Is it true that the world is running out of sand to produce concrete, and if so, why is that?
In: 92
It’s like the world is running out of water or the world is running out of space/resources due to over population
Edit: shiishh ppl dont get jokes nowadays 😁😁
No, that is nonsense.
Maybe the type of sand that is most optimal (or cheapest) but you can make concrete with all sorts of sand.
You could use the sahara if you wanted to
It kinda is but not quite really so. The best sand for concrete production is riverbed sand, or sand which has recently been on riverbed (like beach sand). There obviously is a limited number of riverbeds and beaches on Earth, and also people need rivers and beaches which haven’t been basically destroyed by sand mining. Another thing is that sand is heavy and therefore rather expensive to transport around in the massive quantities required. So overall we are running out of good concrete-making sand that is close to where it’s needed and that can be mined without massive environmental damage. So it’s not really like we are actually going to run out of sand anytime soon, but it will likely become significantly more expensive with time.
Ecological reasons also play a part, places that once were considered ripe for sand dredging and excavation are now protected for ecological reasons.
Much of the sand used in concrete comes from “ancient” river bed deposits which is good sharp sand, free of salt water but many areas once mined for sand are now in environmentally protected areas because they are near to rivers.
You want very specific sand for the use in concrete. It has to be river sand because the grains are small but coarse.
You want minimum contaminants in the sand so no salt water.
The world is also not running out of sand, but locally the places where a lot of construction is being built is running out of sand. This is because you don’t want to transport sand for long as it’s very expensive(sand is cheap but heavy) to do so.
Yeah, but no. Yes the desert sands of Saudi and UAE etc are not great for concrete, but we do have a near infinite supply of material that can be made into sand. Eg you can crush rocks down to a particle size / shape for use in concrete.
Source: that’s what I’m doing now.
We are not running out of sand for concrete, but maybe cheap naturally occurring sand in the right shape? dunno, but whatever the issue, it’s localized. It’s a big world.
Concrete needs “sharp” sand. The grains are angular with sharp edges. This is different to desert sand or deep sea sand, which tends to be round.
When you make concrete you are essentially using cement to glue together sand and rocks. If the grains are rounded, then the smooth surface can allow a bit of movement and slippage against the cement. Irregular shaped, angular sharp gains end up getting locked in place against each other as well as the cement, so the structure is stronger.
Sharp sand and angular gravel basically come from recently eroded or crushed rocks. Old sand and gravel gets smoothed out.
Sharp sand typically comes from rivers, so you need a river with a sandy bed close to where you want to build, and which doesn’t have rare fish or other sensitive ecosystems. In certain parts of the world, where a lot of building is taking place, there can be limited availability.
One option is to artificially crush gravel and grit with machines. The freshly crushed grains have sharp edges, so work well. This process is often used for preparing gravel for concrete,
Beaching river sand is good sand for concrete, but there’s not that much of it.
Desert sand is not good for concrete, too smooth because of the wind. But there’s a lot of desert sand available.
Sort of but at the same time no. Where do you have the sandpits? Close to big cities where you need all that concrete, of course, these pits have bottoms and you run out. There are plenty of places farther away you can dig for sand, but it’s farther away and maybe the quarry is not next to shippable river so it’s more expensive to transport. So you have run out of cheap and convenient sand, but pay more and of course there is more sand.
The producers are running out of “cheap” sand for their customers. Here in middle Tennessee our river sand is dredged form the Ohio river near Paducah, KY and barged down the local rivers to us for use. With the rising costs of labor, barges and tugboats to move the barges the cost of river sand is rising. We have some companies in Monteagle and Jackson, TN who crush sand from local deposits. The problem with man-made sand is that there are more fine particles in it than naturally occurring river sand. Local concrete producers prefer river sand as it has less fines and uses less water to produce a higher strength concrete. Man-made sand takes more water and more cement to produce the same strengths, it also has some negative qualities on finishing the concrete placement contractors complain about.
Latest Answers