再生混凝土骨料的高孔隙率特性对砂浆抵抗冲击荷载具有积极作用,为研究再生细骨料水泥砂浆在复杂地下环境中应用于井下支护的可能性，制备了0、10%、30%、50%四种不同再生细骨料质量替代率的水泥砂浆。使用50 mm的分离式变截面霍普金森压杆(Split Hopkinson Pressure Bar,SHPB)试验装置，对水泥砂浆进行0.25、0.35和0.45 MPa三种加载气压下的冲击试验，并测试再生细骨料水泥砂浆的静态抗压强度。通过比较不同替代率的再生细骨料水泥砂浆在不同冲击气压下的动态特性，研究再生细骨料砂浆的抗冲击性能。试验结果表明，随着替代率的提高，再生细骨料水泥砂浆的静态抗压强度呈先增长后降低的趋势，在替代率为10%时最大，替代率为30%以及50%时，其静态抗压强度也并未低于对照组；在相同冲击气压下，随着再生细骨料替代率的提高，试块所能承受的冲击荷载也随之提高；在相同替代率下，试块的动态抗压强度以及极限韧性随着冲击气压的增大呈现增加趋势；在应变率60.29～143.379 s^-1时，50%替代率再生细骨料砂浆的动态强度增长因子(DIF)均高于其他组，该替代率的水泥砂浆的动态抗压强度、极限韧性最高，并且静态抗压强度也不低于对照组试块，具有较好的抗冲击性能。

The high porosity of recycled concrete aggregate have a positive effect on the resistance of mortar to impact load. In order to study the feasibility of recycled fine aggregate mortar used in underground support,4 types of cement mortars with different recycled fine aggregate mass replacement rates(0,10%,30% and 50%,resdetiuely) were made. 50 mm Split Hopkinson Pressure Bar (SHPB) test device was used to test these cement mortars under different pressure loading(0.25,0.35,0.45 MPa). And the compressive strength of these mortars was also tested. Comparing the dynamic characteristics of cement mortar under different impact pressure loading,the impact resistance performance of recycled fine aggregate mortar was studied. The results show that the compressive strength of recycled fine aggregate cement mortar increases first and then decreases with the increase of the substitution rate,and reaches the maximum when the substitution rate is 10%,while the substitution rate is 30% and 50%,the compressive strength is not lower than that of the control group. Under the same impact pressure,with the increase of the replacement rate of recycled fine aggregate,the impact load that the mortars can bear also increases. Under the same substitution rate,the dynamic compressive strength and ultimate toughness of the mortars increases with the increase of impact pressure. Within the strain rate range from 60.29 to 143.379 s-1,the dynamic increase factor (DIF) of the recycled  fine aggregate mortar with 50% substitution rate was higher than that of other groups. The recycled fine aggregate cement mortar with 50% substitution rate has the highest dynamic compressive strength and ultimate toughness under three different pressures,and its compressive strength is no less than that of the control group.

0 引言

1 试验方案

   1.1 试验材料

   1.2 试样制备

   1.3 SHPB试验装置与试验方法

2 试验结果与分析

   2.1 静态抗压强度

   2.2 应力-应变曲线分析

3 结论