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ChuckMcM10/02/20240 repliesview on HN

I look forward to wind powered stamping mills.

I heard his comments on smooth sand differently; As I heard it he was saying "People say smooth sand is worse but I can't find any research that would back that up, and even the paper cited in support of that argument doesn't say smooth sand is worse." He then goes on to reason why people might think that (the slump test) but the slump test is really about ratio of water to cement and not the texture of the sand. When he adjusted his water for smooth vs non-smooth sand to achieve equivalent slump tests, he found that the smooth sand concrete was stronger in his experiments.

My summer job as the 'mud man' for the masons building walls in Las Vegas certainly didn't go into this aspect of cement but my brother-in-law who is a civil engineer has a similar reverence / amazement that Grady does for concrete and seemed to agree with Grady's points. He pointed out the 'problem' was getting folks using concrete to change their mix recipes depending on the type of sand, that was, in his opinion, the big stumbling block. He felt any concrete that was mixed with the wrong ratios would under perform and the guys doing the mixing would never admit to screwing it up. They would always blame the ingredients.