为研究外掺一定量的MgO，能否使碾压混凝土产生微膨胀，并利用其膨胀来补偿碾压混凝土在温降时产生的收缩，防止或减少碾压混凝土由于温降产生的裂缝。使用一种新型MgO材料，从施工现场取样进行了碾压混凝土的全级配自生体积变形试验。试验结果证明：掺MgO的碾压混凝土在标准养护条件下365 d龄期的最大膨胀量为114×10-6，高温养护条件下365 d龄期的最大膨胀量为168×10-6；其膨胀量满足设计的要求。二级配碾压混凝土的膨胀量稍大于三级配碾压混凝土的膨胀量。

Due to addition of a new type MgO material, RCC shows a stable expansion to compensate the shrinkage resulted from internal or external temperature gradient, thus minimizing the risk of cracking. Autogenous volume deformation of full -  sized RCC is tested, the experimental results show that the maximum expansion ratio is 114×10-6 and 168×10-6 at the age of 365 days under standard temperature or high temperature curing conditions, respectively. Expansion ratio of wet -  screened RCC is a little more than that of full -  sized RCC.