Do you know how far the history of concrete dates back? 100 years? 200 years? Apparently, concrete was first used by the roman empire, 2000 years ago, for monuments like Pantheon, Colosseum.
Surprising enough? Not for me though. Concrete structures are meant to last a lifetime, and this explains why they are chosen for wharves, breakwaters, and other harbor structures. They are meant to last for at least 50-100 years, if not more.
But this doesn’t mean that using concrete will ensure that it will last so long. There is premature deterioration and even structures so highly durable like concrete can lose their longevity if not maintained well.
That being said, all that can be avoided, by doing a few things right, and avoiding a few things. Below, I’ve compiled everything that you need to know about how to increase the durability of the concrete structure.
1. A suitable design mix
To start with, you need to know the mix design suitable for the service conditions the concrete will be exposed to. The amount of water, that is the ratio of water to concrete is the single most important factor when it comes to the design mix.
In most cases, a low water to cement ratio is what one should aim at. This means around 0.40 and 0.50 is normally what is ideal. Additional or extra water is what leads to lower strength and increases the chances of permeability with an increased likelihood of scaling.
Also, what is important, but ignored most times is that the contamination aggregates, which can cause pop-ups or alkali-silica reactivity. Make sure your concrete isn’t contaminated.
2. Avoiding premature moisture loss
Do you know what will ensure maximum strength, increased density, lower permeability, and greater resistance to scaling? Keeping the concrete moist and at a proper temperature, providing required hydration.
You need to put special emphasis on the finishing. Oftentimes, excessive or premature finishing can lead to blistering or reduced surface air content or durability.
During the toweling process, adding water to concrete means you are increasing the chances of scaling and spalling. As discussed in the previous point, a rise in the water to cement ratio always weakens the concrete. Preferably, use evaporation retardants, in rapid moisture loss conditions.
3. Lower Permeability
A lot of factors must be matched to the working conditions, but one thing that stays common is low permeability.
Good mix proportioning and reducing admixtures, or plasticizers is what will help you get low permeability. Use a waterproofing admixture to protect concrete from water intrusion.
Curing means maintaining conditions that allow the concrete to harden and gain strength, and as it suggests, this step is very important for the life of the concrete. By conditions, the primary ones are humidity and temperature.
The ideal temperature is above 10 degrees centigrade, for strength development, which is easily achievable. Also, moisture levels, especially in the initial days, need to be maintained so that the concrete doesn’t end up drying, shrinking, or cracking.
5. Avoiding frequent wetting and drying
The possibilities of scaling multiply manifolds when frequent wetting, drying, happen during the early stages of the concrete. Concrete should be protected from freezing temperatures, during the first days of hydration.
Treating the surface with something like aqua peel, where there is the presence of deicer agents cannot be eliminated.
6. The placement of concrete
Placed properly, and consolidated into a solid mass that is free from any voids or pockets, concrete must be placed in the correct manner.
Voids should be avoided below or behind reinforcing steel bars. There shouldn’t be any amount of water, prior to the concrete placement.
7. Working with the right people
Well, you aren’t going to handle all the concrete by yourself. For a fact, you might not have a thing to do with the concrete.
So, this makes it all the more important that you hire the right people, like people from https://civilmart.com.au/ to do the job for you. They are experts in the field and know exactly what needs to be done.
They are doing this year after year and have a great list of satisfied clients. So, it will be wise if you get them on board. They understand concrete better than anyone.
Over to you…
How the building will be in the future is decided today, when its foundation is laid, and concrete has a lot to do with it. So, it will be a good thing, if you pay attention to all the factors like mix design, reducing permeability, paying attention to good jointing, and the placing and curating practices.