粉煤灰对MgO混凝土长龄期自生体积变形的影响

Influence of fly ash on the long-term autogenetic volume deformation of concrete mixed with magnesium oxide

为了探索粉煤灰对MgO混凝土长龄期自生体积变形的影响规律,在室内测试了长达4a龄期的不同粉煤灰掺量的MgO混凝土的自生体积变形,并从部分试件中钻孔取芯进行电镜扫描观测及能谱分析。结果表明：随着龄期的延长,粉煤灰对MgO混凝土的长龄期自生体积膨胀变形的抑制作用增强,且粉煤灰对一、二级配MgO混凝土的长龄期自生体积膨胀变形的抑制作用强于三级配MgO混凝土。同时,掺入适量粉煤灰后,长龄期MgO混凝土的微观结构更加致密。

In order to explore the influence of fly ash on the long-term autogenetic volume deformation of concrete mixed with magnesium oxide（MgO）,the long-term autogenetic volume deformation of up to 4-year-old MgO concrete specimens with different contents of fly ash was measured,and cores were taken from part of specimens for scanning election microscopy（SEM）and energy spectrum detection.The results showed that the longer the time was,the stronger the inhibitory effect of fly ash on autogenetic volume deformation of MgO concrete was,and it was strongest for one-grade MgO concrete,followed by the twograde MgO concrete and three-grade MgO concrete.The microstructure of MgO concrete with fly ash in proper content was densified gradually with ages.