粉煤灰钢纤维超高强混凝土抗压性能试验研究

通过钢纤维体积含量为1.5%的粉煤灰钢纤维超高强混凝土(FSFRUHSC)不同尺寸的立方体试件和棱柱体试件的抗压试验,初步探讨了不同尺寸试件的抗压强度和压缩破坏模式。结果显示,粉煤灰钢纤维超高强混凝土大尺寸立方体试件抗压强度高于小尺寸立方体试件抗压强度,立方体试件抗压强度高于棱柱体试件抗压强度;粉煤灰钢纤维超高强混凝土立方体和棱柱体试件的压缩破坏模式分别为韧性拉伸破坏和脆性剪切破坏。

Mechanical properties and failure characteristics of fractured sandstone with grouting and anchorage

Based on uniaxial compression experimental results on fractured sandstone with grouting and anchorage, we studied the strength and deformation properties, the failure model, crack formation and evolution laws of fractured sandstone under different conditions of anchorage. The experimental results show that the strength and elastic modulus of fractured sandstone with different fracture angles are significantly lower than those of intact sandstone. Compared with the fractured samples without anchorage,the peak strength, residual strength, peak and ultimate axial strain of fractured sandstone under different anchorage increase by 64.5–320.0%, 62.8–493.0%, and 31.6–181.4%, respectively. The number of bolts and degree of pre-stress has certain effects on the peak strength and failure model of fractured sandstone. The peak strength of fractured sandstone under different anchorage increases to some extent, and the failure model of fractured sandstone also transforms from tensile failure to tensile–shear mixed failure with the number of bolts. The pre-stress can restrain the formation and evolution process of tensile cracks, delay the failure process of fractured sandstone under anchorage and impel the transformation of failure model from brittle failure to plastic failure.

聚氨酯涂层对复合材料层板冲击后压缩性能的影响

对聚氨酯喷涂复合材料层板进行反复低速冲击试验和冲击后压缩试验,研究了损伤程度、层板厚度和涂层厚度对聚氨酯喷涂复合材料层合板冲击后压缩强度的影响,并通过数字图像相关(DIC)检测压缩过程分析了不同损伤程度试样的破坏过程和破坏模式。结果表明:随着冲击次数的增加冲击后压缩强度存在拐点,随着层合板厚度的增加试样的冲击后压缩强度降低,随着涂层厚度的增加含聚氨酯的试样冲击后压缩强度明显提高;压缩破坏位置与损伤程度有关,试样的损伤程度不同其压缩破坏过程也不同。