On June 21 2023 at 16.00, Nicolas Ospitia Patino will defend his PhD entitled “UNRAVELING TEXTILE-REINFORCED CEMENTITIOUS COMPOSITES BY MEANS OF MULTIMODAL SENSING TECHNIQUES”.
Everybody is invited to attend the presentation at the Room D.0.08.
Textile Reinforced Cementitious (TRC) sandwich composites are innovative construction materials composed of two slender TRC facings, and a thick thermal and acoustic insulating core. Their non-corrosive nature allows for slender structures, resulting in a reduction of the cement used, and therefore a decrease of the negative impact on the environment. The sandwich technology brings superior bending resistance while enforcing the lightweight nature of the composite. Despite the numerous advantages of TRC sandwich composites, they present a complex and possibly unpredictable fracture behavior, and manufacturing issues such as a weak interlaminar bond and therefore, need status verification in the different stages of their service life: at manufacturing stage (curing), final product quality (manufacturing defects), deterioration during use (damage accumulation). Up to the moment, there is no reliable non-invasive inspection protocol that assesses the curing of the cementitious facings, provide quality control, and damage monitoring.
Along this study, a combination of Non-Destructive Testing (NDT) techniques is employed to provide a protocol that allows to monitor the composite from the hardening of the cementitious facings, quality control, and finally, damage characterization. Electromagnetic millimeter wave (MMW) spectrometry is employed for the first time in this kind of material to monitor the hydration of cementitious media, quality control, and damage characterization. Additionally, passive, and active elastic wave-based NDT techniques, like Acoustic Emission (AE) and Ultrasound, respectively, are also used in combination with Digital Image Correlation(DIC) to characterize the material along its lifetime, and benchmark MMW spectrometry. This thesis summarizes the results of an extensive experimental campaign, highlighting the innovative contributions. Previously unknown relations between electromagnetic properties measured by MMW and mechanical properties by ultrasound are revealed owing to the common origin of hydration reaction that dictates the permittivity and stiffness development. AE during proofloading reveals the effect of manufacturing defects due to the local stress field variations they impose under mechanical test. In addition, cracking and debonding leave a strong fingerprint on the electromagnetic transmission, enabling a multi-spectral methodology for the structural health monitoring (SHM) of such innovative components during their lifetime.