Concrete is a very special two-phase composite material, that is, there exists difference of the properties between the matrix and coarse aggregate and this difference would change markedly as the ages increase.

• 从两相复合材料角度分析，混凝土是一种非常特殊的两相复合材料，表现在粗集料和砂浆基体两相之间的性能存在差异，且这种差异随着龄期的变化而发生非常大的变化。