Resumen de Concrete Bridge Design and Construction series No. 9: High performance concretes and new materials

Concrete Bridge Development Group CBDG

• Here, we examine the various high performance concretes that might be used for concrete bridges, to make them either quicker and easier to build, or more economic. The advantages of high strength, lightweight, fibre reinforced and self-compacting concretes are described, together with the use of new materials that can replace steel for both reinforcement and prestressing.

  The specification for high performance concretes needs to identify the required concrete strength, cover to the reinforcement, cement content, water/cement ratio and cement type — all of which will depend on the particular site and environmental conditions. Working to these specifications will ensure that the concrete is best suited to its location in the bridge, as well as being resistant to carbonation and chloride ingress, in order to provide a long (and low maintenance) working life.

  The choice of cement and admixture type will also have an impact on the speed of construction, due to the rate of gain of strength; which in turn has an influence on some of the construction methods. Many of these topics are discussed in CBDG TG 51.