Concrete is one of the sturdiest and most durable building materials we have at our disposal. Having said that, even concrete faces challenges, with many environmental stressors causing it to degrade and crack.
Here we’ll go over some of the most common stressors that affect concrete, as well as pointing out the best course of action if your concrete constructions start to show signs of wear and tear.
Water Ingress
Water can naturally infiltrate through the capillary pore structure of even reinforced concrete, leading to potential issues such as reinforcement corrosion, cracks or spalling.
Areas with carbonated concrete or high chloride content on the surface of steel reinforcing bars are particularly prone to these problems.
Excess Weight
Structural challenges like overloading from increased traffic, inadequate design, damage, stress/fatigue failure, earthquake effects or mechanical impacts such as vehicle collisions can either surpass or start to diminish the structure’s load capacity.
Chemicals
Certain structures, like chemical plants, sewer systems or wastewater treatment plants, face varying degrees of chemical attacks, creating the need for special coatings.
Chloride Ingress
Chlorides, originating from de-icing salts in winter or saltwater in marine environments, can infiltrate concrete structures. Once they reach the reinforcement bars, they have the potential to locally destroy the passivation film, leading to rapid pitting corrosion which requires urgent repair.
Freeze/Thaw Process
The freeze-thaw process induces stress in the concrete due to water expansion in capillary pores during freezing conditions. This stress can result in surface scaling, especially in poor-quality concrete and is exacerbated by chlorides present in the water.
Temperature Changes
Buildings and bridges experience temperature fluctuations from day to night or winter to summer, so they undergo thermal stresses and movements in the concrete structure, potentially causing cracks in the material.
Fire
Reinforced concrete is susceptible to damage from fire exposure and protective intumescent coatings may be employed to safeguard structures against fire without adding fuel to its intensity. Tunnels, in particular, require special considerations for this risk.
Carbon Dioxide
The reaction between carbon dioxide and calcium hydroxide in the cement matrix pore liquid results in the deposition of calcium carbonate , a process known as carbonation. This can diminish the strength of embedded steel reinforcement once carbonation reaches them.
So those are the different stressors that concrete faces. If you’ve spotted some cracks or degradation starting to appear in your concrete structure then it’s probably best to nip the issue in the bud before it becomes much worse. Or if the damage is already significant, don’t put it off any longer as it could become a significant danger to you and the public.
Even before cracks appear there are ways to assess the condition of your concrete to help give you an idea of whether your structure is likely to deteriorate. This is done with a concrete condition survey.
With a survey, we will look at the state of your concrete and tell you how strong it is, which can ensure safety and save money in the long run.