Tried mixing lime into my concrete for a post setting job...

I used a 10% lime mix for a gate post near the coast in Galveston and the concrete actually cracked in 3 weeks... must be something about the salt air. Anyone else have trouble with lime in coastal areas?

3 comments

3 Comments

kai_park1mo ago

That line about "something about the salt air" is probably the wrong angle here. Salt air isn't going to react badly with lime in the concrete, it's more about the lime itself being the issue. A 10% lime mix is actually pretty high for a post setting job, especially in a coastal environment where you want the concrete to cure fast and strong. Lime slows down the curing and makes the mix more porous, so that's likely why it cracked, not because of the salt. Was the mix a standard bagged concrete or did you add extra lime to it?

bettys511mo ago

Wait, you're saying 10% lime is actually high for post setting? That blows my mind because I've had old-timers swear by adding lime for workability. They always said it made the mix easier to handle, especially in tricky spots. But now I'm wondering if that's why my buddy's fence posts all started leaning after two years. He used a custom mix with extra lime like his grandpa taught him, and the whole thing turned into a crumbly mess near the beach. Were those old-timers just lucky with inland jobs where salt's not a factor?

oscar_ellis22d ago

My neighbor up the coast in Corpus Christi tried the same thing with a mailbox post. He was real proud of his granddad's recipe too. The post lasted about a month before the concrete started flaking off like a bad sunburn. He ended up having to jackhammer the whole thing out and start over with straight Quikrete. Now he just tells people his granddad's method worked great for building chicken coops in Oklahoma, not so much for anything near salt water.