Study on property and deterioration of whole boned bolt in heat-harm tunnel

Transcription

1 Study on the Anti-corrosion Properties of HPC in Contrasting Seasonal Change Environment Study on property and deterioration of whole boned bolt in heat-harm tunnel Dr. Fuhai LI A Prof Southwest Jiaotong University EBS (HK) Technology Development Co.,Ltd 1

2 Outline 1 Background 2 Research methods and contents 3 Experiments 4 Numerical simulation 5 Microstructure 6 Conclusions

3 1 Background Changes in cement production in some countries of the world

4 With the rapid development of civil construction in China, length of railroad lines will reach to 120,000 km before 2020 in the layout of medium-term and long-term railway network. The bridge substructure will use reinforce concrete structure as load-carrying members. In special corrosion environment, the durability of concrete which will ensure engineering long-term quality and operation safety gets great attention. Frost resisting property is an important parameter weighting the durability of concrete.

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6 City Average temperature of the coldest month( ) F-T times/year City Average temperature of the coldest month( ) F-T times/year Haerbin Zhengzhou Mudanjiang Wuhan Shenyang Hefei Changchun Nanchang Yanji Chongqing Xining Hangzhou Wulumuqi Shanghai Lanzhou Ningbo Huhehaote Changsha Taiyuan Guiyang Lasa Nanjing Shijiazhuang Chengdu Beijing Fuzhou Yinchuan Xiamen Dalian Nanning Tianjin Guangzhou Jinan Haikou Xian Kunming Qingdao F-T times in major city of the China

7 Problem: Beijing-Shanghai Highspeed Railway:100 Year Environment:H3 H4 L2 L3 D3 and D4

8 Concentration of corrosion ion between sections The concentration of corrosion ions around bridge substructures along the railway are investigated.

9 The sulfate ions concentrations of some sections are higher than seawater. The chloride ions concentration of a section is almost near the seawater Salt ions of seawater and some sections Sections PH SO 2 2- /mg.l -1 Cl -- /mg.l -1 Mg 2+ /mg.l -1 CO 2 /mg.l -1 Seawater No Langfang- Huayuan Huayuan- Cangzhou Cangzhou- Dezhou

10 The temperature of the city along the Beijing Shanghai high speed railway

11 2 Research methods and contents 试验设计材料基本性能试验不同冻融环境防护试验强度动弹性模量强度动弹性模量应变及应力形貌变化质量损失率微观形貌分析体式显微镜分析扫描电镜分析 X 射线衍射分析对比分析及验证结论试验及理论研究数值仿真研究有限元软件前处理有限元软件计算 ( 参数变化 ) 结构尺寸边界防护条件降温速率强度变化对比分析工程应用

12 3 Experiment Mix proportions used for concrete specimen Strengt h grade W/B Water kg/m 3 Cement kg/m 3 Sand kg/m 3 Aggregat e kg/m 3 GGBS kg/m 3 Fly ash kg/m 3 Water reducer/% C C C

13 Specimen and Equipment

14 Sample Antifreeze Monitoring Sample Temperature Sensor Freezing media 200mm The strain gauge Internal structure of rapid freezing and thawing cycles chamber

15 Strength grade (MPa) Specimen size (mm) Specimen grouping Type Mixed solution Sulfate solution Distilled water W WHD25-1 ~ 3 WLD25-1 ~ 3 WQD25-1 ~ 3 C25 Φ T THD25-1 ~ 3 TLD25-1 ~ 3 TQD25-1 ~ 3 G GHD25-1 ~ 3 GLD25-1 ~ 3 GQD25-1 ~ 3 W WHD35-1 ~ 3 WLD35-1 ~ 3 WQD35-1 ~ 3 C35 Φ T THD35-1 ~ 3 TLD35-1 ~ 3 TQD35-1 ~ 3 G GHD35-1 ~ 3 GLD35-1 ~ 3 GQD35-1 ~ 3 W WHD50-1 ~ 3 WLD50-1 ~ 3 WQD50-1 ~ 3 C50 Φ T THD50-1 ~ 3 TLD50-1 ~ 3 TQD50-1 ~ 3 G GHD50-1 ~ 3 GLD50-1 ~ 3 GQD50-1 ~ 3 Note: W unprotected concrete specimen, shaped by plastic pipes with inner diameter of 100mm. T concrete specimen protected by SPUA, shaped by plastic pipes with inner diameter of 100mm. G concrete specimen protected by steel pipe. The numbers after letters represent strength grade and specimen number. 25,35,50 strength grade C25,C35,C50; -1,-2,-3 specimen number 15

16 Result Mass Loss (unprotected) % WQD25 WLD25 WHD25 质量 (kg) % 冻融循环次数 ( 次 ) 质量 (kg) WQD50 WLD50 WHD 冻融循环次数 ( 次 ) -0.85% 质量 (kg) WQD35 WLD35 WHD 冻融循环次数 ( 次 ) Mass loss of specimens after different times of F-T action -1.98%

17 Result Mass Loss (unprotected) 质量 (k g ) WQD25 WQD35 WQD 冻融循环次数 ( 次 ) WLD25 WLD35 WLD WHD25 WHD35 WHD % 质量 (kg) 冻融循环次数 ( 次 ) 质量 (kg) % -4.36% 冻融循环次数 ( 次 ) Mass loss of specimens after different times of F-T action

18 Result Mass Loss (SPUA) 质量 (kg) 冻融循环次数 ( 次 ) TQD25 TLD25 THD 质量 (kg) 冻融循环次数 ( 次 ) TQD35 TLD35 THD35 质量 (kg) 冻融循环次数 ( 次 ) TQD50 TLD50 THD50 Mass loss of specimens after different times of F-T action

19 Result Mass Loss (Steel pipes) 质量 (kg) 冻融循环次数 ( 次 ) GQD25 GLD25 GHD 质量 (kg) 冻融循环次数 ( 次 ) GQD35 GLD35 GHD35 质量 (kg) 冻融循环次数 ( 次 ) GQD50 GLD50 GHD50 Mass loss of specimens after different times of F-T action

20 The relationship models between mass loss of unprotected specimens in mixed solution, water-binder ratio and times of F-T cycles W C Distilled water : W= exp N 2 W C R 2 =0.951 Sulfate solution: 2 W W W W= exp 2.686E-6N C C C R 2 =0.931 Mixed solution: 2 W W W W= exp 1.48E-6N C C C R 2 =0.961

21 Strength Compressive strength after 300 times of F-T cycles No. Compressive strength(mpa) No. Compressive strength(mpa) No. Compressive strength(mpa) WQD TQD GQD WQD TQD GQD WQD TQD GQD WLD TLD GLD WLD TLD GLD WLD TLD GLD WHD THD GHD WHD THD GHD WHD THD GHD d 56d Cylinder Compressive strength under standard curing (MPa) Age C25 C35 C50 28d d

22 Strength Compressive strength ratio between specimens after F-T cycles and standard curing specimens No. 28d Ratio 56d Ratio No. 28d Ratio 56d Ratio No. 28d Ratio 56d Ratio WQD WQD WQD WLD WLD WLD WHD WHD WHD TQD TQD TQD TLD TLD TLD THD THD THD GQD GQD GQD GLD GLD GLD GHD GHD GHD

23 Frost heaving stress and strain Strain variation with F-T

24 Single cyclic strain variation 24

25 Stress values of C35 specimens after F-T cycles No. Times-Stress(MPa) GHD GQD GLD WHD WQD WLD

26 Volume expansion of various of salt crystallization after absorbing Salt crystallization V% CaCl 2 2H 2 O CaCl 2 4H 2 O 35 CaCl 2 4H 2 O CaCl 2 6H 2 O 24 MgSO 4 H 2 O MgSO 4 6H 2 O 145 MgSO 4 6H 2 O MgSO 4 7H 2 O 11 Na 2 CO 3 H 2 O Na 2 CO 3 10H 2 O 148 NaCl NaCl 2H 2 O 130 Na 2 SO 4 Na 2 SO 4 10H 2 O

27 Morphology change Unprotect specimen in Mix Solution after 50 and 100 F-T Unprotect and steel pipe specimen after 300 F-T Unprotect specimen of C25 in sulfate solution and distilled water after 50 F-T Unprotect and SUPA specimen after 300 F-T

28 Morphology change 150 Times F-T C25 Ordinary Concrete 150 Times F-T C40 Ordinary Concrete Fracture specimen

29 4 Numerical simulation 温度 Tm 不稳定温度场 冻融循环阶段 初始期 运行期 时间 /t Sketch of concrete temperature change process

30 Deformation component, temperature difference and heave deformation to express stress component 1 E E E E T w x 2 x 2 y 2 z E E E E T w y 2 y 2 z 2 x E E E E T w z 2 z 2 x 2 y xy E v u 21 E w v yz zx x y 21 y z 21 E u w z x

31 E 1 e E T E x 2 1 x 2 1 x 2 w u 0 E 1 e E T E y 2 1 y 2 1 y 2 w v 0 E 1 e E T E z 2 1 z 2 1 z 2 w w 0 u v w e x y z x y z

32 Model 混凝土试件 400mm 混凝土混凝土 A B C A B 计算模型试件 混凝土计算模型 防护层 100mm Model(a)(b)

33 混凝土试件 A B 混凝土计算模型 模型网格划分 4000mm A C D E F B 五点 ( 左至右 ) 2000mm Model(c) A-F:0mm,1000mm,62.5mm,125mm,187.5mm,250mm

34 Model(a)A:Curve of Temperature -Time 8.8MPa Model(a)B:Curve of Temperature -Time 7.2MPa Model(a)A:Curve of Temperature stress -Time Model(a)B:Curve of Temperature stress-time

35 Different structure size(modelc) A:Curve of Temperature -Time B:Curve of Temperature -Time C:Curve of Temperature -Time F:Curve of Temperature -Time

36 13.2MPa A:Curve of Temperature Stress-Time B:Curve of Temperature Stress-Time C:Curve of Temperature Stress-Time F:Curve of Temperature Stress-Time

37 Different boundary conditions 模型 (a)a 点 模型 (b) 钢护筒 A 点 应力 (MPa) 时间 (h) MPa Model(a)(b) A:Curve of Temperature Stress-Time 应力 (M P a ) 10.0 模型 (a)b 点 模型 (b) 钢护筒 B 点 时间 (h ) MPa Model(a)(b) B:Curve of Temperature Stress-Time

38 Different cooling rate 应力 (M P a ) Model(a)A:Curve of Temperature Stress-Time 时间 (h ) 3h-A 5h-A 12h-A

39 Different cooling rate 应力 (MPa) 时间 (h) 3h-B 5h-B 12h-B Model(a)B:Curve of Temperature Stress-Time

40 Different Strength 应力 (Mpa) C25-A C35-A C50-A A: Curve of Temperature Stress-Time 时间 (h) 应力 (MPa) 时间 (h) C25-B C35-B C50-B B: Curve of Temperature Stress-Time

41 5 Microstructure SEM WHD25-1(100X) WQD35-1(100X) WHD25-2(5000X) Compactness Second Hydration

42 WHD25-3(3000X) WQD25-6(1000X)

43 WHD25-3 EDS WHD25-6 EDS

44 WQD25-1(1000X) WHD25-4(1000X) WQD25-7(3000X)

45 XRD

46 6 Conclusion (1) Mass loss rate of unprotected specimen become increased as F-T cycle proceeds. But the specimens protected by SUPA or steel pipes exhibit different phenomena.the relationship between the mass loss rate of HPC, water-binder ratio and times of F-T cycles are be proposed.

47 (2) Periodically varying strains are produced during F-T cycles. In the process of F-T cycle, internal strain and tensile stress become larger as the temperature decreases. But there will still be the presence of residual deformation when the temperature rises to the initial value. Corrosive ions will accelerate the damage of concrete. The damage of unprotected specimen under mixed solution is the most serious. The internal stress is greater than sulfate solution and distilled water. The internal stress of unprotected specimen under sodium solution is greater than distilled water. 47

48 Thanks for listening and for your questions!