摘要
为研究碳化后混凝土的气体渗透性能和细观结构的关系,针对普通混凝土(C)和聚丙烯-玄武岩纤维混凝土(BP)进行碳化龄期分别为0、7、14、28、56、80天碳化试验和气体渗透性试验,采用丹麦Rapidair457混凝土气孔结构分析仪获取混凝土细观结构特征参数,基于不同孔径范围、计算方法对混凝土含气量、分形维数的影响水平不同,将混凝土孔径划分为0~160、160~300、300~4000μm三个范围,分别计算含气量和分形维数,分析碳化龄期和材料对于宏、细观性能的影响,研究混凝土气渗性能、分形维数和细观结构的内在联系,给出敏感孔径范围。结果表明:BP气体扩散系数和含气量总体上小于C,说明纤维混掺可从不同层次上改善纤维三维分布的均衡性,提高混凝土抗碳化性能。随碳化龄期增加,对于C,小孔径范围下孔隙质量分形维数的变化趋势与气体扩散系数相反程度较高;对于BP,中孔径范围下固体质量分形维数的变化趋势与气体扩散系数相反程度较高。固体质量分形维数能更好地反映混凝土内部结构的复杂程度。综合混凝土气渗性能、分形维数和细观结构分析,均可得到:小孔径范围是C的敏感孔径范围,中孔径范围是BP的敏感孔径范围。
In order to investigate the relationship between gas permeability and meso-structure of carbonated concrete,carbonation tests and gas permeability tests of ordinary concrete(OC)and polypropylene basalt fiber concrete(BP)with 0,7,14,28,56 and 80 days carbonation were performed respectively.The parameters of concrete meso-structure were obtained by RapidAir 457 concrete pore structure analyzer(Denmark).Based on the influence levels of different pore size ranges and calculation methods on the air content and fractal dimension of concrete,the pore size of concrete is divided into 0-160μm,160-300μm,300-4000μm.The air content and fractal dimension were calculated respectively.The influences of carbonation age and materials on the macroscopic and microscopic properties were analyzed.The internal relationship among the gas permeability,fractal dimension and meso-structure of concrete was studied.Then,the sensitive pore size range was given.The results show that the gas diffusion coefficient and air content of BP are less than that of OC in general,which shows that hybrid can improve the carbonation resistance of concrete by improving the balance of three-dimensional distribution of fiber from different levels.With carbonization age increasing,for OC,the correlation between pore mass fractal dimension in small pore size range and gas diffusion coefficient is higher than other ranges.For BP,the correlation between solid mass fractal dimension in medium pore size range and gas diffusion coefficient is higher than other ranges.The solid mass fractal dimension is employed to characterize the concrete internal structure more accurately than pore mass fractal dimension.Based on the comprehensive analysis of air permeability,fractal dimension and meso-structure,it is identified that the sensitive pore size range of OC is the small pore size rang,and the sensitive pore size range of BP is the medium pore size range.
作者
李艺
苏悦琦
LI Yi;SU Yue-qi(School of Resources and Civil Engineering,Northeastern University,Shenyang 110819,China)
出处
《吉林大学学报（工学版）》
EI
CAS
CSCD
北大核心
2021年第4期1287-1295,共9页
Journal of Jilin University:Engineering and Technology Edition
基金
“十三五”国家重点研发计划项目(2016YFC0700801-1)
辽宁省自然科学基金项目(20180510019).
关键词
纤维混凝土
碳化
气体扩散系数
细观结构
分形维数
fiber concrete
carbonization
gas diffusion coefficient
meso-structure
fractal dimensi
