Microstructural and Microanalytical Study on Concrete Exposed to the Sulfate Environment

2017 4th International Conference on Advanced Materials, Mechanics and Structural Engineering

材料科学;机械制造

Fang, Qing^1 ; Li, Beixing^2 ; Yin, Jiangang^3 ; Yuan, Xiaolu^4

Hubei Electric Power Survey and Design Institute, Wuhan

430040, China^1

State Key Laboratory of Silicate Materials for Architecture, Wuhan University of Technology, Wuhan

430070, China^2

State Grid Hubei Electric Power Company, Wuhan

430077, China^3

College of Civil Engineering and Architecture, China Three Gorges University, Yichang

443002, China^4

关键词: Energy dispersive spectroscopies (EDS);    Ground blast furnace slags;    Internal surfaces;    Mercury intrusion porosimetry;    Micro-structural properties;    Mineral admixtures;    Ordinary Portland cement;    Sulfate resistance;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/269/1/012070/pdf
DOI  :  10.1088/1757-899X/269/1/012070

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Microstructural properties have been examined to investigate the effect of mineral admixtures on the sulfate resistance of concrete. Concrete and cement paste specimens made with ordinary Portland cement (OPC) or ordinary Portland cement incorporating 20% fly ash (FA) or 30% ground blast furnace slag (GBFS), were made and exposed to 250 cycles of the cyclic sulfate environment. Microstructural and Microanalytical study was conducted by means of x-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and mercury intrusion porosimetry (MIP). Results indicate that the pore structure of concrete after sulfate exposure possesses the fractal feature. The OPC concrete presents more complex pore internal surface, higher porosity and less micro-pores than the concrete incorporating fly ash and GBFS. Portlandite in OPC concrete and OPC-FA concrete is mainly converted to gypsum; while for OPC-GBFS concrete, both gypsum and ettringite are formed. In the cyclic sulfate environment, repeated hydration and dehydration of sulfates produce the expansive stress in pores, aggravating the demolishment of concrete structure.