摘要
为探究溶蚀条件下纳米SiO 2混凝土微观特性和宏观性能的规律,采用2M NH 4 Cl溶液加速溶蚀试验,通过核磁共振技术、场发射扫描电镜和能谱分析研究孔隙特征、微观形貌及微结构的演变规律,同时采用灰熵法研究不同溶蚀龄期与不同纳米SiO 2掺量下混凝土的孔隙结构参数和孔隙半径分布对溶蚀损伤的影响规律,并在此基础上建立混凝土孔隙特征与抵抗溶蚀度的关系模型.在该试验中,水胶比为0.29,纳米SiO 2掺量分别为0,1%,3%和6%.结果表明:纳米SiO 2的掺入可显著提高混凝土的抗压强度,在经过溶蚀循环后,<100 nm孔径占比对混凝土抗溶蚀度影响程度最大,灰熵关联度均大于0.999;相对于基准组,纳米SiO 2混凝土溶蚀后有向外辐射的纤维状C-S-H生成,填充因溶蚀作用产生的裂隙,使其抗溶蚀性提高,延缓混凝土的劣化损伤;建立了混凝土抗溶蚀度与孔径占比为<100 nm,100~1000 nm和孔隙度的灰色模型GM(1,4)模型,4组混凝土GM(1,4)模型预测值与试验值的平均绝对误差分别为8.18%,7.03%,7.83%和7.90%.该研究可为纳米SiO 2混凝土在实际工程中的应用提供理论依据.
In order to investigate the microscopic and macroscopic mechanical properties of nano-SiO2 concrete under the dissolution condition,the 2M NH4Cl solution was used to accelerate the corrosion test,and the evolution of pore characteristics,microscopic appearance and microstructure of nano-SiO2 concrete were explored by means of nuclear magnetic resonance(NMR)technique,field emission scanning electron microscopy and energy spectrum analysis.Meanwhile,the influence of pore structure parameters and pore radius distribution of nano-SiO2 concrete on the corrosion damage under different dissolution ages and nano-SiO2 dosages was studied by using grey correlation entropy analysis.Based on this,the relationship model between concrete pore characteristics and corrosion resistance was established.In the test,the water to binder ratio was 0.29 and the replacement ratios of nano-SiO 2 were 0,1%,3% and 6%,respectively.The results show that the incorporation of nano-SiO2 significantly improves the compressive strength of concrete;<100 nm pore size ratio has the greatest influence on concrete corrosion resistance after dissolution cycle,and the grey entropy correlation degree is greater than 0.999.Compared with the reference group,the nano-SiO2 concrete is formed by the outwardly radiated fibrous C-S-H after dissolution,filling the cracks caused by the dissolution,which improves the corrosion resistance and delays the deterioration damage of the concrete.A grey model GM(1,4)is established for the influence of pore size ratio<100 nm,100-1000 nm and porosity on the corrosion resistance of concrete.The average absolute errors between predicted and experimental values of four concrete GM(1,4)models are 8.18%,7.03%,7.83% and 7.90%,respectively.This study provides a theoretical basis for practical engineering applications of nano-SiO2 concrete.
作者
王宗熙
姚占全
何梁
吴晗晗
刘紫玫
WANG Zongxi;YAO Zhanquan;HE Liang;WU Hanhan;LIU Zimei(Water Conservancy and Civil Engineering College,Inner Mongolia Agricultural University,Hohhot,Inner Mongolia 010018,China)
出处
《排灌机械工程学报》
EI
CSCD
北大核心
2020年第8期841-847,共7页
Journal of Drainage and Irrigation Machinery Engineering
基金
内蒙古农业大学博士科研启动基金资助项目(BJ2014-4)。
关键词
混凝土
核磁共振
溶蚀劣化
微观结构
纳米SiO
2
演变
灰熵
模型
concrete
nuclear magnetic resonance
dissolution degradation
microstructure
nano-SiO2
evolution
grey entropy
model
