## 1 Introduction  
Calcium sulfoaluminate (CSA) cement is attracting attention as an ecofriendly cement that reduces CO\({}_{2}\) emissions during manufacturing compared with ordinary Portland cement (OPC) [1; 2; 3; 4]. Many previous studies show that CSAe linker with various ratios of calcium sulfate can be used to control the setting time, early and late strength, expandability, and volume stability of cement [5]. The main constituent of CSA clinker is ye'elimite (C\({}_{4}\)A\({}_{5}\)S) [5; 6] (hereafter, cement chemistry shorthand notation will be used: C = CaO, S = SiO\({}_{2}\), A = Al\({}_{2}\)O\({}_{3}\), \(\overline{S}\) = SO\({}_{3}\), H = H\({}_{2}\)O, F = Fe\({}_{2}\)O\({}_{3}\), and M = MgO). The ye'elimite forms etrtingite (AFt\({}_{5}\)C\({}_{6}\)A\({}_{5}\)H\({}_{32}\)), which is the main hydration product and plays an important role in the cement's mechanical and expansion properties [7]. For binary cement mixed with CSA and OPC, CSA has an important influence on the early hydration reaction and mechanical properties (within 24 h), and OPC plays a dominant role thereafter [8]. Many previous studies focused on the expansion properties of CSA clinker or CSA cement [9; 10; 11; 12]. In recent years, research has expanded on the control of the expansion and contraction properties of cement and multicomponent binders in which CSA and various cementitious materials are mixed. Various studies on the properties of cement mixed with CSA have been published. [PERSON] et al. [13] conducted a study on shrinkage and creep for three concrete mixtures: pure CSA, portland-limestone cement, and a blend of the two (50:50 ratio by mass). They argued that the shrinkage and creep analysis model developed for Portland cement concrete currently in use is not suitable for application to Portland-CSA-based concrete because the main input data are based on compressive strength. [PERSON] and [PERSON] [14] conducted an experiment on the effect of a shrinkage-reducing admixture (SRA) or lightweight sand (LWS) on the expansion/contraction and compressive strength properties of an OPC-CSAsystem. The LWS or SRA had a significant effect on shrinkage and expansion properties compared with the OPC-CSA mixture alone. In particular, the use of SRA and LWS together in an OPC-CSA-based system improved performance while reducing the required wet hardening period. [PERSON] et al. [15] reviewed the effects of an SRA and CSA cement on OPC-based high-strength strain-hardening cementitious composites on the shrinkage reduction and mechanical properties of the cement under various conditions. SRA reduced shrinkage, CSA affected the degree of hydration and setting time, and both SRA and CSA reduced the mechanical strength. [PERSON] et al. [16] conducted a study on the volume stability of a CSA-CaO-based expansive agent (CSA-CaO EA) on ultra-high-performance concrete. They explained that low \(w/b\) and dense microstructure are among the factors hindering the expansion effect of the CSA-CaO EA. [PERSON] et al. [17] studied the effect of CSA cement on the early properties and hydration of Portland cement. [PERSON] et al. [18] examined the manufacture of precast concrete at ambient temperatures using the Portland-CSA cement system. The CSA clinker or CSA cement has been published in a number of studies on properties based mainly on OPC. In addition, regarding the characteristics of CSA, [PERSON] et al. [19] studied hydrates and porosity according to curing temperature and relative humidity (RH). According to their report, the hydration products and pore characteristics of CSA cement depend on the curing conditions. There are also microstructural studies on the AH\({}_{3}\) phase of the AFt-AFm-AH\({}_{3}\) hydration product system in CSA cement [20]. The effect of water and gypsum content on CSA-belite cement paste has also been explored [21]. In addition, research results on the effect of alkalis content on the hydration of CSA cement have been reported [22]. There have also been characterization studies on CSA mixtures with various admixtures.