Concrete Repair

A variety of reasons exist for why concrete degrades. The following are some of the most common:

• Expansion of aggregate: the aggregate included in the concrete mix undergoes chemical reactions. Opal and quartz are some of the components in aggregates that are known to cause reaction. Recrystallizations and dolomitization can occur causing pop-outs in the concrete. When concrete is reinforced with steel, there remains a possibility that the iron oxides can corrode, resulting in cracks. This can be due to normal wear and tear or due to improper curing and installation. (This is one of the reasons why concrete is a professional’s task – to save time and effort in the present and future!) Reactions of chemicals within the concrete mixture can cause structural damage and cracks or flaking on the surface. Alkali-silica reactions can specifically cause a swelling inside the concrete due to a gel-like substance. Cracks follow. Carbonation can occur due to a reaction between carbon dioxide and calcium hydroxide. This is a progressive cycle and start outwards, moving inwards. To establish whether this is the cause, a pH indicator can be used to determine whether carbonation is the root cause of the cracking. Delayed ettringite formation occurs when the concrete is treated at high temperatures. Later, the ettringite will absorb moisture, making the concrete swell and leading to cracking. Leaching occurs when water flows into pre-existing cracks and reacts with various minerals inside the concrete. Depending on the minerals the water reacts with, different situations can arise. For instance, rusting can cause an orange discoloration in the weak area. The salty water from the ocean can also cause chemical reactions within a concrete structure. Wind and surf can also cause erosion to the structure.
  
• Believe it or not, but even bacteria can cause great damage to concrete structures! Bacteria in sewage can cause reactions, leading to the formation of sulfuric acid. This will deplete strength in the structure. This is one of the reasons why concrete should be mixed with potable water. This problem can also be combatted by treating sewage with an increased pH to stop the reaction with the bacteria in the sewage. 
  
• Physical damages to the concrete structure can occur over time due to a variety of reasons. Though concrete is strong and sturdy, it is not immune to the elements and normal wear-and-tear. Seismic activity, exposure to extreme temperatures and even mining activity (causing underground tremors) can cause damage to concrete. 
  
• Though concrete is one of the safest materials to build with due to its inherent fire-resistance, it can still be damaged by fire. Due to its low thermal conductivity, concrete is often used to fireproof steel. Concrete can typically withstand heat up to 100˚C. Exposure to 300˚C and above will cause thermal expansion, lead to water loss and shrinkage. Explosive spalling can occur. 
  
• Concrete is often used to contain dangerous nuclear discharge. Concrete that gets exposed to neutrons and gamma-radiations can cause structural damages.
  

Don’t be alarmed. Concrete is still a wonderful building material and we are professionally equipped to handle any concrete repair! Our team is skilled and trained to investigate the root cause of the degradation and damage and to address the problem accordingly. 

Like all things in life, concrete ages. Concrete Resurfacing is a useful process whereby concrete is cleaned, repairs are made and the old surface gets overlaid with a new surface. 

We can repair any concrete structure, be it concrete sidewalks, a concrete walkway, patio or driveway.

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