Flooring That Lasts, Safety That Endures

Concrete Basics 101

Ascoat provides a comprehensive guide on the basics of concrete

When it comes to concrete flooring, it’s not just a matter of mixing the concrete and pouring it in. In fact, there are many factors that go into making sure that concrete floors are prepped, applied and maintained correctly to ensure longevity, durability, safety and effectiveness.

To help you make sure that your concrete flooring is fit for purpose, we’ve put together a quick guide on concrete basics.

What is concrete?

First and foremost, what exactly is concrete? While concrete is often interchanged with the word cement, it’s not technically correct.

Concrete is actually a mixture of Portland Cement, water, a blend of coarse and fine aggregates and optionally, admixtures.

How is concrete placed?

Successful concrete placement requires a number of important steps to ensure a good result, importantly it needs to be placed into extremely well designed, engineered and constructed formwork, with critical steps being taken to;

1. consolidate the ground underneath the slab to prevent future uneven settlement.

2.  placement of a physical moisture barrier between the ground and the bottom of the slab to prevent moisture migration up through the slab

3. Reinforcing the slab with the correct grade of steel reinforcement sitting at the correct height off the bottom of the slab to ensure long term strength and cracking control.

Finally, the concrete is usually pumped into place in a steady and continuous process before being leveled, trowelled and initially cured by either a physical or chemical process to prevent too much moisture evaporating out of the top of the slab too quickly.   

How long does concrete take to set?

As soon as concrete is poured, it undergoes a curing process, where it dries and hardens over time. The differences in strength are significant and as this graph shows, this initially wet and weak concrete takes quite some time to dry and strengthen.

Concrete strength increases as it hardens through the curing process

What influences the strength and durability of concrete?

There are nine key factors influencing the strength and durability of concrete:

  1. Alkalinity -the typical desirable range is between 12-14 pH. Moisture can cause damage, moisture with a high pH is devastating. The internal alkaline state of concrete is the very chemistry that prevents reinforcing steel from rusting.
  2. Permeability -although concrete is somewhat porous, the degree is what matters, for example continuous capillary pores are of greater concern than discontinuous pores.
  3. Air Voids –think, sourdough bread! You don’t want any or too many large air voids.
  4. Cover Thickness– the distance between the reinforcing steel and the surface is a factor when in a more corrosive/severe environment.
  5. Aggregate Composition– size, distribution and gradation
  6. Cracking– allows ingress of water/chemicals to reach reinforcing steel
  7. Concrete Proportioning– mix design must be well balanced and considered
  8. Concrete Cure– the goal is optimum hydration, controlling the gradual drying of the concrete.
  9. Coating of Concrete– placing a physical barrier in the form of a coating on the concrete. Even if you’ve got some, most or all the above points wrong, a coating can save the day!

What causes concrete to deteriorate?

Concrete is a very durable flooring, however if it is not installed or maintained correctly, it can deteriorate or sustain damage.

The most common form of concrete deterioration occurs in the following 6 ways:

  1. Reinforcement Corrosion
  2. Freeze – Thaw (when water freezes to ice, it expands and shatters the concrete around it)
  3. Chemical Attack
  4. Alkali Reaction
  5. Surface Defects –including cracks
  6. Abrasion/Erosion

Concrete may be coated to:

  •  provide a barrier against chemical or abrasive exposures,
  •  impart waterproofing properties,
  • improve aesthetics such as colour, texture, cleanability, stain resistance and reflectivity
  • enhance functionality, for example adding anti-static protection
  • improve thermal resistance by providing better insulation from hot or cold

Why does concrete surface preparation matter?

Before you coat concrete, it’s vital to understand the critical need for correct surface preparation.

By following the correct surface preparation methodology and the coating manufacturers’ specified recommendations.

One size does not fit all, however, this is where those 4 key elements that come into play when preparing for the application of concrete flooring:

  1. A SOUND surface is the foundation for success
  2. Surface CLEANING increases adhesion by removing contaminants that reduce the number of bonding sites
  3. A DRY Surface allows the coating system to optimally bond to the surface
  4. Surface PROFILING produces more areas for bonding

Inadequate surface preparation is a LEADING CAUSE of coating failure and, in turn, influences the strength and durability of the concrete.  More on this in our surface preparation blog.

To get the most out of your concrete floors, it’s crucial to understand the best preparation methods, how to maintain the flooring and what coating system is the most suitable to apply. Ascoat’s experience, equipment and expertise places us in a unique position to provide the best outcome on your next commercial and industrial concrete flooring project, so give us a call today on (03) 9587 7433.

Ascoat’s Technical Manager, Arthur Karayannis, has worked in the epoxy flooring and protective coatings industry since 1991, with extensive experience as an epoxy applicator and materials supplier. With a Level 2 Concrete Coatings Inspector qualification through the SSPC, he holds the highest concrete coating inspection qualification currently available. Arthur prides himself on delivering industry-leading customer service, educating clients on appropriate flooring solutions, and solving even the most complex flooring problems for customers and stakeholders.

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