Self consolidating concrete for precast prestressed concrete bridge elements
The proportioning plant inspector is responsible for inspecting control of materials and batching operations.The inspector's duties will start at the time materials are being stockpiled and will continue until final records for the project are complete.The entire sample for slump and air tests and for molding compressive strength specimens may be taken at one time, after approximately one cubic yard of concrete has been discharged.
Each sample should be large enough to permit completion of all necessary tests.
When concrete is being pumped our procedure has been to take samples at the truck chute.
Usually there is no significant difference unless a new or reconditioned pump is being used, the concrete is being pumped a long distance or if there are high vertical drops in the line. The difference between the truck and the pump should be checked regularly, especially if there are significant changes in drop or distance, and certainly if a different pump is used.
If contractor elects to use an optimized mix, the mix design shall be submitted with the target gradation and allowable gradation range.
Representative samples may need to be sent to Construction and Materials for laboratory testing.