PSI - Issue 17

Ana Isabel Marques et al. / Procedia Structural Integrity 17 (2019) 1002–1009 Ana Isabel Marques / Structural Integrity Procedia 00 (2019) 000–000

1007

6

In order to determine the static E of the specimen, the average loading cycle is determined with the data from the three loading cycles (Step 5). For this average loading cycle, the data points near both inversions of each loading cycle are removed to avoid data disruption. On average this corresponded to removing the top and bottom 5% of the curve. After calculating the resulting stress-strain curve, a linear trend line is applied to the data. The slope of this trend line is the specimen’s static E value, according to Hooke’s Law

4. Results

This section presents the results of the experimental tests previously described. Concerning the dynamic E data obtained, the values are in accordance with relevant bibliography (Veiga et al., 2010; Veiga, 2017) regarding expected values ranges. In addition, dynamic E values obtained with both methodologies used in this study are relatively similar with each other, further reinforcing both methods as reliable and high quality dynamic experimental methodologies for coating mortar tests (Marques et al., 2019). The expected higher dynamic E values than static E values are also observable. The mechanical characterization values obtained (Table 3) are also consistent with the reference bibliography (Veiga et al., 2010; Veiga, 2017). Fig. 4 illustrates the E data collected for all cement composition used in this study. The colored lines represent the average static E data for the different ages tested and the average dynamic E data for both experimental methodologies. This data shows similar evolutions between static and dynamic E values for all compositions, i.e., when the static E changes due to an increase in specimen age, both corresponding dynamic E values also change with similar magnitudes. Age evolution seems to have relatively low impact on the mechanical characteristics of all cement compositions tested. Static E values obtained also showed the lowest standard deviation values from all three experimental test methodologies.

Fig. 4. E data collected for all cement composition in study.

Having analyzed the obtained static and dynamic E data, ratios between both types of data were calculated. Table 4 shows partial ratios for each mortar composition and for each test parameters sets, together with average overall ratios according to binder type or age (grouping both dynamic methodologies in the same values). By comparing the