PSI - Issue 64

A. Alecci et al. / Procedia Structural Integrity 64 (2024) 1951–1958 Alecci et al. / Structural Integrity Procedia 00 (2019) 000 – 000

1954

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4.1. Mechanical properties of the thermal plasters Three mortar specimens of size 40x40x160 mm 3 for each type of thermal plaster (Int_01-Int_11) were obtained using standardized metal molds and tested, after curing for 28 days in a controlled temperature room, under three point bending tests, according to UNIEN1015 (2019). Next, axial compression tests were performed on the two stumps obtained after failure of each specimen due to the bending test. The tests were carried out under displacement control, using an Instron-Satec universal hydraulic machine with a 600 kN hydraulic actuator. Results of the three-point bending tests and compression test are summarized in Table 2 where compressive strength (f c ), compressive elastic modulus (E c ), and flexural strength (f b ) are reported. The elastic modulus was calculated and evaluated between 30% and 60% of the maximum load in the first linear branch of the stress-strain curves, Alecci et al., (2019), Simões et al., (2015), Valluzzi et al., (2005).

Table 2. Mechanical properties of Int.01- Int. 11 matrices (Laboratory results). Thermal Plaster Compressive strength σ [N/mm 2 ]

Compressive Young’s modulus [N/mm 2 ]

Flexural strength [N/mm 2 ]

Int_01 Int_02 Int_03 Int_04 Int_05 Int_06 Int_07 Int_08 Int.09 Int.10 Int.11

2.41 0.38 0.46 0.73 0.89 2.49 0.11 1.23 1.15 1.86 0.76

138.7

0.30 0.07 0.06 0.06 0.10 0.27 0.10 0.02 0.03 0.07 0.12

75.9 10.7

132.0

63.7

292.5

3.2+

222.2 211.3 385.1 77.30

Figures 2a) and 2b) plot the compressive and flexural stress-strain curves of the texted thermal plaster specimens recorded during the tests.

Fig. 2. a) Compressive stress-strain curves of Int.01-Int.11 specimens

b) Flexural stress-strain curves of Int.01-Int.11 specimens.

The results obtained from the experimental campaign provided an average compressive strength of 1.13 [N/mm 2 ] corresponding to the CS I category (0.4 ÷ 2.5 N/mm2), of the mortar classification as reported in the technical standard for the design, execution and testing of masonry constructions in according to UNIEN998-1 (2016) standard. For flexural and compressive strengths, respectively, the values are in the ranges of 0.02 [N/mm 2 ] and 0.30 [N/mm 2 ] for flexural strength and 0.11 [N/mm 2 ] and 2.49 [N/mm 2 ] for compressive strength. Accordingly, the flexural and uniaxial compression tests show that the thermal mortar with the best compressive strength is Int_06, with a compressive strength value of 2.46 [N/mm 2 ]. Thermal plasters Int_06, Int_01, and Int_10 showed the highest values of compressive strength, flexural strength, and Young’s modulus, respectively.