摘要
【目的】提高面板混凝土的抗裂性能。【方法】设计了单掺粉煤灰、粉煤灰+MgO混掺、粉煤灰+纤维素纤维混掺的3种不同组合的对比试验,以检验不同掺和料对面板混凝土强度、变形性能、宏观抗裂性能、微观早期抗裂性能等的影响,并分析了其抗裂机理。【结果】纤维素纤维增强面板混凝土的劈拉强度和极限拉伸值最高,初裂起始时间最晚,单位面积裂缝数目最少,说明掺纤维的效果最好,抑制了水泥浆体早期裂缝的发展,其抗裂性能最优。另外微观扫描电镜分析表明,掺粉煤灰和纤维素纤维后面板混凝土的90 d龄期的试块结构较为致密,后期形成大量的团簇状短棒产物,能谱分析显示产物中钙的比例下降,硅铝比例提高,后期的粉煤灰水化消耗了一定的钙,降低了产物的钙硅比,形成产物进一步填充密实,强度得到提高。【结论】纤维素纤维对于面板混凝土的抗裂性能有显著提升,这为提升混凝土抗拉强度提供了一种新的思路,具有广阔的应用前景。
【Objective】Cellulose fiber is a material increasingly used to reinforce concrete and this paper investigates its improvement of concrete slabs against cracking.【Method】Concrete slabs made by cement mixed with fly ash,cement mixed with fly ash and Mg O,were compared with slabs made by cement-fly ash reinforced by cellulose fiber.For each slab,we measured its strength,deformation property,resistance against macro-cracks and emergence of micro-crack.【Result】Concrete slab reinforced by cellulose fibers are mechanically best,and its splitting tensile strength and ultimate tensile strength are both higher than other slabs.The cellulose fibers not only delays the initiation of cracks but also reduces cracking density(numbers of cracks per unit area).Ninety days after the slab is casted,SEM analysis shows that the structure of the reinforced slabs is relatively compact and a large number of short-rod clusters are formed inside it.Energy spectrum analysis shows that the cellulose fiber reduces the proportion of calcium while increasing the proportion of silicon and aluminum in the slabs.Fly ash hydration consumes a certain amount of calcium,thereby reducing the calcium-silicon ratio and increasing the strength of the slabs.【Conclusion】Comparison shows that reinforcing concrete slabs by cellulose fiber can significantly improve their resistance against cracking and tensile strength.
作者
陈小攀
常世举
贾朋
余传永
王立奎
赵杰
谭建军
CHEN Xiaopan;CHANG Shiju;JIA Peng;YU Chuanyong;WANG Likui;ZHAO Jie;TAN Jianjun(Henan Tianchi Pumped Storage Power Company Limited,Nanyang 473000,China;China Power Construction Group Guiyang Survey Design&Research Institute Co.,Ltd.,Guiyang 550000,China)
出处
《灌溉排水学报》
CAS
CSCD
北大核心
2023年第2期123-129,共7页
Journal of Irrigation and Drainage
关键词
纤维素纤维混凝土
面板混凝土
抗裂性能
cellulosic fiber concrete
face slab concrete
crack resistance
