中文摘要：

为促进外掺MgO混凝土的推广应用,对外掺MgO三级配混凝土的微观结构及其压蒸膨胀变形进行了试验研究。结果表明,当MgO掺量超过按照目前方法确定的MgO极限掺量后,对应的压蒸试件的微观结构出现裂纹,但使用相应MgO外掺量拌制的2年龄期的MgO混凝土的微观结构完好。因此,混凝土中MgO的极限掺量仍然可以提高,其确定方法值得进一步研究。

英文摘要：

To accelerate application of magnesium oxide concrete,the microstructure and autoclave-treated expansibility of three grading concrete mixed with magnesium oxide （MgO） had been studied.The results indicated that the microstructure of autoclave-treated test specimen emerges cracks when the MgO content was bigger than the limit content ascertained by the test method in force,but the microstructure of two years age＇s MgO concrete using corresponding MgO content was in good condition.Therefore,the limit MgO content can still increase, and this test method deserves further research.