Posts

Important irrigation projects of India

Image
 There are numerous large irrigation projects have been established in for the agricultural development of India. In this article, we will mention the some important irrigation projects with their location and the service they provide. 1. Nagarjunasagar project (Andhra Pradesh) Location - across the river Krishna in Nalgonda district. Type - composite earth and masonry dam. Size - 4865 m long and 125 m high. Benefit - irrigates 8.3 lakh ha. 2. Godavari barrage (Andhra Pradesh) Location - across the river Godavari in East Godavari district. Type - barrage. Size - 3600 m long with 175 bays Benefit - irrigates 5.2 lakh ha. 3. Gandak project (Bihar) Location - across the river Gandak at Valmikinagar in Champaran district. Type - barrage, multipurpose scheme. Size - 740 m long. Benefit - irrigates 15.07 lakh ha in India and Nepal, 15,000 kW Power house as a gift to Nepal. 4. Ukai project (Gujarat) Location - across river Tapti in Surat district. Type - composite earth and ...

Why are the buildings made higher ?

Image
 In the modern era, a culture of higher building has been developed. All the big cities in this world have higher buildings in great numbers. Now, the question comes in our mind is that what is the need of higher building ? Why we are frequently constructing high rise buildings?  With the development of our cities, it became a need to accommodate the city's population. This need promotes the city to grow horizontally as well as vertically. The construction of higher buildings is the part of this development. In this article, we will talk about causes and effects of Higher building.  Before talking about higher buildings, we need to understand the term 'urban sprawl'. Urban sprawl means outwards expansion of city. The cities for which space is not an issue, urban sprawl is an easy solution for a growing population. but we can't leave the cities to expand outwardly. It has adverse effects on the environment as well as on the society. Urban sprawl requires a large network ...

Why is the false ceiling becoming popular ?

Image
 False ceiling is continuously getting a popularity these days. Installing a false ceiling was the part of offices, hotel, auditoriums, meeting halls and other public gathering places before. But in recent years it has become popular in residential building and also a symbol of modernity. False ceiling is the ceiling which is established below the traditional one. It is hung below the traditional ceiling. It is the part of finishing not the part of construction. It is the matter of appearance not of strength. False ceiling may be of various types - Gypsum false ceiling, plaster of parish false ceiling and wood ceiling etc. Among these types, gypsum board ceiling is more common. But why is the false ceiling becoming popular ? False ceilings are becoming popular due their efficacy, which they carry.  Installing a false ceiling is an easy task with suitable tools. It hides the wiring components and gives a clear look to the ceiling. In case of ceiling, it is easy to dismantle an...

Ultrasonic pulse velocity test

Image
  Ultrasonic pulse velocity method is an non-destructive test which is used to determine the compressive strength of concrete structure without any damage. This method consists of measuring the time of travel of and ultrasonic pulse passing through the concrete to be tested. In this method, A pulse generator circuit is used which consists of electronic circuit and transducer. Electronic circuit generates pulses and transducer transforms it into mechanical energy having vibration frequencies in the range of 15 to 50 kHz. The time of travel between initial onset and the reception of the pulse is measured electronically. The path length between transducer divided by the time of travel gives the average velocity of wave propagation. When mechanical impulses are applied to a solid mass, three different kinds of waves are generated - longitudinal wave, shear wave and surface wave. The longitudinal waves travel about twice as fast as the other two types. The shear waves are not so fast,...

Shrinkage of concrete - Plastic, Drying and Thermal shrinkage

Image
 Shrinkage of concrete means volumetric change in concrete which affects the long term strength and durability of concrete. It is an inherent property of concrete. It appears in form of cracks.   Shrinkage of concrete is classified in three category - Plastic shrinkage Drying shrinkage Thermal shrinkage Plastic shrinkage - This type of shrinkage occurs when concrete is in plastic stage or we can say it occurs just after the concrete is placed. Plastic shrinkage takes place due to loss of water by evaporation or absorption by aggregate. poorly made concrete with high water - cement ratio. unintended vibration or yielding of formwork. extreme bleeding at the same time rapid drying. Plastic shrinkage crack can be reduced by preventing the rapid loss of water on surface. This is done by covering the surface with polythene sheet after placing the concrete immediately. by working at night. by applying mono-molecular coating by fog-spray. Drying shrinkage - After placing the concre...

Bogues compounds and their properties.

Image
 When water is added to the cement, its ingredients react to each other with the help of water and forms some complex chemical compounds . These complex compounds are called Bogues compound. They are - Di - calcium silicate Tri - calcium silicate Tri - calcium aluminate Tetra calcium alumino Ferrite Properties of Bogues compound - C3S -  It is having faster chemical reaction with greater heat of hydration as compared to C2S. It is responsible for maximum strength of cement. It contributes in strength from 24 hours and last upto 28 days, where maximum contribution due to C3S last upto 14 days. In rapid hardening cement, C3S containing is more as compared to OPC. C2S - It is having slow hydration and less heat of hydration. It imparts more contribution in later days strength. (14 days to 28 days) It is more stable compound than C3S. C3A - It is responsible for faster chemical reaction and very high heat of hydration. It contributes in strengths of 24 hours. Flash setting prope...

Dry process of manufacturing Portland cement

Image
 There are two process of manufacturing cement - 1) Dry process and 2) Wet process.   In dry process, water is not mixed with raw materials during manufacturing process while in wet process, mixing of water takes place while manufacturing.   The raw materials used for manufacture of Portland cement are calcareous materials like lime stone and argillaceous materials like clay . Dry process of cement includes following steps :- The raw materials are first reduced in size of about 25 mm in crushers. A current of dry air is then passed over these dried materials. These materials are then pulverized into fine powder in ball mills and tube mills.  All of the above operations are done separately for each raw material and they are stored in hoppers. They are then mixed in correct proportions and burned in a rotary kiln at a temperature of about 1300 - 1500 degree celsius. In the kiln, the materials sinter and then they gets fused to form nodular shaped clinker.  The cli...