Research on Alkali-Silica Reaction of Limestone-siliceous River Sand mixed Aggregates
In order to study the effect of coarse and fine aggregate matching ratios in concrete on the alkali-active coarse aggregate alkali-silicate reaction(ASR),four kinds of mixed aggregate ratios are designed according to the common coarse and fine aggregate ratios in engineering,and the alkali activity of the four kinds of mixed aggregates with different ratios was evaluated by Accelerated Mortar Bar Test(AMBT).The inhibition effects of 25%fly ash alone,25%fly ash and 5%silica fume on the ASR of mixed aggregates are investigated,and the reaction products of the specimens are analyzed by XRD.The results show that the four different ratios of mixed aggregates still have alkali reactivity,and there is no obvious"pessimum"phenomenon.The inhibition of ASR expansion is more pronounced for mixed aggregates with lower proportions of alkali-active aggregates after the addition of fly ash and fly ash with silica fume in mortar bar specimens.Fly ash and silica fume inhibit ASR mainly by reducing CH,increasing C-S-H and modifying C-S-H to enhance its ability to bind alkali ions in cement hydration products.
alkali-silica reactionalkali-reactivity inhibitionaccelerated mortar bar testfly ashsilica fume
NETL
NSTL
万方数据
维普
