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Invention of Self-compacting Concrete happened to circumvent the crisis of labour shortage. It is these kinds of circumstances that stretch the imagination to overcome the shortcomings and enrich product features. In this Special Issue on Self-compacting Concrete, different methods and materials are experimented to further improve concrete durability properties and also contribute to sustainability.

Three packing models are tested for three grades of concrete to determine the optimal proportions and combinations of aggregates required for Self-compacting Concrete (SCC). This study also examines modifications to the existing grading curves mentioned in the IS 383 code to suit mix design for SCC and the authors derive an economical and reliable mix design using Compressible Packing Model method with minor modifications in the existing IS 383 grading for conventional mixes. The second paper studies mix design methodologies for SCC using IS 10262:2009 based on optimized aggregate fractions obtained from Compressible Packing Model.

Replacement of river sand with Quartz sand in varying dosages is experimented confirming its suitability for use in SCC. Significant improvements in concrete properties were observed with usage of quartz in SCC. An extensive study was carried out to investigate the effect of paste volume on the fluid-solid system of SCC and its influence on the compressive strength of SCC mixtures. Results indicate increase in compressive strength of SCC with paste content for the same w/c ratio. Author also suggests modification in concrete mix design to economize on cement content.

Various durability studies are conducted on quaternary blended SCC containing Fly ash, GGBS and Microsilica. Results are compared with control SCC and the performance observed on durability parameters is encouraging. Using these materials also contribute to reusing waste and thus promoting sustainability! There are three papers under Point of View. The development of nano technology has enabled the development of concrete with improved physical, mechanical and durability characteristics. This paper studies the improvement in concrete properties with the use of Carbon Nano Tubes.

Partial replacement of Rice-husk ash and Bagasse ash with cement to produce self-compacting mortar is investigated for their fresh and hardened properties. Finally, the third paper under POV compares guidelines as per EFNARC and ICAR for designing SCC with a practical model developed by the author for predicting void content of aggregate for different proportions to optimise concrete mix for achieving SCC properties. Trust you must have by now got the recipe and understood the art of designing SCC!! Do write to us, if you wish to cover subjects of your choice.

The Indian Concrete Journal, ACC Limited, L.B.S. Marg, Near Teen Haath Naka, Thane 400 604, Maharashtra

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