Cement Energy and Environment

A.... but also made the specimens more ductile. It is confirmed from the deflection values obtained. Cracking Behaviour and Ductility As discussed already with fibre have demonstrated better cracking characteristics unlike the specimens without fibre, in the case of fibrous specimens the crack has gradually spread till the final failure. As a result, the specimens have under gone more deflection for the same load compared to the fibre without fibre. Need for Triple Blending Fixed triple blending percentages of 20% fly ash and 10% of CSF are considered with a total replacement of 30% by weight of cement (OPC). 20% fly ash helps in increasing the workability and durability properties of the matrix. The loss of strength is negligible with this. 10% of CSF contributes towards increase in the strength besides the other beneficial properties. Fly ash contributes towards economy where as CSF contributes towards strength increase. Use of Fibres As discussed earlier, fibres are contributing towards vast increase in the split tensile strength and flexural strength respectively. This is true with or without admixtures. Light weight concrete mixes generally possess lesser strength compared to ordinary mixes. Strength gets decreased more and more with increase in the percentage of light weight aggregate used as replacement to the conventional aggregate. Addition of admixtures has contributed towards increasing the strength properties to certain extent, and with the presence of steel fibres where the strengths are increased further. The cracking and ductility properties are vastly improved. Addition of steel fibres (by 1 %) to the light weight concrete composites contributes towards making an optimum fibrous triple blended light weight cement concrete. Application of Light Weight Concrete Mix Fibrous triple blended light weight concrete composites can be employed for making thin wall panels, light weight roof panels, and pillar Conclusions Based on the present experimental investigations the following conclusions are drawn. 1) Use of superplasticizer is necessary for fibrous triple blended light weight aggregate pumice) concrete to maintain workability. 2) Light weight aggregate reduces the unit weight of concrete considerably. 100% replacement of conventional aggregate by light weight pumice aggregate reduces the unit weight of concrete by nearly 31%. 3) By with an optimum combination of 20% fly ash and 10% of CSF used as replacements to cement in the triple blended concrete mix, light weight concrete mixes are rendered more economical and stronger. 4) The addition of mineral admixtures like fly ash and CSF in the triple blended mixes of light weight concrete, contributes towards increase in the compressive strength considerably. 5) Addition of fibres increases the compressive strength further marginally. Fibres contribute towards considerable increase in the tensile and flexural strength . 6) 50% replacement of conventional aggregate by light weight aggregate with admixtures and with 1% fibres may be considered as the optimum fibrous triple blended light weight concrete mix. 7) The flexural strength increases with increase in percentage of fibre. Even in the case of light weight concrete certain percentages of steel fibres are required to be added to improve the flexural load carrying capacity, deflection capacity and ductility. Courtesy: The Masterbuilder, March 2016, Pg. No. 52-58 INVESTIGATION OF EARLY HYBRADATION DYNAMICS AND MICROSTRUCTURAL EVELOPMENT IN ORDINARY PORTLAND CEMENT USING 1 H NMR RELAXOMETRY AND ISOTHERMAL CALORIMETRY M.W. Bligh, M.N. d'Eurydice, R.R. Lloyd, C.H. Arns Abstract Benchtop 1 H NMR relaxometry was used to measure the fine temporal resolution of microstructural development during the early walls... etc. structural components. They are hydration of ordinary Portland cement under economical and reduce the weight of the structure different levels of retardation. Isothermal which results in economical construction. calorimetry was used to correlate the various 53