Fire resistance of self-compacting concrete, SCC

This article outlines laboratory and full-scale studies on fire resistance of SCC. For this purpose 40 pre-stressed columns and 140 cylinders of concrete were subjected to compressive loading at high temperature. The SCC included water-binder ratios, w/b, between 0.40 and 0.70 and large amount limestone powder. Comparison was done with vibrated concrete, VC, with the same w/b. Mix proportions were chosen as regards tunnel concrete (w/b = 0.40), prefabricated concrete (w/b = 0.55) and concrete for production of dwelling houses (w/b = 0.70). The water-powder ratio, w/p varied between 0.28 and 0.70. The fullscale behaviour showed extensive fire spalling for water-cured concrete at w/p < 0.40 and for air-cured concrete at w/p < 0.35. One way of avoiding the fire spalling was to introduce polypropylene fibres, PPF, in the mix proportions, which was chosen to be very effective. The laboratory results on small cylinders indicated similar material behaviour of SCC and VC at high temperature when spalling did not occur. The project was performed 1999-2002.