纤维增强地质聚合物混凝土早期冲击力学性能的对比研究

Early impact properties of fiber reinforced geopolymeric concretes

为对比研究玄武岩纤维和碳纤维对地质聚合物混凝土(geopolymeric concrete,GC)早期冲击力学性能的改善效果,首先以矿渣与粉煤灰作为原材料,并采用液体硅酸钠与NaOH作为碱激发剂,配制了纤维体积掺量分别为0、0.1%、0.2%、0.3%的玄武岩纤维增强地质聚合物混凝土(basalt fiber reinforced geopolymeric concrete,BFRGC)和碳纤维增强地质聚合物混凝土(carbon fiber reinforced geopolymeric concrete,CFRGC),再采用Φ100 mm霍普金森压杆(split Hopkin-son pressure bar,SHPB)试验装置测试了两种材料3d、7d的冲击力学性能,并对试验进行对比分析。结果表明:纤维增强地质聚合物混凝土(fiber reinforced geopolymeric concretes,FRGCs)早期冲击力学性能具有显著的应变率相关性;BFRGC的早期动态强度特性优于CFRGC;BFRGC在10—102s-1范围内的能量吸收能力与CFRGC的相当,但BFRGC相对于CFRGC在吸收冲击能上的优势,将会随着应变率的增加而越发明显。对比可知:BFRGC较CFRGC而言,具有更加优越的早期冲击力学性能,主要体现在动态强度和能量吸收能力上。

A comparative study on the effect of various fibers on early mechanical properties of geopolymeric concretes(GC) was presented here.First,slag and fly ash were used in the fabrication of GC reinforced with basalt and carbon fibers of various volume fractions,and liquid sodium silicate and sodium hydroxide were used for slag and fly ash activation.Then,after 3 and 7 days standard curing,impact properties of basalt fiber reinforced geopolymeric concrete(BFRGC)and carbon fiber reinforced geopolymeric concrete(CFRGC) were investigated using a 100-mm-diameter split Hopkinson pressure bar(SHPB) apparatus,and comparison between the results of experiments was performed.The results showed that early impact properties of fiber reinforced geopolymeric concretes(FRGCs) exhibited strong strain rate dependency.Early dynamic strength properties of BFRGC are better than those of CFRGC.In the range of 10-102 s-1,BFRGC and CFRGC possess the same ability of specific energy absorption,but compared to CFRGC,the priority in energy absorption capacity of BFRGC became more and more prominent with increase in average strain rate.From the above comparison,it was concluded that BFRGC possesses excellent early impact properties,which can be mainly displayed by dynamic strength properties and energy absorption capacity.