# Effect of Cu, Cr, S Doped TiO\({}_{2}\) for Transparent Plastic Bar Reinforced Concrete
## 1 Introduction  
In the 1960s, [PERSON] et al. demonstrated that TiO\({}_{2}\) photocatalyst was found to have a powerful oxidation effect by hydroxyl radical [1]. Although it has various advantages, such as anti-corrosion action, removal of harmful substances, and super-hydrophilicity, it is difficult to use indoors because it has a strong photocatalysis reaction in ultraviolet areas (under 380 nm). As a result, there is active research to develop photocatalytic compounds that can react in visible light areas around the world [2; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16]. For example, a lot of research has been done, such as doping using the solgel method and calcination by mixing metal or non-metal with a photocatalyst. In the field of architecture, shortening construction periods and cost cutting are very important factors. Therefore, the minimum process required was to manufacture the doped photocatalyst through simple calcination and milling [2; 3; 4]. In Korea, research by [PERSON] et al. reported that a photocatalyst doped with Cu, Cr, and S removes harmful substances such as nitrogen oxides in the visible light region [5; 9; 12].  
A KA-100 photocatalyst and transition metals such as Cu, Cr, and Fe were calcined at 1000 \({}^{\circ}\)C to verify reactivity in the visible light region and performance of removing harmful substances. As mentioned earlier, in the field of construction, shortening the construction period and reducing costs are very important factors, so this study aimed to use relatively inexpensive doping materials such as Cu, Cr, S and manufacture the photocatalyst doped by the high temperature calcination method [9].  
TPBRC (Transparent plastic bar reinforced concrete) is a kind of light transmitting concrete that was developed in Korea, by arranging plastic bars into concrete. They can be expressed in various ways, such as text, pictures, etc. [17]. However, for concrete reinforced with plastic bars, the difference between the sleek surface of the plastic bar and the concrete matrix caused the mechanical performance to deteriorate and the plastic bar in the interface to slip [18; 19]. Furthermore, the flowability of concrete is an important problem because plastic bars are inserted into the concrete matrix. Therefore, the UHPC (Ultra high performance concrete) materials started to be applied to various indoor spaces [20; 21; 22; 23; 24]. Transparent plastic bar reinforced concrete can be filled with different kinds of plastic type. This means the loss of a section of photocatalyst-incorporated concrete. However, TPBRC can be said to increase the area and efficiency of the photocatalysis reaction because there is a light transmitted concrete surface as well as a light transmitting concrete surface.  
In order to utilize this advantage, this study intends to secure a TiO\({}_{2}\)-incorporated UHPC mix and use it in the transparent plastic bar reinforced concrete. In addition, it is intended to produce a visible light-reactive photocatalyst whose process is through calcination at high temperature. The final purpose of the study is to find out the possibility of the utilization of TPBRC advantages by estimating the NOx removal performance.