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| 099 | 9 | _aAIT Thesis no. ST-91-20 | |
| 100 | 0 | _aTanin Osotcharoenphol | |
| 245 | 1 | 0 | _aModelling of heat generation process for cement in concrete |
| 260 |
_aBangkok : _bAsian Institute of Technology, _c1991 |
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| 300 | _a46 p. | ||
| 490 | 1 |
_aThesis ; _vno. ST-91-20 |
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| 500 | _aA thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology | ||
| 502 | _aThesis (M.Eng.) - Asian Institute of Technology, 1991 | ||
| 520 | _aThis research is aimed to set up a more generalized mathematical model for heat generation process that is applicable to several types of cement. Cement particle is regarded as multi-component material composed of four main compounds of cement i.e. ~A, C4AF, ~S and C2S. Each of these chemical compounds is treated to have the same hydration characteristics as a single compound when hydrate alone. C3A and C4AF are grouped according to their hydration rate as the most rapid hydrating compound whereas C3S and C2S are regarded as the intermediate and the slowest hydrating compounds respectively. Instead of using the conventional procedure, where the heat generation rate is a function of time only, the coupled analysis of heat generation and heat conduction is introduced. The heat generation rate is considered to depend upon the temperature and past hydration process. The rate of heat generation process of cement compounds are calculated based upon the Arrhenius's equation. The activation energy and maximum heat generation rate are assigned corresponding to the hydration characteristics of each compounds. The heat generation rate of cement is computed from the summation of weighted heat of hydration generated by individual component comprising cement. An experimental program is performed to verify the analytical model. Thermocouples, which are used as a temperature measuring device throughout the test program, are installed at various positions of specimen before the placing of concrete. Thereafter, cubical concrete blocks insulated all sides by foam plates with 2 inches in thickness except the top surface are casted with different mix proportions and the temperature rise of concrete samples are measured at interval of 1 hour upto 7 days. The analytical results exhibit good corresponding with the experimental curves. It is noted that the peak temperature obtained from the experiment and computational method occurred almost at the same time, around 11 hours after placing of concrete. In the case of ordinary Portland cement, the peak temperature is slightly lower than the predicted values. When cement partially replaced with fly ash is introduced, the peak temperature become more of less the same. However, the temperature rise predicted by the proposed model increase more slowly than the measured temperature while decreasing rate of temperature after the peak value become higher than the experimental results. The comparison between the temperature rise curve obtained from multi-component model and temperature predicted by existing model is also carried out and satisfactory correlation is attained. It can be realized that the multi component model introduces a new approach to deal with prediction of temperature rise of any type cement possessing different chemical composition. | ||
| 650 | 0 |
_aConcrete _xChemistry |
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| 700 | 1 |
_aMaekawa, Koichi, _eChairperson |
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| 700 | 1 |
_aKarasudhi, Pisidhi, _eExamination Committee |
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| 700 | 0 |
_aPichai Nimityongskul, _eExamination Committee |
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| 710 | 2 |
_aGovernment of New Zealand, _eScholarship Donor |
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| 810 | 2 |
_aAsian Institute of Technology. _tThesis ; _vno. ST-91-20 |
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| 856 | 4 | 0 |
_3Full-Text _uhttp://203.159.5.9/ait-thesis/detail.php?q=B17728 |
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