Experimental evaluation of alkali-silica reaction in mortars containing silica fume

In this study, the effect of silica fume on preventing expansion in concrete due to alkali-silica reaction (ASR) was investigated. ASTM C1260 accelerated mortar bar test method was used in the experimental study. For this purpose, preliminary experiments were carried out on aggregates obtained from different locations in the Eastern Black Sea Region. In this way, the aggregate that was evaluated as the most reactive in terms of alkali-silica reaction in accordance with the relevant standard was determined and this aggregate was used in the experimental study. Mortar mixtures were produced by substituting silica fume in certain proportions instead of cement in order to prevent expansion due to ASR. In these productions, silica fume has been substituted for cement at 5%, 10%, 15% and 20% by weight. As a result of the periodic measurements, the expansion of the silica fume-replaced mortar samples was evaluated in comparison with the reference sample that did not contain silica fume. With the experimental study carried out, the positive effect of silica fume substitution in preventing expansion caused by alkali-silica reaction is clearly seen. It has been determined that this effect is much more pronounced, especially when the silica fume substitution ratio is 10% and above.