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AssigneesRhodia Chimie, Bouygues Travaux Publics, Lafarge
InventorsGilles Orange, Evelyne Prat, Pascal Casanova, Mouloud Behloul
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The invention concerns the use of organic fibres having a melting point lower than 300° C., an average length l more than 1 mm and a diameter Ø not more than 200 μm, in ultra high performance concrete for improving the concrete fire resistance, the amount of organic fibres 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.
The use of organic fibers having a melting point of less than 300° C., an average length l of greater than 1 mm and a diameter ø of at most 200 μm, in an ultrahigh-performance concrete in order to improve the fire resistance of the concrete, the amount of organic fibers being such that their volume ranges between 0.1 and 3% of the volume of the concrete after setting and the concrete having a characteristic 28-day compressive strength of at least 120 MPa, a characteristic flexural strength of at the month 20 MPa and a spread value in the unhardened state of at least 150 mm, these values being given for a concrete stored and maintained at 20° C., said concrete consisting of a hardened cementitious matrix in which metal fibers are dispersed, which is obtained by mixing, with water, a composition which comprises, apart from the fibers:
The use as claimed in one of the preceding claims, characterized in that the organic fibers have a diameter of less than 80 μm.
The use as claimed in one of the preceding claims, characterized in that the ratio V1/V of the metal fibers to the organic fibers is at least 2.
The use as claimed in one of the preceding claims, characterized in that the amount of organic fibers is such that their volume is less than 2% of the volume of the concrete after setting.
The use as claimed in one of the preceding claims, characterized in that the organic fibers consist of a homopolymer or copolymer chosen from polyacrylamide, polyether sulfone, polyvinyl chloride, polyethylene, polypropylene, polystyrene, polyamide and polyvinyl alcohol groups, by itself or as a mixture.
The use as claimed in one of the preceding claims, characterized in that the organic fibers are polypropylene fibers.
The use as claimed in any one of the preceding claims, characterized in that the metal fibers are steel fibers.
The use as claimed in one of the preceding claims, characterized in that the metal fibers have a length lying within the range from 5 to 30 mm.
The use as claimed in one of the preceding claims, characterized in that the particle size D75 of the aggregate particles (b) is at most 6 mm.
The use as claimed in any one of the preceding claims, in which the organic fibers have a melting point of less than or equal to 200° C.
A fire-resistant ultrahigh-performance concrete having a characteristic 28-day compressive strength of at least 120 MPa, a characteristic flexural strength of at least 20 MPa and a spread value in the unhardened state of at least 150 mm, these values being given for a concrete stored and maintained at 20° C.;
The concrete as claimed in one of claims 16 to 18, in which the l/Ø ratio of the organic fibers is between 20 and 500.
The composition as claimed in claim 35, which comprises the cement, the pozzolanic-reaction particles, the dispersing agent and the organic fibers.
The composition as claimed in claim 35 or 36, in which the melting point of the organic fibers is less than 200° C.
Dependencies are inferred from the claim text.