Effects of Mixing Water and Environmental PH Value on the Properties of Sulfoaluminate Cement-based Ultra-high Water Materials

In order to grasp the influence of the pH value of mixing water and environmental water on the properties of ultra-high water materials, this article separately carried out the influence of different pH values of mixing water on the properties of ultra-high water materials and the conservation of high-water materials in water environments with different pH values. Using test methods such as loss of flow time, compressive strength, Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), Thermogravimetric-Differential Thermal Analysis (TG-DTA), to conduct regular exploration and mechanism analysis. The study found that with the continuous increase of the pH value of the mixing water, the loss of flow time of the ultra-high water material gradually decreased, and the compressive strength of the samples at the same age continued to increase. A lower pH value will affect the compressive strength of the consolidated body of the ultra-high water material, but when the pH = 13 in the reaction solution, the compressive strength of the consolidated body will no longer increase and begin to produce a weakening effect. The pH of the construction water for ultra-high water materials is recommended to be 4-13. At the same time, it was found that under the conservation of an acidic environment, the consolidated body was severely eroded and the strength loss was large. The acid-base environment of the goaf suitable for filling with the ultra-high water material should be between pH = 7-10 to ensure that the filling body is not weakened by erosion.