Normally,ready mixed concrete is transported by truck to projects place from long distance from batching plant,at hot weather,the water in the ready mixed concrete is lost,and have a negative influence to concrete flowability and workability,result big slump loss,and the concrete setting time is shorter than that is expected.
Retarding admixtures just solve problem above,it can slow down the speed of the reaction of cement and water,by slow down the hydration process or reducing the rate of water penetration to cement particles.
The retarding admixture has no negative influence to final strength of concrete,when adding it to concrete.
Sodium gluconate is one to main ingredients to formulate retarding admixture,the cost of sodium gluconate is not too high,and adding rate is not high.