Durability and thermal gravimetric analysis of high volume palm oil fuel ash concrete
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Date
2014
Authors
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Publisher
Universiti Teknologi Malaysia
Abstract
Palm Oil Fuel Ash (POFA) is a pozzolanic material derived from controlled incineration of palm biomass and has been widely acknowledged to greatly influence the properties of concrete. Inspite of various researches carried out to investigate this phenomenon, very little is known on high volume application of ash in concrete. The research is dedicated at investigating various properties of concrete containing High Volume Palm Oil Fuel Ash (HVPOFA). Except some few tests which involved the use of mortar specimen, the performance evaluation of HVPOFA had largely been accomplished with specimens made of concrete where Ordinary Portland Cement (OPC) was replaced by 50 up to 70% POFA. The fundamental properties including the pozzolanic behaviour of the ash were investigated. From the study, it was observed that, the use of high volume POFA did not impact positively on the workability of concrete. However, the inclusion of superplasticiser has shown a tremendous influence in realising the workability. In comparison with other high volume ash concrete, early compressive strength development of concrete containing HVPOFA was impaired. The later age strength was noted to be almost the same as the control. Other strength properties of HVPOFA concrete showed a similar pattern of behaviour, though with a different magnitude. The influence of high volume POFA on deformation properties of concrete in terms of creep and shrinkage was also investigated. It has been demonstrated that a replacement of 50% OPC with POFA had no significant effect on creep and shrinkage of concrete. The research critically examines various aspects of durability of concrete containing HVPOFA against physical and chemical attack. As compared with the specimen made from OPC alone, specimen containing high volume ash demonstrated higher performance to destructive chemicals like chloride, acid and sulphate as well as elevated temperature. It is the pozzolanic effect of the ash that has contributed to the tremendous performance against aggressive environment. Specimens containing HVPOFA, however showed slight weakness in the carbonated environment as compared to OPC specimen. Test results on heat of hydration show that replacement of cement with HVPOFA is advantageous, particularly for mass concrete where thermal cracking due to excessive heat rise is of great importance. Microstructural tests in terms of X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-Ray (EDX) and Thermal Gravimetric Analysis (TGA) were concurrently conducted on both OPC and HVPOFA concrete in order to determine the interaction and effect of the particle that brings about the performance of the concrete containing HVPOFA. Finally, the performance of HVPOFA concrete has, in general, found to be quite satisfactory and can be used as high volume cement replacement material in concrete
Description
Thesis (Ph.D (Civil Engineering))
Keywords
Concrete—Additives, Ash (Combustion product), Superplasticity