Designing a novel waterproof thin-layer based on silicon-modified polyacrylate grafted 2D-graphene nanosheets for chloride-induced corrosion protection of rebar in concrete structures

Abstract

BackgroundRebar plays a critical role in reinforcing concrete structures by providing tensile strength and improving their resistance to various loads. The chloride-induced corrosion of rebar is a major concern in the construction industry, as it can lead to significant structural damage and compromise the safety and integrity of concrete structures. For the first time in this work, a thin hydrophobic layer based on polyisocyanate functionalized graphene oxide (PIF-GO) was synthesized by modifying graphene oxide (GO) nanosheets with a silicon-modified polyacrylate through covalent grafting with polyisocyanate (PI) bridges to diminish water and chloride permeability of concrete. MethodsThe characterization of the synthesized nanomaterials was done by FT-IR, TGA, Raman spectroscopy, FE-SEM, and EDS analyses. Corrosion measurements were done by EIS and the waterproof properties of the applied thin film were investigated by contact angle and Capillary tests. Significant findingsCharacterization techniques exhibited that PI and silicon-modified polyacrylate were successfully grafted on GO. The PIF-GO dispersion was sprayed on the concrete surface. The water contact angle of GO increased significantly from 43° to 102° after modification. Capillary water absorption of concrete covered with the PIF-GO thin layer (60.4 g.cm−2.h−1/2) showed excellent waterproofing performance compared to GO (684.8 g.cm−2.h−1/2). EIS was used to scrutinize the corrosion behavior of rebar in concrete immersed in a saline solution for 71 days, revealing a significant diminish in the chloride and water penetration into the concrete.