Design Engineer | General Contractor | Pumping Contractor | Ready Mix Producers | Testing Labs
1. Be realistic on air dry densities. Know capabilities of the market area.
2. Specify max. size aggregate.
3. Allow 7" slump into pump.
4. Have testing lab run design curves based on 7" slump.
5. Specify pre-pump meeting with the following present: Design Engineer, General Contractor,
Ready Mix Supplier, Lightweight Aggregate Supplier, Testing Agency, and Pumping Contractor
6. Same people should be present at the first concrete pump placement.
7. Specify exactly where concrete should be tested. (Preferably at end of discharge line).
8. Define free water and absorbed water for w/c ratio and fresh densities.
1. Keep everyone communicating (team effort).
2. Check history of pumping contractor.
3. Make arrangements for two r/m trucks to unload at one time.
4. Designate a laborer to help testing lab inspector move concrete test specimens.
5. Provide washout area of r/m trucks.
6. Make use of r/m truck radio when placement delay occurs.
7. Specify to r/m supplier how many yards per hour you want.
1. Know what density you are pumping.
2. Order concrete for the time you will be ready to start pumping.
3. Stagger coffee breaks.
4. Operator should know max. slump he can use.
5. 5" minimum steel lines; minimum rubber at end of line.
6. Low pressure pumps will have the least slump loss.
Ready Mix Producers
1. Soak the aggregate.
2. Moisture content should be checked every time bins are filled.
3. Make drivers aware that pump aid and/or fly ash is being used.
4. Minimum slump of 4" for high range water reducers.
1. Monitor moisture properly.
2. Field inspector should have roll-a-meter, scale, and strike off plate.
3. Suggest same inspector on critical job.
4. Inspector should know min. and max. fresh density.
5. Test cylinders should not pre-set on floor concrete is being placed on.
6. Fresh density will vary depending on the moisture absorbed in the aggregate.