What is Abrasion / Erosion?
Abrasion and abrasion erosion are two processes that lead to the deterioration of concrete structures but occur through different mechanisms.
Abrasion refers to the wear on concrete surfaces, such as pavements and industrial floors, caused by dry attrition from traffic movement. This wear results from physical contact and grinding against the concrete surface by vehicles, machinery, or pedestrian traffic, which gradually wears down the material.
Abrasion erosion, conversely, describes the wear caused by the abrasive action of fluids, often containing solid particles in suspension, against concrete. It typically affects hydraulic structures like canal linings, spillways, and concrete pipes, as well as piers in rivers, where the movement of water carries abrasive particles that wear away at the concrete surface causing material loss, reduced durability and potential strength reduction.
Additionally, in high-velocity water flow, erosion can be exacerbated by the impact of collapsing air bubbles, which can remove significant amounts of concrete and negatively impact the structure's strength.
Abrasion and erosion in concrete structures lead to surface wear and deterioration, impacting the structural integrity and functionality. Abrasion results in the physical wearing away of the concrete surface while erosion involves damage from the abrasive action of fluids containing solids, causing material loss and potential strength reduction.
In severe cases concrete loss can reduce the depth of cover concrete increasing the risk of other deterioration mechanisms such as reinforcement corrosion.
What causes Abrasion / Erosion of concrete structures?
Concrete Abrasion is most often the result of continuous movement and heavy loads from vehicles and machinery which cause significant surface wear over time, particularly to floors in industrial settings.
Structures exposed to fast-moving water, such as dams and spillways, endure erosive forces that gradually scour away the concrete on the surface layers most exposed to water action which can lead to severe concrete loss and undermine the structure of particularly bridge support columns over time.
A weak, poorly cured, low density concrete mix created with high water to cement ratio, poor quality, weak aggregates, poor aggregate grading and a binder composed solely of Portland cement is more prone to wear.
What are the signs of Abrasion / Erosion of concrete structures?
Loss of concrete.
Loss of paste and/or aggregate.
Surface damage.
How can I identify Abrasion / Erosion in concrete structures?
Visual survey | Non-destructive testing | Destructive testing |
How can I prevent Abrasion / Erosion in concrete structures?
To prevent abrasion and erosion in concrete structures, incorporating several strategic approaches and materials into your construction and maintenance practices is crucial.
High-strength, good-quality concrete forms the foundation for resisting these types of wear. Utilizing Ground Granulated Blast Furnace Slag (GGBS) as a partial replacement for cement in your concrete mix can enhance durability and resistance to such damage. GGBS improves the concrete's overall performance against the abrasive forces of water and mechanical stresses.
Surface protection systems, such as impregnations and coatings, provide an additional layer of defence, shielding the concrete from direct exposure to abrasive elements. These systems are particularly effective in preventing water infiltration, which is a common cause of erosion in structures exposed to high-speed water flow or submerged parts.
Incorporating wave blocks or designing with sacrificial layers can offer physical barriers to erosion, especially in coastal defences or hydraulic structures. These methods aim to absorb the energy of impacting water or debris, thereby protecting the main structure from direct wear.
Admixtures like Hard-Cem have also been identified as effective in improving the concrete's resilience to wear. Hard-Cem can be integrated directly into the mix to provide uniform durability throughout the concrete, making it a valuable addition for areas expected to face high abrasion or erosion forces.