# Short-Term Deformability of Three-Dimensional Printable EVA-Modified Cementitious Mortars
## 1 Introduction  
Construction processes are intrinsically labor-intensive and accompanied by a high risk of accidents, and thus would benefit from the introduction of automated solutions. The construction industry, however, lags behind other fields in implementing such automation. Encouragingly, an additive construction method intended for concrete structures has recently been developed and applied to small building projects, such as pedestrian bridges [1; 2; 3]. Cementitious concrete is one of the most widely used construction materials worldwide, and is mostly in the form of ready-mixed concrete. Cementitious concrete placement, however, typically requires a formwork. Formwork installation costs a great deal in terms of material, human labor, and equipment resources. Also, the construction process is inevitably long term, due to the labor intensity of formwork installation and removal. In addition, the waste produced by formworks may have a negative impact on the environment [4].  
The additive construction method was introduced to address these chronic issues associated with concrete work. This process is a computer-controlled construction technology that is used to build structures by layering extruded cementitious concrete without a formwork [5]. Also known as 3D concrete printing (3 DCP), this process was first successfully applied in the construction industry by [PERSON] [6], who developed a contour crafting (CC) method in which a fresh mixture is firstextruded in a layer, and then additional layers are added on top. This free-form construction process is possible because the method does not require formwork to construct the cement concrete structure [7].  
Compared to conventional construction technologies, 3 DCP is commonly viewed as a sustainable design solution that offers almost unlimited possibilities for implementing geometrically complex designs. The technology is advantageous in various ways, such as in reducing construction cost and time, minimizing environmental degradation. The technology can also be used to streamline environmentally friendly construction processes, reduce industrial waste, and decrease energy consumption resulting from producing the raw materials used in formwork [8].  
The 3 DCP process consists of three components: a concrete printer, 3D modeling software, and printing material. The procedure draws from three specialized areas, including the mechanical, 3D design, and concrete materials fields [9]. Printing materials comprise the primary concern of the present study, especially cementitious mixtures. In recent relevant research, the most frequently examined materials for 3 DCP contained Portland cement, sand, fly ash, and silica fume as base materials, along with small amounts of additives such as superplasticizers and viscosity-modifying agents [4; 10; 11; 12; 13]. Comparatively speaking, the information available on specific additive construction methods using redispersible ethylene-vinyl acetate (EVA) powder is very limited, even though EVA provides excellent adhesive strength and dynamic cracking resistance [14].  
In a previous study conducted by the author, EVA-modified cementitious mortars were produced with various EVA/cement ratios. Then, the properties of fresh EVA-modified cementitious mixtures intended for use in additive construction via extrusion were experimentally investigated [15]. It was clear from this earlier work that EVA-modified cementitious mortars are applicable to the 3 DCP process. However, it is still unknown whether or not three-dimensional printable EVA-modified cementitious mortars would be sufficiently stable after the 3 DCP process. Thus, in the present study, three-dimensional printable EVA-modified cementitious mortars were experimentally investigated with regard to various properties associated with dimensional stability, such as elasticity and drying and thermal shrinkage. This work provides fundamental research data that will assist in the adoption of EVA-modified cementitious mortars for additive construction applications.