The challenge
Kattupalli Port is described as one of the largest shipyards in Asia. Its protective perimeter is a breakwater armoured with Accropodes: unreinforced, single layer concrete armour units with several angled legs, placed to resist wave action. The project used a 50% slag binder that, with an admixture, had to meet requirements for fineness, air permeability, activity index and compressive strength. A sodium naphthalene sulfonate formaldehyde condensate (SNF) admixture was chosen for its slump control, one hour workability retention, strength gain, compatibility with different cements and because it does not corrode reinforcement. Concrete grades from M10 to M45 were designed, with the main Accropodes at M30. The units were cast in highly flowable concrete, with close attention to bleeding, surface blemishes and compaction.
The DCP solution
After mock studies and research, DCP provided Supaflo Special, a tailor-made SNF high range water reducing admixture with an emphasis on workability retention. The improved workability reduced or removed problems with segregation, bleeding, placing and compaction.
DCP products used
How it was applied
- Run mock studies to set the admixture and mix.
- Batch the final mix: cement 230 kg/m³, GGBS 160 kg/m³, free water 165 L/m³ and 100% crushed sand, with Supaflo Special.
- Cast the M30 Accropode units in flowable concrete, watching for bleeding, blemishes and compaction.
The result
The project criteria were met, and Accropodes with the required finish, durability and ultimate strength were produced.
