P. Raivio et L. Sarvaranta, MICROSTRUCTURE OF FIBER MORTAR COMPOSITES UNDER FIRE IMPACT - EFFECT OF POLYPROPYLENE AND POLYACRYLONITRILE FIBERS, Cement and concrete research, 24(5), 1994, pp. 896-906
Citations number
13
Categorie Soggetti
Construcion & Building Technology","Material Science
Two polymer fibre types (PP and PAN) and different microstructural met
hods were used to compare the porosity of fibre mortar composites and
the effect of rapid thermal exposure on the fibre structure. Polished
thin sections were prepared from fibreless reference mortar and fibre
mortar samples before and after fire impact. Polarizing light microsco
py indicates increased air void porosity in the fibre mortars. Polariz
ing light microscopy and scanning electron microscopy reveal that PP a
nd PAN fibres react entirely differently to heat PP fibres melt, where
as PAN fibres become dark in appearance, presumably due to chemical tr
ansformations, and exhibit a zoned structure at the outer part of the
fibre. A transition zone program shows that porosity detected by backs
cattered electron images is higher at the fibre/matrix contact zone th
an in the bulk matrix. Fire impact broadens this porosity region at th
e contact zone. On the whole, the porosity level at the contact zone s
eems to be higher in the PAN than in the PP fibre mortar.