Pre-Study of Graphene-Enhanced Cementitious Materials

Cement-based concrete is the most widely used building and construction material in the world. Although concrete itself is relatively durable when used under the mild environments, its intrinsic weak tensile strength greatly limits its application due to its porous structure. Traditional strategies to overcome this weakness of concrete include utilization of various reinforcing materials, such as steel bars, steel fibers, carbon fibers, polymer fibers and mineral fibers. However, some challenges raised from materials themselves limited their applications. For example, steel reinforcement suffered the corrosion problem caused by carbonation or chloride ingress. Polymer fibers have good tensile strength but poor reliability. Large amount of addition of fibers into concrete could significantly decrease the workability of concrete. Previous strategies are basically modifying concrete at macro level without changing the microstructure of concrete, which is quite essential for a high mechanical performance. Mechanical strength of concrete is mainly contributed by the hardened cement paste. During the cement hydration process, the formation of calcium silicate hydrate (C-S-H) gel acts as adhesive and offers the original mechanical strength of concrete. Therefore, the shape and density of the C-S-H gel plays key roles in determining the mechanical properties of the concrete. Seeking a method that can significantly improve the strength of hardened cement paste through regulation of its microstructure is certainly worth considering.