**5. Wall coating material with anti-corrosion and anti-leakage properties**

Wall coatings are decorative or protective layer that are applied to the interior or exterior surfaces of walls. Coating is applied to the surface of the wall via different methods depending on the nature of that wall and the nature of the coating itself. Among these methods are plastering [59], paint brush [60], roller [61], air spray [62] and etc. Coating designed for thermal energy storage and thermoregulating should be corrosion resistance, anti-leakage and anti-heat [63–65].

Corrosion is the gradual destruction of the concrete matrix by chemical reaction with the environment [66, 21]. This reaction enhances the porosity and permeability in the concrete matrix. Moisture, CO2, chloride, and other harmful ions could reach the surface of reinforcement bars, thereby causing corrosion of the bars and reducing the mechanical and structural properties of the concrete.

To reduce the water absorption and chloride diffusion coefficient, Zheng et al. [67] coated the concrete with Epoxy resin nanocomposites containing 0.3 wt% of graphene oxide. The chloride ion penetration resistance is due to the formation of crosslinking in the composite coating, improvement of hydrophobicity and shielding effects of graphene oxide.

To prevent penetration of hostile elements, and early crack of concrete, epoxy resin nanocomposites modified with graphene oxides (GOs) were prepared using a solution blending process and then sprayed onto testing blocks of concrete [68].

Waterborne silicate coating is an anticorrosive coating used to protect steel bar in the concrete, it consists of alkali metal silicate, rust-proof pigment, and modification material (to modify the alkali metal silicate solutions) such as acid modification, silicone acrylic emulsion, styrene acrylic emulsion… [69, 70]. The waterborne silicate coating has excellent corrosion resistance, good acid-alkali resistance and high heat resistance [71]. The zinc silicate works with the alkali metal silicate, forming a dense and stable film on the metal surface, and reducing the penetration rate of water and other ions. Coatings for reinforcement bars are widely available. In addition, the reinforcement bars are embedded in the concrete matrix and they do not expose to the hostile environment. Moreover, geopolymer materials have high corrosion resistance. The coating of the reinforcement bars may be not necessary The interaction between geopolymer-based coating material and the superficial elements of reinforcement bar or mild steel leads to formation of passive layer which prevent reinforcement bar and mild steel from corrosion [66]. Fly ashslag geopolymer has good corrosion resistance and low corrosion rate compared to fly ash geopolymer [72].

#### *Incorporation of Phase Change Materials and Application of 3D Printing Technology... DOI: http://dx.doi.org/10.5772/intechopen.96886*

Afshar et al. [73] reported that the zinc-rich epoxy primer as a coating on mild steel rebar has the best performance when used in combination with concrete containing 25% fly ash, 10% silica fume and 3% inhibitor by cementitious material weight.

Zhao et al. [74] believed that adding ultrafine silica powders dispersed by hexamethyldisilazane (HMDS) and polyacrylic acid PA emulsion improved the water, acid, alkali, heat and aging resistance of the polymer modified cementitious coatings PCCs. The appropriate amount of the modified ultrafine silica powders is about 5% of the mass of the PA emulsion, because higher water absorption and decreased tensile properties happened when the amount is too large (10%). Hexamethyldisilazane (HMDS) disperses the ultrafine silica SiO2 powders and reduces their agglomeration. SiO2 chemically interacts with the polyacrylic acid PA emulsion to form a cross-linked network structure. It was found the PCCs with 4 wt% HMDS modified SiO2 powders had fewer micro-defects and more compactness, thus the tensile properties and durability under different conditions, such as water, acid, alkali, heat and artificial aging, were significantly improved. The water absorption and chloride ion permeability coefficient of concrete coated by the PCCs with 4 wt% well-dispersed SiO2 powders were also decreased.

Xu et al. [75] developed a colorful and robust superhydrophobic concrete (CSC) coating composed of cement, sand, water-based stone protector, and dyes, and meets both performance and esthetic requirements. And they reported that this coating exhibits excellent chemical durability and weather resistance, and has promising application prospects on the outside wall of concrete.

Several studies demonstrated that usage of glass waste in concrete enhances its acid resistance as well as its physical and mechanical properties. Bisht et al. [29] have used waste of glassy materials made of soda lime to produce acid resistance concrete. They have shown that the best optimized performance in terms of compressive strength and acid resistance can be obtained by substituting up to 21% of sand by glass waste. The overadding of glass waste above to 21%, although it increases the acid resistance, it enhances the porosity which decreases mechanical strength of the concrete. Glass waste can also be used as aggregate or as source of silicate in the manufacturing of geopolymer concrete [30]. In contrast the addition of glass waste reduces the plasticity of the fresh paste, thereby reduce its workability, thus a super-plasticizer is needed [31].

Morefield el al. [76] have developed a novel coating that is based on hydraulically reactive silicate cement blended with a glass enameling frit and fused onto the steel reinforcement: If the enamel coating is cracked the freshly exposed calcium silicate cement grains will react with any humidity in contact with them to produces a cement paste in the crack.
