On May 2, 6:24 pm, "DanG" wrote:
Concrete is one of the very few things that grows stronger in
contact with water. If rain is eating the local concrete, you
must be in an industrial area prone to acid rain. Water does not
hurt concrete - the Hoover dam hasn't melted just yet!

Lake Mead water tends to be alkaline, where rain water is naturally
acidic (pH=5.6, which is why you don't use rain water in fish tanks -
it's too acidic). The concrete at Hoover Dam that they have erosion
problems with is the part that is exposed to the rain, but it's not
that bad since it doesn't rain very much - I know, I used to live
about 15 minutes up the road from the dam, and I've been there many
times. We used to take the tours back when you could actually take the
elevator down into the dam, see the generator rooms, walk out on the
bottom platforms, etc. I was there when water was flowing over the
spillways on the east side of the dam - something that has not
happened for a long long time.

But I digress - rain water is acidic and will naturally erode
concrete. I see it everywhere, and it's very noticeable where the
concrete is partially protected from the rain.

Tnx for the product referrals - my driveway is about 5 weeks old, so
it sounds like we are ready to coat.