CA1163278A - Demolition-facilitating substance - Google Patents

Abstract

DEMOLITION-FACILITATING SUBSTANCE ABSTRACT A novel demolision-facilitating substance comprises a clinker containing 1.0 ? 40% by weight of a calcium-almino-ferrite solid solution and 60.0 ? 99.0% by weight of both free line and free magnesia, and optionally, a reaction moderator consisting of least one member selected from the group consisting of gypsum, sugars, polyhydric alcohols and borate.

Description

7 ~

D _ LITION-FACILITATING SVBSTANCE

FIELD OF THE INVENTION

The present invention relates to a demolition--facilitating su~stance and more particularly to a substance for facilitating demolition processes, for example, processes for demolishing concrete, rocks and similar durable structures, by means of an expansion force which is generated by a hydration reaction of an expansible clinker.

BACKGRO~ND OF THE INVENTION

Up to nowr as a method for demolishing concrete structures and roc~s, the following methods have commonly been used; for example, a mechanical method of using an impact force by means of a heavy weight, or a method of utili~ing an explosive force such as dynamiteO However, those methods of demolishing durable structures co~ta:in many practical restrictions in their use, considerating safety, noise, dust and so on. For example, the above--mentioned conventional demolishing methods cannot be carried out in a place where human domiciles are close.
Considering the above-mentioned circumstances, the inventors of the present invention carried out a wide range of systematic research to find a demolition-facilitating substance.
DETAILED DESCRIPTION OF T~E INVENTION
An object of the present invention is to provide a substance for facilitating demolition processes, which is suitable for saely and easily demolishing concrete, rocks "..

7 ~3 and such durable structures, at a low cost.
Another object of the present invention is to provide a substance for facilitating demolition processes, which cause no pollution of the environment.
As a result of the in~entor's systematic research, it has been discovered that a CaO-A12O3-Fe2O3-MgO type clinker having a specific composition, exhibited a large e~pansion caused by a hydration reaction thereof, then the demolition stress originating from said large expansion could be utilized for demolishing concrete and roc~s easily.
According to the present invention, there is provided a substance for facilitating demolition processes which comprises a clinker containing 1.0 ~ 40~ by weight of a calcium-almino-ferrite solid solution (in future, abbreviated to C4AF) and 60.0 ~ 99.0% by weight of both free lime and free magnesia.
The above-mentioned clin]cer can be prepared by calcining a mixture of raw materials comprising a calcareous material such as limestone and/or a dolomitic material such as dolomite, as well as a ferrite material such as hammerscale, or a mixture of a ferrite material and an aluminous material, such as bauxite at a temperature of from 1200 to 1800C.
The reason for limiting the amount of C4AF to the range of from 1.0 to 40.0~ by weight is as follows.
~ hen the amount of C4AF is less than 1.0% by weight~
the lime crystals can not grow sufficiently so that enough handling time and sufficient demolishing force could not be obtained.
When the amount of C4AF is more than 40.0~ by ~eight, the amount of free lime and free magnesia would become less than 60.0% by weight inevitably, so that a demolition stress produced by the volume expansion arising from hydration reaction of free lime and free magnesia becomes less than the service number.
The reason for limiting the total amount of free lime and free magnesia to the range of from 60.0 to 99.0% by weight is as follows. When the total amount of free lime and free magnesia is less than 60% by weight, a practically eEfective demolishing force cannot be obtained. When the total amount of free lime and free magnesia is more than 99~o% ~y weight, the amount of C4AF ~ecomes less th~n one percent inevitably, so that the lime crystals are no~: able to grow sufficiently; moreover enough handling time and sufEicient demolishing force after insertion of the substance for facilitating demolition processes can not be obtained because of the very rapid occurrence of hydration.
The preferable ratio in wel~ht of free lime to free magnesia in ~he clinker is in the range of from 60:40 to 99:1. The reason for selecting the above-mentioned range is as follows.
When the calcining temperature for the clinker is relatively low, for example, about 1200 to 1300C, the e~pansion of MgO caused by the hydration reaction thereof can be carried out at a proper stage so that a practical satisfactory demolishing force can be created. Therefore, 3~8 the component consisting of free lime and free magnesia may be dolomite alone in which the ratio in weight of the free lime to the free magnesia is about 60:40. However, if the calcination of the clinker is carried out at a high temperature of 1300C or more, the expansion of MgO occurs too slowly. Therefore, it is impossible to create a practical satifactory demolishing force. Accordingly, in this case, the component consisting of the free lime and the free magnesia may be limestone alone in which the ratio in weight of the free lime to the free magnesia is about 99:1.
The demolition-Eacilitating substance according to the present invention may be employed in the following manner.
Firstly, concrete structures and such like materials to be demolished are provided with holes made by using a drill or similar tools, and then, (a) filling up the holes with the demolition-facilitating substance, and, thereafter, adding water to this substance, or (b) preliminarily mixing the demolition-facilitating substance with water and, then, inserting the mixture into the holes, or (c) placing the above-mentioned mixture into a tube made of plastic material and, then, inserting the tube into -the holes. Either one of the above-mentioned demolishing methods may be used taking into consideration the kind and size o~ the structure or material to be demolished as well as the location of the structure or material into which the demolition-facilitating subs~ance is inserted.
The demolition-facilitating substance of the present ~ J ~3~8 invention may be composed of -the above-mentioned clinker alone. A1-ternatively, the demolition-facilitating substance of the present invention may be composed of the above-mentioned clinker and a reaction moderator. As a reaction moderator, at least one member selected from the group consisting of gypsum, sugars, polyhydric alcohols, borate, organic acids and organic acid salts may be used.
Each of the above-mentioned reaction moderators except for organic acids and organic acid salts can be used alone, or in an appropriate combination of them. Some examples of the combinations will be described hereinafter.
~ he term "gypsum" used herein includes gypsum dihydrate, gypsum hemihydrate and gypsum anhydride. These gypsums are not restricted to natural gypsum, but may be an industrial product. When gypsum is used as the reaction moderator, the amount of gypsum in the resultant demolition-facilitating substance is preferably in the range of from 5.0% to 40.0~, in terms of gypsum anhydride, based on the total weight of gypsum and clinker.
The reason for limiting it to the above percentage range is as follows.
When the amount of gypsum is less than 5.0%, the hydration reaction of the resultant demolition-facilitating substance is carried out too fast so that a long enough handling time can not be obtained. Also, when the amount of gypsum is more than 40.0~ the total arnount of free lime and free magnesia in the resultant demolition-facilitating substance decreases to less than 60% inevitably, so that a ~ ~ 63~7~3 satisfactory demolishing force can not be obtained in an actual demolition process.
The sugars usable as the reaction moderator may include sucrose, glucose, fruit sugar, and blackstrap molasses. Also, the polyhydric a:Lcohols usable as the reaction moderator, may include sorbitol, mannitol and xylitol. A liquid polyhydric alcohol such as glycerine can also be used. When liquid polyhydric alcohol is used, it is necessary that the alcohol be first dissolved in water and, then, the solution be mixed with the clinker.
The reaction-moderating effect of the sugars or polyhydric alcohols added to the cllnker is due to the fact that a layer of a sparingly water-soluble calcium complex with sugars or the polyhydric alcohol is formed on the surface of the active lime particles This layer is effective for temporarily delaying thè hydration reaction of the active lime. The amount of sugars or polyhydric alcohols to be added to the clinker is in the range of from 0.1 to 5.0% based on the total weight of the resultant demolition-facilitating substance.
When the amount of the reaction moderator consistinq of sugars and/or polyhydric alcohols is less than 0.1%, the hydration reaction-moderating effect is not satisfactory.
~lso, if the amount of the reaction moderator is more than 5.0%, it is not effective in increasing the reaction moderating effect thereof.
The demolition-facilitating substance comprising the above-mentioned clinXer, gypsum and sugars and/or i ~ 5~7~

polyhydric alcohols has an advan~age in that the handling time can be optionally controlled as compared with another demolition facilitating substance composed of the clinker alone. Therefore, the demolition-facilitating substance comprising the above-mentioned clinker, gypsum and sugars and/or polyhydric alcohols can be very easily used in various working places. Also, this type of demolition--facilitating substance is superior than other demolition--facilitating substances consisting of the above-mentioned clinker, and sugars and/or polyhydric alcohols in that the handling time can be sufficiently controlled.
~ en a borate was used as a reaction moderatorc it was found that the borate exhibited a retarding effect on the hydration reaction. Borates usable as the reaction moderator may include sodium borates ~deca hydrate; penta hydrate, anhydride), potassium borate, anmonium borate, calcium borate and the like. The amount of borate to be added to the clinker is in the range of from 0.1 to 20.04 based on the entire weight of the resultant demolition~
-facilitating substrate. When the amount of borate is less than 0.1~, a good retarding effect on the hydration reaction can not be obtained. If the amount of borate is more than 20.0~, the resultant, aqueous slurry of the demolition--facilitating substance exhibits a remarkably decreased fluidity. In order to prepare a slurry having a satis~
factory fluidity, it is necessary that the slurry contain a large amount of water. A large amount of water causes the resultant slurry to exhibit a poor demolishing force.

~ :1 63~

The reaction moderator, usable for the present invention may sonsist of borate and at least one member selected from a group consisting of sugars, polyhydric alcohols, organic acids and organlc acid salts.
The sum of the weight of borate and at least one member selectecl from the group consisting of sugars, poly-hydric alcohols, organic acids and organic acid salts in the resultant demolition-facilitating substance is pre-ferably in the range of from 0.1 to 20.0% based on the total weight of the resultant demolition-facilitating substance.
sy using this type of reaction moderator, an excellent hydration-retarding effect can be obtained due to the synergistic action of an inorganic component consistiny of borate and an organic component consisting of sugars;
polyhydric alcohols, organic acids and/or organic acid salts. The addition of an organic component to the borate is effective for increasing the fluidity of the aqueous slurry of the resultant demolition-~acilitating substance.
This feature is effective for decreasing the amount of water contained in the slurry, and for increasing the demolishing force of the slurry. O~ing to the above-mentioned advantages the demolition-facilitating substance containiny borate as the reaction moderator is suit~ble for filling a large hole having a diameter of more than about 50 mm. Because, an undesirable effusion of the demolition-facilitating substance from the hole can be prevented The present invention will be understood more readily ~ ~ ~3~78 with reference to the following examples. However, these examples are intended to illustrate the invention and are not to be construed as to limit the basic conception of the present invention.
Examples 1 through 6 and Comparison Example 1 through 3 In each of the Examples 1 through ~ and Comparison Examples 1 through 3, a demolition-facilitating substance was prepared and its expanding property and workability were tested. A clinker of the demolition-facilitating substance was prepared in the following manner. A
limestone, dolomite, hammer scale and bauxite were ground separately, the resultant powders were mixed in a pre~
determined mixing ratio to prepare a raw material, having a composition as indicated in Table lo ~The raw rnaterial~
were molded into pellets, the pellets were calcinated at a temperature indicated in Table 1 by using an e]ectric furnace to prepare a clinker. The clinker was ground by using a ball mill to prepare a clinker powder having a distribution of grain size as shown in Table 1. The powder was used as a demolition-facilitating substance. The demolition-facilitating substance was mixed with water and the workability and percentage of linear expansion o~ the resultant aqueous slurry was measured. The results o these measuremerlts are indicated in Table 2~
As can be seen from Table 2, the demolition-facili-tating substances according to the present invention exhibited a long enough handling time, excellent t :1 ~3~ 7~

workability and satisfactory linear expansion coefficient thereof, and, therefore, were very useful as practical demolition-facilitating substances.
However, comparative demolition-facilitating substances, which fell outside the scope of the present invention, exhibited a very short handling time, poor workability and/or unsatisfactory linear expansion coefficient. Therefore, they were useless as practical demolition-facilitating substances.

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- ZT -1~3~7 Exam~les 7 through 11 -In each of the Examples 7 through 11, the same clinker as that described in Example 1 was mixed with an additive as indicated ln Table 3 to provide a reaction moderator-ccntaining dernolition~facilitating substance having acomposition as indicated in Table 3.
The resultant demolition-facilitating substance exhibited properties as indicated in Table 3.

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From Table 3, it is clear that each of the demolition~
facilitating substances which include gypsum semihydrate, gypsum dihydrate, or gypsum anhydride, as a reaction moderator exhibits a satisfactory handling time, a good workability and an excellent expansion property. Also, it is clear that the handling time can be prolonged with an increase in the content of the gypsum in the demoli-tion--facilitating substance.
Example 12 through 20 In each of the Examples 12 through 17, a clinker A
which was the same as that described in Example 1 was mixed with an additive as indicated in Table 4 to provide a reaction moderator-containing demolition-facilitating substance having a composition as indicated in Table 4O
The resultant demolition-facilita~ting substance exhibited properties as indicated in Table 4.
In Example 18, 19 and 20, clinker B, clinker C or clinker D which are the same as those described in Example 2, 3 or 4 respectively, was mixed with an additive as indicated in Table 4 to provide a reaction moderator--containing demolition-facilitating substance having a composition as indicated in Table 4.
The resultant demolition-facilitating substance exhibited properties as indicated in Table 4O
Table 4 clearly shows that the addition of a very small amount of sucrose or sorbitol to a clinker is effective for prolonging the handling time. Also, the addition of glycerol is effective for enhancing the ~ ~3~

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Examples 21 through 23 In each of the Examples 21 through 23, a clinker A
which was the same as that described in Example l, was mixed with an additive as indicated in Table 5 to provide a reaction moderator-containing demolition-facilitating substance having a composition as indicated in Table 5.
The resultant demolition-facilitating substance exhibited properties as indicated in Table 5.
From Tables 3 and 5, it is clear that the addition of the sucrose to the mixture of the clinker and the gypsum is effective prolonging the handling time.

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- 2 _amples 24 through 28 In each of the Examples 24 through 28, the same clinker as that described in Example 1 was mixed with a reaction moderator having a composition as indicated in Table 6 to provide a reaction moderator-containing demolition facilitating substance having a composition as indicated in Table 6.
The resultant demolition-facilitating substance exhibited properties as indicated in Table 6.
From Table 6, it is clear that the borates were very effective for prolonging the handling time of the demolition-facilitating substance. Accordingly the demolition-facilitating substances containing the borate are suitable for demolishing a large scale of rigid materials in a hot weather.
Use of the demolition-facilitating substance according to the present invention in the demolition of a rock, concrete, or firm ground will be illustrated by the following examples.

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i 3 ~78 Example 29 -A small hole being 2 cm in diameter and 20 cm in depth was drilled in the center position of a limestone having an upper surface area or about 50 cm square. 100 parts by weight of a demolition-facilitating substance which was the same as that described in Example ~ was added to 1.0 part by weight of sorbitol and 30 parts hy weight of water. The mixture was stirred for two minutes to prepare a slurry.
The above-mentioned hole in the limestone was filled up by the slurry and said slurry was left for hardening. After three hours, the slurry was hardened, af-ter twenty--four hours, the limestone was demolished completely.
Example 30 A small hole being 2 cm in diameter and 20 cm in depth was drilled in the center portion of a column made of concrete, which was 20 cm in diameter and 40 cm in length.
70 parts by weight of the same demolition facilltating substance as that described in Example 1 was mixed with 30 parts by weight of gypsum anhydride, 0.4 parts by weight of sucrose and 30 parts by weight o~ water. The mixture was stirred for two minutes to prepare a slurry. The above-mentioned hole in the column was filled up by the slurry, and the slurry was allowed to harden. After one hour, the slurry was hardened and after six hours, the 25 column was cracked in all directions and thereafter, demolished completely.
The tenacity of the column was estimated to be 500 ~v 600 kg/cm.

~ ~fi3~7~

Example 31 In a hard shale mine, an exposed rock floor having a horizontal upper surface and a vertical side surface, was demolished in the following manner.
In the upper surface of the rock floor, 11 holes each having a vertical depth of i.7 m and a diameter of 0.6 m and located at intervals of 1 m from each other along a line spaced 1 m from the vertical side surface and ~eing parallel to the vertical side surface, were drilled. Also, another 11 holes having the same size as those mentioned above were drilled in the upper surface along a line spaced 2 m from the vertical side surface and being parallel to the vertical side surface. The holes were formed at intervals of 1 m from each other.
A demolition-facilitating substance consisting of 70 parts by weight of a clinker which was the same as that described in Example 1, 30 parts by weight of gypsum anhydride and 0.4 part by weight of sucrose, was mixed with 30 parts by weight of water, and the mixture was stirred for 10 minutes to prepare a slurry.
The holes were filled with the slurry. The slurry started solidification one hour after the filling operation. Five hours after the filling operation, many cracks were fonned around the holes and, 12 hours after the filling operation, the rock floor was demolished to an extend that the rock floor could be ripped by using a bulldozer.
Example 32 ~ ~ 63~7~ -A ground consisting of a granite was demolished in the following manner.
In the upper surface of the ground, 105 holes each having a de?th of 3 m and a diameter of 68 rnm were drilled at an angle of 65 degrees from the upper surface along five lines spaced 1 m from each other and being parallel to each other. On each line, the holes were located at intervals of l m from each other.
In order to prepare a slurry, 96.7 parts by weights of the same clinker as that described in Example l was uniformly mixed with 3 parts by weight of sodium borate decahydrate and 0.3 parts by weight of sucrose, and the mixture was suspended in 30 parts by weight of water. The suspension was stired for 2 minutes.
The holes were filled with the slurryO One hour after the filling operation, the slurry started solidification.
Fine hours after the fillins operation, many cracks havlng a length of frorn 0.5 to 1 mm were formed around the holes.
24 hours after the filling operation, the ground was demolished to an extend that the ground could be ripped by using a bulldozer. During the demolishing operation, no ejecting phenomenon of the slurry was found.

Claims (7)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. A demolition-facilitating substance which comprises a clinker containing 1.0 ? 40.0% by weight of a calcium-almino-ferrite solid solution and 60.0 ? 99.0% by weight of both free lime and free magnesia.

2. A demolition-facilitating substance as claimed in claim 1, which contains, in addition to said clinker, 5.0 ? 40.0% of at least one member selected from the group consisting of gypsum dihydrate, gypsum hemihydrate and gypum anhydrate based on the total weight of the demolition--facilitating substance.

3. A demolition-facilitating substance as claimed in claim 1, which contains, in addition to said clinker, 0.1 ? 5.0% at least one member selected from the group consisting of sugars and a polyhydric alcohol based on the total weight of said demolition-facilitating substance.

4. A demolition-facilitating substance as claimed in claim 1, which contains, in addition to said clinker, 5.0 ? 40.0% of at least one member selected from the group consisting of gypsum dihydrate, gypsum hemihydrate and gypsum anhydrate and 0.1 ? 5.0% of at least one member selected from the group consisting of sugars and polyhydric alcohols based on the total weight of said demolition--facilitating substance.

5. A demolition-facilitating substance as claimed in claim 1, which contains, in addition to said clinker, 0.1 ? 20.0% of a borate based on the total weight of said demolition-facilitating substance.

6. A demolition-facilitating substance as claimed in claim 1, which comprises, in addition to said clinker, 0.1 ~
20.0% of an additive consisting of a borate and at least one member selected from the group consisting of sugars, polyhydric alcohols, organic acids and organic acid salts based on the total amount of said demolition-facilitating substance.

7. A demolition-facilitating substance as claimed in claim 1, wherein the weight ratio in weight of free lime to free magnesia in the clinker is in the range of from 60:40 to 99:1.