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What is the purpose of keeping tremie pipe’s tip immersed in freshly-placed concrete for about 1m in underwater concreting?

  What is the purpose of keeping tremie pipe’s tip immersed in freshly-placed concrete for about 1m in underwater concreting? The size of tremie pipe is about 300mm with sections having flange couplings fitted with gasket to prevent water leakage. The tremie pipe should be closed initially to prevent water from entering the pipe. It should be designed with sufficient thickness and weight so that it would not be buoyant when empty inside water. The placement of tremie concrete is commenced by putting the closed pipe underwater to the location for concreting, followed by partial filling of tremie pipe with concrete. In order to have tremie concrete flowed out of the pipe, it is necessary to fill the pipe with concrete of sufficient height to overcome the water pressure and frictional head. After that the tremie pipe is raised about 150mm to allow concrete to flow out. To enhance sufficient bonding, each succeeding layer of concrete should be placed before the preceding layer has reached
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What Is Fly Ash???Advantages Of Fly Ash

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WHAT IS FLY ASH??  Fly ash is a by-product of the combustion of pulverized coal in thermal power plants. The dust collection  system removes the fly ash, as a fine particulate residue, from the combustion gases  before they are discharged into the atmosphere. Fly ashes exhibit pozzolanic activity. The American Society for Testing and Materials (ASTM)  defines a pozzolan as “a siliceous or siliceous and aluminous material which in itself possesses  little or no cementitious value but which will, in finely divided form and in the presence of  moisture, chemically react with calcium hydroxide at ordinary temperature to form compounds  possessing cementitious properties.” Advantage of using Flyash 1) Improvement in durability. 2) Less heat of hydration. 3) Higher strength at later age. 4) Improvement in workability and cohesion. 5) Environment-friendly material. 6) Economy. Fly ash is tested as per IS 3812 & Requirements of IS code are as follows Physical requirements. For Siliceous fl
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What Is The Procedure Of STP WATER TESTING

  STP Water Testing. This procedure is applicable to check Quality of STP Water. 1.0 Purpose:   To Check Quality of STP Water using O- Tolidine, Universal    Indicator, Hardness A, B, & R.   2.0 Apparatus:   Measuring Jar 50ml capacity. 3 .0 Material:   STP Water, O- Tolidine, Universal Indicator, Hardness A, B, & R. 4.0 Procedure: 4.1 For Checking of Free Chlorine a) Take 10ml of S.T.P. water in a cylinder and add approximately 6 drops   of O- Tolidine to it. b)Shake the cylinder and observe the change in colour. c)Then match the colour with the PPM tube sample and note the PPM.   4.2 For Checking of pH a) Take 25ml of STP water in a cylinder and add 0.5ml of universal   indicator to it. b) Shake the cylinder and see the colour change. c) Match the colour change with the pH sample colour on the pH universal   indicator bottle. d) Note the pH in standard format. 4.3 Hardness Test a) Take 25ml of STP water in a cylinder and add a pinch of Hardne
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BLOCK MASONRY STEP BY STEP PROCEDURE...WHAT IS H/B RATIO

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BLOCK MASONRY Generally we are using in both residential and commercial buildings Hollow and Solid Block masonry as per site requirement.   Specification And General Guidelines For Block Masonry 1) Before starting any block work, prepare masonry layout on Typical Floor Plan  (Architecture Plan/ Chaapkam drg.). Thickness of each wall to be marked on plan in  different colours (Legend Type) and to be approved by the Project Incharge. Drawing is prepared before starting of first slab to put Electrical Conduits. 2. For H/B Ratio for less than or greater than 4 meter long masonry wall, the specs are given in below Para’s. 3. At the time of deciding the thickness of block for that particular wall, note that H/B ratio should not be greater than 20 for all walls less than 4 meter in length & for wall which is greater than 4 meter in length, H/B ratio should not be greater than 18. Where H = Height of block masonry and B = breadth of block masonry including plaster on both faces of block ma
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