To Brad805: An interesting paper. Thanks you for sending it. Much appreciated. However, his conclusion is that more research is required. His conclusion includes the paragraph below (in italics).
In my opinion, the paper is based on the premise that the primary cause of corrosion is cracks, whereas it is generally accepted by researchers in North America that the primary cause is the permeability of the concrete. And Beeby, who I believe is British, also pointed this out at least 20 years ago. Although the author of the paper does reference Beeby, he seems to not take Beeby's view into account.
As for my own experience, it was convincingly demonstrated to me 30 years ago that cracking was not the primary mechanism of corrosion, when investigating a large post-tensioned garage in Ottawa that had zero cracks due to the unusually high level of prestress in the slab, yet the top surface was delaminated to a very high percent due to top bar corrosion. As a practicing engineer with 40 years experience dealing with chlorides and concrete and corrosion, I just wouldn't count on steel fibres in concrete not corroding away as the chloride front etxends down into the cncrete. I expect that is one reason why the marketers if steel fibres also market stainless steel fibres.
If there is a phenomenon protecting steel fibres from corrosion, to a significantly greater degree than rebar, then I agree with the author of the paper that more research is needed.
"Despite most of the findings in this review suggest
that fibres could be used in reinforced concrete structures exposed to chloride environments to improve the overall durability performance the review has found some contradictory results from different investigations. Furthermore, the mechanisms that cause reduced corrosion rates are not yet fully understood and require further research. Therefore additional experimental results from tests specifically aimed at comprehending these mechanisms would be extremely valuable".
