cement

CEMENT

                        One of the most important and widely acceptable construction material. The binding property of the cement makes the cement this much important. cement have both cohesive and adhesive property this property of cement is helpfull or desirable to bind the ingrediant of mortar and concrete.

         The cement was first time manufactured by "Joseph Aspdin". The name given by him to the cement is portland cement because the the texture of harden cement mass resembles the stone quary of portland area in england. 

Cohesive property

                                   It is the property of cement which binds the particles of same nature that is when cement particles gets binded with another cement particle the it is referred as cohesive property.

Adhesive property

                                       It is referred as the property of cement where cement particles get binded with the particles of different nature. for example when cement particles get binded with the sand particles then it is referred as adhesive property of cement.

   MANUFACTURING OF CEMENT

The cement is a composition of calcareous component and argilaceous component, where the calcareous component is the one which has rich content of calcium(Ca) eg- lime stone, chalk. whereas the argilaceous component is the one which has rich content of alumina and silica  eg-sand stone, blast furnace slag and fly ash etc...

   The cement can be manufactured by...

• Wet process ( old method )
• Dry process ( new metod )

                                     DRY PROCESS

• Grinding 

                      When the grinding of lime stone and stand stone is done in the absence of moisture the it is known as dry grinding and the grinder used for grinding is ball mill and tube mill, ball mill offers greater grinding capacity when compared to tube mill.

• Mixing 

                 The calcareous and argilaceous component i.e lime stone and sand stone are mixed in a ratio 3:1 respectively
      The strength of cement is majorly governed by the content of lime therefore lime stone is kept on a higher side with respect to clay or sand.

• Burning

               The burning of dry mix involves the burning in preheater and post heater ( rotary kiln )

    Preheater Tempreture is less than 800 c

                  It removes the moisture from raw mix.

                  It certainely reduces the size of raw mix.

                  It make the raw mix pre heated

    Postheater Tempreture is between 801-1500 c ( rotary kiln )

               generally rotary kiln is divided in 3 parts virtually 

            1. Dry zone ( temp. 801-1000 c ) 

            2. Nodules zone ( temp. 1001-1200 c)

            3. Burning zone ( temp. 1201-1500 c)

                             In dry zone if the process is wet process then the moisture is removed from the slurry it is less significant for dry process.

In nodules zone raw mix converted in nodules  (lumps).

                              In burning zone the calcareous and argilaceous component ingredient get reacted with each other at a temp. 1200-1500 c to form the compound called bouge's compound. and this bouges compound is responsible for binding strength in cement.

                              The product obtain from rotary kiln is called clinker which has property of quick setting which is referred as flash set property. In order to prevent quick setting gypsum is added to it about ( 3-4 % of weight of clinker) 

            and finally the clinker and gypsum is grinding together in tubemill or ballmill to get cement....   

                    

                                                 

Ground water recharging

                                                     By rain water harvesting and recharging pit

            Now a days, water scarcity is one of the major issue. And to fight with this problem we have to come together and giving technical solutions on this.

·       Introduction

                  Recharging pit is one the economical and feasible method of ground water recharging. Water is collected from the roof and allow to flow through the pipe (dia. 90mm) upto the recharge pit. Pit is made of such material which having high permeability (generally gravell of large size used at bottom and fine aggregates used at top), so water can percolate with high rate.

  

·       Advantages

1.       In 1000 sq feet area, per 100 c m rain about 1,00,000 liters of water recharge the ground water.

2.       If the water is converted in runoff the it can produces the problem of city road flooding, some time minor flood.

3.       Helps to maintained the water level in well, tubewell, in summer.

4.       Increases soil fertility.

5.       Reduces the chance of drought. And many more…..

·       Locality

            If the pit aims to recharge a borewell, it should be built as close to it as possible. Ideally it should be in the valley of the surface layout. Or it can be constructed anywhere away from any water pollution source.

  

·       Site identification

                  The site should have a sufficient clean and large catchment. It should also permit fast infiltration and percolation. And geological condition also supports the water percolation. Many factors affect the suitability of a site as an infiltration facility for the disposal of recharge pit. Among these, the following are most important : depth to groundwater, surface and underlying soil type.

·       Conveyance pipe

              Pipe is made up of chemically inert material like p v c. and of sufficient size to carry the water as per roof size. Proper arrangement should me made at inlet so the solid impurities can be filtered out at inlet.

·       Excavation

             The excavation should reach porous soil / weathered rock / fracture. Generally it happens from 6 to 8 feet deep. The diameter of the pit will depend on the catchment area and  the rate of percolation of the soil... It can vary between half a meter to 3 mete.

·       Filling of the pit

                    You need gravel of different sizes and sand for the top of the pit. The big gravel at the bottom. The smaller ones on the top of it will support the layer of sand. A mesh between the sand and the gravel will prevent the sand to escape below. Instead of the sand, you can put a layer of soil (leaves or planted earth). These materials will also filter the water. A supporting wall is made to reduce erosion of material. Splash pad is made for prevention of sand /soil erosion due to water pressure.

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  Finished recharge pit

 Final finish the pit for good ashtetic. It will look like the normal surface of the ground.