# Influence of Waste Filler on the Mechanical Properties and Microstructure of Epoxy Mortar
## 1 Introduction
The PVC waste can be recycled and used to make various products, including pipes, flooring, and docking [19]. The following materials are used in this proposed work: steel slag, marble dust, and polyvinyl chloride (PVC) waste. There are several reasons for selecting industrial waste materials, such as steel slag, marble dust, and polyvinyl chloride (PVC) waste, in various applications. Industrial waste materials are more economical than virgin materials, as they can often be easily obtained for free or at a low cost. Therefore, this strategy helps to conserve natural resources and reduce environmental impacts associated with resource extraction and processing [20]. The mechanical properties of a commercially produced epoxy mortar are worse than those of the composites. This is probably due to a few factors, namely the highest filler presence, the larger filler grain size, which reduces the filler-matrix contact surface/filler volume ratio, and a different epoxy [21]. Previous research has reported different fillers and varied epoxy resin-to-filler ratios for various uses [22; 23]. A thorough examination revealed that research had been conducted on the impacts of using steel slag, marble dust, and PVC waste along with natural sand as a filler in epoxy mortar [17; 18; 19; 21]. Due to their widespread availability and compatibility with building materials, these wastes could be utilized as filler in place of sand in epoxy composites [16]. The epoxy resin depends on the constituents of the mortar. It is necessary to improve the proportion of the epoxy resin mortar. The main objective of this research work is to develop the concept of waste recycling and utilize waste as a source of materials in an innovative and valuable manner, thereby promoting environmentally sustainable industrial waste management. The aim is to enhance the mechanical strength and durability of epoxy mortar while promoting green sustainable concepts. An epoxy mortar was selected having an epoxy binder and filler with a ratio of 1:3, representing proportions of 25% and 75%, respectively, to prepare a sample for compressive and tensile strength testing. The epoxy binder consisted of epoxy resin plus epoxy hardener. On the other hand, various fillers such as steel slag, marble dust, PVC waste, and sand were incorporated into the preparation of each individual specimen of epoxy resin mortar. Then compressive and tensile strength testing was performed for each sample. It was observed that the epoxy steel slag gives maximum compressive and tensile strength compared to the epoxy marble dust, epoxy sand, and epoxy PVC waste. To determine why epoxy steel slag gives maximum strength, microstructure analysis was performed. For this purpose, X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared radiation spectroscopy (FTIR), and scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDX) were used. The findings of the mechanical strength test indicate that the specimens' strength can be improved by the addition of steel slag and marble dust due to the higher peak densities of these two materials and the stronger particle interactions that occur from their combination. In the microstructure of epoxy resin-based mortars, XRD, SEM, FTIR, and SEM-EDX analysis indicated the production of calcium (Ca), magnesium (Mg), and other phases. Microstructure analysis of the epoxy steel slag and epoxy marble dust reveals lower water absorption and porosity, which induce an enhancement of compressive and tensile strengths and durability. The main contributions of this research are as follows:  
* The improvement of the specimens' strength due to the mixing of epoxy with steel slag and epoxy with marble dust. * The enhancement of compressive and tensile strengths and durability of the epoxy steel slag and epoxy marble dust, and their lower absorption of water and lower porosity.