# Effect of Adding Waste Polyethylene and GGBFS on the Engineering Properties of Cement Mortar
## 1 Introduction  
Concrete is the most widely used man-made material on the planet and is used in all construction structures. Types of concrete have continuously increased and improved with the development of technology. However, the extensive use of concrete has led to increased carbon dioxide emissions discharged by the cement industry and serious environmental pollution and ecological problems. Cement manufacturing can be identified as a significant source of CO\({}_{2}\) emissions, from production to emissions, making it the largest source of industrial emissions [1]. The cement industry is the second largest source of CO\({}_{2}\) emissions, accounting for 27% of CO\({}_{2}\) emissions from the industrial sector and 8% of global CO\({}_{2}\) emissions [2, 3]. It is estimated that by 2050, cement production will increase by approximately 12-22% compared to 2014. Therefore, efforts to mitigate CO\({}_{2}\) emissions from concrete production have focused on (i) using alternative fuels and raw materials during cement production, (ii) developing alternative low-carbon binders, and (iii) substituting with raw or mineral materials a part of the clinker during cement production or a part of cement during concrete manufacturing [4]. During the process of making iron with blast furnaces in consistently operated steelworks, each ton of steel generates approximately 300 kg of blast furnace slag [5]. Replacing cement with by-products from the ironmaking industry (such as blast furnace slag) can not only effectively reduce cement consumption and carbon emissions, but also achieve the goals of energy conservation and carbon reduction [6]. The hardened blast furnace slag is formed after rapid cooling among the different types of blast furnace slag cooling [7]. Ground Granulated Blast Furnace Slag (GGBFS) belongs to a type of blast furnace slag. GGBFS has become the main construction material to replace cement and can improve the strength of concrete in the late period. GGBFS is widely used in many important engineering projects around the world [8; 9]. The GGBFSS generated by regular steelmaking by Sino Steel Corp. has become a resource under long-term study and vigorous promotion in Taiwan. The GGBFSS is generated by regular steelmaking by Sino Steel Corp of Taiwan in this study. The chemical composition of GGBFS is very similar to that of Portland cement; its composition consists of varying proportions of lime and alumina. Magnesium, silicon, calcium, aluminum, and oxygen make up 95% of the total GGBFS content [10]. Proper use of ground-granulated blast-furnace slag (GGBFS) to replace cement can reduce cement use and slag emissions, and the properties of ground-granulated blast-furnace slag can also be used to improve its engineering properties. In the 1950s, plastics or synthetic organic polymers were mass-produced and used. Packaging is the largest market for plastic use, and the use of single-use containers is falling. In high and middle-income countries, the proportion of solid waste generated from these containers increased from less than 1% in 1960 to more than 10% in 2005 [11]. Although the growth of plastic use does not yet exceed that of steel and cement materials widely used in civil construction, the impact of plastic waste on the environment and how to deal with and eliminate it is still an important issue that cannot be ignored [12]. Most monomers used to make plastics, such as ethylene and propylene, come from fossil hydrocarbons. None of the common plastics is biodegradable [13]. The only way to permanently eliminate plastic waste is through destructive thermal treatment, such as combustion or pyrolysis, which tends to cause secondary environmental pollution as a result of subsequent carbon dioxide emissions. If the waste is buried in a landfill, it will accumulate only in the natural environment and will not decompose [13; 14].