中文摘要：

MgO膨胀剂具有延迟微膨胀效应，能够有助于解决大体积混凝土因温度应力而开裂的问题，而在大坝混凝土中得到广泛应用，对解决大坝温度裂缝、简化施工工艺、保障混凝土顺利浇筑开辟了一条新的有效途径。为了更好地了解和使用MgO膨胀剂，详细介绍了MgO的活性、膨胀机理、影响因素、水化动力学模型及亟需解决的相关问题。

英文摘要：

MgO expansion agent has an effect of delayed micro-expansion,which can effectively solve the mass concrete cracking problem due to thermal stress, and be widely used in the dam concrete engineering, having been made an outstanding contribution of dam concrete＇s tempera- ture control and pouring.In order to facilitate other scholars better understanding and using of MgO-type expansion agent, Described the details of MgO, including the activity.the expansion mechanism.influencing factors.dynamic model and the need of further address the problem of MgO.