What are the recommended dosage levels for sodium gluconate in concrete?

The recommended dosage levels of sodium gluconate in concrete depend on the desired effects.

Fluidity and Setting Time:
sodium gluconate enhances initial fluidity without decreasing it within the first hour.
Dosages ≥0.06% slightly increase slumps at 30 minutes and 60 minutes.
Inhibits calcium hydroxide (CH) formation, significantly extending setting time.
At 0.15% dosage, initial and final setting times are 5.0 and 4.5 times longer than the blank group, respectively.
Heat of Hydration:
sodium gluconate has no significant effect on hydration rate during the accelerated period.
Increases peak hydration temperature at dosages of 0.03% to 0.12%.
Strength Development:
1-day and 3-day strength decrease with higher sodium gluconate dosages.
Promotes formation of ettringite (AFt) at pores and aggregate interfaces.
Improves compressive strength at 28 days, 60 days, and 90 days.
At 0.12% dosage, 90-day strength increases by 13%1