I'm new to this side of the site, so go easy on me....I've been roped into pouring a 30ft concrete sidewalk, but the guy I'm helping is hell-bent on using those fiber-based expansion joints every 5ft. Personally I'd just come back and saw-cut it, but to each their own. My question is, how on earth would you install those as you go, seeing as how this is going to be a continuous pour? Being as that they're flexible, I don't see any way of keeping them perfectly straight so that you have nice,clean,even lines when you're done. Any help or input is appreciated.