This paper investigates the effect of free water on the dynamic compressive properties of mortar. Total-dried and full-saturated specimens are prepared through oven drying and water soaking processes. Common and high-porosity mortars are studied to examine the influence of porosity. Compression tests are carried out, covering strain rates between 1 × 10⁻⁶/s and 280/s. The test results show both dry and saturated mortar specimens are strain-rate sensitive. Free water results in softening effect in both common and high-porosity mortars at quasi-static and dynamic states. Retarding effect by pore water in the mortar is observed, which leads to lower longitudinal wave velocities in the saturated specimens. Water saturation increases the hydrostatic-pressure and leads to more severe water bursting; consequentially reduces the compressive strength. The experimental results demonstrate the free water deteriorates the compressive properties of mortars as a result of hydric expansion, which induces new cracks, especially in the high-porosity mortar.

本文研究了游离水对砂浆动态压缩性能的影响。通过烤箱干燥和水浸泡过程可以制备出完全干燥和完全饱和的样品。研究了普通和高孔隙率的砂浆，以检验孔隙率的影响。进行压缩测试，覆盖应变率在1×10 ^-6之间/ s和280 / s。测试结果表明，干粉砂浆和饱和砂浆样品均对应变速率敏感。游离水导致普通和高孔隙度砂浆在准静态和动态状态下均具有软化作用。观察到砂浆中孔隙水的缓凝作用，导致饱和样品中的纵向波速降低。水饱和会增加静水压力，并导致更严重的水破裂。因此降低了抗压强度。实验结果表明，游离水会因水力膨胀而降低砂浆的压缩性能，从而引起新的裂缝，特别是在高孔隙度砂浆中。