It’s not too unusual to hear someone asking about which is better, concrete vs cement? On the other hand, you might hear someone asking if concrete and cement the same thing? They are different things, only that cement is part of the concrete mix that binds it all together.
What is concrete mix made of
Usually, concrete is made of sand, gravel (crushed stones), and cement. When you mix it with water, water and cement will form a paste that will keep everything together. So comparisons like concrete vs cement are actually useless as most of the time people are asking about the same thing.
On the other hand, we could make a comparison of concrete with different amounts of cement. Does adding more cement make concrete harder? Surprisingly the answer is no.
Adding cement to the sand and gravel will only help strengthen it to a certain point, after that it will affect negatively. The concrete will get too strong and it might cause it to crack. So it’s important to keep the right amount of cement to aggregate ratio to achieve the wanted results.
Another thing that affects concrete strength is the amount of water we use. Lower water means more strength, but too low water causes low strength. Then again too much water weakens the strength again so what is the proper amount? It depends on the amount of cement in the mix.
Cement usually makes something like 10-15% of concrete weight when sand and gravel make around 60-80% depending on the case. Rest is left for water and air. You can sometimes see workers using the vibrating tools on fresh concrete. That tool actually helps the concrete to set tight as it removes air that’s on the mix.
Concrete cures over time
One thing to remember is also that concrete doesn’t dry in the traditional sense. Water reacts with cement and forms a paste that will “cure” over time. It will continue to harden over time and that’s why you see workers wetting concrete. Outdoor plasters are the same with cement, you need to spray them with water a few days after rendering.
With help of watering the concrete can achieve greater strength as the moisture will evaporate more slowly. Most of the time we want to achieve the best results, so it’s good to almost always water the concrete. It will provide a stronger foundation to tile, plaster, render, and paint on.
Gravel or crushed stone also affects the strength of the concrete. It’s usually rough-surfaced because it has more surface for sand and cement to bind to, making it a stronger combination.
Concrete vs cement vs mortar?
We’re clear at this point that there is a difference between concrete and cement and their uses are quite different. So what is the mortar used for and is it any different from concrete?
Mortar is another mix of sand and cement. It hardens/cures just like concrete, but it’s a weaker mix. It is mostly used to hold bricks together so the water and cement ratio is higher than concrete. It’s important to pick the right kind of mortar for your work as it can crack if too hard and wear down if it’s too soft.
Good examples would be cold and windy places. Rain might pour on tall walls and snow will fall on them as well. That will cause erosion in the mortar, weakening its properties. Hot weather on the other hand will affect the curing process and might affect the end result badly.
Mortar can also be used to render brick walls outside as it can handle the weather. The cement to sand ratio is different from the one used for laying bricks, but the principle is the same. With rendering mortar, a level outlook or ornamental forms can be achieved.
The amount of cement for mortar varies a lot, but personally, I’ve seen recommendations from 1:6 (1 cement: 6 sand) to even 1:3. There is also ready mix mortars for hobbyist and small projects which should be the safest bet. Still, it’s good to check the place where we need it, if it has to take lots of change in weather and temperature a harder mix might be needed for it to last.
Mortar vs grout
Grout is often associated with mortar as it’s one of the materials we need when we do ceramic tiling at home. Can grout be used as mortar? I’d not advise so as they are most often quite different from each other, hard grout could easily break under tiles.
Grout has more water in the mix than mortar as it needs more ability to fill gaps. For example, grout is used for filling in the spaces between ceramic tiles mentioned before. That’s why it needs to be more fluid to be used to get in between tiles.
We want to fill all the gaps as we don’t want any filth/dirt to start gathering in our washing rooms or kitchens. Grout is good to apply with pressure so it really goes deep in the gaps. After applying extra is washed off with a sponge for example.
So there isn’t much difference on the material level, only how each part is measured. Grout also doesn’t have much sand, if all, at it as it’s supposed to be like paste and almost as hard as the material around it. They shouldn’t be compared as their uses are different and so are meant to have different features.
That being said, if you mix them with close enough ratios, you could use mortar and grout in one mix. I’d do that in places like outside where I’ll use the mortar to adhere the tiles and make it little more runny to do the joints.
What is thinset?
Finally, there is thinset. Thinset is used as mortar, helping two things to stick together. Thinset also contains the same materials as mortar so what is the difference this time? Thinset is better with heavier materials and is most commonly used in places like bathrooms that have ceramic tiles.
Thinset is actually very good for tiling inside and outside, because of its adhering features. You can also use it for leveling floors and walls before tiling. That’s because for tiling you need to have as level a surface as possible and the thinset adheres well to the surface we’re working on.
Also because it’s the same material, a new layer of thinset with ceramic tiles installed will have a strong grip on the concrete or tiles that’s on the bottom level.
Cement, aggregate, and water combinations shouldn’t be compared as they have different uses. You shouldn’t try to work with the wrong materials, because the end results won’t work as it should. Concrete and mortar might sometimes be mixed up as some mortar combinations might look a bit like concrete when it’s wet, but it won’t achieve the same result.
Also, concrete used for building is most of the time reinforced with steel, which will give it a stronger structure. Mortar has its own uses in laying bricks and covering brick walls and grout can be used on seams. It’s amazing how changing the cement ratio can bring out such different applications.