PSI - Issue 17

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

1004

3

Each mortar composition was molded in standard metal molds, following the standard EN 1015-11 (2006), obtaining prismatic specimens with the standardized dimensions 40 x 40 x 160 mm 3 . The curing process of the specimens was performed in a controlled environment, following the standard EN 1015-11 (2006).

2.2. Mechanical characterization

Mechanical characterization of each mortar composition at different specimen ages was performed, with the following tests: determination of specimen’s compressive strength ( σ c ) and determination of specimen’s static and dynamic E values. Dynamic E was determined with the Resonance Frequency methodology (DME-RF) and the Direct Ultrasound methodology (DME-US). The σ c tests were performed in accordance with the standard EN 1015-11 (2006). This destructive test allows the determination of the compressive strength of hardened mortars by applying compressive load until failure of the specimen, and served as a validation tool for the E results. These tests were carried out on a mechanical test machine (ETI – HM-S/CPC from PROETI). For the dynamic E tests, two non-destructive methodologies were used: the Resonance Frequency dynamic methodology, according to the standard EN 14146 (2004), and the Ultrasonic dynamic methodology according to the standard EN 12504-4 (2004). The Resonance Frequency methodology was performed using a Zeus ZRM 2005 test machine, with the Longitudinal Resonance Frequency procedure. The Ultrasonic dynamic methodology was carried out using a Steinkamp Ultrasonic tester BP-7. Table 3 presents the test parameters used for the previously described mechanical characterization tests and the mean values obtained for the σ c validation tests.

Table 3. Experimental campaign test parameters and mean values of the σ c tests.

Compressive strength ( σ c )

Mortar Composition

Age [days]

Standard deviation [MPa]

Coefficient of variation [-]

Average [MPa]

14 21 28 90 14 21 28 90 14 21 28 90 14 21 28 90

23.3 28.2 25.0 28.2 27.6 11.1 10.5 10.7 10.3

0.68 2.35 2.34 1.55 1.80 0.46 0.51 0.74 0.19 1.80 0.20 0.32 0.14 0.27 0.00 0.10 0.09 0.06 0.28 0.18

0.029 0.083 0.094 0.055 0.065 0.042 0.048 0.069 0.018 0.210 0.037 0.057 0.028 0.061 0.000 0.014 0.015 0.009 0.053 0.036

Ci_1:2

365

Ci_1:3

365

8.6 5.4 5.6 4.8 4.4 4.1 6.9 6.2 6.3 5.4 4.9

Ci_1:4R

365

Ci_1:4A

365