Articulated Concrete Block for Erosion Control
An articulated concrete block (ACB) system is a matrix of individual concrete blocks placed together to form an erosion-resistant overlay with specific hydraulic performance characteristics. The system includes a filter layer underlay that allows infiltration and ex-filtration to occur while providing particle retention of the soil subgrade. The filter layer may be comprised of a geotextile or properly graded aggregated or both. The blocks within the matrix must be dense and durable while providing a matrix that is flexible and porous.
Articulated concrete block systems are used to provide protection to underlying soil materials. The term "articulated" implies the ability of individual blocks of the system to conform to changes in subgrade while remaining interlocked or otherwise restrained by virtue of the block geometric interlock and/or additional systems components such as cables, ropes, geotextiles, or geogrids. The interlocking property provided by the special shapes of ACBs also allow for expansion and contraction. They are either hand-placed or installed as pre-assembled mats on top of a filter layer on prepared subgrade, and act as a soil revetment.
Articulated concrete blocks (ACBs) are an effective erosion control system used to solve a wide variety of erosion problems:
- ponds
- canals
- lay down yards
- drainage channels
- river fronts
- coastal shorelines
- pipeline protection
- boat ramps
- lake shorelines
- low water crossings
- wildlife habitat
- bridge abutments/piers
- dikes and levees
- spillways
- retention basins
- overflow channels
- dam over-topping - read more
The systems are easy to install, simple to produce, and environmentally friendly. ACB systems are often used as an alternative to cast-in-place concrete bulkheads and slope paving, gabions, soil cement, roller compacted concrete, or rock riprap. ACBs can also be used as grid pavers. However, grid pavers manufactured according to ASTM C 1319 are not considered ACBs.
One of the environmental benefits of ACB erosion control systems is that the vertical cores and spaces can be incorporated int the blocks throughout the system, which allow vegetation to grow. Properly selected plant species can almost completely cover the entire hard surface of the ACBs, allowing them to blend in with the natural look of the project. During peak storm events, the ACB layer beneath the vegetation will protect the soil from erosion. The ability to support the ecosystem's habitat is a major advantage of ACB systems over other erosion control methods. Additional advantages of ACB systems are:
- serviceability
- pedestrian safety
- cost effectiveness
- aesthetics
- ecological
- flexibility
NCMA TEK 11-9A (Ref. 2).