冷热-荷载耦合下纤维锂渣混凝土柱偏心受压性能

Eccentric compression performance of polypropylene fiber lithium slag concrete column subjected to loading and thermal-cold cycles

为研究冷热循环作用及耦合应力对纤维锂渣混凝土(PLiC)柱偏心受压性能的影响,制作6根PLiC柱和2根对照柱,将其施加0、0.10、0.20、0.35的耦合应力之后,经历0次、100次、200次、300次冷热循环作用后进行偏心受压静力试验,研究冷热循环次数、耦合应力比对PLiC柱偏心受压性能的影响。结果表明:单掺锂渣对试验柱的破坏形态、延性、开裂荷载和极限荷载影响均较小,而掺入1.2 kg/m^(3)的PLiC柱受压破坏时无明显混凝土压溃现象,且变形性能更好,延性提高24.7%、开裂荷载提高3.5倍、极限荷载提高24.73%;耦合应力比不变,冷热循环次数从100次增加到300次时,PLiC柱裂缝数量增加且呈现多而密的特点,延性系数提高8.6%,极限承载力下降33.56%;冷热循环200次时,耦合应力比从0.10增加到0.35,构件延性系数变化较小,极限承载力下降34.55%。试验中冷热循环温差为58℃,可为中国西部地区大温差环境下混凝土结构设计提供一定参考。

To investigate the eccentric compressive behaviors of polypropylene fiber lithium slag concrete(PLiC)column after therma-cold cycles and coupling stresses,6 PLiC columns and 2 contrast concrete column were fabricated.After applying coupling stresses of 0,0.10,0.20 and 0.35,and the corresponding static eccentric compressive experiments after 0,100,200,300 times therma-cold cycles were carried out.The effects of the number of therma-cold cycles and coupling stress ratio on eccentric compression performance of PLiC columns were investigated.The results show that the single-doped lithium slag has little influence on the failure form,ductility,cracking load and ultimate load of the test column,but there is no obvious concrete collapse phenomenon when the PLiC column is mixed with 1.2 kg/m^(3),and the deformation performance is better,the ductility is increased by 24.7%,the cracking load is increased by 3.5 times and the ultimate load is increased by 24.73%.When the coupling stress ratio is unchanged and the number of cracks increases from 100 to 300 times of therma-cold cycles,the cracks of PLiC columns are more and more dense,the ductility coefficient increases by 8.6%,and the ultimate bearing capacity decreases by 33.56%.When the coupling stress ratio increases from 0.10 to 0.35,the ductility coefficient changes little and the ultimate bearing capacity decreases 34.55%.In this experiment,the temperature difference between hot and cold cycles is 58℃,which can provide some reference for the design of concrete structures in the environment of large temperature difference in western China.