冲击荷载作用下改良水泥-粉煤灰试样力学特性研究

Research on the dynamic mechanical properties of stabilized cement-fly ash samples

为探究石膏和石灰改良水泥-粉煤灰在冲击动载下的力学特性,采用了分离式霍普金森压杆(SHPB)对不同养护龄期和不同配合比下的改良水泥-粉煤灰试样进行冲击试验。研究了相同冲击荷载作用下试样的破坏特征和动态力学特性,并重点分析了动态抗压强度(DCS)与养护龄期和石膏、石灰掺量之间的关系。试验结果表明:随着试样龄期的增加,石膏改良水泥-粉煤灰的脆性逐渐增强,而石灰改良水泥-粉煤灰的试样总体偏延性;随着固化剂掺量的增加,石膏改良试样强度呈现出先增长后降低的趋势,掺量为6%时,DCS达到峰值,早期石灰改良试样强度表现为先上升后降低,而后期呈现出持续上升的趋势并在掺量为12%时,90 d DCS达到最大值14.36 MPa。

In order to study the dynamic mechanical properties of cement-fly ash stabilized by gypsum and lime under impact load,the device of SHPB was adopted to study the gypsum-cement-fly ash and lime-cement-fly ash samples under different curing time and mix proportion.The analysis was made on the failure characteristics and mechanical properties of the sample,meanwhile,the dynamic compressive strength(DCS)on different curing time and mix proportion was researched.The results show that the brittleness of gypsum-cement-fly ash increases with curing time.However,the malleability of lime-cement-fly ash increases with curing time;when the gypsum content arises,the DCS of stabilized cement-fly ash exhibits a trend of increasing first and then decreasing,the DCS reaches a peak with the gypsum content of 6%;when the lime content increases,the DCS of stabilized cement-fly ash first increases and then decreases in the early stage,but the DCS constantly increases in the later stage and reaches maximum value of 14.36 MPa(90 d)with lime content of 12%.