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Reactive
Powder Concrete
The Need
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The upper limit
of compressive strength for materials that can be used in commercial applications
continues to be pushed higher and higher. Within the past three years Portland cement
based materials have been developed which have compressive strengths greater than 200 MPa
(2 to 4 times greater than High Performance Concrete). These materials allow remarkable
flexural strength and extremely high ductility, more than 250 times greater than that of
conventional concrete. |
Sherbrooke bridge, Quebec, Canada
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The Technology
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Reactive Powder
Concrete is an ultra high-strength and high ductility composite material with advanced
mechanical properties. Developed in the 1990s by Bouygues' laboratory in France. It
consists of a special concrete where its microstructure is optimized by precise gradation
of all particles in the mix to yield maximum density. It uses extensively the pozzolanic
properties of highly refined silica fume and optimization of the Portland cement chemistry
to produce the highest strength hydrates. RPC represents a new class of Portland cement-based material with compressive
strengths in excess of 200 MPa range. By introducing fine steel fibers, RPC can achieve
remarkable flexural strength up to 50 MPa. The material exhibits high ductility with
typical values for energy absorption approaching those reserved for metals. |
Design of the Pedestrian Bridge
Construction of the Sherbrooke bridge
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The Benefits
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- RPC is a better alternative to High
Performance Concrete and has the potential to structurally compete with steel.
- Its superior strength combined with higher
shear capacity results in significant dead load reduction and limitless structural member
shape.
- With its ductile tension failure mechanism,
RPC can be used to resist all but direct primary tensile stresses. This eliminates the
need for supplemental shear and other auxiliary reinforcing steel.
- RPC provides improve seismic performance by
reducing inertia loads with lighter members, allowing larger deflections with reduced
cross sections, and providing higher energy absorption.
- Its low and non-interconnected porosity
diminishes mass transfer making penetration of liquid/gas or radioactive elements nearly
non-existent. Cesium diffusion is non-existent and Tritium diffusion is 45 times lower
than conventional containment materials.
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Status
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The firm HDR Engineering
Inc.is responsible for the development and promotion of RPC in North America. An application of RPC can be seen in the Pedestrian
Bridge in the city of Sherbrooke, Quebec, Canada. RPC has also been used for isolation and
containment of nuclear waste of several projects in Europe.
This product was nominated for the 1999
Nova Awards from the Construction Innovation Forum. |
Barriers
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In a typical RPC mixture
design, the least costly components of conventional concrete have been basically
eliminated or replaced by more expensive elements. The fine sand used in RPC becomes
equivalent to the course aggregate of conventional concrete, the Portland cement fills the
role of the fine aggregate and the silica fume that of the cement. The mineral component
optimization alone results in a substantial increase in cost over and above that of
conventional concrete (5 to 10 times higher than High Performance Concrete.) RPC should be used in areas where substantial weight
savings can be realized and where some of the remarkable characteristics of the material
can be fully utilized. |
Points of Contact
- William Dowd, HDR Engineering, Inc. 8404
Indian Hills Dr., Omaha, Nebraska, 68114. Phone: (402) 399-1080, Fax: (409) 399-4979,
Email: bdowd@hdrinc.com
References
- 1999 Nova Award Nominations, The Nova Award,
Construction Innovation Forum, Inc., October 1998.
- O'Neil, E. F. and Dowd, W. M. "Reactive
powder concrete (RPC), a new material for the construction industry." NCMEC Session:
Practitioners Guide to Materials for Concrete and Masonry Structures.
- Gilliland, S. K. "Reactive powder concrete (RPC), a new
material for prestressed concrete bridge girders." Building an International
Community of Structural Engineers Structures Congress - Proceedings. v 1 1996. ASCE, New
York, NY, USA. p 125-132.
- Dauriac, C. "Special concrete may give steel stiff
competition." Building with Concrete. The Seattle Daily Journal of Commerce. May 9,
1997. http://www.djc.com/special/concrete97/10024304.htm.
- HDR Engineering web site http://www.hdrinc.com.
- Sherbrooke Footbridge, VSL Post Tensioning
Contractor web site
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. |
LHM
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