The precast industry has always been looking for ways to improve production. Be that ease of casting or finishing, faster turnaround or better economics due to less damage or reduced concrete costs. The advent of self compactting concrete (SCC) has enabled some of these aspects to be realised. The development of SCC and new mixture design procedures has improved certain facets of the precast industry. However, the excessive use of fillers or very high cement contents has had equal drawbacks for the use of SCC in this environment. With the advances in software allowing very precise particle packing analyses to be made of the materials, new mix designs with lower total binder contents – and little or no fillers – are possible. Designs with supplementary cementitious materials (SCMs), including silica fume, can be very effective for SCC, not only giving excellent flow and non-segregation, but also enhancing the finished quality of the concrete. This paper reviews the use of silica fume in SCC, information from the Technically Optimised Piling Concrete (TOPIC) research in the UK, and gives examples of the use in some precast operations in Sweden.
Elkem ASA Materials
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