*2.1. Experimental Materials*

Cement: Portland Type I cement produced by Taiwan Cement Corporation was used; the properties of this cement conformed to ASTM C150, the specific gravity was 3.15, and the fineness was 3450 cm2/g. Waste PE: The waste PE was provided by the manufacturer, with a specific gravity of 0.92 and a water content of 8.2%. It had the appearance of spherical large granules. After it was decomposed by pulverization, it appeared as flocculent plastic fibers, as shown in Figure 1a, with a specific gravity of 0.92. Figure 1 shows the Fourier-transform infrared spectroscopy (FTIR) spectrum for waste PE. GGBFS: GGBFS was provided by CHC Resources, conforming to CNS12549, with a specific gravity of 2.9 and a fineness of 4000 cm2/g. The fine aggregate was derived from the river sand of the Ligang River, and the specific gravity was tested according to ASTM C127. The specific gravity was 2.65, and the water absorption was 1.48%. The chemical compositions of the test materials are shown in Table 1.

**Table 1.** Physical properties and chemical composition of test materials.


#### *2.2. Test Variables and Mix Proportions*

The tested fresh properties included the slump and flow. Cement mortar specimens were prepared and cured in saturated limewater. Their hardened properties, durability, and microscopic properties were discussed at the ages of 3, 7, 28, 56, and 91 days. The ratio of unit weight and the test methods and specifications are shown in Tables 2 and 3.

**Figure 1.** Material appearance and Fourier-transform infrared spectroscopy (FTIR) analysis of polyethylene.


**Table 2.** Mixture proportions of cement mortar (unit: kg/m3).

**Table 3.** Test method and regulations.


For micro and component analysis, a scanning electron microscope (SEM) is used to generate secondary electrons by striking the specimen with an electron beam, and the cathode ray tube is used to observe the surface microstructure of the specimen. An energydispersive spectrometer (EDS) can be used for qualitative and quantitative analysis of the

composition of the experimental specimen by scanning a high-energy focused electron beam on the surface of the specimen.
