utilization of organic fibers, ultra high performance concrete, and preparation process.

摘要

The invention concerns the use of organic fibers having a melting point lower than 300° C., an average length l more than 1 mm and a diameter Ø not more than 200 mum, in ultra high performance concrete for improving the concrete fire resistance, the amount of organic fibers being such that their volume ranges between 0.1 and 3% of the concrete volume after setting and the concrete having a compressive strength at 28 days of at least 120 Mpa, a bending strength of at least 20 Mpa, and a spread value in non-hardened state of at least 150 mm, the values being for a concrete preserved at 20° C., the concrete consisting of a particularly hardened cement matrix wherein metal fibres are dispersed.