碱的阈值及矿物掺合料组分对碱-硅酸反应的影响

Effect of alkali threshold and mineral admixtures on alkali-silica reaction

矿物掺合料是抑制碱-硅酸反应(ASR)膨胀的有效方法之一,其种类、掺量不同,抑制效果也不同。以陶瓷抛光渣、粉煤灰、矿渣粉为掺合料取代部分水泥制备砂浆棒,通过膨胀率测定和能谱分析,研究碱的阈值及矿物组分对ASR膨胀的影响。结果表明:陶瓷抛光渣、粉煤灰对ASR膨胀的抑制效果优于矿渣粉;掺合料可使碱的阈值增大,降低因碱而发生较大ASR膨胀的风险;钙的含量也有阈值效应,达到50%以上时,会使ASR膨胀陡然增大;矿物化学组分与ASR膨胀的关系有一定规律可循,14 d膨胀值与(2Na_(2)O_(e)+CaO)/SiO_(2)获得最佳拟合。

The one of the effective methods to inhibit the expansion of alkali-silica reaction(ASR)is using mineral admixtures.The kinds and contents of mineral admixtures are different,and the inhibition effect is different.The mortar bar was prepared by using ceramic polishing slag,fly ash and slag powder as admixture to replace part of cement.The effect of alkali threshold and mineral composition on ASR expansion was studied by means of expansion rate measurement and energy spectrum analysis.The results show that the ceramic polishing slag and fly ash are better than slag powder in inhibiting ASR expansion.The admixtures can increase the threshold of alkali and reduce the risk of alkali-induced ASR expansion.Calcium content also has a threshold effect,reaching more than 50%,will make ASR expansion sharply increased.The relationship between mineral chemical composition and ASR expansion has a certain regularity.The best fit between(2Na_(2)O_(e)+CaO)/SiO_(2) and the 14 d expansion value was obtained.