不同区域MgO的膨胀量对结构整体的影响和对延迟膨胀的时间加以控制是外掺MgO微膨胀混凝土技术的两个关键问题。通过有限元方法，研究外掺MgO混凝土浇筑块温度应力的时空效应，比较了不同部位、不同浇筑层MgO掺率对温度应力的影响。研究指出：掺MgO将使结构最大拉应力值变小并且出现的时间有所提前；内部掺多则会降低内部应力最大值，而外侧掺多对改善表面应力作用不大；保证上下层新老混凝土之间的MgO膨胀协调是十分重要的。所得的成果反映了外掺MgO混凝土结构的温度应力的变化趋势。

The influence of expansive volume of concrete mixed MgO in different parts on integrated structure and the control to its delaying time of expansion are the two key problems in MgO concrete technique. The effect of the thermal stress of concrete mixed MgO pouring block was studied. Mixing with MgO in concrete can make tensile stress lessen in structure and the stress appears earlier than ordinary concrete slightly. The more the MgO content, the less the tensile stress. It is important to ensure that the swelling of MgO must be coincident with up - down different lifts of puring blocks. The results show the properties of thermal stress of concrete mixed MgO.