Concrete has micro cracking at the interface of aggregate and cement paste (A. M. Neville). Marine concrete is exposed to harsh environment of high winds laden with moisture, salts and fine sand that results in corrosion and surface erosion. To improve concrete durability, US Navy recommends micro reinforcement with fibrillated polypropylene fibres (UFGS-03 31 29, February 2010). Addition of fibres provide the following benefits:
- Maintains concrete cover over primary reinforcement to protect against corrosion.
- Reduce water penetration in concrete.
- Provide lasting secondary reinforcement in concrete.
- Inhibits plastic settlement cracking.
- Control plastic shrinkage cracking up to 80%.
- Lowers water migration in concrete and control bleeding.
- Improve flexural properties of concrete up to 30%.
- Resist impact/shatter forces up to 14 times more than plain concrete.
- Increase abrasion resistance significantly.
- Provide fatigue endurance in fibre reinforced concrete not available in plain concrete.
- Improve fire resistances of concrete.
Recommendation of Fibrillated Fibre
Fibrillated Fibre Reinforced Concrete Recommended by US Navy
Marine Concrete Specifications
Design Manual Civil Engineer Division-3