LI Guirong
,
WANG Hongming
,
DAI Qixun
,
ZHAO Yutao
,
LI Jingsheng
钢铁研究学报(英文版)
The flux agents in common mould fluxes were fluoride and sodium oxide, which would do great harm to environments. B2O3 was selected as flux. The physical properties of B2O3containing mould fluxes were studied. The corresponding physical properties of 3791%CaO4309%SiO25%Al2O35%MgO2%Li2O7%B2O3 mould fluxes were as follows: the melting point was 909 ℃, the flowing temperature was 1 160 ℃, the viscosity and surface tension at 1 300 ℃ were 04 Pa·s and 032 N/m respectively, which could meet the demands for certain kinds of steels for mould fluxes in continuous casting.
关键词:
B2O3containing mould flux;fluoridefree flux;harmless flux;physical property
Ali Nazari Shadi Riahi
材料科学技术（英文）
In the present study, split tensile strength of self-compacting concrete with different amount of CuO nanoparticles has been investigated. CuO nanoparticles with the average particle size of 15 nm were added partially to self compacting concrete and split tensile strength of the specimens has been measured. The results indicate that CuO nanoparticles are able to improve the split tensile strength of self compacting concrete and recover the negative effects of polycarboxylate superplasticizer on split tensile strength. CuO nanoparticle as a partial replacement of cement up to 4 wt% could accelerate C-S-H gel formation as a result of increased crystalline Ca(OH)2 amount at the early ages of hydration. The increase of the CuO nanoparticles more than 4 wt%
causes the decrease of the split tensile strength because of unsuitable dispersion of nanoparticles in the concrete matrix. Accelerated peak appearance in conduction calorimetry tests, more weight loss in thermogravimetric analysis and more rapid appearance of related peaks to hydrated products in X-ray diffraction (XRD) results all also indicate that CuO nanoparticles up to 4 wt% could improve the mechanical and physical properties of the specimens. Finally, CuO nanoparticles could improve the pore structure of concrete and shift the distributed pores to harmless and few-harm pores.
关键词:
Self-compacting concrete (SCC)
,
null
,
null
,
null
,
null
,
null
Ali Nazari Shadi Riahi
材料科学技术（英文）
In the present study, split tensile strength of self-compacting concrete with different amount of CuO nanoparticles has been investigated. CuO nanoparticles with the average particle size of 15 nm were added partially to self compacting concrete and split tensile strength of the specimens has been measured. The results indicate that CuO nanoparticles are able to improve the split tensile strength of self compacting concrete and recover the negative effects of polycarboxylate superplasticizer on split tensile strength. CuO nanoparticle as a partial replacement of cement up to 4 wt% could accelerate C-S-H gel formation as a result of increased crystalline Ca(OH)2 amount at the early ages of hydration. The increase of the CuO nanoparticles more than 4 wt%
causes the decrease of the split tensile strength because of unsuitable dispersion of nanoparticles in the concrete matrix. Accelerated peak appearance in conduction calorimetry tests, more weight loss in thermogravimetric analysis and more rapid appearance of related peaks to hydrated products in X-ray diffraction (XRD) results all also indicate that CuO nanoparticles up to 4 wt% could improve the mechanical and physical properties of the specimens. Finally, CuO nanoparticles could improve the pore structure of concrete and shift the distributed pores to harmless and few-harm pores.
关键词:
Self-compacting concrete (SCC)
,
null
,
null
,
null
,
null
,
null
