Category Archives: Construction

New Dam For Tibet

One of the biggest hydro-electric projects worldwide may be built on the upper parts of the Tibetan Tsangpo-Brahmaputra river. Lobbyists in China are pushing for this dam to be constructed to have access to the renewable energy in the Himalayas, despite the concerns of Bangladesh and India downstream which use the river for power and water.

The deputy general secretary Zhang Boting of China’s Society for Hydropower Engineering indicated that the construction of a huge dam located on the bend of the Tsangpo-Brahmaputra river would help the world because it may prevent 200m tonnes of carbon from being produced per year. 200M tonnes is equivalent to 1/3 of the United Kingdom’s CO2 emissions. He further commented that for the sake of the world every water resource that can be developed should be developed.

Zhang stated that only research has been done on the project. However, a government agency’s website has documents indicating that China is considering the massive 38 gigawatt hydropower facility. The facility would be over half the size of the Three Gorges dam and possess almost half the capacity of the United Kingdom’s electrical grid.

Professor Tsering of the University of British Columbia said that the huge facility will be 1 of 28 dams already built or planned to be built. He published a map of the proposed dam locations and a State grid map of China’s future transmission lines at http://tibetanplateau.blogspot.com.

The grid map transmission lines appear to lead from a 38 gigawatt hydropower facility in the remote Motuo area along the Tsangpo-Brahmaputra river to the current Chinese power supply. Professor Tsering has cited newspapers reporting survey teams looking through the region, although the government has denied any plan exists.

China has publicly stated that it is planning to construct 5 dams upstream such as the 500MW hydropower in Zangmu, being built by the Huaneng power company. Professor Tsering believes the largest dam will be at Motuo at the river’s bend. The construction would require tunnels, reservoirs, piping and turbines to access the 2,000-metre drop in the river as it winds down towards India’s border.

At an important Chinese science forum, secretary Zhang indicated that the Tsangpo-Brahmaputra river dam may produce as much electrical power as the entire amount of gas and oil from the South China sea. He said that further delays would let India gain access to the river’s resources and may reignite territorial disputes.

China and India have made an agreement to exchange information on hydropower plans regarding the Tsangpo-Brahmaputra river to reduce possible conflicts. Still, the Indian press continues to publish concerns about China channelling the water away from India’s northern dry plains. Professor Tsering disagrees because the natural laws of physics would prevent it and the purpose of the dam would be limited to the production of hydropower.

The Steps Involved In A Road Construction Project

There are many steps involved in the road construction process, involving many teams of people and much organization. From the use of a surveying company to handle land surveys to project managers, there are a large number of people involved. The steps must be carefully followed to ensure a successful project is completed.

Yes, it often seems that we are plagued with construction projects, especially in those states where the weather stays relatively nice year round. While construction is a daily part of life, if we stop to consider how difficult it is just to plan the process, we might find it to be less of a hassle and more of an important part of life.

Plan
The first step to a good construction process is to identity the needs of the transportation in the area and of the road. Teams must thoroughly examine the road and define the project in order to get buyoff from the appropriate officials. Make sure the project selected is going to actually enhance the roads.

Design
After a plan is defined the design can be constructed. This is where a boundary or land surveyor may come in, especially in the event of a new road being developed or lanes being added to an existing road. If additional property must be purchased or arranged that would enter into this phase, as would any review of environmental concerns or land in the area that might be impacted by the project. Once the design plans are completed then bids for work can be solicited and awarded.

Construct
The construction begins and drivers begin to grumble. However, even the times of day that construction takes place and any detours that need to be set up have to be considered. If the road is a busy one or if the construction is taking place on a highway then it is very essential that construction companies take into consideration when rush hours are in the city and when the least amount of people will be inconvenienced. Once completed, the project is wrapped up and the road is again open to travel.

Maintenance
Although the project may be completed, the work is never done. Proper maintenance and observation must be done to ensure that the road stays in proper working order. When a road is traveled on extensively it can seem that it is always wearing down. Proper analysis must be done of the road to keep it in working order.

Each state may have different rules and regulations regarding the construction process. From start to finish, it is essential that each piece of the construction puzzle is done right. The last thing any contractor wants is the reputation of taking forever, making drivers upset and creating roads that need to be immediately fixed again. When assembling a team to begin and complete a large scale construction project, it is essential to develop a team that will work well together and will provide excellent service. Its true that the construction process can be difficult to understand from the perspective of an angry driver. All we see are delays and frustration. However, take a moment to consider the immense planning and people involved in the process to making our roadways safe, secure and drivable.

Construction Company Qatar, Constructions Companies In Qatar

A construction company in Qatar may have specialization in a particular aspect of the construction process or may have complete resources to finish the entire project, from design to build, all on its own. It is often a good idea to hire a company that is capable of finishing a project from the start to the end. This helps minimize the cost involved and meet the deadlines defined at the planning stage.

However, in cases when you need to restore or remodel an existing building structure, you would probably require a firm specialized in certain aspects of the construction process. It helps to have a list of companies that have different specializations and also those that can offer all construction-related services under one roof. A Yellow Pages directory is the place where you are likely to find information on such construction companies in Qatar.

From a small house to a large-scale industrial edifice, or an infrastructure-related project, the constructions companies are able to provide services to a variety of clients and for a variety of purposes. They are also one of the largest employers of people of various skills.

Architects, interior designers, civil engineers, project managers, quantity surveyors, building services engineers, structural engineers, and supervisors are some of the skilled groups of people that necessarily comprise a constructions company in Qatar. A construction project also requires the help of people like contractors, plumbers, building material suppliers, landscape designers, electrical engineers, financial advisers, legal specialists, and many more to take the final shape.

The industry comprising the various groups of companies and people who contribute to the successful development of a construction project in Qatar is expected to get a further boost in the coming years. The reason for this is the fact that the country has been chosen as the host nation for the FIFA World Cup 2022.

This is the first time that any Middle East country is given an opportunity to organize such a large-scale sporting event of the world. It is an honor to be able to get this opportunity, but at the same time, the pride of the nation is at stake. It is a great responsibility to fulfill the expectation of the global community and the people of the country will leave no stone unturned to make this happen.

We can expect to see an unprecedented surge in all sorts of construction activities across all corners of the country. This makes the role of a construction company in Qatar extremely important. All big or small construction companies in Qatar share the responsibilities to speed up their activities with quality deliveries and bring a substantial change in the sporting as well as the general urban infrastructure in Doha and other cities, in tune with the international standard.

The expectations are high, but the construction companies in Qatar have means and resources to meet these expectations well before the deadlines reach. Yellow Pages industry plays its own role of giving enough exposure to the constructions companies that have operational bases located in Qatar. One can find an elaborate listing of these companies and firms in one of the best online business directories in Qatar known as yellowpageqatar.com.

For more details about Construction companies please visit on http://www.yellowpageqatar.com

Insurance Inspection Company Performs Loss Control Inspections

Insurance Inspections are a mandated part of obtaining insurance coverage for commercial properties and residential properties alike. Insurance Inspection Companies provide these inspection services on behalf of the Insurance Company whos providing the insurance coverage for the property owner. These insurance inspections, also known as loss control inspections, field inspections and loss control surveys, are performed by insurance inspectors to ensure that the property being insured is safe for the insurance coverage and to try an attempt to prevent any losses on behalf of the building owner, insurance company and any persons who are occupying or visiting the premises.

Typically, these inspections are performed for property and casualty policies, but also are performed for general liability, workers compensation, construction job sites for contractors insurance coverage, product liability, business owners policies, manufacturers and contractors, garage operations, auto fleet coverage, mixed use property, liquor liability, homeowners insurance, restaurant coverage, day care centers, houses of worship and vacant properties.

In order to minimize their potential risk exposure, an insurance company will request that the loss control inspection is conducted by the inspection company. The term “insurance inspection” is typically associated with an inspection that occurs after a loss occurs, for example, after a commercial property has a loss from a fire, someone trips over a broken sidewalk or when someone is hurt while working, i.e. workers compensation. Loss control inspections are on the complete opposite end of the spectrum, as they are performed in an attempt to avoid any of these losses.

After the inspection is requested by the insurance company, the loss control company will assign it to one of their inspectors to perform the inspection. An inspection request will provide the needed information such as the address of the property, the type of insurance coverage, the insureds name and contact information, the policy number, as well as the insurance brokers information and general agents information in case the insured cant be reached to schedule the inspection.

The insurance inspector will then contact the insured and schedule the inspection. The type of coverage being provided will determine how long the inspection takes, what type of inspection report is provided and what areas of the property are being inspected. For example, a commercial property being covered for property and liability coverage will consist of the inspector inspecting the construction type and condition of the property, the exterior features such as the roof type and condition, sidewalk condition, interior and exterior walkways, type of heating, emergency lighting, type and percentage occupancy, etc.

The loss control inspector will provide the insurance inspection company with the completed report in the form of a narrative, checklist, recommendations, supplements and photos, which is then reviewed by the inspection company to make sure there are no errors within the report before sending it over to the insurance company. If recommendations are found during the course of the inspection, it is up to the insurance company to decide if these recommendations need to be complied with. In the case that there are mandatory recommendations that need to be complied with, the inspection company will send out an inspector to check to see if the recommendations were complied with. An additional report is provided to the insurance company, usually including photos that the inspector took while out in the field.

Insurance inspections are an essential part of the insurance process that often gets overlooked, unless youre one of the parties involved. Insurance Inspection Companies play a vital role in between the insurance company and the property owner, ensuring the safety of all parties involved and reducing the risk of the insurance company, thus performing loss control inspections.

Eddie Bauer Bassinet – Style And Comfort For Your Baby!

Thinking of investing in an Eddie Bauer bassinet? Did you know that you’re about to make a very sound investment? Eddie Bauer has been in the business of baby accessories since 1920. Since then, it has developed a reputation for building accessories that are safe, durable and comfortable. They have a very exciting variety of bassinets that are easy to assemble and come with a wide range of features.

Something For Everyone

While some parents prefer to go for simple bassinet styles, there are those who like to provide those little extras to their little ones! The Eddie Bauer line of bassinets has something for every kind of taste and price range. For example, the Eddie Bauer Newport Musical Bassinet comes with five songs as well as a gentle vibration option. While the bassinet does rock, it has a lock out feature as well. The bassinet also comes with washable bedding that you can easily remove as well as a small nightlight. Four locking wheels allow you to push the bassinet wherever you like!

For those who are looking for something simple but stylish, Eddie Bauer has a range of classic bassinets that come in wood finishes like Cherry and Oak. These bassinets come with features like convenient storage space as well as a sturdy metal frame construction. For the parents that would like to give their little one a bassinet and a play yard all in one – check out the Eddie Bauer Complete Play Yard with Bassinet & Changing Station Bryant Collection. This is in every sense of the word, the ultimate in bassinets. Its features include a changing station with diaper organizer, mobile with music and a vibrate option!

Bassinet Tips

While you can’t go wrong with buying any Eddie Bauer bassinet, there are a few tips you can keep in mind to ensure you get the best bassinet for your baby. First of all, make sure that the bassinet has a sturdy bottom and a very stable base. Make sure that the rocking action isn’t too much, as this can press your baby against the sides of the bassinet. Always check for sharp objects, splinters or anything your child might put into his or her mouth. When it comes to the bedding, make sure it fits snugly inside the bassinet. The mattress should not be more than 1 inches thick.

If for any reason you need to get replacement parts for your bassinet, make sure you buy company parts. Don’t think that you can save money by getting generic materials – getting company parts will ensure they are the right fit and suited to your bassinet. Last, but definitely not least, keep an eye on your baby. Once you notice that they are pushing up on their hands and knees, it’s time to move them to a crib!

Eddie Bauer bassinets are easy to assemble as well – you won’t have to spend hours trying to figure out what goes where. But perhaps most importantly, your baby will be safe and comfortable in these bassinets. At the end of the day, this should be the most important aspect of any bassinet.

Eddie, Bauer, Adventurer, Travel, System

How To Cool Down Swimming Pool Water

During this especially hot summer, people with pools are enjoying them more than ever as a way to cool off and have fun. However, with many areas seeing hotter temperatures than usual this year, bringing a new problem to the attention of pool owners and those who just love to enjoy someone elses pool: how do you lower the temperature of a pool when it has become so warm that it is no longer refreshing?

Try these ideas to cool off

To get your pool feeling more like a swimming pool and less like a bathtub, there are two things that will definitely help: running your solar panels at night and installing a fountain or two. Although they may not seem like they would be certain ways to drop the temperature a few degrees, these are proven solutions to a too-hot pool.

– Solar panels. Although most people probably associate solar panels with raising the temperature of a pool, running them at night instead of during the day can actually accomplish the opposite effect. Since the panels cool off at night, running the water through them lowers the temperature of that water, allowing it to return to the pool cooler than when it left. Just remember to turn the panels off during the day, or you can end up hotter than when you started!
– Fountains. Not only do they make your pool area more attractive, but the spray of water leads to evaporation, which lowers the temperature by expending energy. You will get a more significant cooling effect by running them at night, and you will need to add water to the pool to compensate for the water that evaporates.

These ideas wont help

During a hot summer, you might be tempted to try just about anything to cool off your pool. Before you waste your time and/or money, skip these ideas:
– Pool covers. Despite what they may advertise, in hot climates, a pool cover wont help with cooling. Instead, they stop evaporation, making it harder for the temperature of the water in your pool to drop.
– Adding ice. It works in a glass, so why not in a pool? Think again the amount of water in a pool is simply too large to be affected unless you added an enormous amount of ice, and even then the effect would wear off quickly.

CHAPTER ON FLY ASH FOR GRADUATE (CIVIL ENGINEERING) COURSE STUDENTS

CHAPTER ON FLY ASH FOR GRADUATE (CIVIL ENGINEERING) COURSE STUDENTS Subhash Chandra Sr Engineer AUD NTPC Limited Noida Office

Fly Ash – A Resource Material

Contents

1.Fly ash Introduction

1.1.General 1.2.Production and Classification 1.3.History of Fly Ash Utilization 1.4.Properties of Fly Ash 1.5.Geo-technical Properties 1.6.Chemical Properties 1.7.Quality of Fly Ash as per BIS, ASTM

2.Main avenues for use of fly ash

2.1Cement concrete and mortar 2.2Fill Material – Road and embankments construction 2.3Reclaim wasteland 2.4Mine filling 2.5Bricks, blocks and tiles Manufacturing 2.6Agricultural soil 2.7Ash Dykes 2.8Autoclaved Aerated Concrete 2.9Lightweight aggregates 2.10Cenosphere

3.Legal Issues – Ash Utilization

4.Major Successful examples

5.Conclusion

1Fly Ash Introduction 1.1General

The Fly ash word sounds its own definition i.e. material which flies along with gases and ash – a residue of burnt material. This name is used for residue of coal which is used as pulverized fuel for generation of electricity in thermal power station. In present life style electricity has become one of the most important part of day to day of human life. For generation of electricity coal is continued to be used as a major source of fuel in many countries in the World including India. In the process of electricity generation, large quantity of fly ash gets produced and becomes available as a by-product of coal-based power stations.

Fig. 1: Fly Ash mound Fig. 2: Fly Ash-microscopic view

1.2Production and Classification

In thermal power station, pulverized coal is fed into boiler furnace, after burning; the lighter and finer particles fly along with hot flue gases which are passed through Electrostatic Precipitators (ESP). In ESP these particles are arrested and then taken out either pneumatically to a storage silos in dry form or sluiced through with water and sent to ash ponds. The particles collected in ESP are called Fly Ash. It is then collected by either using electrostatic precipitators, baghouses or a combination of both.

There are four categories of Ash normally available from a coal based thermal power station. a.Fly Ash: This kind of ash is collected from different rows of Electro-Static Precipitators (ESP) in dry form. This is characterized by comparatively lower carbon content and higher fineness. Fineness of fly ash is more in subsequent field of ESP as compared to initial fields. This ash comprises about 80% of total ash produced in a station. b. Bottom Ash: This kind of ash is collected at the bottom of Boiler furnace as a result of coal burning activity. This is characterized by comparatively higher carbon content and coarse size. This comprises about 20% of total ash produced in a station. c.Pond Ash: The slurry formed after mixing ash with water is pumped to the nearby ash ponds wherein water gets drained away. The ash thus stored in ash ponds is called Pond Ash. d.Mound Ash: Fly ash conveyed in dry form and deposited dry in mounds.

1.3History of Fly Ash Utilization

Utilization of fly ash is not a new phenomenon rather it is about seven decades old. The fly ash became available in coal based thermal power station in the year 1930 in USA. In order to find out its properties, scientist started research activities and in the year 1937, R.E. Davis and his associates at university of California published research details on use of fly ash in cement concrete. This research had laid foundation for its specification, testing & usages. The research had established that fly ash possesses specific property called as pozzolanic property which was similar to volcanic ash and deserves to utilize in lime/ cement concrete works.

The pozzolanic property of a substance is defined as -A Siliceous or Siliceous and Aluminous material, which in itself possesses little or no cementitious value but will, in finely divided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures to form compounds possessing cementitious properties.

The pozzolana term came from Roman city. About 2,000 years ago, Roman used volcanic ash along with lime and sand to produce mortars, which possesses superior strength characteristics & resistances to corrosive water. The best variety of this volcanic ash was obtained from the locality of pozzoli and thus the volcanic ash had acquired the name of Pozzolana. The investigations had also established that the geo-technical properties of fly ash are similar or better than many of the soils and can be utilized for structural fill & embankment construction substituting soil.

In India, to establish more uses of fly ash produced from Indian coal, research activities were continued at various research institutes of Council of Scientific and Industrial Research (CSIR) like Central Building Research Institute, Roorkee, Central Institute for Mining Fuel Research Institute, Dhanbad, Central Road Research Institute, New Delhi etc and other Institutes like National Council for Cement & Building Materials, Ballabhgarh, IIT Kanpur, IIT Chennai, NTPC (R&D)etc. Studies have revealed that fly ash can be used in manufacture clay ash bricks, fly ash lime/ cement bricks and other building products, in agriculture, road embankments construction and fill applications.

1.4Properties of Fly Ash

Fly ash is complex material having wide range of chemical, physical and mineralogical compositions. The chemical composition of fly ash depends on the type of coal burnt in boiler furnace, oil firing, oxygen flow temperature of furnace, degree of pulverization of coal, efficiency of ESP etc. Physical properties of fly ash such as fineness or particle size, reactivity with lime / cement etc depends on design and efficiency of boiler, combustion process, coal grinding techniques employed, process of ash collection and handling method and efficiency of Electrostatic Precipitator etc.

1.5Geo-technical Properties

The majority of fly ash particles are glassy, solid or hollow, slightly to highly porous and spherical in shape. The specific gravity falls within the range of 2.1 to 2.6 and dry density is commonly found to be in the range of 950-1200 kg/m3 depending on the degree of compaction. The particle size of fly ash generally ranges from 1 micron to 100 micron in diameter of glassy spheres and 7 to 300 microns in diameter for angular carbon particles. In terms of soil grain size analysis, most fly ash particles fall within the silt range, with small percentages in the fine sand and clay sizes.

Table 1: Geo-technical properties of Fly Ash

Specific gravity g/cc1.90-2.55 PlasticityNon Plastic Proctor compaction – Maximum dry density (g/cc)0.90-1.60 Optimum moisture content (%)38.0-18.0 Angle of internal friction ( o)300-400 Cohesion (kg/cm2 )Negligible Compression index0.05-0.4 Permeability (cm/sec)105-103 Particle size distribution Clay size fraction (%) Silt size fraction (%) Sand size fraction (%) Gravel size fraction (%) 1-10 8-85 7-90 0-10 Coefficient of uniformity3.1-10.7

1.6Chemical Properties

The major constituents of most of the fly ashes are Silica (SiO2), alumina ((Al2O3), ferric oxide (Fe2O3) and calcium oxide (CaO). The other minor constituent of the fly ash are MgO, Na2O, K2O, SO3, MnO, TiO2 and unburnt carbon. There is wide range of variation in the principal constituents – Silica (25-60%), Alumina (10-30%) and ferric oxide (5-25%). When the sum of these three principal constituents is 70% or more and reactive calcium oxide is less than 10% -technically the fly ash is considered as Siliceous fly ash and also called as Class F fly ash. Such type of fly ash is produced by burning of anthracite or bituminous coal. Siliceous fly ash characteristically contains a large part of silicate glass of high silica content and crystalline phases of low reactivity mullite, magnetite and quartz. The active constituents of this type of fly ash is siliceous or alumino-silicate glass. If the sum of these three constituents is equal or less than 70% and reactive calcium oxide is not less than 10%, fly ash will be considered as Calcareous fly ash and also called as Class C fly ash. This type of fly ash is commonly produced by burning of lignite or sub-bituminous coal and possesses self setting property similar to cement.

Table 2: Chemical composition

ComponentBituminous Sub bituminous Lignite

SiO2 (%)20-6040-6015-45 Al2O3 (%)5-3520-3020-25 Fe2O3 (%)10-404-104-15 CaO (%) 1-125-3015-40 LOI (%) 0-150-30-5

1.7Quality of Fly Ash as per BIS, ASTM

To utilize fly ash as a Pozzolana in cement concrete and cement mortar, Bureau of Indian Standards (BIS) has formulated IS: 3812 Part-1 2003. In this code quality requirement for siliceous fly ash and calcareous fly ash with respect its chemical and physical composition has been specified. These requirements are given as below.

Table 3: Chemical Requirements of fly ash as a Pozzolana in cement concrete and cement mortar as per Bureau of Indian Standards (BIS)

S. No.CharacteristicsRequirements Siliceous fly ashCalcareous fly ash 1Silicon dioxide (SiO2) + Aluminium oxide (Al2O3) + Iron oxide (Fe2O3), in percent my mass, minimum7050 2Silicon dioxide in percent my mass, minimum3525 3Reactive silica in percent my mass, minimum (Optional test)2020 4Magnesium Oxide (MgO), in percent my mass, max.5.05.0 5Total sulphur as sulphur trioxide (SO3), in percent my mass, max.3.03.0 6Available alkalis as sodium oxide (Na2O), in percent my mass, max.1.51.5 7Total chlorides in percent my mass, max0.050.05 8Loss on Ignition, in percent my mass, max.5.05.0

Table 4: Physical Requirements of fly ash as a Pozzolana in cement concrete and cement mortar as per Bureau of Indian Standards (BIS)

S. No.CharacteristicsRequirements Siliceous fly ash and Calcareous fly ash 1Fineness – Specific surface in m2/kg by Blaine’s permeability method, Min.320

2Particles retained on 45 micron IS sieve (wet sieving) in percent, Max. (Optional Test)34 3Lime reactivity – Average compressive strength in N/mm2, Min4.5

4Compressive strength at 28 days in N/mm2, Min.Not less than 80 percent of the strength of corresponding plain cement mortar cubes 5Soundness by autoclave test – Expansion of specimen in percent, Max.0.8

ASTM International for fly ash: ASTM International C-618-03 specifies the chemical composition and physical requirements for fly ash to be used as mineral admixture in concrete. The standards requirements are given as below.

Table 5: Chemical Requirements of fly ash as a Pozzolana in cement concrete and cement mortar as per ASTM International

S. No.CharacteristicsRequirements Class F (Siliceous fly ash)Class C (Calcareous fly ash) 1Silicon dioxide (SiO2) + Aluminium oxide (Al2O3) + Iron oxide (Fe2O3), in percent my mass, minimum7050 2Sulfur trioxide (SO3), max. Percent5.05.0 3Moisture content, max., percent3.03.0 4Loss on ignition, max., percent6.06.0

Table 6: Physical Requirements of fly ash as a Pozzolana in cement concrete and cement mortar as per ASTM International

S. No.CharacteristicsRequirements for class F & class C fly ash 1Fineness – amount retained when wet-sieved on 45 micron (No. 325) sieve, Max., percent.34

2Strength activity index oWith portland cement, at 7 days, min., percent of control oWith portland cement, at 28 days, min., percent of control75c

75c 3Water requirement, max., percent of control105

4Soundness Autoclave expansion or contraction, max., percent0.8 5Uniformity requirements: The density and fineness of individual samples shall not vary from the average established by ten preceding tests, or by all preceding tests if the number is less than ten, by more than Density (max.) variation from average percent. Percent retained on 45 micron (no. 325), max variation, percentage points from average

5

5

2Main avenues for use of fly ash

2.1Cement concrete and mortar 2.2Fill Material – Road and embankments construction 2.3Reclaim wasteland 2.4Mine filling 2.5Bricks, blocks and tiles Manufacturing 2.6Agricultural soil 2.7Ash Dykes 2.8Autoclaved Aerated Concrete (AAC) 2.9Lightweight aggregates 2.10Cenosphere

2.1Using fly ash in cement concrete and mortar

Portland Pozzolana Cement fly ash based is manufactured either by intimately intergrinding Portland cement clinker and fly ash with addition of gypsum or calcium sulphate or by intimately and uniformly blending with OPC and fine fly ash. The pozzolanic property of fly ash makes it suitable as raw material for manufacture of PPC. IS:1489 Part-1-1991(Reaffirmed 2005) is BIS specification for this cement. As per the BIS specification, fly ash constituent shall not be less than 15 percent and not more than 35 percent by mass of Portland Pozzolana Cement.

Portland Pozzolana cement produces less heat of hydration and offer greater resistance to the attack of aggressive waters than Ordinary Portland Cement. It is particularly useful in marine and hydraulic construction and other mass construction structures. This cement is equivalent to Ordinary Portland cement on the basis of the 28 days and above compressive strength. Use of fly ash in cement manufacturing helps to conserve raw material such lime stone, clay etc and also conserve coal required for clinkerization for manufacture of cement clinker. During this process generation of CO2 is also reduced, therefore, eco-friendly.

It may be noted that, Bureau of Indian Standard also permits use of Fly ash up to 5% as a Performance Improver in the manufacturing of 33 grade, 43grade and 53grade of Ordinary Portland Cement.

2.1.1How fly ash woks with cement?

Fly ash being a pozzolanic material is found to be useful for part replacement of Ordinary Cement in cement concrete and Mortar. In the concrete, cement chemically reacts with water and produces strength bearing gels called as C-H-S gels that binds other component together and provide strength to concrete and creates strength bearing materials. The reaction process is called ‘hydration’ of cement. In this process some amount of lime [Ca (OH)2] is also liberated. Fly ash available in concrete reacts with this lime and forms additional similar strength bearing gel which provides strength to concrete. As we know Ordinary Portland Cement (OPC) is a product of four principal mineralogical phases. These phases are Tricalcium Silicate – C3S(3CaO.SiO2), Dicalcium Silicate – C2S(2CaO.SiO2), Tricalcium Aluminate – C3A(3CaO.Al2O3) and Tetracalcium alumino-ferrite – C4AF(4CaO.Al2O3Fe2O3). The setting and hardening of the OPC takes place as a result of reaction between these principal compound and water [H2O(H)] as shown under:

2C3S + 6H = C3S2H3 + 3CH (tricalcium silicate) water (C-S-H gel)(Calcium hydroxide) 2C2S +4H = C3S2H3 + CH (dicalcium silicate) (water) (C-S-H gel)(Calcium hydroxide)

The hydration products from C3S and C2S are similar but quantity of calcium hydroxide (lime) released is higher in C3S as compared to C2S. The reaction of C3A with water takes place in presence of sulphate ions supplied by dissolution of gypsum present in OPC. This reaction is very fast and shown under:

C3A + 3(CSH2) + 26H =C3A(CS)3H22 (tricalcium Aluminate (gypsum) (water) (ettringite)

C3A + CSH2 + 10H =C3ACSH2

(monosulphoaluminate hydrate) (S – SiO2, C – CaO, A – Al2O3, F – Fe2O3)

Tetracalcium alumino-ferrite forms hydration product similar to those of similar of C3A, with iron substituting partially for alumina in the crystal structures of ettringite and mono sulpho-aluminate hydrate.

Above reaction indicate that during the hydration process of cement, lime is released out and remains as surplus in the hydrated cement. This leached out surplus lime renders deleterious effects to concrete such as make the concrete porous, give chance to the development of micro-cracks, weakening the bond with aggregates and thus affects the durability of concrete.

If fly ash is available in the mix, this surplus lime becomes the source for pozzolanic reaction with fly ash and forms additional C-S-H gel having similar binding properties in the concrete as those product by hydration of cement paste. The reaction of fly ash with surplus lime continues as long as lime is present in the pores of liquid cement. The process is illustrated as below.

2.1.2Advantage of use of Fly ash with concrete

Fly ash concrete3 was as early as used in the U.S. for the Hoover Dam, where engineers found that it allowed for less total cement. It is now used across the world. Consisting mostly of silica, alumina and iron, fly ash is a pozzolana substance containing aluminous and silicious material that forms cement in the presence of water. When mixed with lime and water it forms a compound similar to portland cement. The spherical shape of the particles reduces internal friction thereby increasing the concrete’s consistency and workability, permitting longer pumping distances. Improved workability means less water is needed, resulting in less segregation of the mixture.

(i)Reduced Heat of Hydration

In concrete mix, when water and cement come in contact, a chemical reaction initiates that produces binding material and consolidates the concrete mass. The process is exothermic and heat is released which increases the temperature of the mass. The large temperature rise of concrete mass exerts temperature stresses and can lead to formation of micro cracks. When fly ash is used as part of cementitious material, quantum of heat liberated is low and staggers through pozzolanic reactions and thus reduces micro-cracking and improves soundness of concrete mass. (ii)Improved Workability of Concrete Fly ash particles are generally spherical in shape; this gives a ball bearing effect to the mixing of aggregates & cement. This way part mixing is achieved and leads for reduced water requirements for a given slump. The spherical shape helps to reduce friction between aggregates and between concrete and pump line and thus increases workability and improve pumpability of concrete. Fly ash use in concrete increases volume of fines and decreases water content and thus reduces bleeding of concrete. (iii)Reduced Permeability & increased corrosion protection Water is essential constituent of concrete preparation. When concrete is hardened, part of the entrapped water in the concrete mass is consumed by cement mineralogy for hydration. Some part of entrapped water evaporates, thus leaving porous channel to the extent of volume occupied by the water. Some part of this porous volume is filled by the hydrated products of the cement paste. The remaining part of the voids consists capillary voids and give way for ingress of water. Similarly, the liberated lime by hydration of cement is water-soluble and is leached out from hardened concrete mass, leaving capillary voids for the ingress of water. Higher the water cement ratio, higher will be the porosity and thus higher will be the permeability. The permeability makes the ingress of moisture and air easy and is the cause for corrosion of reinforcement. Higher permeability facilitate ingress of chloride ions into concrete and is the main cause for initiation of chloride induced corrosion. Additional cementitious material results from reaction between liberated surplus lime and fly ash, blocks these capillary voids and also reduces the risk of leaching of surplus free lime and thereby reduces permeability of concrete. (iv)Improved Resistance for Carbonation Phenomena Carbonation phenomenon in concrete occurs when lime of the hydrated Portland Cement react with carbondioxide from atmospheres in the presence of moisture and form calcium carbonate. To a small extent, calcium carbonate is also formed when calcium silicate and aluminates of the hydrated Portland cement react with carbon dioxide from atmosphere. Carbonation process in concrete results in two deleterious effects (i) shrinkage (ii) Corrosion. Concrete immediately adjacent to steel reinforcement may reduce its resistance to corrosion. The rate of carbonation depends on permeability of concrete, quantity of surplus lime and environmental conditions such as moisture and temperature. When fly ash is available in concrete; it consumes surplus lime by way of pozzolanic reaction, reduces permeability and as a result improves resistance of concrete against carbonation phenomenon.

(v)Increased Sulphate Resistance

Sulphate attacks in concrete occur due to reaction between sulphate from external origins or from atmosphere with surplus lime leads to formation of etrringite, which causes expansion and results in volume destabilization of the concrete. Increase in sulphate resistance of fly ash concrete is due to continuous reaction between fly ash and leached out lime, which continue to form additional C-S-H gel. This C-S-H gel fills in capillary pores in the cement paste, reducing permeability and ingress of sulphate ions.

(vi)Reduced alkali- aggregate reaction Certain types of aggregates react with available alkalis and cause expansion and damage to concrete. These aggregates are termed as reactive aggregates. It has been established that use of adequate quantity of fly ash in concrete reduces the amount of alkali aggregate reaction and reduces/ eliminates harmful expansion of concrete. The reaction between the siliceous glass in fly ash and the alkali hydroxide of Portland cement paste consumes alkalis thereby reduces their availability for expansive reaction with reactive silica aggregates. (vii)Greater long – term strength

The pozzolanic reaction between fly ash and lime liberated from hydration cement continue for longer period & generates additional cementitious gel which provide greater strength to concrete mass.

In a nutshell, it can be summarized that permeability and surplus lime liberated during the hydration of Portland cement are the root causes for deleterious effect on the concrete. Impermeability is the foremost defensive mechanism for making concrete more durable and is best achieved by using fly ash as above. Use of fly ash in concrete saves the cement requirement for the same strength thus saving of raw materials such as limestone, coal etc required for manufacture of cement and thus activity is eco-friendly.

The Indian Standards IS: 456-2000-entitled Plain and Reinforced cement concrete code of practice permits use of fly ash (conforming to IS:3812 Part-1) up to 35% as part replacement of OPC in the concrete. 2.2Use of Fly ash as a fill material i.e. for road embankment construction and similar projects One of the most significant characteristics of fly ash in its use as a fill material is its strength. Well-compacted fly ash has strength comparable to or greater than soils normally used in earth fill operations. In addition, fly ash possesses self-hardening properties which can result in the development of shear strengths. Significant increases in shear strength can be realized in relatively short periods of time and it can be very useful in the design of embankments6.

Construction of road embankments using fly ash, involves encapsulation of fly ash in earthen core or with RCC facing panels. Since there is no seepage of rain water into the fly ash core, leaching of heavy metals is also prevented. When fly ash is used in concrete, it chemically reacts with cement and reduces any leaching effect. Even when it is used in stabilization work, a similar chemical reaction takes place which binds fly ash particles. Moisture content of pond ash to be nearer to OMC after having been taken out from pond and stored for one or two days.

Use of fly ash in the construction of road embankment of the second Nizamuddin Bridge in New Delhi, has amply demonstrated its suitability as a material for road/embankment construction. The site proximity to the river Yamuna posed a challenge to use the conventional material; moreover, the embankment of 7 to 8 metre height was to be constructed for a stretch of about two kilometers in a flood zone.

The construction work has been completed in a record time. The on-site quality control was maintained with simple tests and procedures. These were similar to the corresponding requirements in case of earthworks. No operational or execution problems have been faced on technical aspects, rather the working with fly ash has been found to be easier and better. Further, use of fly ash results in an enormous amount of cost saving.

Advantages of using fly ash for road construction

a)Fly ash is a lightweight material, as compared to commonly used fill material (local soils), therefore, causes lesser settlements. b)Easy to handle and compact because the material is light and there are no large lumps to be broken down. Can be compacted using either vibratory or static rollers. c)High permeability ensures free and efficient drainage. After rainfall, water gets drained out freely ensuring better workability than soil. d)Work on fly ash fills/ embankments can be restarted within a few hours after rainfall, while in case of soil it requires much longer period. e)Conserves good earth, which is precious topsoil, thereby protecting the environment. f)Higher value of California Bearing Ratio as compared to soil provides for a more efficient design of road pavement. g)Pozzolanic hardening property imparts additional strength to the road pavements/ embankments and decreases the post construction horizontal pressure on retaining walls. h)Amenable to stabilization with lime and cement. i)Can replace a part of cement and sand in concrete pavements thus making them more economical than roads constructed using conventional materials.

2.3Use of Ash in waste land Reclamation

It is a very difficult task to convert a wasteland to greenery. Tata Energy and Resources Institute (TERI) had identified certain strains of naturally occurring mycorrhizal fungi that provide nutritional support and high level of stress tolerance to the plants. These were applied to plants on fly ash dumps in Korba Super Thermal Power Station with additional doses of organic and Mycorrhizal fertilizers. The fungi form a reciprocating relationship with the living roots by providing nutrition to plants from the substrate and receive carbon in turn from them. The mycelial network of the Mycorrhizal fungi, accumulate heavy metal from fly ash and retain them in their living cells. In a short period of time, the grey, toxic fly ash laden waste land was converted to that of green vegetation. The technology was successfully replicated in Badarpur and Vijayawada Thermal Power Stations

Waste5/degraded land/low lying areas near in the vicinity of different TPPs viz. Farakka STPP, Bhusawal TPS, Chandrapur STPP, Harduaganj/ Obra/ Anpara TPPs of UPRVUNL, NLC and in the State of Jharkhand have been reclaimed and made suitable for crop farming /social forestry /medicinal plants through bulk use of fly ash. Thus Fly Ash has been established to act as excellent soil conditioner/ modifier.

2.4Use of fly ash in Mine filling

Fly ash in back filling of opencast mines and stowing of underground mines can be used. In open cast mines after extraction of coal and completion of mining operation, mines are back-filled with over burden materials and remaining area can be backfilled with ash.

In case of under ground mines the conventional material for back filling is river sand. NTPC has got studies conducted (including fields trials) through Central Mining Research Institute, Dhanbad for use of bottom ash from Ramagundam for stowing operation in the under ground mines of Singreni. The study indicates that it is technically feasible to utilize bottom ash in stowing operations. More than 1,00,000 tonnes of bottom ash have already been stowed in these underground mines.

2.5Use of Fly Ash in Bricks and other building product Manufacturing

Fly ash can be used for making a variety of building materials such as Bricks, Blocks, Cellular concrete, Tiles etc. Brick is a basic need for the development works. Several studies show that fly ash brick is a far superior building material than burnt clay brick. The use of fly ash brick provides a stronger, more durable construction that is better protected from efflorescence and salinity with meaningful savings in construction costs. Fly Ash Brick Making Machines used for manufacturing bricks of different sizes from fly ash.

The process of manufacturing lime fly ash bricks is based on the reaction of lime with silica of fly ash to form calcium silicate hydrates(C-S-H) which binds the ingredients to form a brick. The quality of bricks8 obtained is highly dependant on the quality of fly ash. The manufacturing of Lime-Fly ash bricks are generally designed such that they stand at par with burnt clay bricks used conventionally. Fly ash bricks have good compressive strength, low water absorption, high density and low shrinkage value as compared to burnt clay bricks. 3.5.1Fly ash bricks can be divided into the following types

Clay Fly ash Bricks: Manufacturing process of clay fly ash bricks by manual or extrusion process involves mixing of fly ash (20 % – 80 %) with clay of moderate plasticity. The green bricks are dried under ambient atmospheric conditions or in shed to equilibrium moisture level of below 3 %. Dried bricks are fired in traditional brick kilns at 1000 30 C with a soaking period of 5 – 7 hours at maturing temperature. Fly ash Sand Lime Bricks: In presence of moisture, fly ash reacts with lime at ordinary temperature and forms a compound possessing cementitious properties. After reactions between lime and fly ash, calcium silicate hydrates are produced which are responsible for the high strength of the compound. This process involves homogeneous mixing of raw materials (generally fly ash, sand and lime), moulding of bricks and then curing of the green bricks. 3.5.2Advanced work: Cold Bonded Lightweight Fly ash Bricks, Blocks and Tiles: The material can be produced in a variety of building blocks, bricks and tiles, depending on local markets and regulations. The mixed raw material is cast in moulds, after which the moulds are processed in a microwave oven for transportation to the building site. Flux Bonded Fly ash Bricks Blocks and Tiles: The process is similar to the one in the conventional tile industry: fly ash is mixed with less than 10 % plastic clay and a few additives and tiles, bricks or blocks are pressed. These shapes are fired in the range of 900C to 1000C to make the final product. More than 85% of fly ash is used in the process. 3.5.2Advantages of fly ash bricks over clay bricks:

1)Growing cold crushing strength 2)No efflorescence 3)Compact construction & Consistent quality 4)Better thermal insulation properties 5)Availability through out the year. 6)Better shape & finish 7)Rationalization of Mortar with optional need of Plaster.

Fly ash Bricks v/s Normal Clay Bricks – Comparison

NORMAL CLAY BRICKFLY ASH BRICK Varying colour as per soil Uniform pleasing colour like cement Uneven shape as hand made Uniform in shape and smooth in finish Lightly bonded Dense composition Plastering required No plastering required Heavier in weight Lighter in weight Compressive strength is around 35 kg/cm2Compressive strength is around 100 kg/cm2 More porous Less porous Thermal conductivity 1.25 – 1.35 w/m2 C Thermal conductivity 0.90-1.05 w/m2 C Water absorption 20-25%Water absorption 6-12%

Subhash Chandra Sr Engineer AUD NTPC Limited Noida Office

Normal Clay Brick Fly Ash Brick

3.5.3Blocks

Day by day the uses of concrete blocks are gaining importance due to its own importance and advantages, except for its cost. The cost of concrete blocks can be cut drastically with the use of fly ash for its manufacturing. Manufacturing of fly ash blocks requires following ingredients Fly Ash: The fly ash should conform to IS requirement; dry fly ash with lime reactivity more than 60 kg/cm2. Cement: 43 grade Ordinary Portland Cement conforming to IS Sand: sand required for the mix should be free from dirt, impurities and fall in zone II. Coarse Aggregate: Crushed aggregate of maximum nominal size 10 mm.

Manufacturing: The fly ash concrete blocks can be manufactured on machine. Blocks are partially compacted and it requires to attend early strength so that transportation is easy. The fly ash is mix dry with the cement, before adding the raw materials to the mixer. The properly mixed concrete is placed in the block making machine. The blocks extracted from the machine is air dried and then sent for curing. Fly ash concrete requires more period for curing than ordinary concrete.

2.6Use of Ash in Agriculture Fly Ash consists of practically all the elements present in soil except organic carbon and nitrogen. Thus it was found that this material could be used as an additive material in agriculture applications. In view of the above, some agencies/ individuals/ institutes at dispersed locations conducted some preliminary studies on the effect and feasibility of fly ash as an input material in agricultural7 applications. It was generally observed that both sandy and clayey soils tend to become loamy in texture. Optimum bulk density in turn improves the soil porosity, the workability of the soil, the root penetration and the moisture retention capacity of the soil. The application of Fly Ash has been found to increase the available water content of loamy sand soil by 120% and of a sandy soil by 67%. RRL Bhopal reported that application of Fly Ash increase the porosity of Black Cotton Soil and decreases the porosity of sandy soils and thereby saves irrigation water around by 26% and 30% respectively. This improvement in water holding capacity is beneficial to the plants especially under rainfed agriculture. Further, in India most of the Fly Ash produced is alkaline in nature. Hence an application of these to agricultural soil increases the soil PH; it simultaneously adds essential plant nutrients to the soil. Some fly ash is acidic which may be used for reclamation of alkaline soils. Fly ash application helps in reducing surface encrustation, which is a problem in red soils. Studies in this context have revealed the followings. It improves permeability status of soil Improves fertility status of soil (soil health) / crop yield Improves soil texture Reduces bulk density of soil Improves water holding capacity / porosity Optimizes ph value Improves soil aeration Reduces crust formation Provides micro nutrients like Fe, Zn, Cu, Mo, B, Mn, etc. Provides macro nutrients like K, P, Ca, Mg, S etc.

Keeping the above important findings in view, pond ash at a dose of 30-50 tonne per hectare on one time basis along with recommended dose of fertilizers / manures is recommended for its use agriculture/ forestry sector/wasteland management or cultivation of different cereals / pluses/ oil seeds / vegetables etc., the repeat application of which can be made after 4-5 years as it would have significant residual effect on the yield of succeeding crops over a period of 4-5 years. 2.7Ash Dyke Raising

A number of ash disposal facilities across the country have been designed. Ash dyke9 maintaining is one of them. It can be raised both by dry disposal and wet disposal system. In dry disposal, the fly ash is transported by truck, chute or conveyor at the site and disposed of by constructing a dry embankment (dyke). An important aspect of design of ash dykes is the internal drainage system. The seepage discharge from internal surfaces must be controlled with filters that permit water to escape freely and also to hold particles in place and the piezometric surface on the downstream of the dyke. The internal drainage system consists of construction of rock toe, 0.5m thick sand blanket and sand chimney. After completion of the final section including earth cover the turfing is developed from sod on the downstream slope. 2.8Autoclaved Aerated Concrete Autoclaved Aerated Concrete (AAC) is a precast structural product made with all-natural raw materials. In 1914, the Swedes discovered a mixture of cement, lime, water and sand that expands by adding aluminum powder. The material was further developed to what we know today as autoclaved aerated concrete (also called autoclaved cellular concrete). It is an economical, sustainable, solid block that provides thermal and acoustic insulation as well as fire and termite resistance. AAC is available in a variety of forms, ranging from wall and roof panels to blocks and lintels. To manufacture AAC, Portland cement is mixed with lime, silica sand, fly ash, water and aluminum powder or paste and poured into a mold. The reaction between aluminum and concrete causes microscopic hydrogen bubbles to form, expanding the concrete to about five times its original volume. After evaporation of the hydrogen, the now highly closed-cell, aerated concrete is cut to size and formed by steam-curing in a pressurized chamber (an autoclave). The result is a non-organic, non-toxic, airtight material that can be used for wall, floor, and roof panels, blocks, and lintels which according to the manufacturers, generate no pollutants or hazardous waste during the manufacturing process AAC may be beneficial in climates where outdoor temperature fluctuates over a 24-hour period from above to below the indoor temperature conditioned air set point. Advantages of AAC: 1.Light weight construction hence lighter foundation 2.Faster construction 3.Higher thermal and sound insulation 4.Higher resistively to fire 5.Lesser size of structural member i.e. lesser section of beams and columns 2.9Manufacturing lightweight aggregates from fly ash These are in great demand where stone mining is banned. However it is not true replacement of stone aggregate but good alternative where local requirement are of lower range. Lightweight aggregates have been manufactured by sintering fly ash and crushing the product into suitable sizes. These aggregates possess unique characteristics that make them suitable for high strength and high performance concrete. Concrete produced using these aggregates is around 22% lighter and at the same time 20% stronger than normal weight aggregate concrete. Drying shrinkage is around 33% less than that of normal weight concrete. Moreover, the aggregates possess high durability characteristics required in high performance structures. The importance of the new aggregates lies mostly in the fact that superior qualities are achieved without having to increase the cement content. Thus it is possible to reduce the amount of cement by as much as 20% without affecting the required strength. The use of lightweight aggregate in concrete has many advantages. These include: (a) Reduction of dead load that may result in reduced footings sizes and lighter and smaller upper structure. This may result in reduction in cement quantity and possible reduction in reinforcement. (b) Lighter and smaller pre-cast elements needing smaller and less expensive handling and transporting equipment. (c) Reductions in the sizes of columns and slab and beam dimensions that result in larger space availability. (d) High thermal insulation. (e) Enhanced fire resistance. 2.10Cenosphere – Fly Ash by-product The process of burning coal in thermal power plants produces fly ash containing ceramic particles made largely of alumina and silica. The ceramic particles in fly ash have three types of structures. The first type of particles are solid and are called precipitator. The second type of particles are hollow and are called cenospheres. The third type of particles are called plerospheres, which are hollow particles of large diameter filled with smaller size precipitator and cenospheres. Thus Cenosphere is a by-product of fly ash. A cenosphere is a lightweight, inert, hollow sphere filled with inert air or gas. The color of cenospheres varies from gray to almost white and their density is about 0.4-0.8 g/cm, which gives them a great buoyancy. These are hard and rigid, light, waterproof, innoxious, and insulative. This makes them highly useful in a variety of products, notably fillers. 3Legal Issues – Ash Utilization United Nations Conference on the Human Environment held at Stockholm in June, 1972, in which India participated, to take appropriate steps for the protection and improvement of human environment. In view of this, parliament passed THE ENVIRONMENT (PROTECTION) ACT, 1986 on 23rd May, 1986 for protection and improvement of environment and the prevention of hazards to human beings, other living creatures, plants and property. Consequently Ministry of Environment and Forest, Govt of India has issued Gazette Notification regarding use of Fly Ash, which is as under:

1st Notification – 14.09.1999

Use of fly ash, bottom ash or pond ash in the manufacture of bricks and other construction activities.- (1) No person shall within a radius of fifty kilometers from coal or lignite based thermal power plants, manufacture clay bricks or tiles or blocks for use in construction activities without mixing at least 25 per cent of ash (fly ash, bottom ash or pond ash) with soil on weight to weight basis. ‘ (2) There shall be a authority for ensuring the use of specified quantity. In case of non-compliance, the said authority may cancel the license of brick kiln or may cancel mining lease (3) In case of non-availability of ash from thermal power plant in sufficient quantities as certified by the said power plant, the stipulation under para (1) shall be suitably modified (waived/ relaxed). (4) Each coal or lignite based thermal power plant shall constitute a dispute settlement committee. (5) Annual implementation report providing information about the compliance of provisions in this notification shall be submitted by the 30th day of April every year to the Central Pollution Control Board, concerned State Pollution Control Board/Committee and the concerned Regional Office of the Ministry of Environment and Forests by the coal or lignite based thermal power plants. (6) Power Plants to issue ash free of cost for ten years. (7) Use of fly ash, 100% utilization of Ash by all thermal power stations in – 15 years for existing stations – 9 years for new stations Specifications for use of ash-based products.- (1) Manufacture of ash-based products such as cement, concrete blocks, bricks, panels or any other material or the use of ash in construction activity such as in road laying, embankments or use as landfill to reclaim low lying areas including back filling in abandoned mines or pitheads or for any other use shall be carried out in accordance with specifications and guidelines laid down by the Bureau of Indian Standards, Indian Bureau of Mines, Indian Road Congress, Central Building Research institute, Roorkee, Central Road Research Institute, New Delhi, Building Materials and Technology Promotion Council, New Delhi, Central Public Works Department, State Public Works Departments and other Central and State Government agencies. (2) The Central Public Works Department, Public Works Departments in the State/Union Territory Governments, Development Authorities, Housing Boards, National Highway Authority of India and other construction agencies including those in the private sector shall also prescribe the use of ash and ash-based products in their respective schedules of specifications and construction applications, including appropriate standards and codes of practice, within a period of four months from the publication of this notification. (3) All local authorities shall specify in their respective building bye-laws and regulations the use of ash and ash-based products and construction techniques in building materials, roads, embankments or for any other use within a period of four months from the date of publication of this notification.

2nd Notification – 27.08.2003 (Amendment)

1.Radius for Use of ash for Brick manufacturing increased from 50 km to 100 km 2.Buildings within a radius of 50 Km to use ash based Bricks / Blocks /Tiles in phased manner i.e. 50% by 31st August 2004 100% by 31st August 2005 3.Buildings within a radius of 50 to 100 Km 25% by 31st August 2004 50% by 31st August 2005 75% by 31st August 2006 100% by 31st August 2007 4.It is responsibility of the construction agency either undertaking the construction or approving the design or both to ensure the implementation of the above provision 5.In case of non-compliance, consent order & mining lease of brick kilns to be cancelled. 6.Power plants to maintain month-wise record of ash made available to each brick kiln. 7.Implementing authority shall be Regional Officer of the State PCB or the Pollution Control Committee.

3rdNotification – 03.09.2009 (Amendment)

1.Mandate of compulsory use of fly ash in clay bricks/ tile/ block within 100 km of TPS-deleted 2.Free issue of fly ash and pond ash to Cement, Ready Mixed Concrete, Asbestos Products etc.-deleted 3.Existing TPS / expansion units in operation to achieve ash utilization levels (from date of Notification), as mentioned below: At least 50%- 1 year, 60% -2 years, 75% – 3 years,90% -4 years, 100%-5 years 4.New TPS / expansion units commissioned after this notification At least 50% – 1 year, 70% – 2 years, 90%-3 years, 100%- 4 years

5.TPS would be free to sell fly ash to User Agencies subject to: Pond ash -to be given free on -as is where is basis- to manufacturers of Bricks/ Blocks and tiles, Farmers, Central / State Road Construction Agencies, PWD and to agencies engaged in Mine filling. At least 20% of dry ESP fly ash -free of charge to units manufacturing fly ash/ clay-fly ash bricks, blocks & tiles on a priority basis over other users. No fly ash to be made available to defaulting users. 6.The amount from sale (including by subsidiary / sister concern) to be kept in separate account head and to be utilized only for development of infrastructure / facilities and promotion / facilitation activities for use of fly ash, until 100% ash utilization is achieved. 7.The amount can be utilized for other development programs as long as 100% ash utilization level is maintained. 8.TPS to constitute dispute settlement committee which shall include GM of plant, representatives of relevant construction and fly ash brick manufacturing association. 9.Fly ash means all type of ash such as ESP ash, dry fly ash, bottom ash, pond ash and mound ash. 10.Mandatory to use at least 25% of fly ash within a distance of 50km (by road) under the guidance of DGMS

4Major Successful examples World Over The ash generated from Volcanoes was used extensively in the construction of ancient Roman structures i.e. The Aqueduct of Segovia, Spain, Dome of the Pantheon, Insula in Ostia Antica, The Baths of Caracalla, etc. Colosseum (in the year 100 A.D.) is a classic example of durability achieved by using volcanic ash. Volcanic Ash acts just like our Fly Ash. In the United States of America more than six million tonnes and in Europe more than nine million tonnes are used annually in cement and concrete. So it is hard to think about concrete construction without considering the use of fly ash. Some of the most prestigious projects of recent times have relied on fly ash concrete, including dams, power stations, offshore platforms, the Channel tunnel, highways, airports, commercial and residential buildings, bridges, pipelines and silos. No wonder that fly ash is used in all sectors of the concrete industry, covering ready-mixed, precast and on-site applications. Fine examples of application of minerals from coal can be seen throughout world: Water Tower Place in Chicago, the Eisenhower Expressway in Chicago, Picasso Tower in Madrid, the Commerzbank Tower in Frankfurt, Puylaurent dam in France, the Channel Fig. 5: Burj Dubai Tunnel between France and United Kingdom, the Underground railway tunnel in Vienna, in the East Bridge in Copenhagen, and the Eindhoven Airport landing strip in the Netherlands. High performance concrete is used in the construction of the world’s tallest building (Burj Dubai) in Dubai, United Arab Emirates: 990 fine aggregate, 810 coarse aggregate, 350 Portland cement, 120 Class F fly ash (probably exported from India), 30 Microsilica, 135 water and superplasticizer (kg/m3). India Fly Ash has been used successfully in many prestigious projects in India. Some of them are: Okhla Fly over Bridge, New Delhi, Hanumaan setu, the fly over near Yamuna Bazar, Delhi, Sarita Vihar flyover in Delhi, Noida-Greater Noida Expressway, plant roads at Budge-Budge thermal power station, NH-6 four laning work near Kolkata, one km long rural road near Raichur in Karnataka etc. Use of Roller Compacted concrete technology using high doses of fly ash for construction of Saddle Dam and upper Dam of Ghatghar pumped storage Scheme near Nashik, have been implemented. 5.Conclusion:

Use of fly ash in various applications imparts several technical and environmental benefits and thus it is eco-friendly. Large quantity of fly ash is being produced every year in power generation process and huge area of agriculture land is being used for its storage / disposal. Since electricity is requirement of every individual, it is the responsibility of every user to make sincere efforts for its gainful utilization and protection of environment. References: – 1.IS 3812-2003, Pulverized Fuel Ash specification, part 1for use as pozzolana in cement, cement mortar and concrete. 2.ASTM international C: 618-03 Standard specification for coal ash and Raw or Calcined Natural Pozzolana for use in concrete. 3.V M Malhotra and A A Ramezaniapour March 1994, Fly Ash in Concrete. 4.Seminar document, May 1996 Maharshtra India Chapter of ACI, Use of fly ash in concrete. 5.Using fly ash Extracting value from waste Published by INEP. 6.Vimal Kumar and Mukesh Mathur Fly ash in roads and embankment, National seminar and Business Meet in Use of Fly Ash in Roads and Embankment, Allahabad, June 2005, pp.3-15. 7.Chand, S.K. and Rao, Bhuganga D.D. Fly ash disposal or utilization?, International Conference on Fly Ash and Utilization, 1998, Central Board of Irrigation and Power, pp. I-5, 35-40. 8.Bhanumathidas, N. and Kalidas, N. Fly ash for bricks, cement and concrete: The Indian perspective, Paper presented at the plenary session of the CANMET/ACI Conference on Fly ash, Silica fume, Slag and Natural Pozzolanas in Concrete, Chennai, July 2001. 9.Extract from paper ‘Technology: Fly ash Disposal and Utilization: The Indian Scenario’ by Rajiv Sinha, Department of Civil Engineering, IIT Kanpur Subhash Chandra Sr Engineer AUD NTPC Limited Noida Office CHAPTER ON FLY ASH FOR GRADUATE (CIVIL ENGINEERING) COURSE STUDENTS

Pneumatic Jackhammers

Jackhammer, also known as a pneumatic drill or pneumatic jackhammer, is a handy percussive drill powered by compressed air. The pneumatic drill is used for a variety of tasks that may include drilling rock, break up pavement, and various other tasks that require powerful hammering. The pneumatic jackhammer works similar to a hammer and chisel, by jabbing with its bit, not rotating it. The pneumatic jackhammer is one of the most popular rugged tools that are available today. Although, the portable pneumatic jackhammer is not viable for use on walls and steep slopes, as it relies on the inertia of the mass of its body to drive the bit into the work, and directing that mass when not supported by the work is difficult.

Also, for the pneumatic jackhammer to be effective, gravity is required to bring the mass back into contact with the work after each blow. For using the pneumatic jackhammer effectively, the operator may bend over the tool to assist but is not really capable of overcoming the forces involved when not assisted by gravity. A technique developed by experienced laborers is the use of two man teams to overcome this obstruction of gravity. One laborer operates the hammer and the second assists by holding the hammer either on his shoulders or supported in his arms. Both men can use their collective weight to push the bit into the workface. This method is widely referred to as horizontal jack hammering. Another method is overhead jack hammering, which requires strength conditioning and endurance to hold a smaller jackhammer, called a rivet buster, over ones head.

Jack hammers are widely used in construction projects. The jackhammers find a typical use particularly for knocking down and putting up the foundation of structures. However, the pneumatic jackhammers also find extensive use in the fields of excavation and mining. The pneumatic jackhammers are one of the important tools. The pneumatic jackhammers are faster and more efficient than the traditional hammer-and-chisel. Thus, when employed in projects which demand tasks to be finished in time, the pneumatic jackhammers come forth as the most reliable solutions. The pneumatic jackhammers are thus especially needed in demolition projects that need to be finished in time.

The pneumatic jackhammers are quite difficult to operate considering the tasks they perform and require some basic skills to work with. Therefore appropriate care should be taken whenever theyre used. To promote occupational safety, construction companies must require their operators to read a pneumatic jackhammers guide. Before you start using the pneumatic jackhammer, it is strongly recommended that you wear your safety gear when it. The recommended safety gear is mentioned clearly in the user guide but generally include boots, gloves, goggles and ear muffs. While operating a pneumatic jackhammer stout clothing helps too. Usually the bits of the jackhammer get very hot in operation so use caution handling them. The rest of the machine can get quite warm also. So it is always better to count on the safety precaution while operating a pneumatic jackhammer.

Honda Eu3000is Power Generator

The Honda EU300IS generator is the most popular generator on the market for several reasons,it is very quiet for a generator that puts out 3000 watts (49 to 58db),most of the generators its size are loud and sound like a big construction project is underway rattling like crazy. This generator is much different you can actually speak and carry on a conversation in a normal tone of voice when standing fight next to it,honda has employed what is called a 2 tier damper muffler coupled with a eco throttle that ensures the most quiet opperation and that makes this a excellent choice of a generator if you tailgate at ballgames or go camping where people are trying to relax instead of trying to talk over the noisy generator which can be anoying as hell.

Using the eu300is is so easy because it has an electric start,just turn the switch and she starts up without any trouble,of course you have to maintain this piece of equipment just as if it was any other type of motorized equipment such as changing the oil at intervals of time ,also changing or cleaning the air filter,these important things will insure that you generator last a long time. Before shutting your generator off for a length of time you need to shut the fuel flow off and let the carburetor run dry of gas because when gas gets old it will gum up your carb and cause major problems resulting in having to remove the carb and cleaning it. Another thing to consider is the gas in this day and time is very poor and has ethanol in it ,ethanol is corrosive and causes problems when it ages making the fuel unstable,it will not burn as it should so always add fresh gas to your tank if it has been sitting for very long.

If your looking to save some fuel and keep the operation cost at a minimum the eu3000is is the excellent choice,it will get up to 20hrs use per tank of fuel,if you use a lot of power it will be lower but a normal load will run it for 20hrs and that is very reasonable for a 3000 watt generator. There are tri fuel kits available so LP or Natural gas can be used which is even better ,these gasses have very little pollutant emissions and will actually make you generator last longer. You see gasoline has a lot of carbon byproduct that builds up in the oil which makes your oil dirty and black also causes carbon buildup on the piston and valves,LP and Natural gas have no carbon emissions or buildup and will make your generator run extremely clean,you can run it for hundreds of hrs and the oil will not get black however it is still adviseable to change the oil at times because there are metal filings that are small and get filtered out.

Honda thinks ahead of the other generator manufactures with innovations that set standards others would like to follow,the eu3000is is dynamic in ways other generators cant match. Honda makes parallel cable kits that you can hook 2 of the same generator types together,linking 2 eu300is together will put out 6000 watts and that’s a bunch of power,sure it will double the fuel consumption but also double the power. This generator has a reliability record that is unsurpassed just like all honda products it will last and last if taken care of properly. An inverter is built into this package which means you can have AC or DC power,DC power is great to do such things as charge up a battery. If you want to use the eu300is for emergency or standby power it is suggested to use a transfer switch that will assure there is a safe connection to the home so it won accidentally electrify external power wires and cause a fire or injury.

Construction Industry In Kazakhstan Fostered By Government-initiated Programmes

One of the most prominent programmes prepared by the government is the State Programme on Forced Industrial-Innovative Development for 2010-2014, the main aim of which is to diversify the economy and increase its competitiveness. The programme calls for the expansion of several sectors, such as chemicals, nuclear and manufacturing, and to this effect, numerous investment projects are being implemented. Within the programme, 227 industrial plants and facilities have already been completed, at a total cost of $6.2bn. In turn, within the Road Map programme, 1,535 social system facilities were renovated in 2009-2010 as well as 2,634 educational facilities, 764 healthcare facilities, 119 sports facilities, and 361 cultural facilities. This led to an 18.6% increase in the value of renovation and reconstruction works in 2010.
However, government support was not sufficient to counterbalance the reduction in volumes of private sector investment. As a result, there was a reduction in the volumes of both residential and non-residential buildings, with housing construction being the most severely affected. The share of residential construction work as a proportion of the total volume of construction output in Kazakhstan fell from 19.3% in 2007 to 5.8% in 2009. In 2010, there was a slight increase in housing construction value, but the figure was still 62% lower than the figure in 2007, when this market area reached its peak. Overall, construction output grew by 1% last year and a similar growth rate was seen in the first half of 2011.

The total value of investment in residential construction decreased by 2% in 2010, though this could be considered mild in comparison with the 41% decline observed in 2009. State support continues to be provided and, coupled with increased volumes of loans, hope of a recovery on the residential construction market in Kazakhstan is strong. In the first half of 2011, the value of capital investment in the sector increased by 24.3%, with almost half of the total investment coming from the Kazakh people. Another positive sign of an ongoing revival on the residential market is that the number of buy/sale transactions has increased substantially, which indicates that demand for housing is back and strong. Housing development will also continue to be supported by the government and substantial amounts have been allocated for this purpose through the 2011-2014 housing construction programme.

This press release is based on information contained in the latest PMR report entitled Construction sector in Kazakhstan 2011 – Development forecasts for 2011-2013.

For more information on the report please contact:
Marketing Department:
tel. /48/ 12 618 90 00
e-mail: [emailprotected]