Infrastructure Engineering - Research Publications
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ItemStrength Development and Thermogravimetric Investigation of High-Volume Fly Ash Binders(MDPI, 2019-10)To address sustainability issues by facilitating the use of high-volume fly ash (HVFA) concrete in industry, this paper investigates the early age hydration properties of HVFA binders in concrete and the correlation between hydration properties and compressive strengths of the cement pastes. A new method of calculating the chemically bound water of HVFA binders was used and validated. Fly ash (FA) types used in this study were sourced from Indonesia and Australia for comparison. The water to binder (w/b) ratio was 0.4 and FA replacement levels were 40%, 50% and 60% by weight. Isothermal calorimetry tests were conducted to study the heat of hydration which was further converted to the adiabatic temperature rise. Thermo-gravimetric analysis (TGA) was employed to explore the chemically bound water (WB) of the binders. The results showed that Australian FA pastes had higher heat of hydration, adiabatic temperature rise, WB and compressive strength compared to Indonesian FA pastes. The new method of calculating chemically bound water can be successfully applied to HVFA binders. Linear correlation could be found between the WB and compressive strength.
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ItemNo Preview AvailableParametric study of the effect of thermal properties and ambient temperature on tensile stress and strength development in mass concrete(The International Federation for Structural Concrete (FIB), 2019-01-01)Thermal stress typically takes place at early ages when concrete is undergoing exothermic hydration reaction and is restricted from expansion and contraction by surrounding structural elements. In mass concrete structures, the relatively large temperature differences between the core and the surface produce differential dilation which leads to tensile stresses. Potential tensile cracks develop when the stress experienced by the concrete exceeds the concurrent strength of the maturing concrete. This effect in turn can lead to performance reduction, or in some instances, instability of structure and must be dealt with care. While published literature reports extensively on hydration based mechanical properties of concrete, only a few has considered investigating the in-situ performance of the material accounting for thermal stresses. In what concerns crack formation, consideration of the thermo-mechanical boundary conditions are important nuts that have not been investigated explicitly. This research aims to provide insight into the impacts of thermal related parameters on early age concrete crack formation through computational modelling.
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ItemMaintenance of building structural systems(Nethwin Printers, 2016)The aim of this paper is to review the current literature on maintenance of building structural systems. It emphasises the importance of maintenance as an item for consideration from the beginning of the conceptual design stage. Building sustainability concept is generally understood to have better energy efficiency focus and maintenance of structural components ensures they serve their designed service life and beyond. The conventional design approach considers structural maintenance during the “product use” phase. This paper argues that if the accessibility of the building and maintenance (inspection, repair and retrofitting) are considered from the early conceptual design stage, it would save resources and maintenance cost. Case studies of buildings subject to earthquake loading and corrosion and their maintenance are presented.