Note: Descriptions are shown in the official language in which they were submitted.
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
7 8
-- 3
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
-- 6
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~
-- 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~
-- 8
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~
-- 10 --
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.
i 1~327~3
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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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expansion property of the demolition-facilitating
substance.
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- 18 -
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.
I~63~
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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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- 22 -
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~
- 23 -
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~ -
- 24 -
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.
