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PRODUCTS |
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ALOFIX MC, BRISTAR, EXPAN, Pre U-LOX, TETRAGUARD AS20/AS21, TETRAGUARD PW |
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BRISTAR |
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WHAT IS BRISTAR |
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BRISTAR is a non-explosive demolition agent which is
quite different from ordinary demolition agents such as explosives
and dangerous materials. It does not cause any flyrock, noise, ground
vibration, gas, dust or any other environmental pollution when used
properly.
As requirements for demolishing rock or reinforced concrete in construction
increase in tight quarters, the use of explosives and explosive
agents are becoming more restricted as far as safety and environmental
pollution problems are concerned.
BRISTAR is a solution.
When BRISTAR mixed with an appropriate quantity of water is poured
into cylindrical holes drilled in advance in rock or concrete to
be demolished, it hardens and expands and then causes cracks systematically.
After that, the material with cracks can be easily removed with
a pick hammer, a pneumatic breaker, an excavator, etc.
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ADVANTAGES |
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- SOUNDLESS CRACKING
Unlike the exsisting method of demolition done by explosives
or breaking equipment, BRISTAR quietly and gradually demolishes
rock or concrete with its expansive stress (more than 30 N/mm
2 caused by hydration reaction, so that BRISTAR does not cause
any noise, vibration, flyrock, dust and gas.
- NO LICENSE
Using BRISTAR does not require a special license unlike explosives,
explosive agents, etc.
- SIMPLE HANDLING
Neither capping with mortar, sand, etc. nor tamping with a bar is necessary after BRISTAR mixed with
water is poured into drilled holes in rock or concrete.
- SYSTEMATICAL DEMOLITION AND DEMOLITION IN WATER
BRISTAR can demolish rock or concrete systematically, and also
demolition work in water is possible.
- HIGH-EFFICIENCY DEMOLITION WORK
Since rock or concrete previously cracked with BRISTAR is easily broken with breakers etc., the
amount of time required for breaking of rock or concrete can be remarkably reduced.
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COMPARISON OF DEMOLITION METHODS |
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There are many superior points in the demolition work
performed by "BRISTAR" as compared with the other demolition methods.
It is also seen to be more economical.
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USES OF BRISTAR |
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Since BRISTAR demolishes objects by expansive stress, it is used for various purposes. In particular,
BRISTAR is very suitable for demolition work in tight quarters where large-sized breaking machines or
explosives cannot be used due to their causing environmental problems.
ROCKS
- Splitting of boulders
- Slabbing
- Excavation of rock wall or bedrock
- for road expansion
- for harbour expansion
- for residential development
- for various types of construction work etc
- Excavation associated with tunneling
- Trenching,Shaft sinking
- Quarrying
- Others
CONCRETE
- Demolition of mass concrete
- Demolition of foundations for machinery and structures
- Demolition of pillar, beam, wall or slab of bridges
- Demolition of temporary concrete structures
- Demolition of piers
- Demolition of retaining wall
- Partial demolition of various concrete structures
- Others
OTHERS
- Demolition of fire-bricks
- Demolition of bricks for structures
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PROPERTIES | |
- CHEMICAL COMPONENTS OF BRISTAR
BRISTAR is a powder product consisting of Calcium Oxide and
an organic material.
- SOME EFFECTS ON THE EXPANSIVE STRESS OF BRISTAR
- The expansive stress increases more than 30 N/mm2(Fig.1
& Fig.2). Generally, the compressive fracture stress of
rock is 100 to 200 N/mm2 and that of concrete is 15 to 50
N/mm2. However, the tensile fracture stress is very small,
for instance, it ranges from 4 to 7 N/mm2 in rock and 1.5
to 3 N/mm2 in concrete. Since demolition with BRISTAR is
based on a fracture due to a tensile stress, all kinds of
rock and concrete can be cracked and broken with BRISTAR
when appropriate holes are properly drilled.
- The larger the hole diameter is, the greater the expansive
stress becomes (Fig.3).
- There is little change in the expansive stress when the
water ratio is in the neighborhood of approximately 30%.
However, the stress is decreased as the water ratio is increased
or decreased.
- The expansive stress along the hole depth is almost constant
except for that near the entrance of holes. Generally, the
expansive loss from the hole entrance has little effect
on the demolition work when the hole depth is enough.
- When BRISTAR is properly used within the parameters as
noted in the conditions, no spurt due to heat generation
(blown-out shot) occurs, because of the BRISTAR's strong
adhesion and frictional resistance to the upper surface
of the hole.
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FRACTURE MECHANISM |
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After BRISTAR is poured into holes drilled in rock or concrete, the expansive stress gradually increases
with time and it becomes more than 30 N/mm2 at room temperature after 16 hours. As BRISTAR generates its expansive stress, the object to be cracked undergoes a process of (1) crack
initiation, (2) crack propagation, and (3) the increase of crack width. Therefore, this fracture mechanism is distinguished from a breakage by blasting.
The mechanism by the expansive stress of BRISTAR is shown in Fig.4. Cracks initiate from an inner
surface of the hole, being caused by tensile stress at a right angle with the compressive stress which
occurs by the expansive stress of BRISTAR. Then, as the expansive stress of BRISTAR is kept up
even after the appearance of cracks, the cracks propagate and also new cracks initiate during the
process. Usually, for a single hole, 2-4 cracks initiate and propagate. When a free surface exists, the
crack, as shown in Fig.5, is pushed apart mainly by the shear stress, and a secondary crack also arises
from the bottom of the hole running toward the free surface. When multiple numbers of holes that are
properly adjacent to each other, are filled with BRISTAR, the cracks from the hole propagate to connect
with the neighboring holes, as shown in Fig.6. It is, therefore, possible to determine the directions of the
cracks by appropriately arranging the hole spacing, its depth and its inclination.
Establishment of Free Surface
In the case of trenching, shafting or tunneling, if all holes are
drilled vertically and filled with BRISTAR,
the crack width cannot increase but horizontal cracks are initiated.
Therefore, in order to obtain two free surfaces, inclined
holes or presplitting is required.
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TYPE OF BRISTAR |
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PACKAGE |
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CONTAINER |
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BRISTAR is pacaged in 4 anti-moisture plastic
bags of 5 kgs (11 lb) each , and the bags are placed in a carton
box with a total net weight 20 kgs (44 lb).
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STORAGE |
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Store BRISTAR in a dry place and use it as soon as possible. Though BRISTAR is packed in antimoisture
plastic bags, long storage may cause deterioration of its working ingredients.
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When storing, do not place the cartons or the bags of BRISTAR directly on a floor. Put them on a
pallet and keep in a dry warehouse etc. BRISTAR stored in above-mentioned way can be effectively
used for about 1year.
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BRISTAR should be unpacked right before use.
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When storing the portion of BRISTAR remaining after use, push the air out of the bag, then seal it
with gum tape and use it as soon as possible.
However, since it may get exposed to moisture, there is a risk of BRISTAR losing its effectiveness
once the bag has been opened.
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If you receive broken bags of BRISTAR, they may not work due to possible moisture absorption.
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STANDARD QUANTITY |
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The quantity of BRISTAR to be used for cracking
differs with the hole diameters and hole spacing. In Table 3,
the relation between the quantity of BRISTAR used and the hole
diameters is indicated for a hole of 1 meter in length, where
BRISTAR was mixed at a water ratio of 30%.
* When an object with two or more free surfaces is demolished
perfectly, the quantity of BRISTAR shown in the above Table is
required.
* In case of demolition of boulders or bed rock, the required
quantities of BRISTAR are 80% or 110% of indicated quantity in
the above table, respectively.
* When an object with two or more free surfaces is demolished perfectly, the quantity of
BRISTAR shown in the above Table is required.
* In case of demolition of boulders or bed rock, the required
quantities of BRISTAR are 80% or 110% of indicated quantity in
the above table, respectively. * In case of demolishing an object
which has only one free surface or partial demolition etc. to
smaller-sized blocks, the required quantities of BRISTAR increase
in comparison with those shown in the above Table.
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HOLES FOR BRISTAR |
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- Hole Diameter
Allowable range of hole diameter for BRISTAR is 36- 50mm (1
3/8" -2" ). The larger the hole diameter is, the greater the
expansive stress becomes and the wider the hole spacing becomes.
- Hole Length
This varies with the shape of the object to be demolished or
the break plan. (Refer to Table 5 regarding standard hole length.)
When the length is less than 3 times that of the hole diameter,
less cracking will occur, the breaking effect is lessened and
the time required for demolition is increased.
- Angle of Hole
It is preferable to drill holes vertically, but in case of a
thin material, consideration should be given so as to make a
long hole by drilling it obliquely since a greater effect is
achieved with a deeper hole.
- Hole Spacing
Hole spacing varies with the properties of rock, joint, volume
to be removed, conditions of free surface, quantity of re-bars,
secondary breaking, work period etc.
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APPLICATION OF BRISTAR |
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Selection of Proper Type of BRISTAR |
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Referring to Table 2 on page 7, to avoid blown-out shots the proper type of BRISTAR should be selected in
accordance with the temperature of the object to be demolished.
NOTE :When the season is shifting, ex. winter to spring, or when tunnel or underground demolition work is
carried out, carefully select the proper type of BRISTAR in accordance with the temperature of the object
to be demolished, not outdoor temperature, because the temperature of the object is often great[y
different from the outdoor temperature. If the temperature of the object is higher than the outdoor
temperature and the type of BRISTAR selected in accordance with the outdoor temperature is used,
blown-out shots will certainly occur.
Temperature Estimation
As shown in Fig.7, place a thermometer in the bottom of the hole and leave it in place for 2-3 minutes.
Then quickly pull out the thermometer and take a reading.
NOTE :Avoid taking temperature right after drilling since the temperature
of the hole is higher because of friction heat.
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Test Breaking and Drilling |
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Since work using BRISTAR depends on the placement of the holes, the
drilling must be done in relation to the job to be performed.
Prior to the execution of test breaking, reference should be made to
"Example of Hole Design for Demolition" in this brochure to assist in break
design.
To determine what combination of hole size and spacing is most
desirable, drill several holes of different diameters at different burdens
and spacing, check the break condition of each and then decide hole diameter, length, burden and spacing.
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Drilling |
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Drill holes designed for demolition with a drilling machine.
(1) Drilling machine : Jack Hammer, Leg Hammer etc.
(2) Drilling Direction : It is preferable to drill holes vertically, but in case of a wall or pillar of reinforced concrete
where vertical drilling is hard, an inclined hole may be drilled. For horizontal holes, the
same idea of spacing as with vertical holes can be applied. Try to drill horizontal holes with
some slope.
(3) Drilling machine : Use of Spiral Sheath Pipes
In the case of a temporary concrete structure (to be demolished), place spiral sheath pipes as holes before
placing concrete. When the structure needs to be cracked, fill the holes with BRISTAR after removing the spiral
sheath pipes.
There is no change in breaking effect by the use of spiral sheath pipes.
However, spiral sheath pipes of 36-50mm (1 3/8"-2") diameter should be used.
NOTE : Never use vinyl chloride pipes etc. instead of spiral sheath
pipe. Leg Hammer Spiral Sheath Pipe
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Application Of Bristar |
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Mixing
- Equipment
(1) Container : For one bag of BRISTAR-a metal round-shaped
bucket or clean can with 10-20 liters capacity
(2) Mixer : For instance, hand-mixer with saucer typed blade
(Hand mixing is available.)
(3) Water Measure : Beaker or measuring cylinder
(4) Protector : Protective Glasses, Rubber Gloves, Dust-proof
mask
- Mix Proportion
BRISTAR : 5 kgs (11 lb, 1 bag)
Water : 1.5 liters (0.4 US gallon)
Yield Volume : Approxmately 3.1 liters
NOTE :Standard water ratio to BRISTAR is 30%.
- Mixing Method
(1)Pour 1.5 liters (0.4 US gallon) of clean water into a container
beforehand and add one bag (5 kgs 11 lb) of BRISTAR gradually
and mix well until it has good fluidity.
(2) When the viscosity of the mixture of BRISTAR and water is
too high to pour into holes, add a little water to get good
fluidity.
However, do not exceed 34% of water ratio (1.7 liters, or 0.45
US gallon, per 5 kgs, or 11 Ib of BRISTAR)
(3) Mixing time using a hand-mixer is approximately 2-3 minutes
(it is recommended that a mechanical mixer be used for large-volume
jobs).
When mixing by hand, be sure to wear rubber gloves.
- Mixing Water
(1)Use clean water such as city water, river water, sea water,which
are not contaminated with oil, organic substances, etc.
(2)Use the proper temperature of water for each type of BRISTAR
referring to Table 2 on page 7.
(3)In particular, cool water below 15. (59°F) must be used when
average atmospheric temperature is more than 30. (86°F) for
BRISTAR 100.
(4)The cooler the water is, the longer BRISTAR will remain fluid.
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FILLING |
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- Filling of the hole with BRISTAR
(1) BRISTAR should be poured into holes within 10 minutes after
mixed with water. If BRISTAR is left as it is more than 10 minutes
after mixed with water, the BRISTAR gradually loses its fluidity
so that it gets difficult to pour the BRISTAR into holes.
NOTE :
a. Do not leave BRISTAR in a container beyond 10 minutes because
blown-out shots may occur.
b. Once its fluidity is gone, it should not be diluted by re-mixing
with water since the strength is greatly reduced.
(2) BRISTAR must be poured into a hole to the top.
- Use of Polyethylene Sack in Hole
(1)When there are many joints or large voids in the object to
be demolished and BRISTAR somewhat leaks from the hole or when
there is water in the hole, place a polyethylene thin sack equal
to or slightly larger than the hole diameter into the hole and
then pour BRISTAR into the sack (Ref. Fig.8).
If there is water in the hole, the BRISTAR in the sack will
displace the water in the hole. There is no change in the breaking
effect by the use of this kind of sack.
NOTE :When a clayey layer of a rock creates a pocket in a hole
during drilling, be sure to use the polyethylene sack for filling
because filling of BRISTAR without the sack may cause blown-out
shots.
(2)When the object to be demolished is in water, use the sack
indicated in Fig.8. Try to use the bucket or the pump when filling
into the pipe, remove it, and then tie the sack to prevent the
BRISTAR from be diluted. If there is no flow of water around
the entrance of the hole, BRISTAR may be directly poured into
the hole using a pump and so on. It should gently displace the
water in the hole.
For more convenient filling work, it is recommended to use BRISTAR
PACK, a cartridge type of BRISTAR (Ref. photo on page 7).
(3)When a great deal of water of the slurry is absorbed by the
object to be demolished (for instance, dry concrete), use the
sack or spray water into the hole before filling it with BRISTAR.
In cold temperature, avoid freezing of the water sprayed into
the hole.
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CURING |
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Cover the filled holes with a plastic cover etc. to avoid any accident caused by blown-out shots.
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Tamping with mortar or sand is not required at all after the BRISTAR is poured.
It is also not necessary to put on any restrictive cap.
Just leave as it is and wait until cracks initiate.
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The time required for crack formation in material at 20.(68°F) is approximately 10-20 hours. The
lower the temperature is, the longer the time for crack formation is.
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Spraying the surface with water after cracks initiate tends to expand the width of cracks and speed
up the cracking process.
NOTE :Be sure to wear PROTECTIVE GLASSES when confirming the occurrence of cracks.
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Secondary Breaking |
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After cracks initiate, secondary breaking is carried out with a hand-breaker, a pick-hammer, a giant
hydraulic breaker, a ripper, etc.
It is best to wait until the BRISTAR has worked to full depth before removing rock or concrete since
premature removal at the first sign of a crack hampers the leverage effect of BRISTAR.
NOTE :
a. Be sure to wear PROTECTIVE GLASSES when secondary breaking is carried out.
b. The crack width for rock or concrete continues to increase with
time and can become 10-30 mm (3/8"-1 1/8") after several days, depending
on free surfaces available.
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EXAMPLE OF HOLE DESIGN FOR
DEMOLITION |
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APPLICATION EXAMPLE |
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