1. A) The advantage of using Kemco water mixer for sand 1) To prevent the sand in well balanced grading from its segregation thanks to Meniscus by surface tension of water. Typical segregation cases under the dry conditions: a) At stock pile: Relatively large particles are falling down on the surface of stock pile and those gather at the foot of stock pile. Only small particles are remained on the surface of stock pile. b) When conveying: When conveying the sand, large particles come up and small ones come down. The grading at stock pile becomes lost balanced. Conveyor

2. 2) Sufficient water absorption The sand is required to sufficiently absorb the water to prevent from slump loss of fresh concrete. Remarks: Insufficient water absorbed sand will absorb the water when concrete mixing and cause slum loss. 3) Stable water absorption Appropriate and stable water absorption control. 4) To prevent the sand from having the dust caused when the sand falls down from conveyor to stock pile if it is dry. 5) To prevent the sand at stock pile from having its small particles as the flying dust if it is dry. Especially in case of the above 1)-a), this often happen.

3. B) The pictures of water mixer