Concrete Renovations offers an assessment survey and diagnosis of damage service.
We regularly test concrete for carbonation, corrosive contaminants and chemical reaction, as well as signs of physical and mechanical damage; this allows us to offer the appropriate solution to a given problem.
Concrete, Damage and Defects:
Mechanical
Impact, Vibration and explosion
Abrasion and Wear
Overloading
Chemical
Alkali Aggregate Reaction
Chemical Exposure
Bacterial Action
Physical
Thermal Movement
Freeze Thaw Action
Efflorescence / Leaching
Salt Crystal Expansion
Erosion
Concrete Damage
due to Reinforcement Corrosion:
Carbonation
Carbon Dioxiode (CO2) in the atmosphere reacting with Calcium Hydroxide in the concrete pore liquid.
Soluble and pH 12 - 13 : Almost insoluble and pH9
Steel Passivated : Steel Unprotected
Stray / Electrical Current
Metals of different electropotential are connected to each other in the concrete and corrosion occurs.
Also corrosion can be due to stray electrical currents from transmission networks.
Corrosive Contaminants
(e.g. Chlorides)
Chlorides accelerate the corrosion process however originally caused.
At above 0.2-0.4% they break down the passive oxide.
Chlorides can be from marine exposure or deicing salts.
Their use to accelerate concrete setting at low temperatures is now mostly banned in reinforced concrete.
Freeze / Thaw deterioration
Critically saturated concrete occurs when over 90% of the concrete pores are full of water.
Frozen water has 9% more volume than unfrozen water. The expansion breaks off the concrete surface.
