玄武岩-聚丙烯混杂纤维增强混凝土气孔结构分形分析  

Fractal Analysis of Air-void Structure of Hybrid Basalt-PolypropyleneFibre Reinforced Concrete

作　　者：牛荻涛[1,2] 罗扬[1] 苏丽 黄大观 NIU Ditao;LUO Yang;SU Li;HUANG Daguan(School of Civil Engineering,Xi’an University of Architecture and Technology,Xi’an 710055,China;State Key Laboratory of Green Building in Western China,Xi’an University of Architecture and Technology,Xi’an 710055,China)

机构地区：[1]西安建筑科技大学土木工程学院,西安710055 [2]西安建筑科技大学省部共建西部绿色建筑国家重点实验室,西安710055

出　　处：《材料导报》2022年第13期111-116,共6页Materials Reports

基　　金：国家自然科学基金(51590914);陕西省自然科学基础研究计划项目(2019JQ-481)。

摘　　要：采用Rapid Air 457气孔分析仪测试了玄武岩-聚丙烯混杂纤维增强混凝土(HBPRC)的气孔结构,分析了不同纤维添加方式对混凝土累计气孔含量和气孔表面分形特征的影响。研究结果表明,玄武岩纤维、聚丙烯纤维以及玄武岩-聚丙烯混杂纤维的掺入使混凝土的累计气孔含量增大了76.5%~354.1%,并且混凝土的累计气孔含量随纤维掺量的增加而增大。HBPRC的气孔结构具有明显的分形特征且其分形特征具有尺度相关性,在小孔隙区、中孔隙区、大孔隙区和超大孔隙区,气孔面分形维数(D_(S))依次增大,但在孔径大于1500μm的区域没有分形特征。随着纤维的掺入,混凝土大孔隙区和超大孔隙区的D_(S)发生了明显的变化,单掺0.1%(体积分数,下同)的玄武岩纤维或0.1%的聚丙烯纤维增大了大孔隙区和超大孔隙区的D_(S);掺入0.1%的玄武岩-聚丙烯混杂纤维对大孔隙区和超大孔隙区D_(S)的影响较小;而掺入0.2%的玄武岩-聚丙烯混杂纤维显著减小了超大孔隙区的D_(S)。通过细观分析,认为纤维形成的网络结构对混凝土拌合过程中气泡合并产生的抑制作用是HBPRC大孔隙区和超大孔隙区D_(S)增大的主要原因,而纤维的弱分散性和长时间的搅拌会导致超大孔隙区的D_(S)减小。The air-void structure of hybrid basalt-polypropylene fibre reinforced concrete(HBPRC)was investigated by using a Rapid Air 457 air-void analyser.The effects of basalt fibre,polypropylene fibre and hybrid basalt-polypropylene fibre on the cumulative air-void content and air-void surface fractal dimensions(D_(S))of concrete were analysed.The results indicate that the air-voids structure of the HBPRC has distinct fractal characteristics and its fractal features are scale-dependent and the incorporation of basalt fibre,polypropylene fibre and hybrid basalt-polypropylene fibre increases the cumulative air-void content of the concrete by 76.5%to 354.1%,and that the cumulative air-void content of the concrete increases with the increase of fibre content.The D_(S) of HBPRC in the small-pore,medium-pore,macroporous and superporous regions increase sequentially,although there are no physical characteristics in the region with pore diameters greater than 1500μm.The incorporation of fibre has a significant effect on the D_(S) of the macroporous and superporous regions.The D_(S) of the macroporous and superporous zones are increased with 0.1%(volume fraction,the same below)basalt and 0.1%polypropylene fibre alone;the addition of 0.1%hybrid basalt-polypropylene fibre has little effect on the D_(S) of the macroporous and superporous region;the addition of 0.2%hybrid basalt-polypropylene fibre significantly reduces the D_(S) of the superporous region.Through microscopic analysis,it is suggested that the suppressive effect of the fibre-formed network structure on bubble merging is the main reason for the increase of D_(S) of the macroporous and superporous zones,while the weak dispersion of the fibres and prolonged agitation lead to the deterioration of the pore structure in the macroporous and superporous zones.

关 键 词：玄武岩-聚丙烯混杂纤维 自动图像处理 气孔结构 分形理论 

分 类 号：TU528.01[建筑科学—建筑技术科学]