外加剂对碱激发粉煤灰/矿渣胶凝材料早期性能的影响

为寻找适合碱激发粉煤灰/矿渣复合体系的外加剂,研究了6种不同外加剂对碱激发粉煤灰/矿渣复合体系早期性能的影响。结果表明,无机外加剂氯化钡能够有效延长凝结时间,且同时能改善浆体流动性,使样品微观结构更加致密,抗压强度提高;葡萄糖酸钠、聚羧酸和木质素磺酸钠能稍微延长凝结时间和改善流动性,但改善效果不明显;引起剂十二烷基三甲基氯化铵,十二烷基聚氧乙烯醚能有效延长凝结时间,但浆体流动性变差,气泡引入使得抗压强度下降。碱激发粉煤灰/矿渣的反应产物主要为无定型态与少量铝托贝莫来石,掺入不同外加剂不会改变样品的晶相组成。

The Effect of Admixtures on Early-age Properties of Alkali-activated Fly ash/slag

In order to find suitable admixtures for alkali-activated fly ash/slag composite system (AAFS), this paper studied the effect of six different admixtures on the early-age properties of AAFS. Alkali-activated fly ash/slag. The results showed that mineral admixture barium chloride effectively extended the setting time of AAFS, and improved its fluidity, which lead to a denser microstructure and higher compressive strength. Sodium gluconate, polycarboxylate and sodium lignosulphonate can slightly extend setting time and improve fluidity of AAFS; but the effect is limited. Air-entraining agent, i.e. dodecyl trimethylammonium chloride (DTAC) andlauryl polyoxyethylene, can effectively prolong the setting time of AAFS too; but they reduced the paste fluidity. The air bubbles reduced the compressive strength of AAFS. The main reaction products of the alkali-activated fly ash/slag were amorphous composite and some aluminum-tobermorite. The addition of different admixtures did not change the crystalline phase of AAFS.