Good quality concrete starts with the quality of materials, cost effective designs is actually a by-product of selecting the best quality material and good construction practices. Following are 10 Things to remember during Concrete Mix Design and Concrete Trials.
1. ACI and other standards only serves as a guide, initial designs must be confirmed by laboratory trial and plant trial, adjustments on the design shall be done during trial mixes. Initial design “on paper” is never the final design.
2. Always carry out trial mixes using the materials for actual use.
3. Carry out 2 or 3 design variations for every design target.
4. Consider always the factor of safety, (1.125, 1.2, 1.25, 1.3 X target strength)
5. Before proceeding to plant trials, always confirm the source of materials to be the same as the one used in the laboratory trials.
6. Check calibration of batching plant.
7. Carry out full tests of fresh concrete at the batching plant, specially the air content and yield which is very important in commercial batching plants.
8. Correct quality control procedures at the plant will prevent future concrete problems.
9. Follow admixture recommendations from your supplier
10. Check and verify strength development, most critical stage is the 3 and 7 days strength.
Important note: Technical knowledge is an advantage for batching plant staff, even if you have good concrete design but uncommon or wrong procedures are practiced it will eventually result to failures.