1) use fine sand to make tempered glass 2) break it 3) Now use those small pieces of broken glass as if they were coarse sand to make concrete. Or even better

1) use fine sand to make tempered glass 2) break it 3) Now use those small pieces of broken glass as if they were coarse sand to make concrete. Or even better recicle all those old cracked car panes lying in the dumpster. Problem solved. Maybe you could even obtain cool semitransparent concrete, if you polish the finished stuff. I dunno. Would be cool stuff in any case.