Home Courses Articles Watch! Tools Downloads Request ----------------------------------------------------- Soil Mechanics > Physical Properties of Soil > Soil Phase Relationships > Lateral Earth Pressure > At-Rest State > Rankine's Lateral Earth Pressure > Coulomb's Lateral Earth Pressure > Slope Stability > Effects of Water on Slope Stability > Infinite Slope Analysis > Circular Arc Failure of Slope Analysis > Critical Failure Surface Foundation Analysis and Design > Settlement of Shallow Foundations > Settlement types, definitions, and general equation > Immediate settlement computations > Primary Consolidation > Secondary Compression > Bearing Capacity of Shallow Foundations > Terzaghi's Method > Meyerhof's Method > Brinch Hansen's Method > Bearing from SPT Number > Effect of Ground Water Table > Bearing Capacity of Piles (Deep Foundations) > Ultimate Tip Resistance of Piles > Shaft Resistance of Piles > Sheet-pile Walls: Cantilevered and Anchored > Cantilever Sheet Pile Walls Penetrating Sandy Soils > Anchored Sheet Pile Walls Penetrating Sandy Soils > Factors of Safety for Cantilevered Sheet Pile Walls Load Calculation > Structural Loading > Dead Load vs Live Load > Load Combinations Reinforced Concrete Design > General Topics > What Is Concrete? > Concrete Properties > Section Properties of Reinforcing Bars & Cement Types > Load Combinations of Concrete Design > Design of Concrete Members > Reinforced Concrete Beam Design > Flexural Design of Reinforced Concrete Beams > Serviceability of Reinforced Concrete Beams > Shear Design of Reinforced Concrete Beams Structural Steel Design Construction > Elements of construction > Construction Site Layout Planning Elements > All Types of Roofs And Their Details > Types of Foundations From Construction Point of View > All Types of Foundation Materials Timber Design > Design of Timber Members > Design of Sawn Timber Beams or Joists > Design of Sawn Timber Columns and Compressive Members Masonry Design Finite Elements Method > Basics of Finite Elements > Introduction to Finite Elements And the Big Picture > One-dimensional Bars/Springs > Plane Trusses Introduction Concepts & Formulas Videos Solved problems Download Files Concrete Properties Courses > Reinforced Concrete Design > General Topics > Concrete Properties

Introduction on Concrete Properties :

Concrete has relatively high compressive strength, but significantly lower tensile strength, and as such is usually reinforced with materials that are strong in tension (often steel). The elasticity of concrete is relatively constant at low stress levels but starts decreasing at higher stress levels as matrix cracking develops. Concrete has a very low coefficient of thermal expansion, and as it matures concrete shrinks. All concrete structures will crack to some extent, due to shrinkage and tension. Concrete which is subjected to long-duration forces is prone to creep.

Concepts and Formulas of Concrete Properties:

Typical properties of normal strength Portland cement concrete:

Density : 2240 - 2400 kg/m^{3} (140 - 150 lb/ft^{3} )
Compressive strength : 20 - 40 MPa (3000 - 6000 psi = 432 - 864 ksf)

Compressive strength of concrete (% of 28-day strength) vs age (days)

Flexural strength : 3 - 5 MPa (400 - 700 psi = 57.6 - 100.8 ksf)
Tensile strength : 2 - 5 MPa (300 - 700 psi = 43.2 - 100.8 ksf)
Modulus of elasticity : 14000 - 41000 MPa (2 x 10^{6} - 6 x 10^{6} psi = 288000 - 864000 ksf)
The American Concrete Institute (ACI) suggests the following equation for the modulus of elasticity:

where

w_{c} = weight of concrete (pounds per cubic foot)

f'_{c} = compressive strength of concrete at 28 days (psi)

AASHTO Load and Resistance Factor Design Manual, or "LRFD" suggests the following equation:

where

K_{1} = correction factor for aggregate source (taken as 1.0 unless determined otherwise)

w_{c} = weight of concrete (pounds per cubic foot (pcf))

f'_{c} = compressive strength of concrete at 28 days (psi)

A handy approximate equation:

Permeability : 1 x 10^{-10} cm/sec (2.8346 x 10^{-7} ft/day)
Coefficient of thermal expansion : 10^{-5} ^{o} C^{-1 } (5.5 x 10^{-6} ^{o} F^{-1} )
Drying shrinkage : 4 - 8 x 10^{-4}
Drying shrinkage of reinforced concrete : 2 - 3 x 10^{-4}
Poisson's ratio : 0.20 - 0.21
Shear strength : 6 - 17 MPa (870 - 2465 psi)
Specific heat : 0.75 kJ/kg K (0.18 Btu/lb_{m } ^{o} F (kcal/kg^{ o} C))

Watch! (Videos):
Solved sample problems of Concrete Properties:

Download Files: Read also: Share:

Follow our official Facebook page (@civilengineeringbible) and Twitter page (@CivilEngBible) and do not miss the best civil engineering tools and articles!