objects, which is characterized by injecting a slurry prepared as an expansion component. The present invention will be explained in more detail below. Slitting grooves in brittle objects can be easily done using a cutting machine such as a concrete cutter. If slurry will not be injected for a long time after the slit grooves have been created, or if slurry does not need to be injected at the same time, fill in joint material such as wood or Styrofoam and remove it when injecting. It is better to do so. In the present invention, the reason why the width of the slit groove is limited to 30 mm or less is that if the width exceeds 30 mm, the friction restraining force with the object to be crushed decreases, and the upper surface slurry turns into powder and gushes out. The preferred slit width is 10 to 20 mm. It is preferable to set the slit depth to about 60 to 80% of the thickness of the object to be crushed in order to increase the fracture efficiency (the relationship between the effort of creating the slit grooves and the crushing time). It is desirable that the spacing between the slit grooves be approximately 200 to 600 mm. Regarding the arrangement of the slit grooves, various patterns can be considered as shown in the drawings. Experience has shown that in order to increase the limited crushing effect, it is necessary to apply expansion pressure from multiple directions, but as a result of various studies, we found that using a lattice-like structure as shown in Figure 1, the effect was far greater than expected. It was discovered that it exerts a surprising effect and has been limited in this way. Next, the expandable slurry injected into the slit groove will be explained. The expanding component of the slurry used in the present invention is quicklime (soft burnt quicklime) with a crystal diameter of less than 10 μm. As an expanding component for adjusting this kind of slurry, there is hard calcined lime with a crystal diameter of 10 to 100 μm (Japanese Patent Application Laid-open No. 1983-1999-
67059), the present invention uses quicklime with a crystal diameter of less than 10 μm, which has high hydration activity and is easy to manufacture. An example of a crushing agent containing quicklime with a crystal diameter of less than 10μ as an expanding component is a combination of 30 to 90 parts by weight of quicklime and 10 to 70 parts by weight of a rapidly hardening hydraulic substance such as a mixture of calcium aluminate and anhydrite. Main material consisting of proportion 100
A composition consisting of 0.5 to 15 parts by weight of a hydration inhibitor such as an inorganic carbonate or oxycarboxylic acid and 0.1 to 5 parts by weight of a water reducing agent such as a lignin sulfonate or a polyalkylaryl sulfonate (JP-A Showa 58-
101178), 20 to 80 parts by weight of quicklime whose particle size has been adjusted to 88 to 3000μ, and cement, especially 80 to 20 parts by weight of cement containing calcium sulfoaluminate as a hydraulic component (Japanese Patent Application Laid-open No. 130559/1983).
Publication No.) etc. To make it into a slurry, add about 25 to 45 parts by weight of water to 100 parts by weight of the crushing agent. The most desirable crushing agent for the present invention is crystal size 2~
50-70 parts by weight of quicklime of 7μ, _an amorphous calcium aluminate, especially an amorphous calcium aluminate having a composition of _12CaO.7Al2O3 , and 0.5-70 parts of anhydrite.
Carbonate or bicarbonate of potassium or sodium, citric acid, tartaric acid, gluconic acid and water-soluble salts of these acids per 100 parts by weight of the main material consisting of a mixture of 1.5 and 30 to 50 parts by weight. 0.5 to 15 parts by weight of at least one hydration inhibitor selected from the following, and at least one water reducing agent selected from the group consisting of lignin sulfonate, polyalkylaryl sulfonate, and melamine sulfonate formalin. 0.1～
5 parts by weight. As a commercially available product, there is a trade name such as "Denka Chemiax", and it is convenient to use it. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 Compressive strength using ordinary Portland cement
240Kgf/ ^cm2 concrete slab version (4m x 4
A slit groove (width 10 mm, depth 110 mm, slit groove interval 40 cm) was cut in the center of the sample (width 10 mm, depth 110 mm, slit groove interval 40 cm) in the center of the sample as shown in Figures 1 to 4, and filled with expandable slurry. The expandable slurry used was quicklime with a crystal diameter of 2 to 7μ (Blaine value).
3000cm ² /g) 60 parts by weight, 40 parts by weight of an equal weight mixture of amorphous calcium aluminate with a composition of 12CaO.7Al ₂ O ₃ and type anhydrite, 70% by weight of potassium carbonate,
Sodium gluconate 15% by weight and citric acid 15% by weight
A crushing agent obtained by mixing 5 parts by weight of a hydration inhibitor consisting of 2 parts by weight of a lignin sulfonate water reducing agent
It is made by adding 30 parts by weight of water to 100 parts by weight. The test was conducted indoors at a temperature of 2 to 5°C. As a result, in the case of the present invention shown in FIG. 1, it was possible to crush each block in a limited manner to the extent that each block could be taken out with a crowbar 5 hours after the slurry was injected. In contrast, in Figure 2, only local crushing effects were observed and it took 16 hours after slurry injection. Furthermore, the crushing shown in Figures 3 and 4 was localized and did not result in the entire surface being lifted up, and the crushing time required 12 hours for Figure 3 and 18 hours for Figure 4. Furthermore, for comparison, a slurry was prepared in the same manner as above except that quicklime with a crystal diameter of 20 to 30μ (Blaine value 3300cm ² /g) was used instead of the quicklime, and the slurry was prepared as shown in FIG. Injected into the pattern. As a result, each block was crushed to the extent that it could be taken out with a crowbar, but it took 20 hours to crush it. Example 2 The same procedure as Example 1 was carried out except that the width of the slit groove was changed as shown in Table 1. The results are also listed in Table 1.

[Table] As is clear from the table, the width of the slit groove is 30mm.
In the case (Experiment No. 2-1), the entire block was crushed in a floating state 4 hours after the slurry injection, but when the width of the slit groove was 40 mm (Experiment No. 2-
2) The injected slurry turned into powder and gushed out without being crushed. Example 3 The same procedure as Example 1 was carried out except that the spacing between the slits was changed as shown in Table 2. Table 2 shows the results.
Also listed in

【table】

[Effects of the present invention]

According to the present invention, even a thin brittle object with a poor crushing effect can be efficiently and limitedly crushed compared to the conventional drilling method. Further, conventional drilling requires a great deal of effort and has poor work efficiency, but in the present invention, the slit grooves can be formed with a cutting machine such as a concrete cutter, so construction is easy.

[Brief explanation of drawings]

Figures 1 to 4 show patterns (plan views) of slit grooves formed on a brittle object, with broken lines representing empty grooves and solid lines representing slurry injection grooves. FIG. 1 shows an example of the present invention, and FIGS. 2 to 4 show comparative examples.

Claims (1)

[Claims] 1 Slit grooves with a width of 30 mm or less are arranged in a grid pattern, and the spacing between the slit grooves is 200 to 600 mm.
A limited crushing method for thin brittle objects, which is characterized by injecting into the slurry a slurry prepared by adding quicklime with a crystal diameter of less than 10 μm as an expansion component.