PSI - Issue 64

Irene Palomar et al. / Procedia Structural Integrity 64 (2024) 1435–1443 Irene Palomar et al. / Structural Integrity Procedia 00 (2024) 000 – 000

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3.4. Thermal and hygric properties Thermal and hygric properties measured on hardened mortar samples with SAP and PCM are summarized in Figure 6. Thermal characterization comprised thermal conductivity and enthalpy of heating and cooling cycles from 10 °C to 28 °C and vice versa, respectively. Regarding thermal conductivity, it was observed that SAP particle shape influenced thermal conductivity, as spherical SAP reduced conductivity while 1% of irregular SAP increased this value. On the other hand, PCM reduced thermal conductivity in all mixtures, according to Guardia et al. (2019). Besides, SAP did not modify enthalpy, while PCM increased the energy storage by 4J/g in all cases, as expected. Regarding hygric properties of hardened mortars, SAP reduced capillary absorption from 1.3 to 0.88-1.23 kg/m 2 min 0.5 , while PCM increased absorption up to 1.37-1.47 kg/m 2 min 0.5 due to the larger microporosity of mortars with PCM. On the other hand, SAP reduced vapor permeability both on dry and wet conditions. When PCM was incorporated to mortars already with SAP, permeability was reduced on wet conditions while increased in dry conditions. This behavior can be also related to the microstructural porosity that can be used for mass transfer when is dry and open but got closed in wet conditions. Moisture buffer value (MBV) was measured on mortars according to Nortest test described in Rode et al. (2006) and is also reported in Figure 6. Reference mortar showed high values reaching a class Good . SAP did not modify MBV, also reaching class Good , while PCM slightly reduced MBV and was classified as class Moderate .

Fig. 6. Thermal and hygric experimental results of bio-based self-modulating mortars with SAP and PCM.

Fig. 7. Heat and moisture transfer simulations: heat flux in (a) a cooling cycle; (b) a wetting cycle.