碱激活矿渣地聚物早期水化与碳化耦合作用过程研究

Coupled Effect Process of Early Hydration and Carbonation of Alkali-activated Slag Geopolymer

碱激活矿渣地聚物(AASGP)在早期水化和碳化的耦合作用下其物相和微观结构变化尚不明确。因此围绕在早期水化和碳化耦合作用下AASGP的物相和微观结构的演变过程采用X射线衍射仪(XRD)、孔结构和环境扫描电子显微镜(ESEM)进行分析。结果表明:AASGP的抗压强度在耦合反应开始后的前3 d损失最为显著,损失率为89.75%。AASGP试样在耦合反应开始7 d后累积孔隙体积从2.71 mL/g增加到5.03 mL/g,内部孔隙急剧增加,结构被完全破坏,抗压强度消失,无法满足实际应用。耦合作用对孔结构的影响和C-S-H与CO2反应而导致的脱钙解释了AASGP试样抗压强度衰退的原因。

The phase and microstructure changes of alkali-activated slag geopolymer(AASGP)under the coupled effect of early hydration and carbonation are still unclear.Therefore,the X-ray diffraction(XRD),pore structure analysis and environmental scanning electron microscopy(ESEM)were used to study the evolution of the phase and microstructure of AASGP under the coupled effect of early hydration and carbonation.The results show that the compressive strength of AASGP is the most significant in the first 3 d after the start of the coupled reaction,and the compressive strength loss rate is 89.75%.The cumulative pore volume of the AASGP sample increases from 0.79 mL/g to 5.03 mL/g in 7 d after the start of coupled reaction,the internal pores increase sharply,and the structure is completely destroyed.The compressive strength of the AASGP sample disappear and can not meet the practical application.The coupled effect on the pore structure and the decalcification caused by the reaction of C-S-H with CO2 explain the reason for the rapid decline in compressive strength of AASGP samples.