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Soundless Chemical Demolition Agents
The Need
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The traditional approach to demolishing
concrete structures or reducing the size of large rocks or boulders has typically included
the use of explosives. The resulting explosions are associated with the obvious risks
posed by shock waves and fly rock. These problems, along with other detrimental side
effects of using explosives, have increased an interest in the use of alternative methods
to demolish rock and concrete structures. |
Rock Demolition |
The Technology
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Soundless chemical demolition agents (SCDAs)
have proven to be viable substitutes for the use of explosives. SCDAs are powdery
materials that will expand considerably when mixed with water. This expansion, when
occurring under confinement, generates significant expansive pressures. These pressures
are sufficient to break up rock and concrete when the SCDA is confined in a borehole or a
series of boreholes. Experiments have been conducted with SCDAs to learn more about those
variables that tend to hamper or change SCDA performance. Results show that the amount of
mixing water and the ambient temperature are the most important variables in influencing
the generation of SCDA expansive pressures. |
Pier Demolition |
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The preparatory procedures involved in using SCDAs are similar to those followed in
traditional blasting techniques. As with explosives, boreholes must be drilled to contain
the SCDA. Beyond this, however, the similarities diminish. The SCDA must be mixed with a
measured quantity of water and poured into the boreholes. It will then begin to hydrate,
generating heat and crystallizing while hardening and expanding. If hydration takes place
under confinement, significant expansive pressure will result. The pressures can be of
sufficient magnitude that, after a period of time, they will fracture the confining
material. Depending on the type of SCDA, significant expansive pressure may be generated
as quickly as within 15 min., or as long as within 24 hr.
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The Benefits
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They do not make noise, explode, or generate
fly rock, vibration or toxic fumes. SCDAs are also safer than traditional explosives,
which pose the threat of premature explosion and which may misfire, posing a significant
threat after the planned explosion. Contrary to explosives, SCDAs produce their
destructive forces in rock and concrete by generating significant expansive forces without
generating shock waves. While there are several
advantages to using SCDAs, their relatively high cost makes explosives more cost-effective
in many applications. Nonetheless, SCDAs have become a common means of breaking up
boulders that have rolled onto remote mountain highways. SCDAs have also been used when
excavating rock, or demolishing concrete structures or components of concrete structures
near inhabited areas, natural gas lines, roadways or other areas where the use of
explosives would pose a significant safety risk. |
Status
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SCDAs are manufactured primarily in Japan,
China, Russia, and some countries in Europe. In US, Demolition Technologies
Incorporated is distributor of BRISTAR from Onoda Corp.,
Japan, and Daigh Company is distributor of Fract.AG from
Chimica Adile, Italia.
Although the use of
explosives remains the principal means by which rock and concrete structures are
demolished, there has been and increased use of SCDAs over the past two decades. There is
still little standardization surrounding the manufacture and use of SCDAs. In fact, there
is not even a consensus as to the proper terminology by which reference should be made to
SCDAs. Other terms by which SCDAs are known include soundless cracking agents, expansive
agents, expansive concrete, non-explosive demolition agents, and other related variations
of these terms. |
Barriers
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The relatively high cost of SCDAs makes
explosives more cost-effective in many applications. This makes the SCDA’s market
very limited. |
Points of Contact
- Hinze J., Prof., School of Building Construction, Univ. of
Florida, P.O. Box 115703, Gainesville, FL 32611-5703, Email: hinze@ufl.edu
- Brown J., Christofer Brown Assoc., 879 Rainier Ave. N.,
Suite A201, Renton, WA 98055.
- Piper B., Demolition Technologies Incorporated, 107 Mildred
Street P.O.Box 427, Greenville, AL 36037. Phone: (800) 282-4384,
Fax: (334) 382-7548
- Mike Daigh, Daigh Company, P.O.
Box 2605, Cumming, GA 30028, Phone:
(770) 887-5215, Fax:
(770) 887-3783, E-mail: mikedaigh@mindspring.com
- Archer Company USA, Inc. 100
Lindbergh Drive Suite B, Santa Teresa, NM 88008 Phone: (505)
874-9188 Fax: (505) 874-9108 Email:
sales@archerusa.com
References
- "BRISTAR 2000" Non Explosive Demolition Agent
Catalog. ONODA Corporation. Tokyo, Japan
- BRISTAR Home Page, http://www.onoda.co.jp/overseas/contents.html
- Demolition Technologies
Incorporated, http://demolitiontechnologies.com/
- Fract.Ag, http://www.daighcompany.com/
- Hinze Jimmie and Brown James,.Properties of the Soundless
Chemical Demolition Agents, Journal of Construction Engineering and Management,
Vol.120, No. 4, December, 1994.
Disclaimer Statement
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Neither the Construction
Industry Institute nor Purdue University in any way endorses this
technology or represents
that the information presented can be relied upon without further investigation. |
IRA15/RAY/MA
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