polypropylene fibers in concrete
polypropylene fibers in concrete
(OP)
Does anyone out there know if any research has been done with regard to fire testing on concrete with fibres.
Of particular interest is that do the thickness of multifilament fibres ie (18 micron or 32 micron)improve or reduce explosive spalling
if anybody knows anything about this please let me know
Of particular interest is that do the thickness of multifilament fibres ie (18 micron or 32 micron)improve or reduce explosive spalling
if anybody knows anything about this please let me know





RE: polypropylene fibers in concrete
RE: polypropylene fibers in concrete
Result: All of the combinations which contained the pp fibres (approx 2kg/m3 of fibre) showed no spalling.
RE: polypropylene fibers in concrete
Did you get spalling with the steel fibers?
Thanks,
Ron
RE: polypropylene fibers in concrete
We tested combinations of conventional rebar alone, fibres alone and also fibres plus rebar. In all of these cases where the polypropylene fibres were NOT included, we saw varying degrees of spalling. The inclusion of the PP fibres does appear to have significant benefits at doses between 1 & 2 kg/m3
Andy
RE: polypropylene fibers in concrete
The dosages you mentioned are typical here. That's good info. Thanks again.
Ron
RE: polypropylene fibers in concrete
The dosages you refer to are between 1 and 2 kg per metre as i expected but is there a significant difference between say 1 kg or 2 kg in either temperature or time, i am only interested in reinforced concrete,
Many Thanks
Dominic
RE: polypropylene fibers in concrete
After the good test results, did you also apply the PP fibres in a real tunnelling project and if so were no additional fire prevention/protection measures taken?
thanks,
Jeroen
RE: polypropylene fibers in concrete
We have used a polypropylene and steel fibre mix in a twin bore 8.9m ID road tunnel without any other fire protection measures.
RE: polypropylene fibers in concrete
I noted that earlier you mentioned that you tested the fibres with and without rebar did you find that with the rebar it was more inclined to increase spalling due to the expasion of the reinforcing under temperature.Also what was the maximum temperature you tested to ie cellulose,carbon or TNO.
Regards
Dominic
RE: polypropylene fibers in concrete
Yes, rebar thermal expansion was a reason for the additional spalling. We heated the concrete to 1200 degC.
RE: polypropylene fibers in concrete
Thanks Ginger.
RE: polypropylene fibers in concrete
Steel fibers are great at reducing normal spalling, but they can cause dangerous explosions during a fire.
With PVA fibers you get a structural fiber that can't corrode and a sacrificial fire fiber as well.
Richard
RE: polypropylene fibers in concrete
Recently we have carried out some test with a 80 N/mm2 concrete with 2 kg PP fibres reinforcement. THe concrete was exposed to a temperature of 1200 degrees (TNO). The test result of one piece was acceptabel but the other was very bad. As the steel fibres have no influence on spalling prevention but only at damage reduction you probably used more PP fibres or weaker concrete.
Jeroen