Experimental Research Of Dynamic Characteristics For Ready-mixed Concrete Under Uniaxial State And Confining Pressure

The impact load caused by blasting excavation of mine roadway will cause the damage of concrete support.Study on dynamic characteristics of premixed concrete impact,to ensure it has important engineering significance of roadway safety production.By using the method of combination of theoretical and experimental research,the sand moisture content was 0%,1%,1.5%,2%,storage period of dynamic characteristics under uniaxial and confining pressure under the condition of mixed concrete 0d,3d,7d,15d,20d,30d mixed material,and the comparative analysis.The results show that the peak stress decreases with the increase of storage time and moisture content.The impact pressure is bigger,the uniaxial impact peak stress increases,premix sand moisture content is 1%,the storage period is 3d the maximum peak stress,peak impact pressure in 0.6MPa and 0.9MPa stress were 35.4MPa and 48.9MPa,1.3 times the impact pressure of 0.9MPa 0.6MPa peak stress.When the moisture content is 1.0%and the storage period is less than 3d,the peak stress reaches the static compressive strength of C30 concrete.The results show that the peak stress decreases with the increase of storage time and moisture content.The impact pressure is bigger,the uniaxial impact peak stress increases,premix sand moisture content is 1.0%,the storage period is 3D the maximum peak stress,peak impact pressure in 0.6MPa and 0.9MPa stress were 35.4MPa and 48.9MPa,1.3 times the impact pressure of 0.9MPa 0.6MPa peak stress.When the moisture content is 1%and the storage period is less than 3d,the peak stress reaches the static compressive strength of C30 concrete.Under the condition of uniaxial and passive confining pressure,the peak value of impact stress of ready mixed concrete decreases with the increase of moisture content and storage time.The effect of passive confining pressure on the peak stress of ready mixed concrete is strengthened,and the peak value of impact stress of ready mixed concrete under confining pressure is about 1.5 times of the peak value of stress under the condition of confining pressure.