Effect of Ground Granulated Blast Furnace Slag on Mechanical Properties and Hydration Mechanism of Magnesium Oxysulfate Cement

This dataset originates from a systematic study investigating the effect of ground granulated blast furnace slag (GGBFS) on the mechanical properties, water resistance, and microstructure of magnesium oxysulfate (MOS) cement. The data were obtained through laboratory preparation: pastes were formulated using light-burned magnesia powder, magnesium sulfate heptahydrate, and GGBFS at varying incorporation rates (2.5% to 20.0% by weight). The mixtures were prepared according to a specific molar ratio, cast into 20 mm cube molds, and compacted. Specimens were cured under two distinct conditions: standard curing (25 ± 2 °C, 60 ± 5% relative humidity) and air curing (25 ± 2 °C, 50 ± 10% relative humidity) for periods of 3, 7, and 28 days. Compressive strength at each curing age was tested using a universal testing machine (with the final value representing the average of six parallel specimens). Setting times were determined using a Vicat apparatus. Water resistance was evaluated via the softening coefficient, calculated from the ratio of compressive strength before and after water immersion. For microstructural characterization, phase composition, chemical structure, morphology, elemental distribution, and thermal behavior of 28-day samples were systematically analyzed using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), and simultaneous thermal analysis (TG-DTG).The temporal scope of the data focuses on the early to mid-term stages of cement hydration (3, 7, and 28 days). Spatially, the information corresponds to the material's micro-scale, encompassing phase composition, morphology, and elemental distribution. The dataset primarily consists of experimental results presented in graphical and tabular form: Figure 2 illustrates the development of compressive strength with varying GGBFS content under different curing conditions; Figure 3 shows the relationship between setting time and GGBFS dosage; Figure 4 presents the softening coefficient as a function of dosage and curing regime; Figures 5, 9, and 10 provide spectral data from XRD, FTIR, and TG-DTG analyses, respectively, reflecting the evolution of phases and structure; Figures 6 and 7 display SEM images revealing the micro-morphology; Figure 8 and Table 3 provide semi-quantitative elemental compositions (in atomic percentage) from EDS point analyses, with Table 3 containing data for eight analyzed points (a1 to d2), reporting the content of Mg, O, S, C, Ca, and other elements (Si, Al). Tabular data, such as the oxide compositions of the raw materials (Table 1), include the mass percentages of various oxides for two materials. The data were obtained from a complete set of experiments, with no significant missing data mentioned. Potential errors in the experimental data may arise from batch-to-batch material variations, instrumental measurement accuracy (e.g., in strength testing or thermal analysis), and the representativeness of micro-areas during sample preparation and characterization (e.g., in EDS point analysis). The associated error margins are consistent with standard testing protocols in materials science.The data files are primarily presented as figures and tables embedded within the manuscript. Formats include common image types (e.g., .wmf, .png) and text-based tables, which can be opened and processed using standard document readers, image viewers, and data analysis software.