10Portland Cement Types of Cement Type I: General Purpose Type II: Lower heat of hydration than Type IType III: High Early StrengthHigher heat of hydrationquicker strength (7 days vs. 28 days for Type I)
11Types of Cement Type IV: Low Heat of Hydration Gradually heats up, less distortion (massive structures).Type V: Sulfate ResistingFor footings, basements, sewers, etc. exposed to soils with sulfates.
16Concrete MixingIn the design of concrete mixes, three principal requirements for concrete are of importance:QualityWorkabilityEconomy
17Concrete MixingQuality of concrete is measured by its strength and durability.The compressive strength of concrete is mainly affected by the water/cement ratio, degree of compaction, age, and temperature.Durability of concrete is the ability of the concrete to resist disintegration due to freezing and thawing and chemical attack.
18Concrete MixingWorkability of concrete may be defined as a composite characteristic indicative of the ease with which the mass of plastic material may be deposited in its final place without segregation during placement, and its ability to conform to fine forming detail.
19Concrete Mixing Workability Workability is measured by the slump test 12”slumpLayer 1: Fill 1/3 full. 25 stokesLayer 2: Fill 2/3 full. 25 stokesLayer 3: Fill full. 25 stokesLift cone and measure slump (typically 2-6 in.)
22Concrete MixingEconomical takes into account effective use of materials, effective operation, and ease of handling. The cost of producing good quality concrete is an important consideration in the overall cost of the construction project.
24Mechanical Concrete Properties Compressive Strength,Modulus of Elasticity, EcMaximum ‘Ultimate’ StrainTensile, Splitting and Rupture Strength, ft , fct , fr
25Mechanical Concrete Properties Compressive Strength,Normally use 28-day strength for design strengthIt is determined through testing standard cylinders 15 cm in diameter and 30 cm in length in uniaxial compression at 28 days (ASTM C470-93a)