Effects of Sodium Gluconate on the Fluidity and Setting Time of Phosphorus Gypsum-Based Self-Leveling

To comprehensively utilize industrial by-products of gypsum while reducing the consumption of natural river sand, this experiment was conducted to prepare gypsum-based sandless self-leveling (PGSL) materials by using phosphorus-building gypsum (PBG) and portland cement (PC) as gelling raw materials with the addition of polycarboxylate superplasticizer (PCE), cellulose ethers (CE), and retarders. However, employing phosphogypsum as the source material results in a significant 30 min fluidity loss in the gypsum-based self-leveling system. Therefore, to enhance the flow characteristics of gypsum self-leveling, sodium gluconate was chosen for usage in this research. The impact of single and compound mixing of protein-based retarder (PR) and sodium gluconate (SG) on gypsum-based sandless self-leveling materials was evaluated in terms of heat of hydration analysis, pore structure, fluidity, strength, and setting time. According to the experimental findings, it was possible to considerably decrease the fluidity loss of gypsum-based sandless self-leveling materials, postpone the setting time, boost strength, and enhance pore structure when combined with 0.4% SG and 0.03% PR.