PSI - Issue 78

Anastasios Drougkas et al. / Procedia Structural Integrity 78 (2026) 2102–2109

2109

4. Conclusions

The paper presents a micromechanical model of the piezoresistive response of cementitious materials, such as paste, mortar and concrete. It incorporates coupled mechanical and electrical homogenisation and simulates physical e ff ects that contribute to the heightened piezoresistive response of these materials through a simple phenomenologi cal approach. By modelling crack closure and material component deformation, the model is able to predict the high piezoresistive gauge factor of cementitious materials. Existing models have been successful in capturing the gauge fac tor of cementitious materials with added conductive inclusions, the gauge factor of unmodified cementitious materials has not been up to now adequately modelled. Further computational work along this line includes the consideration of interface e ff ects between the matrix and the inclusions, a random orientation distribution for the crack phase, which must additionally account for reorientation of the cracks in the deformed composite, as well as considering a distribution for the crack aspect ratio. Connectivity and tortuosity of the cracks as well as pore collapse and closure under compression, as well as the skeletal struc ture of the hardened paste matrix, can be taken into account for a more accurate representation of the cementitious microstructure. In the experimental sphere, the present work highlights on one hand the need for standardisation in the piezoresistive characterisation of cementitious materials, as well as the need for its coupling with more dedicated microstructural investigation on the other. This research performed in the context of the research project “Investigation of a 3D printed FRCM composite in sulator for smart building enclosures” COMPI3D, with grant number PID2022-137156OB-I00. The project is funded by the Spanish State Research Agency (Agencia Estatal de Investigacio´n) of the Ministry of Science and Innovation (Ministerio de Ciencia e Innovacio´n). The fourth author is a Serra Hu´nter Fellow. The authors acknowledge financial support for the dissemination of this work from the Special Account for Re search of ASPETE through the funding programme ”Strengthening ASPETE’s research”. Birgin, H.B., D’Alessandro, A., Laflamme, S., Ubertini, F., 2021. Hybrid carbon microfibers-graphite fillers for piezoresistive cementitious com posites. Sensors 21, 1–13. Bruggeman, D., 1935. Berechnung verschiedener physikalischer Konstanten von heterogenen Substanzen. I. Dielektrizita¨tskonstanten und Leitfa¨higkeiten der Mischko¨rper aus isotropen Substanzen. Annalen der Physik 416, 636–664. Drougkas, A., Sarhosis, V., Basheer, M., D’Alessandro, A., Ubertini, F., 2023a. Design of a smart lime mortar with conductive micro and nano fillers for structural health monitoring. Construction and Building Materials 367, 130024. Drougkas, A., Sarhosis, V., Macente, A., Basheer, M., D’Alessandro, A., Ubertini, F., 2023b. Mechanical and Durability Testing and XCT Imaging of a Lime-Based Micro-Scale Modified Smart Intervention Mortar. International Journal of Architectural Heritage 19, 276–291. Eberhardt, E., Stead, D., Stimpson, B., Read, R.S., 1998. Identifying crack initiation and propagation thresholds in brittle rock 35, 222–233. Esposito, R., Hendriks, M.A., 2016. A multiscale micromechanical approach to model the deteriorating impact of alkali-silica reaction on concrete. Cement and Concrete Composites 70, 139–152. Garc´ıa-Mac´ıas, E., D’Alessandro, A., Castro-Triguero, R., Pe´rez-Mira, D., Ubertini, F., 2017. Micromechanics modeling of the uniaxial strain sensing property of carbon nanotube cement-matrix composites for SHM applications. Composite Structures 163, 195–215. Mori, T., Tanaka, K., 1973. Average stress in matrix and average elastic energy of materials with misfitting inclusions. Acta Metallurgica 21, 571–574. Mura, T., 1987. Micromechanics of Defects in Solids: Mechanics of Elastic and Inelastic Solids. Springer Netherlands. Nezˇerka, V., Zeman, J., 2012. A micromechanics-based model for sti ff ness and strength estimation of cocciopesto mortars. Acta Polytechnica 52, 29–37. Song, G., Wang, C., Wang, B., 2017. Structural Health Monitoring (SHM) of Civil Structures. Applied Sciences 7. Ubertini, F., D’Alessandro, A., 2018. 18 - Concrete with self-sensing properties, in: Pacheco-Torgal, F., Melchers, R.E., Shi, X., Belie, N.D., Tittelboom, K.V., Sa´ez, A. (Eds.), Eco-E ffi cient Repair and Rehabilitation of Concrete Infrastructures. Woodhead Publishing, pp. 501–530. Wu, Z., Wong, H.S., Buenfeld, N.R., 2014. E ff ect of confining pressure and microcracks on mass transport properties of concrete 113, 485–495. References Acknowledgements