**1. Introduction**

Developments and research in technology have resulted in new design, fabrication, and construction techniques in the construction industry [1]. Three-dimensional printing as one of these techniques stands out as it requires minimum human intervention and the minimum pre-processing of raw materials [2]. The 3D printing technique draws attention in the construction industry due to its advantages over traditional manufacturing methods. The major advantages of the 3D printing of concrete are its higher precision, safer working conditions, faster construction, and lower cost of construction, owing to the decrease in costs of formwork and labor [3]. It is also more expeditious than conventional construction methods are, optimizes the site works, enhances the constructability, and reduces the amount of material, and decreases the occurrence of labor-related risks [2].

Three-dimensional printing literature encompasses studies in different industries. However, research on the construction industry on 3D printing technology is relatively scarce. Regarding the current literature, studies examining concrete mixture designs and the mechanical properties of 3D printed concrete exist. There are also studies on the production of bricks/briquettes from clay and ceramic materials. Moreover, researchers have investigated the technical properties of these materials, such as strength and thermal insulation [3–6]. In fact, cementitious materials are more popular than clay-based ones are. Despite the fact that concrete paving stones are one of the most frequently used construction materials, there are no studies in the literature on the mechanical or design properties of 3D printed concrete paving stones. The aim of this study was to design a suitable mixture to produce 3D printed concrete paving stones. To do this, a series of experiments in the construction materials laboratory were conducted.
