Associated Effects of Sodium Chloride and Dihydrate Gypsum on the Mechanical Performance and Hydration Properties of Slag-Based Geopolymer

The associated effect of sodium chloride and dihydrate gypsum on the mechanical performance a slag-based geopolymer activated by quicklime was investigated compressive strength, shrinkage, square circle anti-cracking tests mortar with 0.5 water–binder ratio 1:3 binder–sand ratio, as well paste soundness, powder X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy energy dispersive spectroscopy (SEM-EDS), mercury intrusion porosimetry (MIP) paste. results indicate that (1) when is used alone, it combines calcium aluminate hydrate (C-A-H) to form sulfoaluminate (AFt), which encourages hydration process slag. A 7.5% addition can result in an increase 97.33% 36.92% 3-day 28-day strengths, respectively. When NaCl itself, facilitates condensation aluminum silicate tetrahedron unit generates zeolite. 2% dosage lead 66.67% while causing 15.89% reduction strength. (2) combined formation needle-like rod-shaped AFt, Friedel’s salt, plate-like Kuzel’s salt geopolymer. This leads strengths 148% 37.85%, Furthermore, reduces porosity 18.7%. (3) Both enhance soundness geopolymer, they do no harm crack resistance drying shrinkage at 28 days just 0.48 × 10−3, only 66.7% OPC. has simple preparation process, good volume stability, low raw material cost, consumption, carbon emissions. It be instead 32.5 slag Portland cement plain concrete applications, high engineering, economic, environmental values.