http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Penghui Wang,Hongxia Qiao,Qiong Feng,Cuizhen Xue 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.2
The constant current energization accelerated test was carried out to study the effect of asphalt coating on delaying reinforcement corrosion and rust-induced cracks in coated reinforced magnesium oxychloride cement concrete (CRMOCC). CRMOCC with different degrees of damage was scanned by adopting X-ray computed tomography (X-CT) technology, and the spatial information of rust and rust-induced cracks were analyzed visually and quantitatively. In addition, Scanning Electron Microscope (SEM) was used to analyze the non-uniformity of rust-induced crack formation. The results showed that the corrosion amount of coated reinforcement after energization was only 81.6% of that of uncoated reinforcement. Besides, no crack no cracking was observed on CRMOCC after 480h’s energization, while the rust-induced crack of reinforced magnesium oxychloride cement concrete (RMOCC) was 0.11 mm. The coating reduced the potential of rust-induced crack formation such that only three areas in CRMOCC were cracked, while RMOCC had cracks in eight areas. This study also found that interface transition zone (ITZ) played a dominant role in the formation of rust-induced cracks. The surface crack width in CRMOCC had an exponential relation with the crack volume and it had a linear relation with the volume of corrosion products. Further, there was an exponential relation between the volume loss of the reinforcement and the formation of rust-induced cracks. The correlation between surface crack width, corrosion products volume, rust-induced cracks volume and steel volume can be described by quadric surface. Results by SEM analysis indicated that in the ITZ of CRMOCC, Mg and O elements were the two main elements in the hydration products that were loose and needle-like. Furthermore, Si and O elements were the dominant materials in the non-interface transition zone (NITZ), resulting in relatively dense hydration products.
Xi Wang,Hongxia Qiao,Yunsheng Zhang,Wenhua Zhang,Cuizhen Xue,Mubita Majory Mundia,Lei Zhang 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.4
Concrete structure is easy to be damaged by corrosion in natural environment. In order to find a new way to improve the corrosion resistance of concrete. In this paper, the effect of Coal Tar Fuel (CTF) synergist on the corrosion resistance of concrete was analyzed by using MgSO4solution with concentration of 5% as corrosion medium. The change rule of concrete pore structure was studied. And the performance of concrete interfacial transition zone (ITZ) is studied. Finally, the effect of CTF synergist on hydration reaction of cementitious materials was revealed. The results show that the addition of 0.7% CTF synergist can significantly enhance the corrosion resistance of concrete, even with 10% reduction in cement dosage. After 28 days of being cured under this dosage, there is 13.54% increase in the proportion of pores with a diameter less than 100 μm and a 5.36% decrease in the proportion of pores with a diameter greater than 600 μm. Meanwhile, the microhardness of ITZ increases by 41.14%, while the width of ITZ decreases by 12.5%. Additionally, there is a reduction in the maximum crack width at the interface between ITZ and aggregate by 1.8 μm. The exothermic reaction of the cementitious material during hydration is more pronounced when the hydration time exceeds one hour.