civil engineer

       Vacuum concrete :- Vacuum concrete is the type of concrete in which the excess water is removed for improving concrete strength. The water is removed by use of vacuum mats connected to a vacuum pump. Ø Advantages of Vacuum Concrete :- Ø   The final strength of concrete is increased by about 25%. Ø   Sufficient decrease in The permeability of concrete is sufficiently decreased. Ø   Vacuum concrete stiffens very rapidly so that the form-works can be removed within 30 minutes of casting even on columns of 20 ft. high. Ø   This is of considerable economic value, particularly in a precast factory as the forms can be reused at frequent intervals. Ø   The bond strength of vacuum concrete is about 20% higher. Ø   The density of vacuum concrete is higher. Ø   The surface of vacuum concrete is entirely free from pitting and the uppermost 1/16 inch is highly resistant to abrasion. These characteristics are of spe...

              Saw dust concrete  :- The saw dust concrete is prepared by mixing Portland cement with saw dust in specified proportions in the concrete. It is used as a heat and sound insulation material.

       Cellular or aerated concrete :- It is prepared by mixing aluminium in the cement concrete. It is light in weight and spongy in structure. It is used for roof slab and precast unit in partition for heat and sound insulation. It also called air-entrained concrete. Ø Advantages:- a)     Workability of concrete increases. b)     Use of air entraining agent reduces the effect of freezing and thawing. c)     Bleeding, segregation and laitance in concrete reduces. d)     Entrained air improves the sulphate resisting capacity of concrete. e)     Reduces the possibility of shrinkage and crack formation in the concrete surface. Ø Disadvantages:- a)     The strength of concrete decreases. b)     The use of air entraining agent increases the porosity of concrete thereby reducing the unit weight. c)     Air-entrainment in...

       Light-weight concrete :- It is prepared by using coke-breez, cinder or slag as aggregate in the cement concrete. This type of concrete possesses high insulating property. Ø APPLICATION OF LIGHTWEIGHT CONCRETE:- a)     Decks of long span bridges. b)     Fire and corrosion protection. c)     Covering for architectural purposes. d)     Heat insulation on roofs. e)     Insulation of water pipes. f)      Filling for floor and roof slabs. g)     Construction of partition walls and panel walls in framed structures. h)    Production precast building blocks and low cost housing. Ø Advantage:- a)     It is governed primarily by economic considerations b)     Reduced Seismic Forces c)     Improved Structural Efficiency d)     Reduces the dead load of...

       Pre-stressed cement concrete :-   It is a cement concrete in which high compressive strength are artificially induced before its actual work. This type of concrete can take up high tensile and compressive stresses without development of crack. Ø    Advantages:- a)     Longer span length increases untroubled floor space and parking facilities. b)     Thinner slabs, that are important for high rise building as with the same amount of cost, it can construct more slabs than traditional thicker slabs.  c)     As the span length is larger, fewer joints are needed than traditional RC structures.  d)     Because of fewer joints, maintenance cost also becomes reduced during the design life as joints are the major locus of weakness in a concrete building. e)     Long-term Durability.  f)      Better finishing of placed...

1      Reinforced cement concrete :-   Reinforced cement concrete (R.C.C) is the combination of ordinary concrete with the reinforcement to increase its compressive and tensile strength to a great extent. Properties of R.C.C.:- a)       It should be capable of resisting expected tensile, compressive, bending and shear forces. b)     It should not show excessive deflection and spoil serviceability requirement. c)     There should be proper cover to the reinforcement, so that the corrossion is prevented. d)       The hair cracks developed should be within the permissible limit. e)       It is a good fire resistant material. f)      When it is fresh, it can be moulded to any desired shape and size. g)     Durability is very good. h)    R.C.C. structure can be designed to take any load Uses of R.C.C:-. It is a ...

1      Lime concrete :-   A concrete made from a mixture of lime, sand, and gravel is said to be as lime concrete. It was widely used before the lime was replaced by Portland cement. The lime concrete is cheaper and has less strength of plain cement concrete.