Investigation of waterborne epoxy-modified cement mortar with copper slag fillers: Hydration, material performance, and pore structure

In recent years, there has been a growing focus on urban renewal in China. Many cement-based repair and grouting materials have been developed and widely applied in building renovation projects. However, traditional cement mortar materials have disadvantages such as low bonding strength and poor corrosion resistance. As a common polymer modifier for repair mortar, epoxy resin has superior mechanical properties, bonding strength, and corrosion strength. Whereas most epoxy modifiers can be inherently insufficient to prevent crack initiation and propagation, and increase cost. In this work, different amounts of waterborne epoxy resin were incorporated into cement mortar and their impacts on cement hydration, mortar performance, and pore structure were comprehensively investigated. The 28-d compressive strength and flexural strength of the repair mortar reached 41.75 MPa and 7.99 MPa, respectively, with a polymer/cement ratio of 10%. By partially replacing standard sand with solid waste copper slag, the workability and durability of the mortar was further improved. The pore structure of the mortar was altered, leading to a more rational distribution of pores and a reduction in both porosity and pore diameter. Less harmful pores (2.07%) and more harmless pores (47.09% for) were detected within the mortar CPCM10 when an appropriate amount of copper slag fillers was used. This study introduced a strategy to properly enhance the performance of repair mortar by incorporating polymer and fillers. Additionally, it explored a potential solution for solid waste management. • Repair cement mortar was modified with waterborne epoxy resin and copper slag. • Effects of waterborne epoxy resin content on cement hydration was investigated. • Workability, strength, and durability of the mortar were improved by WER. • Copper slag improved the durability and pore structure of the repair mortar.