What Gives Concrete Its Strength?

Concrete Its Strength

Concrete Its Strength Despite the fact that concrete is something which we interact with a hundred different times every day, we rarely ask questions about it. We rarely wonder about what it is made of, how it stays so strong, and why we use it to build sidewalks, housing foundations, and soaring skyscrapers. This wonder material forms the basis of the world around us, but we know very little about it.

It is time to ask some questions about concrete and, particularly, how it can stay so strong; strong enough to keep entire buildings standing, for example. This guide to the basics of concrete will help you get to grips with this versatile material.

What Is Concrete Made From?

The makeup of concrete is surprisingly simple, especially in light of its many varied uses. It is composed of cement, sand, gravel, and water, though it sometimes includes larger rocks too. The mixture grows hard and strong, due to a process known as hydration – to put it simply, the water evaporates and leaves the paste. The ingredients which are left quickly harden and form concrete.

How Strong Can Concrete Be?

The strength of concrete can vary wildly, depending on what it is used for, so you can have materials as ‘weak’ as 2,500 Psi or as strong as 10,000 Psi. Of course, even the weaker concrete blends are extremely strong, because they need to maintain their integrity under heavy foot traffic and pressure from vehicles. The very strongest concrete blends are usually reserved for buildings and special projects.

What Factors Affect the Strength of Concrete?

There are many different factors which can affect the strength (Psi) of concrete. These are the methods which are used to tailor concrete blends to their respective uses. Whilst some make concrete blends which are weaker, others make much stronger mixtures.

1. Amount of Water – it is the cement in concrete which bonds the rest of the ingredients together. The more water which is added, the weaker the mixture and the harder it is for the concrete to form the strongest bond. For concrete which is strong enough to withstand heavy traffic, there must be enough cement for every cubic yard. If the concrete is likely to be exposed to very cold temperatures, there needs to be a minimum of 560lbs of cement per cubic yard.

2. Air Bubbles – whilst air bubbles are a bad thing for most kinds of concrete, in cold temperatures, water can freeze within the material and increase the risk of cracks. If concrete is routinely exposed to freezing climates, tiny micro bubbles can be inserted beneath its surface as way to boost durability. These little bubbles function as shock absorbers and decrease the likelihood of temperature related fissures.

3. Degree of Slope – in order for concrete slabs to stay strong and stand up to intensive wear, they need to have suitable drainage. This usually means a slope or incline of around 1/8 inch per lineal foot (at least), so that they can keep surface water moving. If water is allowed to pool and freeze on the top of concrete slabs, the risk of cracking increases.

4. Suitable Curing – to become strong and firm, the water needs to evaporate gradually from the mixture, via the process of hydration. If it is allowed to escape from a concrete slab too quickly, hydration will only be partially successful. To prevent this from happening, concrete specialists cover and protect curing concrete with moistened burlap.

5. Use of Silicone – if you need to seal concrete, it is best to avoid silicone based products. These are film formers and they do not allow the material to breathe or naturally settle. You should use a breathable sealant or a water repellent product. If possible, pick one which contains both silanes and siloxanes; these compounds are similar in nature to silicone, but a lot stronger and more durable.

If you seek the help of a reliable concrete specialist or paving expert, it will be able to help you determine what strength of concrete you need for your project. It is always best to opt for stronger concrete if you are not quite sure – the stronger the material, the longer it will last and the more wear it will withstand before showing signs of aging.

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