## 1 Introduction  
Owing to the increasing demand for stone construction and decoration materials world wide because of the continuing growth in the world's population, a tremendous amount of stone powder waste has been generated in the natural and artificial stone industry during the cutting and carving processing stages, which could account for up to 35% of the weight of the stone that was used. The waste powder ranging from nanometers to millimeters is disposed of in landfills or arbitrarily discharged to the surrounding environment, and is prone to drift in air, which has not only caused severe environmental and ecological damage, but also carried risks to public health [1]. Fortunately, a growing awareness of these issues has been raised by both local municipal managers and many researchers from different fields. Several methods have been adopted and implemented to recycle the waste stone powder. At present, the reuse strategies concentrate upon incorporating the stone byproduct as additives into the traditional construction materials, such as cement and concrete, to regulate their mechanical properties [2; 3; 4; 5]. Other applications for reusing the stone powder have been developed by researchers in the area of functional nanomaterials, such as a self-cleaning coating based on waste marble [6],or a marble powder derived paint for indoor air quality improvement [1]. However, the stone powder is reused as a type of auxiliary material, which consumes a pretty negligible amount of waste. Moreover, adding the stone powder into the products sometimes degrades the performances of the products. Recently, a recycling strategy of converting the waste stone powder into aerated bricks has gained considerable interest, since it makes full use of the stone powder as a main source for massive production, and has great application potential in the building and construction areas. Additionally, the manufacturing cost is relatively low. The aerated brick made from the waste stone powder exhibits a porous structure, which leads to its exceptional properties, such as light weight, low bulk density, high heat resistance, excellent sound insulation, and small shrinkage [7; 8]. However, it is precisely because of the pores that the aerated bricks easily absorb rainwater and suffer from water erosion, which degrades the mechanical and thermal performances and facilitates mold growth [8]. In order to solve the water invasion problem and maintain the edge of the aerated bricks, some reports have utilized rick husk ash to reduce the water absorption of the aerated bricks [9], or combined fly ash with silica to form dense matrixes for water resistance [10]. However, most of the above approaches make the manufacturing process more complicated and costly. Instead, creating hydrophobic surface by means of surface modification to achieve waterproof function would be more cost-effective and convenient for mass production. Inspired by the lotus leaf, a super-hydrophobic surface could be built through a highly textured epidermis layer combined with extremely low water affinity materials [6; 11; 12; 13; 14; 15]. In this paper, an environmentally friendly aqueous based super-hydrophobic suspension was prepared, which contains homemade highly dispersed TiO\({}_{2}\) nanoparticles modified by super-hydrophobic groups deriving from perfluorooctyltriethoxysilane (PFOTS). The particle size of the nano-TiO\({}_{2}\) in anatase phase dispersed in water concentrates at about 0.28 \(\upmu\)m with a relatively narrow distribution, indicating an extremely high degree of water dispersion. The aerated bricks were fabricated in a factory near the stone processing plants in Fujian Province, China, where our studies were conducted. Then the bricks were coated with the above suspension, creating a super-hydrophobic surface. A contact angle of 146\({}^{\circ}\) has been achieved on the modified surface of the aerated brick, demonstrating the excellent water repellency.