There are so many deserts on the earth, why doesn't anyone transport sand to build houses?

Why can't desert sand be used as building sand?

There are many deserts and beaches on the earth. They are all sand. Why can't so much sand be used as building sand? In short, the sand in the desert is too fine and the surface of the particles is too smooth to be used as building sand. If you elaborate, there are several reasons:

The sand in the desert is impure and contains a lot of harmful substances such as clay, which will affect the strength of concrete in the later stage.

The sand in the desert has a high alkali content. As we all know, the sand in the desert is formed by natural weathering, and its alkali content is too high. Because cement itself has a certain alkalinity, in this case, the alkali content of the whole material will be too high.

Hazards of high alkali content: alkali-aggregate reaction will occur, and alkali will react with silica in sand to form alkali-silicic acid gel, which will expand in volume after absorbing water, leading to concrete cracking, which will affect the stability of the whole concrete structure in serious cases, with great potential harm. Therefore, when checking building materials, we should strictly control the alkali content in cement, and not only that, we should also strictly control the alkali content in other additives. In this way, the damage of the reaction to the project can be reduced.

It is for these reasons that desert sand cannot be used as building sand.

On the other hand:

The desert is too far away from the project land. Who will go to the desert to transport sand? Whether it is transported by train or truck, no matter what kind of car is used, the cost is too high.

Having said the answer to the question, let's talk about the current situation of using sand in the world:

At present, sand is an indispensable raw material for engineering construction. The world uses 32-50 billion tons of sand every year. What are you doing with so much sand? Sand is used to make glass, buildings and electronic products, and it is still widely used in most industries.

However, the problem we are facing now is that due to the acceleration of urbanization in the world, the demand for sand will increase greatly every year, but the natural regeneration rate of sand is relatively stable. It is predicted that by 2050, the demand for sand may exceed the supply, resulting in a shortage of sand.

Will sand really become a scarce resource?

In fact, the sand available in nature is completely enough for human use, but the sand in many places cannot be mined. Do you think you should use sand or protect the environment? This is a dilemma in itself. In short, there is no shortage of sand, but I am worried about how to collect sand at the lowest cost.

Sand mining is not random, some places can be mined, and some places cannot be mined. Only after scientific argumentation, it is determined that it is harmless, legal and reasonable, and can it be mined. If indiscriminate blind exploitation, such as blind exploitation of river sand, will bring these effects:

Endangering shipping: after sand mining, it will leave one pit after another at the bottom of the river, change the surface morphology of the river bed, form eddies or other complex water flow patterns on the water surface, and threaten the safety of passing ships.

Endangering the safety of dams and bridges: unreasonable sand mining is likely to cause serious consequences of dam failure, and the breach of river banks will pose a great threat to the surrounding environment. Where mining should not be done, sediments will be eroded by water flow, and the ability of buildings on the river bank, such as bridges, to resist lateral loads will be greatly weakened, threatening the safety of bridges.

Therefore, sand mining must be legal and reasonable.

In fact, I don't think sand will become a scarce resource as long as human beings start to make rational use of sand now. When demolishing old buildings, old materials can also be reasonably reused, and with the progress of technology, sand substitutes will gradually be widely used. So personally, sand will not become a scarce resource in the future.

What's your opinion?