PSI - Issue 37

Jesús Toribio et al. / Procedia Structural Integrity 37 (2022) 985–988 Jesús Toribio / Procedia Structural Integrity 00 (2021) 000 – 000

987 3

0.9 s

0.1 s

-0.2 kN

-6.4 kN

Fig. 3. Load sequence: sinusoidal (dashed) and complex (continuous).

Tests were performed under load control, measuring the displacements at a test temperature of 20ºC. Two load values were adopted as 1.6 kN (light vehicles) and 6.4 kN (heavy vehicles), using the latter because the former produced a negligible damage and deterioration on the samples. Since the HBMs exhibit a viscous behaviour, the most adequate parameter to evaluate the degradation and evolution of the HBM is the cumulative strain. Two phases were observed: (i) first phase with rapid increase of strain (associated with material accommodation and decrease of voids); (ii) second phase of linear behaviour. The mechanical fatigue behaviour of the HBM depends on the load frequency and on the test temperature. For high frequencies (applying load time of ~0.1 s) and low temperature (<10ºC) the behaviour is linear elastic. However, for higher temperature and longer loading the behaviour is visco-plastic. 3. Role of de-icing salts in the mechanical behaviour of HBMs Tino et al. (2011) analyzed the effect of salts on the mechanics response of HBMs. Visible cracks appear in the samples immersed in salt solution after 48 hours (Fig. 4).

Fig. 4. Sample that was not immersed (left) vs . sample immersed in water during 35 days (right).

4. Influence of external factors on the mechanical response of HBMs Tino et al. (2012; 2013) studied the influence of external factor on the mechanical response of HBMs. The results indicate the damaging effect of: (i) high temperatures; (ii) presence of water and humidity; (iii) presence of de-icing salts; (iv) cyclic (fatigue) repetitive loading.