PSI - Issue 13

Libor Topolář et al. / Procedia Structural Integrity 13 (2018) 1177 – 1182 Author name / Structural Integrity Procedia 00 (2018) 000 – 000

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values for the reference samples have 100%. The subsequent decreases of these values allow easier determination of the resistance of the mixtures against elevated temperatures. Despite the fact that the mixture B has the best flexural strength in absolute values, the relative values show that the decrease is very similar for all three mixtures. From the point of view of relative AE signal durations and energy, the mixture C exhibits the best resistance and the smallest damage to the inner bonds. This is probably caused by the use of fine grain size of the aggregate, which is most likely better at retaining the decomposing Portlandite. On the other hand, the worst is the mixture A. The worst results of the mixture A can be explained by the omission of the aggregate grain size 4/8. The graphs also indicate that all the mixtures reach relatively similar values (relative to the initial values) after sintering and the creation of the ceramic bonds (1200 °C).

Mixture A Mixture B Mixture C

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Realative flexural strength (%)

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Temperature of degradation ( C)

Mixture A Mixture B Mixture C

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20 Realative duration of AE signal (%) 400 600

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Temperature of degradation ( C)

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Realative energy of AE signal (%)

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Temperature of degradation ( C)

Fig. 2. Comparison of the relative values and their subsequent decreases depending on thermal degradation