摘   要：利用菱镁矿尾矿煅烧制备轻烧氧化镁补偿蒸养水泥浆体的自收缩。通过测定水泥胶砂流动度和3d强度来确定氧化镁的合适掺量。通过XRD和TG-DTA表征水泥浆体中氧化镁的水化进程，并结合压汞法（MIP）和场发射扫描电镜二次电子成像（FESEM）分别对浆体的孔结构和氧化镁水化产物的微观形貌进行分析。结果表明，氧化镁在蒸养过程中迅速水化，使得浆体的孔隙率略微增大。蒸养后，浆体中氧化镁在原位继续水化，有效地补偿了浆体的自收缩。掺有4%氧化镁的水泥和粉煤灰水泥浆体14d的自收缩值分别减少了33%、17%。

Abstract: Using light-burned magnesia prepared by calcining magnesite tailing to compensate the autogenous shrinkage of steam-cured cement paste was carried out. The fluidity and 3-day strength of cement mortars were measured to determine the suitable addition of magnesia. The hydration process of magnesia in paste was characterized by XRD and TG-DTA. And the pore structure of paste and microstructure of magnesia hydrates were analyzed by MIP and FESEM respectively. The results indicate that the hydration of magnesia is promoted rapidly in steam curing process, and slightly increases the porosity of paste. The continue hydration of magnesia in situ effectively compensates the autogenous shrinkage of paste after steam curing. The autogenous shrinkage of cement and fly ash cement paste with 4% magnesia is decreased by 33% and 17% respectively at the age of 14d.