Piezoresistivity deterioration of smart graphene nanoplate/cement-based sensors subjected to sulphuric acid attack. (February 2021)

• Record Type: Journal Article
• Authors: Dong, Wenkui; Li, Wengui; Vessalas, Kirk; He, Xuzhen; Sun, Zhihui; Sheng, Daichao
• Is Part Of: Composites communications. Volume 23(2021)
• Publication Date: 2021-02
• Subjects: Graphene nanoplate (GNP) -- Cement-based sensor -- Piezoresistivity -- Sulphuric acid attack
• DOI: 10.1016/j.coco.2020.100563
• Languages: English
• ISSNs: 2452-2139

Abstract

Abstract: Smart cement-based sensors with self-sensing capacity have been explored for structural health monitoring (SHM) with the intrinsic piezoresistive performance. However, few studies had studied the piezoresistivity degradation of cement-based sensors after exposure to the aggressive environments, especially under sulphate acid attacks. In this study, graphene nanoplate (GNP)/cementitious composites were immersed in sulphuric acid solutions (concentrations of 0, 1%, 2%, and 3%) for 90 and 180 days. Then surface appearance, weight loss, mechanical properties, piezoresistivity and microstructure were investigated and compared before and after sulphuric acid immersion. The results show that after acid immersion, the surface deterioration and mass loss were increased, and the compressive strength was significantly decreased. As for the intact GNP/cementitious composite, the piezoresistivity exhibited excellent linearity and repeatability, demonstrating the great potential to act as intelligent cement-based sensors for SHM. After 90 and 180 days of acid immersion, the piezoresistivity was sensitive to the initial low load initially but then turned less sensitive to the later high load. The highly corroded GNP/cementitious composites exhibited porous microstructures associated with the low compressive strength. The fractional changes to resistivity (FCR) under the low load could be attributed to the compressed pores and voids filled with erosion products that would form conductive passages. In contrast, with the increase of applied load, the intact cement matrix became much denser, which in turn constrained the further development of conductive passages in the GNP/cementitious composites. Highlights: GNP filled cementitious composites displayed surface deterioration under sulphuric acid of immersion. Piezoresistivity of GNP filled cement-based sensors were firstly investigated after long-term exposure to sulphuric acid. After sulphuric acid erosion, the piezoresistivity was strongly affected with less linearity and repeatability. The mechanism of altered piezoresistivity is due to the mechanical and microstructural properties of corrosion. Mechanism of altered piezoresistivity is due to the mechanical and microstructural properties of corroded GNP/cementitious composite.