Heterogeneity-dominated surfaces in teff straw ash-based geopolymer mortar: A material ratio curve framework

The geopolymer field is a cornerstone of sustainable construction, providing clear insights into the reduction of carbon dioxide emissions when producing cement. The more closely geopolymer surface solutions resemble actual surfaces, the more suitable they become for use in various construction applications, given the outstanding characteristics of surface roughness parameters. Incorporating the material ratio curves into analysis of construction products is an approach that can be considered for such applications. This study is the first to use material ratio curves to compute the surface roughness attributes of teff straw ash (TSA) geopolymer mortar cured at 7, 14, 28, 56 and 90 days. The research compares the surface roughness characteristics of TSA geopolymer mortar in the Rk and V -groups based on ambient and heat-cured specimens. The surface roughness results (e.g., Rpk and Rvk values ≤ 0.23 µm) show that the TSA geopolymer mortars exhibit smooth surfaces. It is demonstrated that enforced roughness is needed in improving the binding capabilities between two mortar layers. Moreover, for surfaces experiencing roughness changes, crucial factors in material ratio curves responsible for material surface quality are identified. Therefore, the results in this study demonstrate the material ratio curves’ capability to achieve significant surface roughness properties in benchmark problems involving TSA geopolymer mortar.