I don't know how many of them are published in impact factor journals. However, You may find several research papers on hair fiber reinforced concrete here:
https://www.google.com/search?q=hair+fiber+reinforced+concrete&ie=utf-8&oe=utf-8
Moreover, many of our universities have subscription to one or more of international organizations (like Elsevier, Springer, RILEM etc.) that publish impact factor journals. Faculty and students (both MS & PhD) of these universities can download required research papers free of charge, from the relevant web page, using university computers specially designated for this purpose. You should contact your university, to know about this facility and make use of it, in case it is available there.
Regards.