A lecture programme on concrete for the members of the Mysore Centre of Association of Consulting Civil Engineers (ACCE (I)) was held in the city, recently.
Dr R V Ranganath, Professor of Civil Engineering, BMS College of Engineering, Bengaluru, delivered a lecture on ‘Modern concrete: Changing paradigms.’
He elaborated on developments that have taken place right from the time of evolution of concrete. “As the times and needs changed, different types of concrete came into market. While high early strength concrete enabled the early de-shuttering, Self Compacting Concrete (SCC) eased the process of concreting. As the name of SCC suggests, by the highly fluid nature of concrete, the consolidation process is automatically taken care of. In fact, with SCC, all the elements of a building such as columns or walls, beams and slabs could be simultaneously cast and this process has vastly enhanced the speed of construction. Fibre Reinforced Concrete (FRC) has also become very popular. In FRC, metallic and non-metallic fibres are added to achieve higher strengths in concrete. By adding hyper plasticisers, water cement ratio could be considerably brought down consequently enhancing the compressive strength of concrete,” averred Dr Ranganath.
Dr Ranganath further said that fly ash, plentifully generated in thermal power plants in our country, had become one of the vital components of concrete. He also observed that if fly ash could not be used in concrete, disposing of huge quantities of fly ash would have been an arduous and challenging task.
Dr Ranganath talked about the contribution of nano materials in enhancing the properties of concrete microstructure. He quoted references of designing Ultra High Performance Concretes (UHPC) of the order of 120 to 150 MPa using ultrafine, nano materials. “UHPCs have shown a great promise in repair and rehabilitation works.”
Dr Ranganath dwelled in detail on Geopolymer Concrete (GPC) produced with fly ash, Ground Granulated Blast Furnace Slag (GGBS), fine aggregate, coarse aggregate and solutions of sodium silicates and hydroxides. “GPC is a little more expensive as compared with the normal concrete (NC) but has very good properties when compared with latter. Australia has taken a lead role in using GPC while its use is yet to gear up in our country”, said Dr Ranganath.
Past Chairman, Prof C N Yadunandan presented certificates to the new members. Chairman R Sundara Murthy, treasurer H S Deepak and secretary S B Basavaraj were present.
-NGB, K K