本文在试验研究基础上提出了用膨胀效应系数来反映钢纤维与膨胀剂的联合增强效应．膨胀效应系数概念清楚、意义明确，并能充分反映钢纤维与膨胀剂的协同作用效果．而且通过膨胀效应系数可确定钢纤维膨胀混凝土的最优配比和临界配比。 Based on the experimental study, this paper proposes to use the expansion effect coefficient to reflect the joint reinforcement effect of steel fiber and expansive agent. The concept of expansion effect has clear concept and clear meaning, and can fully reflect the synergistic effect of steel fiber and expansion agent. Moreover, the optimal ratio and critical ratio of steel fiber expansive concrete can be determined by the expansion effect coefficient.