| The effects that the form and silica content of silica fume (SF) have on resistance to alkali-silica reaction (ASR) expansion were investigated using: (1) concrete prism expansion, (2) accelerated mortar bar expansion, and (3) paste pore solution analysis. The mixtures, tested included (0%, 4%, 8%, and 12% silica fume replacement by mass of cement.; At 4% SF replacement, performance did vary for different product forms. At higher levels of replacement (i.e. 8% and 12%), there were no differences in the results from the concrete prism expansion or paste pore solution analysis for the various silica fume forms tested. The accelerated mortar bar test results at all levels of replacement indicated that undensified and slurried SFs are significantly better at controlling ASR expansion than are densified or pelletized SFs. Preliminary results show that silica fumes with lower than standard amorphous silica, contents cannot control ASR at the levels of replacement tested in this program. |
