Issue 74

N. Meddour et alii, Fracture and Structural Integrity, 74 (2025) 227-261; DOI: 10.3221/IGF-ESIS.74.16

(a) (f) Figure A2-8: Different steps of the resistance to salt crystallization test on the stone type T1-(a) immersion,(b) drying, (c) repeated cycles, and dimensional measurements taking before and after each cycle for PE1-5 / PE1-3 sample, for MDL-Loss calculation after salt crystallization test. (d) loss in mass (M), (e) loss in diameter(D), (f) loss in length (l). A2-9: Resistance to accelerated ageing by HCl  Tools and software used : For the accelerated ageing test by HCl, the procedure involved exposing samples to HCl over 21 days, with chemical and mineralogical analyses to assess degradation influenced by urban pollution in Algiers, including measured particulate matter (PM10: 122 μ g/m³) and nitrogen dioxide (NO2: 91 μ g/m³) levels.  Objective : The accelerated ageing test by HCl was employed to assess mass loss, physical alterations (colour changes, cracks, etc.), and reductions in uniaxial compressive strength ( σ c, σ caf), as presented in Fig. A2-9. (b) (c) (d) (e)

(a) (f) Figure A2-9: Different steps of the determination of resistance to accelerated ageing with HCl in the presence of moisture- (a) samples washing and drying at 70C ˚ ,(b)samples water immersion during 24h,(c) sample placement in acid solution, and dimensional measurements taking before and after each cycle for PE2-6 / PE2-4 sample, for MDL-Loss calculation accelerated ageing with HCl. (d) loss in mass (M), (e) loss in diameter(D), (f) loss in length (l). A2-10 : Ultrasonic pulse velocity measurement  Tools and software used : For the ultrasonic pulse velocity measurement, the procedure involved using a Pundit-Proceq tester (54 kHz, transducers: 24–250 kHz) in direct, indirect, and semi-direct modes, achieving a precision of ±1%. Measurements were conducted across sample separations of 80–270 mm, using a template and coupling gel to ensure accuracy.  Objective : The ultrasonic pulse velocity measurement was employed to calculate the ultrasonic wave velocity (Vp), defined as Vp = L / T, where L is the known path length of the sample and T is the travel time of the ultrasonic wave, as presented in Fig. A2-10. (b) (c) (d) (e)

(a) (g) Figure A2-10: Different steps for the ultrasonic velocity test -(a) drying the tested block at a temperature of (70 ± 5) °C, (b) determination of reference points, (c)ultrasonic gel (d) Pundit-Proceq tester, and different transducer positions for determining the speed of sound propagation-(e) direct mode (f) semi direct mode (g) indirect mode. (b) (c) (d) (e) (f)

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