1. Properties of Concrete Design and Control of Concrete Mixtures – Chapter 9

2. Overview Freshly Mixed Concrete Hardened Concrete

3. Properties of Concrete Fresh properties Consistency Stability Uniformity Workability Finishability Hardened properties Strength Durability Appearance Economy

4. Freshly Mixed Concrete Plastic or semi fluid---pliable and capable of being molded General must: Be easily mixed and transported Be uniform Have good flow properties Be compactable Be segregation resistant Be finishable

5. Workability

7. Consistency

8. Rheology

9. Bleeding and Settlement

11. Bleeding

12. Bleeding and Settlement

13. Bleeding

14. Air Content

27. Uniformity

28. Hydration, Setting, and Hardening

29. Setting and Hardening

30. Hardened Concrete Properties Curing Drying rate Strength Density Permeability and watertightness Volume stability and crack control Durability Aesthetics

31. Curing

33. Drying Rate

37. Strength

40. Flexural strength – 0.7-0.8 times sq. root of compressive strength in MPa (7.5-10 for psi) Direct tensile strength – 8%-12% of compressive strength Torsional strength – related to flexural strength and dimensions Shear strength – related to compressive strength (ACI 318) Modulus of elasticity – typically 1-4 GPa (2-6 million psi)

41. Density

42. Permeability and Watertightness

44. Volume Stability and Crack Crontrol Volume changes due to temperature, moisture, stress – 0.01%-0.08% Thermal behavior similar to steel Elastic deformation and creep Cracking due to load or volume changes Reinforcing steel used to reduce crack widths

45. Durability Ability to resist weathering, chemicals, and abrasion More exposure variety than other materials Most durability concerns involved water in the concrete Freeze-thaw Corrosion (chlorides or carbonation) ASR Abrasion Sulfate Attack Others

46. Aesthetics

47. Summary Freshly Mixed Concrete Hardened Concrete

48. Questions