PVA-ECC拉压强度尺寸效应试验研究

Experimental study on size effect of tensile and compressive strength of PVA-ECC

工程水泥基复合材料(Engineered Cementitious Composites,ECC)是具有应变硬化性能和优异的裂缝控制能力的高性能水泥基复合材料。为研究PVA-ECC尺寸效应及相关力学性能,试验设计了3组强度,测定了不同PVA掺量、尺寸的ECC立方体抗压强度、劈裂强度和抗折强度。结果表明,ECC的劈裂强度存在尺寸效应,截面越大强度越低,ECC的劈裂强度尺寸效应大于砂浆基体。PVA掺量能显著提高砂浆试件的抗折强度,强度等级越低,PVA掺量对抗折强度的影响越小。

Engineered Cementitious Composites(ECC)is a high-performance cement-based material with strain hardening properties and excellent crack control ability.In order to study the size effect and related mechanical properties of PVA-ECC,three groups of strength were designed,and the 28 d cubic compressive,splitting and flexural strength of ECC and cement mortar matrix with different sizes were measured.The results show that there is a size effect on the splitting strength of ECC.The larger the cross section is,the lower the strength is,and the size effect of ECC is larger than that of mortar matrix.The content of PVA can significantly improve the flexural strength of mortar specimens,and the lower the strength grade is,the less the effect of PVA content on the flexural strength is.