BDCS 1 (conc & masonry)

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BDCS 1 (conc & masonry)
2014-08-01 22:19:20

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  1. Laitance
    chalky white surface deposite of low strength
  2. concrete is strong in...
    • compression
    • weak in tension
  3. hydration
    chemical reaction, rather than drying out of the mix, that causes hardening of concrete
  4. portland cement type I
    • standard concrete
    • for general all-purpose use
  5. portland cement type II
    • modified concrete
    • for slow setting and less heat
  6. portland cement type III
    • high early strength concrete
    • for quick setting and early strength
  7. portland cement type IV
    • low heat concrete
    • for very slow setting (little heat)
  8. portland cement type V
    • sulfate resisting concrete
    • for alkaline water and soils
  9. types of admixture
    • accelerators
    • air-entraining agents
    • retarders
    • waterproofing
    • water-reducing
    • workability agents
  10. accelerators admixture
    • calcium chloride
    • speed up setting time
  11. air-entraining agents admixture
    • resins, fats, and oils
    • resist freezing action
  12. retarders admixture
    • starches, sugars, and acids
    • slow down setting time
  13. waterproofing admixture
    • stearate compounds
    • decrease permeability
  14. water-reducing admixture
    • organic compounds
    • reduce water content
    • decrease the permeability of the concrete
  15. workability agents admixture
    • powdered silicas and lime
    • improve workability
  16. ready-mix concrete
    mixed completed at a central mixing plant and transported to the site in a agitator truck with revolving chamber
  17. transit-mixed concrete
    completed in the truck mixer
  18. reinforcement bar sized
    • #3 (3/8" dia) thru #11 (1-3/4" dia)
    • and #18 (2-1/2" dia)
  19. ASTM A615
    billet steel
  20. ASTM A616
    rail steel
  21. A617
    axle steel
  22. ASTM A706
    low-alloy steel
  23. most common designation for reinforcing bars
    ASTM A615 Grade 60
  24. grade designation
    • grade 40, 50, 60, and 75
    • min specified yeild strength 40,000, 50,000, 60,000, and 75,000
  25. WWF 6x6 - W2.9 x W2.9
    welded wire fabric with wires at 6" on center in each direction, with each wire havign a cross-sectional area of 2.9/100 or 0.029 square inches (which is 6 gauge wire)
  26. lightweight concrete
    90 to 115lbs per cubic foot
  27. slump test
    measures consistency and workability
  28. cylinder test
    measures compressive strength of concrete and utilizes standard test cylinders 6" in dia and 12" long
  29. soft mud process
    uses molds into which moist clay is pressed by hand or machine into rectangular molds
  30. stiff mud process
    • widely used
    • forces the mixture through a die, extruding a clay ribbon that is cut into bricks by tightly stretched wires
  31. Grade SW brick
    • severe weathering
    • used in areas of heavy rain, snow, or continual freezing
  32. Grade MW brick
    • moderate weathering
    • used in areas of average rain and moderate freezing
  33. Grade NW brick
    • no weathering
    • used in areas of minimal rain and no freezing, as in sheltered or indoor locations
  34. Grade FBX brick
    • face brick
    • high degree of mechanical perfection, narrow color range, and min size variations
  35. Grade FBS brick
    • face brick
    • greater size variation and wide color range
  36. Grade FBA brick
    • face brick
    • nonuniform in size, color, and texture
  37. Grade HBX brick
    • hollow brick
    • high dregree of mechanical perfection, min size variation, and narrow color range
  38. Grade HBS
    • hollow brick
    • greater size variation and wide color range
  39. Grade HBA brick
    • hollow brick
    • nonuniform in size, color and texture
  40. backup brick
    inferior brick used behind face brick
  41. paving brick
    very hard and dense brick used in pavements
  42. fire brick
    brick made with greater resistance to high temperatures, as in a fireplace
  43. adobe brick
    brick made from a mixture of natural clay and straw, placed in molds, and dried in the sun. requires protection from rain and subsurface moisture
  44. nail-on brick
    flat brick generally used on interiors where solid masonry cannot be structurally suported
  45. hollow brick
    brick whose net cross-sectional area is at least 60% of its gross cross-sectional area
  46. bed
    top of a brick
  47. cull of brick
    end of the brick
  48. gypsum block
    • gypsum tiles
    • solid or cored units manufactured from gypsum plaster
    • avialable in 2 to 6 inches, in standard panels 12x30 inches in size
  49. rough stone
    • fieldstone
    • natural stone used decoratively
  50. rubble stone
    irregular stone with at least one good face used for ashlar veneers, copings, sills, curbs, etc
  51. dimension stone
    cut stone, used for surface veneers, toilet partitions, flooring, stair treads, etc.
  52. flagstone
    thin slabs used for paving, treads, countertops, etc.
  53. monumental stone
    used for sculpture, monuments, gravestones, etc.
  54. crushed stone
    used as aggregate for concrete, asphaltic concrete, terrazzo, built-up roof surfacing, etc. as well as granular fill
  55. stone dust
    used as filler in asphalt flooring, shingles, paints, etc.
  56. portland cement
    • binding agent of concrete
    • made from lime, silica, iron oxide, and alumina
  57. fly ash
    • waste material obtained from coal-fired power plants
    • used in concrete to increase strength, decrease permeability, reduce temperature rise, increase sulfate resistance, and improve workability
    • can also be used to decrease the amout of cement needed
  58. autoclaved aerated concrete (AAC)
    • precast concrete product manufactured by adding aluminum powder to concrete, hardening it in molds and then curing the molds in a pressurized steam chamber (autoclave)
    • typ in blocks of 10in high by 25in long and 4in,8in,10in thick
    • laid with thin mortar
  59. self-consolidating concrete (SCC)
    • concrete mixture that can be placed purely by means of its own weight without the use of vibration
    • made possible by use of a superplasticizer admixture called a polycarboxlylate polymer
  60. carbon fiber concrete
    • uses epoxy-coated carbon fiber mesh in place of standard steel mesh for secondary steel reinforcement
    • used for precast panels, to make them thinner and lighter
    • less concrete is required because carbon fiber is noncorrosive
  61. calcium chloride test
    • aka moisture dome test
    • most common tests for moisture in concrete and is inexpensive and easy to complete
  62. hygrometer test
    • aka relative humidity test
    • determines the moisture emission by measuring the relative humidity of the atmosphere confined adjacent to the concrete floor
  63. polyethylene sheet test
    • qualitative test conducted by sealing an 18inX18in sheet of plastic to the floor to trap excessive moisture for 16hrs
    • visually inspected
  64. mat test
    • similar to poythylene sheet test
    • uses 24inX24in sheet for 72hrs
  65. electrical impedance test
    • uses proprietary meters to determine the moisture content of the concrete by measuring conductance and capacitance
    • probes of the meter are placed on the concrete and percentage of moisture content in the slab is read out directly
  66. pH levels
    • from 0 to 14, below 7 is acidic
    • concrete should be tested for pH levels
  67. alkali-silica reaction (ASR)
    • process strongly alkaline cement begins to dissolve sand and rock within the concrete
    • chemical reaction produces a gel-like material that creates tremendous pressures in the pores of the concrete surface
    • pressure can buckle or blister the floor finish
    • can be avoided by using aggregates not susceptible to ASR, by using low-lime cement, by prorper curing, or by not finishing the concrete with a hard trowl surface
  68. titration test
    used to determine the level of alkalinity in concrete
  69. construction joint
    occurs wherever there are 2 successive pours; that is, wherever there is a new pour against a cured section of concrete
  70. mortar
    mixture of cement, lime, sand and water
  71. masonry cement
    prepared mixture of portland cement and pulverized limestone
  72. types of mortar
    M, S, N and O
  73. efflorescence
    • white, crysalline deposit of water-soluble salts on the surface of brick masonry
    • caused when water seeps into the masonry and dissolves soluble salts present in the masonry, backup wall, mortar or anything in contact with the wall