Effect of Polycarboxylate Admixture on the Performance of Fluorogypsum-Based Self-Leveling Material

The study explores the influence of polycarboxylate admixture (PCE) on fluorogypsum-based self-leveling material (FSLM) performance. Wev conducted an array of tests to assess workability and mechanical properties, and utilized XRD, TG-DSC, SEM, and MIP techniques for microscopic analysis. The fresh state results showed that PCE enables FSLM to achieve good workability at lower water demand. It was found that PCE partially inhibited plaster hydration from anhydrite to dihydrate, as observed by X-ray diffraction analysis and thermogravimetric analysis, and with the increasing in PCE, the mass loss of samples reached 15.66% at 28 days. The mechanical properties and the microstructure studies proved that the optimal PCE doping level is 0.14%. At this doping level, there is an enhancement in the denseness of the hardened structure, a reduction in porosity—especially when the pores are more than 200 nm, optimization of pore size distribution, an increase in crystal aspect ratio, an enhancement in effective intergranular overlap, and a significant improvement in the 28-day flexural and compressive strength to 7.2 MPa and 36 MPa, respectively. The FSLM prepared under these conditions demonstrates good performance and meets the primary performance index requirements of the Chinese Industry Standard JC/T 1023-2021 (gypsum-based self-leveling floor compound), thereby promoting the comprehensive utilization of fluorogypsum.