# Graphene Nanoplatelets Impact on Concrete in Improving Freeze-Thaw Resistance
## 1 Introduction  
Concrete is the most commonly and widely used civil engineering material in the world. However, we all know that concrete has poor features, such as a quasi-brittle nature, prone to crack formation and low tensile strength; these defects seriously reduce the mechanical property and durability of concrete structures. Numerous concrete structures are served in various environments, for example harsh low-temperature circumstance. Freeze-thaw durability of concrete materials is a key aspect affecting the durability and life span of concrete structures in cold areas. Concrete is an inherently defective material; its F-T performance relies predominantly upon the interior structure of the material, such as its porousness, crack, pores types and size, transportation, etc. Many researchers have paid attention to the usage of nanomaterials, for example, nano-kaolinite clay [1], nano-silica [2; 3; 4], nano-TiO\({}_{2}\)[5], nanoalumina [6] and graphene nanomaterials [7; 8; 9; 10], in the last decade. Studies have shown that the additive of these nanomaterials could improve the mechanical property and durability of cementitious materials. Graphene as an emerging Nano material can be added into cement paste to enhance construction sustainability due to their extraordinary performance. Some researchers reported that the reinforcing effects of graphene on cement composites could enhance the physical and mechanical properties of cementitious materials through tests. [PERSON] et al. [10] showed that the compressive and flexural performance of cement paste increased by adding 0.05 wt% graphene oxide (GO), and observed that GO in cement matrix enhanced the surface area of the GO composite; they thought that GO was a potential entrant in cement-based materials. Some studies demonstrated that the addition of GO could promote hydration of cement, accelerate crystallite formation and increase the tightness of cement paste [11]. [PERSON] et al. [12] firstly investigated the durability of concrete containing low-costtwo-dimensional (2D) Graphene Nanoplatelets (GNP), and evaluated the transport properties of concrete subjected to chloride and water environment, the results showed that GNP could enhance the resistance of concrete to chloride ion and water penetration. [PERSON] et al. [15] found that GO addition could modify the microstructure and improve the compressive strength of cement matrix, and reported the GO could improve the freeze-thaw resistance of cement;however, they did not give the optimum dosage of GO. Experimental investigation showed that the addition of graphene oxide nanoplatelets (GOS) and GNP in mortar samples would increase the frost resistance of materials, and the discovered microstructure and modulus biography found that GNP and GOS could greatly refine the microstructure of mortar specimen [16]. [PERSON] et al. [17] firstly studied GO aggregates as particle size measurement and found that the aspect ratio of GO aggregates is much higher than that of the original GO nanosheets. Adding graphene and GO sheets to cement paste could improve the mechanical properties of the nanocomposite [20] but can reduce the workability of the nano cement materials [13]. Additionally, adding graphene nano-sheets (GNS) to cement paste could accelerate the hydration reaction and increase the quantity of hydration products, and could also improve chloride penetration resistance of cement paste [19]. Furthermore, adding GNP in cement would reduce the resistivity and make composites obvious pressure sensitivity [18]. Some recent research findings showed that graphene nano-sheets and their derivatives (GND) could modify cement-based materials [21]; we found that most recent attention focuses on the performance of graphene-based materials additions in cementitious materials, which can improve the better performance, such as compressive strength and flexural strength and elastic modulus of paste.