高活性偏高岭土及粉煤灰对碱骨料反应的抑制作用

Inhibition Effect of Super Metakaolin and Fly Ash on Alkali-Silica Reaction in Concrete

为研究偏高岭土及粉煤灰对活性骨料膨胀的抑制作用及机理,采用快速砂浆棒法,研究了用石英玻璃为骨料,以5%,10%,15%,20%,25%高活性偏高岭土等质量取代水泥或以10%,20%,30%,35%,40%,45%粉煤灰等质量取代水泥的砂浆棒膨胀率,并采用扫描电镜对其机理进行了分析.结果表明:高活性偏高岭土抑制碱骨料反应(ASR)具有少量高效的特点,而粉煤灰要在等质量取代水泥35%及以上时才能有效抑制ASR;高活性偏高岭土颗粒明显小于粉煤灰颗粒,且具有更高的活性,掺入水泥砂浆后所生成的胶凝材料更加致密.

In order to study the inhibition effect and mechanism of metakaolin and fly ash on alkali-silica reaction（ASR）in concrete,the extension of mortar bar made with activity quartz glass aggregate and super metakaolin powder to cement（5%,10%,15%,20%,25%）and fly ash to cement（10%,20%,30%,35%,40%,45%）mixtures were measured and evaluated in alkali solution according to accelerated mortar bar test（AMBT）.The mechanism of the effect was studied by scanning electron microscope（SEM）analysis.The results show that small amount of super metakaolin powder exerts significant influence,whereas only when the proportion of fly ash is up to 35%,can it control alkali-silica reaction effectively.As super metakaolin powder particles are much smaller than fly ash particles,they have higher activity.