The Factors That Influences The Durability Of Concrete
Many factors can have an effect on the lifespan of multiple concrete services such as Concrete Footing, Concrete Pumping, Concrete Extensions and many more. However, the inferior quality materials can also reduce those lifespans by decades.
One of the predominant factors relating to concrete technology is concrete’s ability to resist chemical migration and water (permeability). The migration of chlorides, sea water, salts, and other harsh chemicals can lead to cracking and deterioration of concrete. Concrete with good chemical and physical durability characteristics are impermeable to migration.
The capability of concrete to withstand environmental conditions is referred to as physical durability. Concrete tends to crack when a change in volume occurs, for example, due to temperature fluctuations.
Abrasion-resistant – the ability to resist friction, rubbing or wearing away. This is affected by:
- Aggregate properties
- Concrete strength
- Exposure conditions
- Cementitious materials
- Surface finish
- Curing methods
When considering the worst-case scenario, concrete can be completely worn away due to abrasion from structural elements. Reinforced concrete can be affected where abrasion can reduce the coverage of the reinforcing steel (rebar) which can result in corrosion.
Freezing And Thawing
Concrete that is exposed to areas with cold temperatures must be resistant to withstand freeze-thaw cycles. Ice is taking up more volume than water, which can result in microfractures in the concrete which can become large cracks. Air-entrainment is a great solution to improving the physical durability of concrete.
Rain And Humidity
Environmental issues and moisture can influence the PH levels of concrete (carbonation) which does not lead to direct damage of the concrete but forming of carbonate can result in loss of alkaline concrete setting for rebars. This can cause corrosion on reinforcing steel which has severe consequences for the structure.
Alkali-Silica Reaction (ASR)
ASR is an expansive effect between contained chemicals in the concrete mix where the silica in aggregates reacts to sodium alkalis and potassium in the cement paste. This may cause spalling of joints, cracks, and movement in certain parts of a structure.
Concrete can withstand most natural chemicals and environments. However, some chemicals can negatively affect concrete and result in deterioration. Concrete with low permeability is more resistant to these factors.
Chloride And Steel
Chlorides found in de-icing chemicals can affect reinforcing steel. Chemical reactions between the steel and chlorides can kickstart the corrosion process can cause profound damage to structural concrete. Surface treatments, deck overlays, and coating of reinforcing steel can help you protect the concrete from corroding as a result of chlorides.
Sulfates in soil and water can have an adverse effect on concrete and result in damage. Sulfates negatively react to compounds in hardened concrete which can lead to pressure which eventually causes disintegration. Concrete used for environments with heavy sulfate must be specially formulated to retaliate against these effects.
A durable concrete is ideally one that performs well under probable exposing factors that can affect the lifespan of a structure. All the above-mentioned factors can influence the durability of concrete.