Chemo-physico-mechanical properties of the interface zone between bacterial PLA self-healing capsules and cement paste

• Published in: Cement and concrete research Vol. 138; p. 106228
• Main Authors: Rodríguez, C. Romero, de Mendonça Filho, F. França, Mercuri, L., Gan, Y., Rossi, E., Anglani, G., Antonaci, P., Schlangen, E., Šavija, B.
• Format: Journal Article
• Language: English
• Published: Elmsford Elsevier Ltd 01.12.2020; Elsevier BV
• Subjects: Backscattering; Bacterial self-healing concrete; Bulk modulus; Cement; Cement paste; Chemical composition; Electron imaging; Hydrates; Interfaces; Lattice model; Mechanical properties; Micromechanics; Modulus of elasticity; Nanoindentation; Poly-lactic acid capsules; Polylactic acid; Stiffness; Tensile strength; Tensile tests; Micromechanics; Poly-lactic acid capsules; Nanoindentation; Lattice model; Bacterial self-healing concrete
• ISSN: 0008-8846; 1873-3948
• DOI: 10.1016/j.cemconres.2020.106228

In this study, the interface between different types of bacteria-embedded self-healing polylactic acid capsules (PLA) and cement paste is investigated. Particularly, the changes in microstructure and mechanical properties of the interface with respect to bulk cement paste were studied. First, nanoindentation was performed to obtain maps of hardness and elastic modulus in the interfaces. Lattice modeling of uniaxial tensile test on the mapped locations was performed then to obtain the overall tensile strength and stiffness of the interface. Moreover, hydrates assemblage and chemical composition around the PLA particles were studied through Backscattering Electron images and Energy Dispersive X-ray Spectroscopy. The ratios between resulting tensile strength and elastic modulus of the interface with respect to bulk paste were obtained for each PLA type. The results suggest that PLA can be tailored to optimize the physico-mechanical properties of the interface and hence, the mechanical behavior and triggering efficiency of the self-healing system.