## 5 Modify the Characteristics of the Cement-Based Materials  
[PERSON] [10] focused on the way to enhance the deformability of three-dimensional printable mortar containing FA and silica fume, using ethylene-vinyl acetate (EVA). Thus, they mainly focused on the effect of the EVA/binders ratio on the modulus of elasticity, drying shrinkage, and the thermal expansion of the mortar. The results show that as the EVA/binders ratio increased, the elastic modulus and compressive strength tended to reduce, and the opposite occurred for drying shrinkage and thermal expansion. Nevertheless, the maximum compressive strain seemed to increase. Accordingly, this path, specifically using a high EVA/binders ratio, is not advisable to enhance the deformability of three-dimensional printable mortar.  
In another study, [PERSON] et al. [11] also intended to improve the mechanical properties of mortar using approximately 0-2.0% (by cement's mass) polyvinyl alcohol (PVA). To understand the effect of PVA on the mechanical properties, hydration products and microstructure of the mortar, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) results were obtained. They show that the optimum PVA content was 0.6% and 1.0% (by cement's mass) for the tensile and compressive strength of mortar. The authors explained that this is due to the fact that PVA formed evenly dispersed, network-like thin films within the cement matrix, and subsequently can act as bridges across microcracks and small voids to arrest cracking in the cement matrix.  
Additionally, [PERSON] et al. [12] made a study under the title \"experimental study on flexural behaviour of TRM-strengthened reinforced concrete (RC) beam: various types of textile-reinforced mortar with non-impregnated textile\", and they showed the feasibility of strengthening RC beams using textile-reinforced mortar (TRM) with non-impregnated textile. The results show that the bearing capacity, strengthening efficiency and crack uniformity of beams can be improved with the use of TRM, especially when the mesh size of the textile was reduced and mechanical end anchorage implemented, and also when the textile lamination and textile reinforcement ratios increased.  
[PERSON] et al. [13] also attempted to modify the performance of the cement-based materials, namely concrete, using different types and combinations of fibers. For that purpose, the basalt fiber (BF) and polypropylene fiber (PF) were jointly and individually incorporated in concrete. The results show that the fibers can be beneficial to the compressive and tensile strength of concrete when a small percentage (each 0.05% of concrete's volume) of both fibers are jointly incorporated into concrete. The authors recommended using a high percentage of the fibers, but accurate control is necessary to disperse the fibers in the cement matrix. Similar to the performance of most fibers, PF and BF are more effective in enhancing tensile strength than compressive strength.  
[PERSON] et al. [14] made an extensive literature review to find a way to solve the issue of the crossover effect phenomenon in cement-based materials when they are subjected to accelerated initial curing. The higher curing temperature (e.g., 40-60 \({}^{\circ}\)C) may promote the cement matrix to rapidly create non-uniform hydration products, and subsequently generate a great porosity at later ages. The authors proposed using different types and incorporation ratios of cement-based materials to overcome this issue.