## 1 Introduction  
Chemical admixtures are the essential materials and core technology for manufacturing modern concrete and key elements in the development of concrete in high-tech fields. Due to their characteristics of low dosage, high water reduction, and lowering slump loss (or improving slump retention), admixture products are a hot topic of research. Water-reducing agents are being developed to offer enhanced performance in terms of a high rate of water reduction, high slump retention ability, high early strength ability, and high durability of concrete. In engineering practices, if the function of the polycarboxylic acid water-reducing agent is only limited to the rate of water reduction and the strength of the concrete, the adaptability and rheological properties of the polycarboxylic acid water-reducing agent and the material in concrete cannot be adjusted, which likely leads to the poor physical workability of the concrete mix and eventually to problems in the stability and durability of the concrete structure, thereby not meeting the service life of the project. Therefore, it is of great significance to study functional superplasticizers based on polycarboxylic acid. Superplasticizers are widely used to produce flowable, strong, and durable Portland cement concretes and mortars. The hydration behaviors of Portland cement in the presence of superplasticizers have been investigated by a number of researchers [1; 2; 3]. [PERSON] et al. [2] studied the effects of different types of polycarboxylic acid superplasticizer on the early hydration of cement using scanning electron microscopy (SEM) analysis and found that the incorporation of polycarboxylic acid superplasticizers inhibited the formation of alumina, ferric oxide, tri-sulfate (AFt), as a hydration product. [PERSON] et al. [4] employed 29 Si MAS NMR and X-ray diffraction (XRD) techniques and discovered that when the cement and water were mixed for 15 min, there was no characteristic peak of AFt in the XRD spectrum of the blank control slurry, but it obviously appeared when polycarboxylic acid water-reducing agent was added to the mixture. The characteristic peak of AFt indicates that the incorporation of polycarboxylic acid water-reducing agent changes the growth rate of AFt. Through differential thermal research, [PERSON] et al. [5] realized that polycarboxylic acid water reducer decreased the amount of Ca(OH)\({}_{2}\) produced in the early hydration products. It was thought that the water-reducing agent suppressed the hydration of the silicate mineral phase and therefore delayed the formation of Ca(OH)\({}_{2}\); thus, calcium silicate hydrate (CSH) had no significant effect on the formation of AFt. [PERSON] et al. [6] used atomic force microscopy (AFM) to observe the morphology of cement hydration products and obtained the same results as those of [PERSON]; they believed that the degree of influence depends on the amount of water-reducing agent and the chemical composition of the solution. Water-reducing agents have obvious effects on micro-morphology in cement pastes [7; 8] as confirmed by the XRD peaks at different ages [9] and SEM analysis used to study the pore structure of cement pastes [10; 11; 12; 13; 14; 15]. Materials based on hardened cement are generally composed of complex structural systems of hydration products, unhydrated cement mineral phases, and multiscale pores and pore solutions. Multiscale pores affect the mechanical properties of cement-based materials and are of considerable importance for the characterization of the multiscale and complex pore structures of hardened cement pastes [16]. The pore structure reflects the microstructure of the material, and the microstructure-performance relationship is the core of modern material science [17]. Concrete has a heterogeneous and rather complex structure; therefore, its macroscopic performance is also extremely complicated.