How does temperature affect the performance of sodium gluconate?
different working temperature,the performance of sodium gluconate in concrete is different
The effect of temperature on sodium gluconate performance, particularly in the context of concrete, is an interesting topic.
Setting Time:
At 35°C, sodium gluconate is less effective in maintaining a significant retarding effect compared to 20°C.
It can still delay the occurrence time of heat evolution peaks during cement hydration, but its impact on reducing the cement evolution rate peak is minimal.
Mechanical Properties and Dispersion:
The positive effect of sodium gluconate occurs when the addition dosage is less than 0.15% (by cement weight).
However, if the addition dosage exceeds this limit, a negative effect may emerge.
Hydration Behavior:
Early hydration:
sodium gluconate inhibits the hydration of C3S (tricalcium silicate) and the formation of portlandite (CH).
Later hydration (beyond 1 day):
sodium gluconate promotes C3S hydration.
Dosage-dependent effects:
sodium gluconate promotes ettringite (AFt) formation at dosages less than 0.06%, but inhibits it at higher dosages