Division 3 to 7

• BUILDING MATERIALS
• Facility Construction Subgroup

  • GENERAL REQUIREMENTS
  • EXISTING CONDITIONS
• CEMENTING MATERIALS
• Lime

  Calcium and magnesium carbonates
• Historical Usage of Lime

  • Egyptians: Lime plaster before 2600 B.C.
  • Greeks: Extensive use for mortars and plasters.
  • Romans: Developed lime putty and volcanic ash mixture for early cement.
• Manufacturing Process of Lime

  1. Calcination of limestone

  2. Carbonates decompose into carbon dioxide and quicklime (calcium oxide, CaO)
• Preparation of Lime

  Quicklime must be mixed with water in the slaking or hydration process
• Hydration of Lime

  Quicklime + Water → Calcium Hydroxide (slaked lime or hydrated lime, Ca(OH)2)
• Applications of Hydrated Lime

  • Ingredient in hard-finish coat for two-and three-coat Portland cement plasters
  • Mixing with cement mortar or concrete for increased workability, decreased permeability to water, reduced cracking due to shrinkage
• Hydraulic Lime

  Lime type that sets underwater, used for slow underwater setting requirements
• Plasticity Enhancement

  Addition of hydrated lime renders gypsum plaster more plastic
• Cohesiveness Improvement

  Fiber or hair is sometimes added for greater cohesiveness
• Fiber Types

  • Hemp, sisal, or jute fibers
• Hair Types

  • Cleaned goat or cattle hair
• Roman Development of Cement

  Romans mixed slaked lime with pozzolana (volcanic ash), creating a hydraulic cement that hardened underwater
• Englishman Smeaton rediscovered hydraulic cement

  1756
• English bricklayer and mason Aspdin invented and patented Portland cement

  1824
• Portland Cement

  Today, "cement" typically refers to Portland cement, the principal type in use
• Manufacturing Process of Portland Cement

  Obtained by finely pulverizing clinker produced from calcining a mixture of argillaceous (silica, alumina) and calcareous (lime) materials with iron oxide and other ingredients
• Types of Portland Cement

  • Slow-setting cement
  • Quick-setting high early strength cement
  • Sulfate-resisting cement for applications with alkaline water and soils
  • White cement (or stainless cement) free of iron impurities
• STORAGE OF CEMENT
• Protection from Dampness

  Cement should be shielded from dampness at the building site
• Storage Conditions

  Stored in a shed with a wood floor raised about 300mm (12") from the ground
• Inspection for Moisture Damage

  Cement should feel soft and silky to the touch, presence of lumps that do not readily break indicates moisture absorption, which can be damaging
• Prompt Usage

  Cement should be used as soon as possible after delivery to prevent moisture damage
• Pile Height Limitation

  Piles of cement should be limited to twelve sacks in height to prevent pressure-induced hardening of lower layers
• Warehouse Set Prevention

  Avoid storing cement in high piles for extended periods to prevent hardening of lower layers due to pressure
• Definition of Concrete

  Proportioned mixture of cement, aggregate, and water
• Properties of Concrete

  • Plastic mass can be cast, molded, or formed into predetermined size or shape
  • Upon hydration, it becomes stone-like in strength, hardness, and durability
• Setting

  Hardening of concrete
• Variants of Concrete

  • Mortar, Stucco, Or Cement Plaster
  • Concrete
  • Reinforced Concrete
  • Plain or Mass Concrete
• Qualities of Good Concrete

  • Strength
  • Durability
  • Uniform Quality
  • Thoroughly Sound
• Achieved Through

  • Careful Material Selection
  • Correct Proportioning
  • Thorough Mixing
  • Careful Transporting and Placing
  • Proper Curing or Protection
• MATERIALS OF CONCRETE
• Usual Tests for Cement

  • Soundness (constancy of volume)
  • Time of setting
  • Fineness
  • Tensile strength
• Cement Quantity per Bag

  Approximately 1 cu. ft., weighs 94 lbs
• Recommended Cement for Reinforced-Concrete Construction

  High-grade Type 1 Portland cement (ASTM C-150)
• Fine Aggregates

  • Smaller than 6mm / ¼" in size, consist of sand, stone screenings, or similar inert materials, specifications: 80-95% pass No. 4 wire cloth sieve; 10-30% pass No. 50 sieve
• Coarse Aggregates

  • Larger than ¼" in size, consist of crushed stones, gravel, or similar inert materials, should be well graded and not exceed 25mm / 1" in size for reinforced beams, floor slabs, etc.
• Special Aggregates

  • Cinders, blast furnace slag, etc., can produce lightweight or thermal insulating concrete