The defoamer is mainly used for defoaming and anti-foaming of concrete polycarboxylate superplasticizer, can effectively controll the air content of concrete. It can be put into polycarboxylate superplasticizer during its manufacturing process, or put into the concrete/mortar together with the admixtures. 
Advantage
Can effectively eliminate the targeted air bubble in the concrete or mortar and remain the flowability of the concrete or mortar. Easy to dilute, good operability, high stability and good compatibility with polycarboxylate superplasticizer(PCE), without discernible effect on the main performance of the concrete after being added polycarboxylate superplasticizer.
Usage
Its recommended amount of usage is 0.1%-0.3% of the total weight of polycarboxylate superplasticizer. Pretest is suggested before the official use of the defoamer. The defoamer is often diluted before it's used.
Put some water into defoamer with advised dilution rate from 1:5 to 1:1 and stir gently in the condition of low interlaminar shear strength.