Soundless Chemical Demolition Agents
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
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.
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
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.
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.
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: firstname.lastname@example.org
- 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: email@example.com
- "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.
the Construction Safety Alliance nor Purdue University in
any way endorses this technology or represents that the
information presented can be relied upon without further