Opportunities for Research in Cement and Building Materials

   The cement industry is responsible for generation of nearly 5% anthropogenic carbon dioxide (CO2) globally. The production of one tonne cement leaves nearly equal amount of CO2 in the atmosphere. Thus while meeting the increasing demand of cement worldwide, adequate attention also need to be paid to produce and use cement  in sustainable manner, i.e. creating minimum impact on the environment and the natural resources. Dr Bapat talked before the 
section of students, researchers and the faculty. While expressing his views on the opportunities, he deliberated on the following aspects:

  • Raw materials
  • Fuels
  • Portland cement substitution
   Cement is manufactured using mainly limestone, clay and certain additives. In the near future, there is no possibility of making any major change in the raw materials and the manufacturing process. However there is good scope for alternative fuels and partially replacing Portland cement in greater proportion in concrete. 

   Among the substitute fuels tried or under trial for cement burning are: refuse-derived fuels (RDF), tire-derived fuel (TDF), meat and bone meal (MBM), waste wood, sewage sludge, municipal wastes, paper and plastics, chemical (including hazardous) waste, biomass. The alternative fuels require modification of the burner and also existing kiln systems. These fuels may influence process stability and product quality. 

   The mineral admixtures like fly ash, blast furnace slag, silica fume, rice husk ash and metakaolin effectively replace cement in concrete and also contribute towards the strength and durability of the structures. These are industrial and agricultural wastes. The volume of these wastes produced globally exceeds their utilisation. Besides there is also good scope to develop new admixtures; those currently under development are: ash produced from biomass, namely corn cob ash (CCA), palm oil residue ash (PORA), sugarcane bagasse ash (SBA), wheat straw ash (WSA), wood waste ash (WWA); sewage sludge ash (SSA) and municipal solid waste ash (MSWA).  

   Attempts can also be made to increase the replacement level of cement with fly ash in blended cements; typically known as high volume fly ash cements. The Portland limestone cement (PLC) should also be considered in countries where it is not yet standardised.  

   The lecture was followed by q/a session and there was active participation.