Unit-1 Lecture-7- Light Weight Construction Materials by Brig. S.K. Sharma - PowerPoint PPT Presentation

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Unit-1 Lecture-7- Light Weight Construction Materials by Brig. S.K. Sharma

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Title: Unit-1 Lecture-7- Light Weight Construction Materials by Brig. S.K. Sharma


1
UNIT-1LECTURE - 7
  • LIGHT WEIGHT CONSTRUCTION MATERIALS
  • Brig. S.K. Sharma (Retd.)
  • Pro Vice Chancellor and Professor Department
    of Civil Engineering,
  • The Northcap University, Gurgaon

2
INDEX
  • WASTE MATERIAL BASED CONCRETE
  • INDUSTRIAL WASTES

3
  • INDUSTRIAL WASTES
  • Some of the industrial by-product wastes can be
    profitably used in the concrete construction
    industry which requires large quantities of low
    cost raw materials. This utilization offers
    triple benefits, namely, conservation of
    fast-declining natural resources, planned gainful
    exploitation of waste materials and release of
    valuable land for more profitable use.
  • The most influential factor that dictates the
    utilization of industrial by-products is the
    economic cost in comparison to the conventional
    materials that would have been otherwise used.

4
  • BLAST-FURNACE SLAG Large quantities of slag are
    generated during the production of iron and
    steel. Granulated or foamed or dense
    blast-furnace slag can be produced depending on
    the rate and manner of cooling the molten slag.
    The granulated slag can be used in the
    manufacture of slag cements. Blast-furnace slag
    cements contain slag up to 60 per cent, hence
    there is considerable reduction in the rate of
    heat evolution and a significant increase in the
    resistance to chemical attack. For the same
    reasons, these cements can be advantageously used
    in mass concrete, and for high chemical
    resistance in marine structures. The dense
    air-cooled slag aggregate may be used as a
    replacement of natural aggregate in concrete. On
    the other hand, foamed blast-furnace slag, a
    lightweight aggregate, is mainly used for block
    making and insulating roofs and floor screeds and
    is suitable for structural reinforced concrete.

5
  • COAL ASH FROM POWER STATIONS The main by-product
    is fly ash or pulverized fuel ash which is the
    fine dust carried upward by combustion gases and
    collected in wet scrubbers and electrostatic
    precipitators. The bulk ash which is greyish in
    color becomes darker with increasing proportions
    of unburnt carbon. It is used as a cement
    replacement. The contribution of fly ash to the
    strength of concrete has been attributed to
  • Direct water reduction.
  • Increase in the effective volume of paste in the
    mix
  • Pozzolanic reaction
  • However, fly ash reduces the rate of development
    of strength and increases drying shrinkage. Since
    the early strength of fly ash concrete is less
    than that of Portland cement, its proportion is
    generally limited to 30 per cent in the
    situations where early strength is important. The
    low rate of heat evolution makes fly ash useful
    in mass concrete.

6
  • SILICA-FUME CONCRETE Silica-fume is a by-product
    of the reduction of high purity quartz with coal
    in electric arc furnaces in the production of
    ferro-silicon metal. Because of its extreme
    fineness and high glass content, Silica-fume is a
    very efficient pozzolanic material i.e., it is
    able to react efficiently with the hydration
    products of Portland cement in concrete.

7
  • Silica-fume in concrete can be used for the
    following purposes
  • To conserve cement
  • To produce ultra high strength concrete
  • To control alkali-silica reaction
  • To reduce chloride associated corrosion and
  • sulfate attack
  • To increase early age strength of fly ash/slag
  • concrete.

8
  • SHOTCRETE OR GUNITING
  • Shotcrete is mortar or very fine concrete
    deposited by jetting it with high velocity
    (pneumatically projected or sprayed) on to a
    prepared surface. The system has different
    proprietory names in different countries such as
    Blastcrete, Blowcrete, Guncrete, Jet-crete,
    Nucrete, Plneukrete, Spraycrete, Torkrete, etc.
  • Shotcrete has wide applications in different
    constructions, such as thin over-head vertical or
    horizontal surfaces, particularly the curved or
    folded sections canal, reservoir and tunnel
    lining swimming pools and other water-retaining
    structures and prestressed tanks. Shotcrete is
    very useful for the restoration and repair of
    concrete structures, fire damaged structures and
    waterproofing of walls.

9
  • Shotcrete has also been successfully used in the
    stabilization of rock slopes and temporary
    protection of freshly excavated rock surfaces.
    Its utility has been proved for protection
    against long-term corrosion of piling, coal
    bunkers, oil tanks, steel building frames and
    other structures as well as in encasing
    structural steel for fireproofing.

10
  • TYPES OF SHOTCRETING
  • DRY MIX PROCESS In the dry mix process, the
    mixture of cement and damp sand is conveyed
    through a delivery hose pipe to a special
    mechanical feeder or gun called delivery
    equipment. The mixture is metered into the
    delivery hose by a feed wheel or distributor.
    This material is carried by compressed air
    through the delivery hose to a special nozzle.
    The nozzle is fitted with a perforated main fold
    through which water is introduced under pressure
    and intimately mixed with other ingredients. The
    mortar is jetted from the nozzle at high velocity
    on to the surface to be shot crated. The
    water-cement ratio should be between 0.33 and
    0.50.
  • Video
  • CD Waste (Construction Demolition) Recycling
    Process - 351 min
  • Construction waste crusher, construction waste
    disposal equipment 410 min
  • Inground swimming pool building process - step by
    step 3121 min
  • Bridge Repair, Gunite, Shotcrete, Concrete
    Repair, Cyclone Gunite Machine Demonstration
    736 min

11
  • Thank You
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