alt Hacker NewsThe whole idea of making your own sand is not sound. It will cost more, perhaps many times more. Seems clear when you think about it: hard to beat the cost of 'natural' sand because you just drive over and load it up. Add any more to that process, it's gonna go up in price. Including crushing rock etc - energy-intensive, then sieving. All add cost over and above, well, just hauling.
And vague comments about 'couldn't find the science behind river sand being less useful' (because it's rounded not jagged). That's no kind of science.
This guy is lauded but I"m not so sure he's someone to listen to. "I hit some rocks in my garage and made my own sand!" isn't any kind of interesting. At what cost? At what scale? It's all about money, baby. Anything that doesn't add up cost is just storytelling.
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Haven't read the article, but I watched the video. He goes on to say that it's not the full story, and he also does some tests where instead of optimizing for a particular water ratio in the mix, he optimizes for a specific texture when mixed, which is termed "workability". If you keep "workability" constant, you can put much less water in the mix, resulting in a stronger concrete when cured.
Did you watch the entire video? I ask because Grady discusses EXACTLY this point.
He explains that the whole 'more expensive' thing is really just noting the actual cost of sand versus ignoring the externalized costs of mining it. When you dig up a river bed there is a cost there that isn't necessarily reflected in the cost of the sand you mined from there, sometimes because that cost is passed on to someone else who has to remediate the site after you mined it (like taxpayers). He empirically points out that different sands need a different water/cement ratio and also points out that the papers on sand use in concrete understand that. The 'bug' seems to be that people just add 'x' water to the mix and if the sand changes they might get different results.