Experiments on Mechanical Properties of Self-Compacting Concrete

1. Experiments on Mechanical Properties of Self-Compacting Concrete Tao Jin Department of Geotechnical Engineering Tongji University, China

2. Outline • Introduction • Concrete Mix Design • Results of Mechanical Experiments • Discussion • Future Work • Other Experiment Results in HPC LAB • Conclusions Http:// Hpclab.tongji.edu.cn

3. Introduction • SCC was used in many high-rise buildings, airport pavement, concrete-filled steel tubes, precast columns and beams. For example, C60 high strength self-compacting concrete was used in the shear wall of Capital Airport. • The high strength self-compacting concretes with ground granulated blast-furnace slag (GGBS) and limestone power used in tunnel are studied in this paper. Http:// Hpclab.tongji.edu.cn

4. Existing Questions • There is no standard method to assess the segregation resistance. • The domestic research of fibre self-compacting concrete is very few. • The shrinkage and creep of SCC are very important questions for research. • Domestic researches on property of SCC structure in fire are very few. Http:// Hpclab.tongji.edu.cn

5. Materials • The cement used is 525 ordinary Portland cement. • The fine aggregate is medium sand. • The coarse aggregates are crushed stone or broken gravel with maximum size of 20 mm. • A superplasticizer(SP) is used in the mix. • The surface area of ground granulated blast-furnace slag (GGBS) is 500m2/kg. Http:// Hpclab.tongji.edu.cn

6. Outline • Introduction • Concrete Mix Design • Results of Mechanical Experiments • Discussion • Future Work • Other Experiment Results in HPC LAB • Conclusions Http:// Hpclab.tongji.edu.cn

7. Results-Workability Http:// Hpclab.tongji.edu.cn

8. Results-Strength Http:// Hpclab.tongji.edu.cn

9. Results- Stress Strain Curve Bulk Strain Longitudinal Strain Transverse Strain Http:// Hpclab.tongji.edu.cn

10. Failure form Http:// Hpclab.tongji.edu.cn

11. Conclusions of this chapter • The compressive strength and elastic modulus at early age are high. • Compared with traditional concrete, SCC has lower surface strength, and the strength at upper surface is obvious. Http:// Hpclab.tongji.edu.cn

12. Outline • Introduction • Concrete Mix Design • Results of Mechanical Experiments • Discussion • Future Work • Other Experiment Results in HPC LAB • Conclusions Http:// Hpclab.tongji.edu.cn

13. Discussion • Influence of the parameters of mix proportion on the workability and compressive strength of self-compacting concrete • The SP content • The total cementitious material • The content of GGBS Http:// Hpclab.tongji.edu.cn

14. The slump and slump flow of SCC increase when the SP content increases. • When the SP content is 1.8%, the segregation resistance declines and the slump flow has less increment, which indicates that the SP content is near saturation dosage. So the optimum SP content is 1.5% of the total cementitious material. Http:// Hpclab.tongji.edu.cn

15. The results indicate that the filling ability increases when the total cementitious material increases. • In order to prepare high-strength SCC, the total cementitious material ought to exceed 550 kg/m3. Http:// Hpclab.tongji.edu.cn

16. The results indicate that the slump, slump flow increase when the GGBS content increases. • The main effect of GGBS is to improve workability of SCC, which is shown in Fig and Table. Http:// Hpclab.tongji.edu.cn

17. Outline • Introduction • Concrete Mix Design • Results of Mechanical Experiments • Discussion • Future Work • Other Experiment Results in HPC LAB • Conclusions Http:// Hpclab.tongji.edu.cn

18. Fire-ResistanceExperimental Program of SCC Element • Effect of high temperature on strength and stress-strain relationship of SCC • Evaluate the structural behavior of SCC beam exposed to high temperature, such as the rigidity, ultimate strength and crack patterns Http:// Hpclab.tongji.edu.cn

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20. Testing Conditions Http:// Hpclab.tongji.edu.cn

21. Test Procedure • Compressive strength, splitting tensile strength • Deformation under different stress-temperature paths • T-S path: Strain induced by stress at constant temperature • S-T path: Strain induced by temperature at constant stress Http:// Hpclab.tongji.edu.cn

22. Mechanical properties of concrete under high temperature • Structural behavior of SCC beam under high temperature Http:// Hpclab.tongji.edu.cn

23. Simply-Supported Beam Test Purpose • Influence of different concrete cover thickness on the capacity of fire-resistance • Influence of different temperature-stress paths on the structural behavior • T-S path • S-T path Http:// Hpclab.tongji.edu.cn

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25. Testing Conditions Http:// Hpclab.tongji.edu.cn

26. Fire test set-up Http:// Hpclab.tongji.edu.cn

27. Outline • Introduction • Concrete Mix Design • Results of Mechanical Experiments • Discussion • Future Work • Other Experiment Results in HPC LAB • Conclusions Http:// Hpclab.tongji.edu.cn

28. Shrinkage at early age of SCC Http:// Hpclab.tongji.edu.cn

29. Free shrinkage of common concrete Http:// Hpclab.tongji.edu.cn

30. Free shrinkage of SCC Http:// Hpclab.tongji.edu.cn

31. Free shrinkage of SCC under 26℃ Http:// Hpclab.tongji.edu.cn

32. Free shrinkage of sealed SCC Http:// Hpclab.tongji.edu.cn

33. Humidity in common concrete Http:// Hpclab.tongji.edu.cn

34. Humidity of SCC Http:// Hpclab.tongji.edu.cn

35. passive restrain shrinkage equipment of concrete Http:// Hpclab.tongji.edu.cn

36. Conclusions of this chapter • The drying shrinkage of SCC is lower than OC. • Temperature has much influence on the shrinkage. • Humidity has little influence on the shrinkage. • The final humidity in concrete is 75-80% Http:// Hpclab.tongji.edu.cn

37. Rubber Concrete • Concrete pavement tends to crack as it is more rigid than asphalt pavements. • Solid waste management has been a major environmental concern around the world. • Making use of waste tire chip as an addition concrete matrix may be an economical and ecological solution. Http:// Hpclab.tongji.edu.cn

38. Introduction • Products of both crushed and ground tire rubber are chosen as an additional components to be mixed as rubberized concrete. • To investigate the mechanical properties of rubber concrete, several laboratory tests on strengths and deformation capacity are conducted. • While replacing 15%, 30% and 45% coarse aggregate by volume in concrete, two typical sizes of scrap tire rubber particles are chosen. • Typical strength index, such as cubic and cylindrical compressive strength, axial compressive strength, flexural strength, as well as splitting tensile strength, are measured according to ASTM or relevant testing guidelines. Http:// Hpclab.tongji.edu.cn

39. Material Used in Experiment Passing (%) Particle size (mm) Sieve Analysis of Aggregate and Rubber Http:// Hpclab.tongji.edu.cn

40. Rubber GR-8 CR-40 Rubber Used in the Experiment Http:// Hpclab.tongji.edu.cn

41. Concrete Mix Design Properties of materials and mix design of concrete control mix Http:// Hpclab.tongji.edu.cn

42. Results-slump Effect of rubber content on slump of fresh concrete Slump (mm) Rubber content by coarse aggregate volume Http:// Hpclab.tongji.edu.cn

43. Results-unit weight Unit weight (kg/m3) Rubber content by coarse aggregate volume Effect of rubber content on density of concrete Http:// Hpclab.tongji.edu.cn

44. Results-Strength Typical specimens used in the experiments Http:// Hpclab.tongji.edu.cn

45. Compressive Strength (MPa)） Rubber content by coarse aggregate volume (%) Results-Strength Effect of rubber content on compressive strength of concrete Http:// Hpclab.tongji.edu.cn

46. Results-Strength Effect of rubber content on axial compressive strength of concrete Http:// Hpclab.tongji.edu.cn

47. Results-Strength Effect of rubber content on splitting tensile strength of concrete Http:// Hpclab.tongji.edu.cn

48. Results-Strength Effect of rubber content on flexural strength of concrete Http:// Hpclab.tongji.edu.cn

49. Results-Deformation Typical specimens used in the experiments Http:// Hpclab.tongji.edu.cn

50. Modulus of Elasticity and Poisson ratio Results of elasticity and Poisson ratio Http:// Hpclab.tongji.edu.cn