Thursday, June 26, 2014

What is Portland cement?

10:41 PM | Posted by | | Edit Post
                                                         Portland cement

      Portland cement is chemically defined as finely ground mixture of Calcium Aluminates and Silicates of varying compositions which hydrates when mixed with water to form a rigid solid structure  with good compressive strength.

      The name Portland cement came from Portland Rock (Stone) of England. 

            

                     Composition

         1.   2 CaO.SiO2 = Dicalcium Silicate (C2S) [54%]

         2.   3 CaO.SiO2 = Tricalcium Silicate (C3S) [16.6%]

         3.   3 CaO.Al2O3 = Tricalcium Aluminate (C3A) [10.8%]

         4.   4 CaO.Al2O3 Fe2O3= Tetracalcium Alumino   Ferrite (C4AF) [9.1%]

         5.    MgO  [1.5%]

         6.    CaO
                   Special types of cement 

  •      White Cement

      The color of the ordinary Portland cement is grayish black due to the presence of iron oxide  as one of the constituents. If iron oxide can be avoided  by suitable selection of raw materials it is possible to get white cement
 
  •         Sulphate Resistant Cement

      This is a cement with higher C2S/ C3S ratio can resist sulphate attack and corrosion by sea water
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Monday, June 16, 2014

Rcc estimate

12:36 AM | Posted by | | Edit Post


                  100 cft  Rcc estimate


                     rcc slab things = 6 "
          
  •  Concrete mixing ratios = 1:2:4
  •  Total ratios = 1 + 2 + 4 = 7
  •  Concrete mixing dry material = 100 × 1.54 = 154 cft
  • Cement = 154 ÷  7 × 1.25    = 17.6  ≈ 18 bag
  • Sand  =154 × 2 ÷ 7    = 44 cft
  •  Concrete  = 154 × 4 ÷ 7   = 88 cft / Brick = 88 × 9 =792 no’s
     Note :- [1 bag cement = 1.25  cft]  [ 9 Brick = 1  cft concrete]  
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Saturday, June 14, 2014

History of Bricks part-2

4:02 PM | Posted by | | Edit Post


    The Manufacturing Process of Bricks


  •  Grinding, sizing and combining raw materials
  •  Pug milling
  •  Extruding
  •  Chamfering the brick 
  •  Coating/coloring
  •  Drying 
  •  Firing
  •  Cooling
  •  Quality control
  •  Store/stacking  
         
             Selection of raw materials

  • Soil: In this study, soil was collected from one of the country kiln brick field (M/s. Habibur Rahman Bricks & Co.) at Ashulia, Savar. The characterization tests to identify the composition of the soil sample and other tests such as grain-size distribution, plastic limit, liquid limit of the representative raw soil sample were done at HBRI laboratories.
  • Fluxing material: Bottle glass, sheet glass and tube light bulb. 
                                                           Grain-size distribution, plastic limit and liquid limit of soil sample


      Grainsize analysis                      Liquid limit and plastic limit  
        
          Clay  -  24%                              Liquid limit  - 44.80
          Silt    -  74%                              Plastic limit  - 30.00
          Sand  -   2%                               Plastic index - 14.80 


Properties of bricks (HOS brand) produced by country kiln  

Compressive strength and water absorption of 4 numbers of burned bricks (HOS brand) produced in the country kiln at Ashulia where from stock soil was collected for the
Purpose of project study was tested in the laboratory and the results are presented in the following Table. 

Quality of bricks produced in the country kiln at Ashulia, Savar 


 
Sample No.
Compressive strength (psi)
Water absorption (%)
1
1198
19.3
2
1740
18.5
3
3141
16.2
4
2168
14.3
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