Concrete

In: Computers and Technology

Submitted By ranjith007
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STUDY REPORT
No. 146 (2005)

Reactive Powder Concrete
N.P. Lee & D.H. Chisholm

The work reported here was funded by Building Research Levy.

© BRANZ 2006
ISSN: 0113-3675

Preface
The low flexural tensile strength of concrete has a number of undesirable consequences for its performance as an effective building material. These include the necessity for auxiliary steel reinforcement and the requirement for thick-sectioned members that are both aesthetically unappealing and consume significant quantities of aggregates. The aggregates are an increasingly scarce resource in many urban areas. An emerging technology with the potential to overcome these limitations is reactive powder concrete
(RPC). RPC is a cold-cast cementitious material in which the mechanical properties of the composite matrix are improved by (i) suppression of the weak interfacial transition zone normally developed around the aggregate through improved particle packing and (ii) refinement of the hydrated paste microstructure by extensive use of pozzolanic silica and elevated temperature curing. Tensile capacity is provided by steel micro-fibres rather than conventional reinforcement. The result is a material with the potential for flexural strength up to 50 MPa and ductility and energy absorption values approaching those of steel. The low and non-connected porosity of RPC also render it extremely durable. RPC offers the possibility of building with concrete using slender members in a ‘steel-like’ fashion with improved seismic response, and may also find application in other areas as a pseudo-plastic cold ceramic.

Acknowledgments
This work was funded by the Building Research Levy.
Kay Card of Industrial Research Ltd is thanked for the electron microscopy work and
Golden Bay Cement provided sedimentological analyses of the cement and silica pozzolans employed.

Note…...

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