| Summary: | 碩士 === 國立中興大學 === 土木工程學系所 === 95 === The purpose of this research is to investigate the effects of adding pozzolanic materials on the hydration characteristics of the cement paste. First, for the conditions of varied experimental parameters including water-to-binder ratios(w/b), pozzolanic material replacements and testing ages, the compressive strength tests, the ignited loss analysis, and the MIP porosity measurements were conducted on three series of pastes— ordinary Portland cement (OPC) paste, fly ash-cement (FC) paste and slag-cement (SC) Paste. Second, the effects of experimental variables on compressive strength, non-evaporable water (wn) content, Ca(OH)2 content, degree of pozzolanic reaction and porosity of the three series of pastes were studied. The interaction existing in these variables was also assessed. Finally, the correlations between the results of each test would be analyzed and canvassed. The correlation formula would be further established according to the obtained experiment data.
Test results show that, for all series of pastes, with w/b increasing, wn content, Ca(OH)2 content, degree of pozzolanic reaction, degree of cement reaction, and porosity would increase. However, the compressive strength and the gel/space ratio of the pastes would decrease; For pozzolan-cement pastes, the wn content would decrease with the increase of the percentage of cement replaced by pozzolanic material; For OPC pastes, with the increase of age and w/b, the Ca(OH)2 content would increase, but after 28 days, the raising tendency has gradually slowed down. Nevertheless, the Ca(OH)2 content of FC and SC pastes would decrease with the age and the proportion of replacement increasing; The reaction degree of pozzolanic material is in connection with age and w/b. For the same w/b, the reaction degree of slag (14.7~40.3%) is higher than that of fly ash (3.1~28.3%); The porosity of paste would increase with the increase of pozzolanic material replacement. For lower w/b and replacement level, pozzolanic materials would have the better capability of filling pores; The gel/space ratio would decrease with the increase of the replacement of pozzolanic material. For both FC pastes and SC pastes, at the highest replacement level, the reduced extent of gel/space ratio would be significantly higher than that at the other replacement levels; As for the correlations between total pore volume and either compressive strength or gel/space ratio, OPC pastes possess the optimum correlation coefficients (R2 = 0.9242 & 0.8845).
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