基于CT技术的预填骨料混凝土孔隙结构特征

Pore structure characteristics of prefilled aggregate concrete based on CT technology

预填骨料混凝土(PAC)由于独特的生产工艺,致使内部容易产生孔隙,进而影响PAC的宏观性能。为考察PAC孔隙率及孔隙形态等细观结构对PAC宏观力学性能的影响,对不同级配的PAC进行抗压强度和抗弯拉强度实验,运用CT(computed tomography)技术对试件进行扫描,利用计算机图像处理技术和三维可视化模型,分别进行二维、三维层面的孔隙结构特征差异分析,通过灰色关联法探究细观结构的特征参数对PAC宏观力学强度的影响程度。结果表明:PAC早期抗弯拉强度发展比较快,且不同的级配对PAC抗弯拉强度有一定影响;孔隙平均球度、平均紧密度与孔隙大小等参数的灰色关联度在0.8以上,对强度发展关系密切,其中孔径大小对强度影响最大。

Prefilled aggregate concrete(PAC)is easy to produce pores because of its unique production process,which affects its macro performance.In order to investigate the influence of microstructures such as porosity and pore morphology of PAC on its macroscopic mechanical properties,the compressive strength and flexural and tensile strength tests of PAC with different levels were carried out first,and then the specimens were scanned by CT(computed tomography)technology.Based on the computer image processing technology and three-dimensional visualization model,the difference analysis of pore structure characteristics in two and three dimensions was carried out,and the influence of the characteristics parameters of PAC microstructure on its macroscopic mechanical strength was explored by the grey correlation method.The results show that the flexural and tensile strength of PAC develops rapidly in the early stage,and different stages have certain effects on the flexural and tensile strength of PAC.The gray correlation degree between pore size and mean pore sphericity is above 0.8,which has a close relationship with strength development,and pore size has the greatest influence on strength.