https://www.sciencedirect.com/science/article/abs/pii/S23527...
41.3mpa on pure desert sand is completely fine. Stronger than your houses slab your probably on now.
Nfi there's plenty of old wives tales from before the time when you could google it and be like "oi gran your talking sh*t" that effect how we do business today. This is probably one of them?
I'm willing to be cynical and conspiratorial, but this doesn't add up for me. There are so many players between "large construction firms in the USA" and "sand mafia in India" that I find it hard to believe that this is the action of a global cartel. Unless large construction firms in the USA specifically are also run by the sand mafia, which of course is possible, but would be a hell of an exposé if anyone ever caught on.
> However, the flexural and tensile strengths tended to decrease as the amount of desert sand increased, particularly beyond a 25% replacement level.
So it is not a 1:1 replacement, and there are further considerations that need to be taken into account into how much (if any) desert sand can be put into a particular mix for a particular purpose. Another paper if you want to get into the weeds somewhat:
> In this paper, the effect of DSRR, temperature and cooling regime on the mechanical performances of concrete produced with desert sand was analyzed. To study the influence of temperature on the microstructure of concrete produced with desert sand, the microscopic experiments (XRD, SEM) were employed.
* https://ijcsm.springeropen.com/articles/10.1186/s40069-020-0...
See also perhaps:
* https://engineering.stackexchange.com/questions/18118/why-is...
It is an area of active research, and perhaps a system will be developed to use it in a cost effective manner.
It is economically cheaper and easier to take beach and river sand. (Especially since some countries designate sand dunes as protected areas)