2.1. Materials

The MSWI slag used in the experiment was taken from Xuyi incineration power plant in Huai’an, Jiangsu Province. The chemical composition of MSWI slag was analyzed by an X-ray fluorescence analyzer, as shown in Table 1. According to the test results in Table 1, SiO₂, Al₂O₃, Fe₂O₃, and CaO in MSWI bottom slag accounted for around 70% of the total mass of the bottom slag, which belonged to a typical CaO-SiO₂-Al₂O₃-Fe₂O₃ chemical system [19]. The particle frequency distribution curve and cumulative distribution curve of MSWI bottom slag are shown in Figure 1. It is shown that most of the MSWI particle sizes were concentrated in the 4.75–1.18 micron range, accounting for around 66.1% of the total particles. The cumulative contents of 20.0%, 60.0%, and 80.0% of particle size were around 4.75, 2.25, and 0.60 micron, respectively.

Grading curves of bottom slag particles.

Chemical composition of MSWI bottom slag.

The ordinary Portland cement used in this test was PO 42.5-grade Portland cement produced by Conch Cement Co., LTD, Huai’an, China. The chemical composition of the cement is shown in Table 2. Xiamen ISO standard sand was selected for the MSWI cement mortar strength test, and its SiO₂ content was not less than 98.0% of natural round silica sand.

Chemical composition of cement (%).

MSWI bottom slag-recycled ECC material used refined quartz sand as a coarse aggregate, with a diameter of around 100 μm and particle size of 150 mesh. The fiber used in this paper was polyvinyl alcohol fiber (PVA), whose important properties are shown in Table 3. The water-reducing agent used was commercial CQJ-JSS model polycarboxylic acid high-efficiency water-reducing agent, and its water-reducing rate was more than 20.0%.

Main parameters of PVA fiber.