PSI - Issue 11

Alisson Rodrigues de Oliveira Dias et al. / Procedia Structural Integrity 11 (2018) 84–90 Author name / Structural Integrity Procedia 00 (2018) 000 – 000

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which would be the exposure to high temperatures of constant form for 30 minutes. Being important to emphasize that the specimens were exposed to the heat during the process of heating of the furnace until the desired temperature for study is reached, according to the heating rate curves of the furnaces used, shown in Figure 1. From this, the counting of time was started.

Fig 1. Heating rate of the used oven.

Finally, aiming at a more detailed analysis of the behavior of the concrete submitted to high temperatures, a analysis of variance (ANOVA) was performed as well as the Tukey test by average of software.

3. Experimental results

The values of the ultrasonic pulse velocity (UPV) for type cooling (in water and in air) are presented in Figure 2. The ANOVA showed that the type of cooling (in air and water) does not have significant influence in UPV.

Fig. 2. Influence of the temperature-cooling rate on the reduction of the UPV.

Analyzing the variation of fck values, the ANOVA demonstrated that this influences significantly the ultrasonic pulse velocity in concrete (Figure 3). Figure 4 shows the values of the UPV for each fck individually with the temperature analyzed and the test of comparisons of average of TUKEY.