High performance fire resistant concrete containing hybrid fibers and nano particles
View Patent ↗A high-workability, fire-resistant, anti-spalling concrete composition is provided. The concrete composition has a slump value of at least approximately 150 mm, a fire-resistant period of at least 4 hours, a compressive strength of at least 120 MPa at room temperature, and a compressive strength of at least 20 MPa at 700° C. The composition includes cement, fly ash, silica fume, aggregate particles having a particle size D 90 of approximately 20 mm or less and superplasticizer. The composition includes fiber additives including steel fibers in an amount ranging between approximately 0.1% and approximately 0.4% by volume of the concrete composition and polypropylene fibers having a melting point of approximately 200° C. or less in an amount ranging between approximately 0.05% and 0.3% by volume of the concrete composition. Carbon nanotubes are also present in an amount ranging between approximately 0.1% and approximately 0.3% by volume of the concrete composition.
1. A high-workability, fire-resistant, anti-spalling concrete composition having a slump value of at least approximately 150 mm, a fire-resistant period of at least 4 hours, a compressive strength of at least 120 MPa at room temperature, and a compressive strength of at least 20 MPa at 700° C., the composition comprising:
cement;
fly ash;
silica fume;
aggregate particles having a particle size D 90 of approximately 20 mm or less; and
superplasticizer;
the composition including fiber additives comprising steel fibers in an amount ranging between approximately 0.1% and approximately 0.4% by volume of the concrete composition and polypropylene fibers having a melting point of approximately 200° C. or less in an amount ranging between approximately 0.05% and 0.3% by volume of the concrete composition and further comprising carbon nanoparticles in an amount ranging between approximately 0.1% and 0.3% by volume of the concrete composition.
2. The concrete composition of claim 1 , wherein the compressive strength at 700° C. is at least 28 MPa.
3. The concrete composition of claim 1 , wherein steel fiber is coated with copper.
4. The concrete composition of claim 1 wherein the water contact angle of the polypropylene fiber is less than 90 degrees.
5. The concrete composition of claim 1 , wherein the carbon nanoparticles are carbon nanotube.
6. The concrete composition of claim 1 , wherein the carbon nanoparticles are dispersed in a slurry.
7. The concrete composition of claim 1 , wherein the polypropylene fibers have an average length greater than approximately 6 mm.
8. The concrete composition of claim 1 , wherein the polypropylene fibers have a diameter less than approximately 42 microns.
9. The concrete composition of claim 1 , wherein the steel fibers have an average length greater than approximately 13 mm.
10. The concrete composition of claim 1 , wherein the steel fibers have a diameter of at least approximately 160 microns.
11. The concrete composition of claim 1 , wherein the superplasticizer is a polycarboxylate-based superplasticizer.