Techno-Market Survey on Flyash Bricks

 

selection of fly ash brick manufacturing technology should be based on the availability of raw materials, financial strength of the entrepreneur, and the market characteristics (size and nature of applications, i.e. required strength and quality of the bricks / blocks etc.).

  • Clay fly ash brick technologies should be encouraged for conversion of large number of clay fired brick units and urgent steps taken is low investment and minimum changes from status quo are required.
  • Sand fly ash bricks should be introduced as a second step to conversion from clay fired bricks, or where semi-mechanized operations are justified on the basis of market demand.
  • Fly ash-lime bricks should be introduced where markets are larger to justify semi-mechanized or mechanized operations, and the entrepreneur has access to larger funds and raw materials.
  • Fly ash –lime gypsum bricks/blocks are very good products and should focus on large high quality markets where higher investment and product cost can be accepted by the market which would ultimately find the product cost-effective.


State agencies and other public construction agencies should draw up plans for the use of fly ash bricks and related technologies to the extent of at least 10% of total annual construction. Towards this, incorporation of the use of fly ash building components in the national standards and specifications and their schedules needs to be taken up urgently. Agencies 

  • BMTPC
  • Research institutions like CBRI, CFRI, NRDC, various CSIR labs, etc.
  • HUDCO, NBO, private builders, architects and town planners
  • Academic institutions like IITs, engineering colleges, schools of architecture etc.
  • Ministry of Urban Development
  • State Government / PWDs / Housing Boards

Certain plant and equipment is required to be imported for availing large scale production of fly ash based products like light weight sintered aggregates and autoclaved blocks. Several European countries like Sweden, France Germany etc. have proven technologies for mechanical plants and material handling systems. The know-how and expertise in processing fly ash for mass consumption, ceramic burning technology, mechanized cutting and drying, and adequate R&D infrastructure are prerequisites for superior quality fly ash product and process development. The import of machinery for automatic cutting and hydraulic pressing and necessary know-how may be allowed on easy terms, wherever necessary, for early commencement of high quality fly ash brick manufacture.
Agencies :

  • BMTPC
  • Ministry of Power
  • Ministry of Finance
  • Ministry of Commerce
  • Ministry of Urban Development
  • Associations of industries like CII, FICCI and ASSOCHEM.


Transportation of fly ash is problematic. Fly ash should be utilized close its source. While this would increase the cost of transportation of bricks, a part of the saving in cost of fly ash disposal should be used to subsidize this cost (disposal of fly ash in any unproductive use should be made penal and expensive).

Transportation of fly ash should be done in bulk by railway tankers or road tankers, suitably fabricated and equipped. Automatic loading and unloading through compressor / vacuum pumps mounted on the tankers should be utilized.

  • NTPC
  • SEBs
  • Ministry of Surface Transport
  • Ministry of Railways
  • Associations of Automobile Manufactures
  • Manufacturers of commercial vehicles and material handling equipment.


Variations in fly ash quality creates special problems for manufacturers of fly ash products. The small entrepreneur may not be in a position to afford adequate testing facilities. There is a need to have technical support in this direction. Each batch of fly ash could also be classified and certified at source to enable the manufacturer to know what he is getting.

Suitable agency should be set up to supply dry fly ash of certified quality conforming to IS:3812-1981.
Agencies :

  • CEA
  • NTPC
  • SEBs
  • BMTPC
  • Research institutions like CBRI, CRRI, NRDC, various CSIR labs, etc.
  • HUDCO, NBO, private builders, architects and
  • Ministry of Urban Development. Industry Associations
  • Bureau of Indian Standards


While it is generally known that lime reactivity of fly ash increases with fineness, no definitive relationship has yet been evolved in this direction. Special research project needs to be taken to evaluate relationship between lime reactivity of fly ash and its physical and chemical properties. This could prove a boon for fine tuning the bricks/block making processes to suit the variations in the fly ash properties as made available by the TPPs. This needs to be done by a set of research institutions along with fly ash generators and potential entrepreneurs.
Agencies :

  • NTPC
  • BMTPC
  • SEBs
  • Research institutions like CBRI, CRRI, NRDC, various CSIR labs, etc.
  • HUDCO, NBO, private builders, architects and
  • Academic institutions like IIT,s engineering colleges, schools of architecture etc.


Application of fly ash as building component is slowly gaining acceptance. This can increase the use of precast fly ash bricks/blocks. Nonetheless, full scale structural engineering and cement chemistry studies are forwarded. An independent code of practice and testing needs to be developed for effecting large scale utilization of fly ash.
Agencies :

  • NTPC
  • SEBs
  • BMTPC
  • Research institutions like CBRI, CFRI, NRDC, various CSIR labs, etc.
  • Academic institutions like IITs, engineering colleges, schools of architecture etc.

 

The present fly ash disposal practices are environmentally very expensive propositions.
Use of clay for brick manufacture costs the nation very heavily in terms of (I) permanently losing valuable top soil which nature takes a few million years to make good (ii) greater use of energy and (iii) often inferior bricks. These costs are not reflected adequately in the market price of clay bricks. The bricks are normally manufactured close to towns and cities which are their main markets. This, therefore, pollutes the urban environment.

Therefore, restrictions should be imposed on the use of clay bricks within a time frame of five years, starting with the four metros, Hyderabad, Ahmedabad, Vadodara, Pune, Kanpur, Nagpur, Roorkee / Hardwar and regions of South Gujarat like Surat / Vapi / Ankaleshwar where there is considerable construction activity taking place, and TPPs are nearby. In the next 18 monhs, other class I towns in next four years, and all towns in five years time.

(The technologies suitable to local conditions should be adopted. Lime stone availability is fairly wide spread in the country. Aspects relating to availability of any non-fly ash raw materials were not found to be consequential).

Simultaneously technical, infrastructural and financial support needs to be provided to encourage rapid building up of capacity for fly ash bricks and blocks, and markets for the same. The financial incentives could be in the form of free fly ash, transport subsidy, tax holiday, preferential purchases by govt. bodies, cheap land near TPPs, etc. Retail outlets and distribution network could be provided, if need be.

This could be effected under an umbrella organization having representation from some of the organizations mentioned below, and its policies should be binding.

Agencies :

  • BMTPC
  • CEA
  • NTPC
  • SEBs
  • Research institutions like CBRI, CFRI, NRDC, various CSIR labs, etc.
  • BUDCO, NBO, private builders, architects and town planners
  • Academic institutions like IITs, engineering colleges, schools of architecture etc.
  • Ministry of Urban Development
  • State Governments/PWDs/Housing Boards
  • Financial institutions
  • Ministry of Environment

 

Existing infrastructure for technological research, information dissemination should be strengthened. Training, technology extension and skill upgradation through a network of building centres in urban and rural areas set up by state agencies, research bodies and voluntary agencies, and dissemination of information to the actual users and communities.

Bureau of Indian Standards should be requested to review the present status of Indian Standards on building materials produced from fly ash and to take up writing of new standards or incorporate suitable amendments in the existing standards to cover these materials, as the case may be on an on-going basis for acceptance by major government and private builders, housing boards and PWDs.

The existence of conventional by-lays, schedules, specifications and contract systems are not suitable for adoption of new materials based on fly ash. Modification of these procedures and systems are necessary for greater utilization of fly ash based building materials and components.

Agencies :

  • BMTPC
  • CEA
  • NTPC
  • SEBs
  • Research institutions like CBRI, CFRI, NRDC, various CSIR labs, etc.
  • HUDCO, NBO, private builders, architects and town planners
  • Academic institutions like IITs, engineering colleges, schools of architecture etc.
  • Ministry of Urban Development
  • State governments / PWDs / housing boards
  • NGOs and voluntary agencies
  • Bureau of Indian Standards.

 

  • Possible effects of radio activity needs to be studied for long term impact. The findings should be integrated into the overall policy framework. Guidelines should be issued regarding design and ventilation aspects for utilizing fly ash based building materials and components.
  • BMTPC
  • BARC
  • Research institutions like CBRI, CRRI, NRDC, various CSIR labs, etc.
  • Ministry of Urban Development
  • Bureau of Indian Standards.



 

    Impact

  • Disposal of 51 million tonne of fly ash per year today is a major problem. The country is productively using only about 3% or 1.5 million tonne of fly ash. Thus, 49-50 million tonne of fly ash per year at present poses environmental threat. This figure will grow to over 87 million tonne per year by the turn of the century, if present dismal level of utilization only ash is maintained.
  • The demand for bricks is expected to be about 100 billion per year by the turn of the century. Even if only 50% of the estimated demand of 100 billion bricks per year, is met from fly ash for productive use saving alternate resources, and reducing environmental hazard to that extent. In addition, it would save thousands of hectares of land from being used as ponding area. And this still does not account for the potential of using other industrial wastes like red-mud.
  • As stated earlier, the demand for bricks is expected to be about 100 billion per year by the turn of the century. Even if only 50% of the estimated demand of 100 billion bricks per year, is met from fly ash by the turn of the century, about 1 lakh ha of land would have been saved from turning into waste land per year.
  • Translating the above two into financial cost can be mind boggling. Add to it, the direct saving in energy cost which can be effected by adopting certain processed for manufacture of fly ash bricks / blocks.

 




Back