硬化水泥净浆微观结构对微观徐变及力学性能的影响

发布时间：2018-03-22 04:10

本文选题：硬化水泥净浆　切入点：微观徐变　出处：《硅酸盐学报》2016年02期 　论文类型：期刊论文

【摘要】：采用点阵压入技术在不同压入荷载和保载时间下测试硬化水泥净浆的弹性模量、压痕硬度和微观徐变,用扫描电子显微镜分析压痕影响区域的微观结构组成,并分析微观结构组成对微观徐变及力学性质的影响。结果表明:对于0.5 N和1.5N的压入荷载,压痕影响区域包含孔隙相、水化产物相和未水化水泥颗粒相,可反映硬化水泥净浆混合相的微观结构组成和微观徐变及力学性能;保载时间和最大荷载会影响硬化水泥净浆力学性能的测试,保载时间越长,则弹性模量和压痕硬度越小,其原因与硬化水泥净浆的徐变性质有关,但是减小幅度不大;当最大荷载由0.5 N增大至1.5 N,力学性能略微增大;采用1.5 N、180 s包含5×5压入点阵的试验制度可得到成熟硬化水泥净浆的微观徐变性质;接触徐变函数具有对数型函数的特征,保载时间越长,接触徐变函数越大,这与接触压痕半径随保载时间增长而增大有关,但最大荷载对接触徐变函数几乎无影响。对于0.3水灰比的硬化水泥净浆,徐变模量和特征时间分别为158~201 GPa和0.43~0.59 s。
[Abstract]:The elastic modulus, indentation hardness and micro-creep of hardened cement paste were measured by lattice indentation technique under different indentation load and loading time. The microstructure of the indentation affected area was analyzed by scanning electron microscope (SEM). The effect of microstructure composition on microcreep and mechanical properties is analyzed. The results show that the indentation effect area includes pore phase, hydration product phase and unhydrated cement particle phase for 0.5 N and 1.5 N indentation loads. It can reflect the microstructure composition, micro-creep and mechanical properties of hardened cement paste mixture, and the loading time and maximum load will affect the testing of mechanical properties of hardened cement paste. The longer the loading time is, the smaller the elastic modulus and indentation hardness will be. The reason is related to the creep property of hardened cement paste, but the decrease is small, when the maximum load increases from 0.5 N to 1.5 N, the mechanical properties increase slightly. The microscopic creep properties of mature hardened cement paste can be obtained by using the test system of 1.5 N ~ (180 s) containing 5 脳 5 pressure lattice, and the contact creep function has the characteristic of logarithmic function, the longer the loading time is, the greater the contact creep function is. This is related to the increase of the contact indentation radius with the increase of loading time, but the maximum load has little effect on the contact creep function. For hardened cement paste with 0.3 water-cement ratio, the creep modulus and characteristic time are 1 58 ~ 201 GPa and 0. 43 ~ 0. 59 s, respectively.
【作者单位】：清华大学土木工程系土木工程安全与耐久教育部重点实验室;
【基金】：国家自然科学基金项目(51578316)
【分类号】：TU528

【相似文献】