## 1 Introduction  
With the rapid development of global urbanization, the emission of construction waste is increasing rapidly. According to the statistics, current construction waste accounts for about 30% of urban solid waste [1; 2; 3; 4; 5], and more than 10 billion tons of construction waste are generated worldwide every year, 80% of which are waste bricks and concrete [6; 7]. At present, the treatment method for construction waste is mainly stacking and landfill, which not only wastes land but also seriously endangers the natural environment [8]. On the other hand, the exploitation of natural building materials in China is protected strictly. Therefore, the recycling of construction waste can not only protect the environment but also save resources and alleviate the current shortage of natural building materials. In recent years, recycled aggregates produced from construction waste have been widely used in recycled concrete [9; 10; 11], recycled mortar [12; 13], roadbase [14] and other fields. In the process of producing recycled aggregate from construction waste, a large amount of fine powder with a size of less than 0.16 mm, which is called recycled fine powder, is produced. Compared with untreated construction waste, the long-term accumulation of recycled fine powder will not only occupy land but also produce dust, pollute water resources and do greater harm to the environment [15]. Geopolymers have many advantages, such as faster hardening, higher strength, excellent acid and alkali resistance, lower carbon emission, and are considered to be the most potential low-carbon green cementitious material to replace ordinary Portland cement (OPC). The reaction mechanism is that the silicon oxygen bond and aluminum oxygen bond in the geopolymer precursor materials break in an alkaline environment to form AlO\({}_{4}\) and SiO\({}_{4}\) tetrahedral monomers, and then polymerize and recombine to form a three-dimensional network structure [16; 17]. The preparation of geopolymers from some wastes, such as metakaolin, slag, fly ash, rice husk ash, etc., with aluminosilicate as the main component is a research frontier [16; 17]. As a material mainly composed of silica and alumina, recycled fine powder has the potential to develop geopolymers. At present, the use of recycled fine powder as a precursor material of geopolymers has been studied [18; 19; 20; 21; 22; 23]. Meanwhile, the mechanical properties of recycled fine powder-based geopolymers have been widely qualified and have great potential to replace OPC [22; 23; 24; 25]. Drying shrinkage is one of the main reasons that durability and applicability of concrete structures are reduced [26]. The shrinkage of concrete will cause tensile stress due to the restraint of itself and external conditions. When the shrinkage is large, it will cause harmful crack formation and eventually lead to serious crack damage of concrete [27]. Compared with OPC, the geopolymer will produce greater dry shrinking under dry conditions, restricting its actual engineering applications [28; 29; 30]. Previous studies [31; 32; 33] have shown that the shrinkage of geopolymer concrete is 2-4 times that of ordinary concrete. Many scholars have studied how to reduce the drying shrinkage of alkali-activated binders in terms of alkali equivalents, activator types, mineral admixtures, chemical additives and curing conditions [31]. [PERSON] et al. [34; 35] found that Si/Al and gel structure are two main parameters of sodium-based geopolymers, which have a direct impact on shrinkage. [PERSON] et al. [36] showed that both incorporating a small amount of fly ash and reducing the modulus of modified sodium silicate reduced the drying shrinkage of geopolymer concrete cured at room temperature. [PERSON] et al. [37] also found that lowering the modulus of activators can effectively reduce the drying shrinkage of geopolymer concrete. Additives are one of the effective means to reduce the drying shrinkage of geopolymer concrete.