How to prevent rebar from rusting in the ground?

Question

I am building a wall with rebar, cinder blocks, and rebar, as I've seen in many YouTube videos.
 ________||_ ___________ ___________ _____
|        || |           |           |     | <--cinder blocks
|________||_|___________|___________|_____|
|     |  ||       |           |           |
|_____|__||_______|___________|___________|````````````` <-- ground
         ||
         || <-- rebar
         ||

The rebar should stop horizontal movement, as part of the wall acts as a retaining wall.
I heard some people warn if I run the rebar into the ground, it will rust and become useless. How can I stop this from happening?

xeeka · Accepted Answer

In some countries rebars are meant to rust in order to get a very durable protection by passivation. The outer thin rust layer of some 1/100 mm protects the inner steel from rust.
This is why on construction sites, these rebars are frequently seen laying unprotected and uncovered for many days before they are used.
In addition, concrete has a basic rather than acidic chemical characteristic, which protects the rebars.
Soil could be a different chemical challenge for rebars, so concrete is a good method to avoid direct contact, as mentioned by others.
In contrast to common believe - and in contrast to the experience with the most expensive throw- away product nowadays, cars - rust can be a very good protection coating.
The famous iron pillar in Delhi/India was made some 1600 years ago, stood probably most of these years outdoor in the humid Indian open air without any cover and - as it seems - won't be destroyed by rust in the next centuries to come.

Mattman944 · Answer

Bury the blocks far enough into the ground so the rebar isn't doing most of the work. Or, use corrosion resistant rebar.
https://handymansworld.net/types-of-rebar/

Ecnerwal · Answer

Bore a 4" hole and pour it full of concrete, so the rebar has 2" concrete cover.

blacksmith37 · Answer

For rebar applications near sea coasts where corrosion is a problem ; coatings like fusion bonded epoxies are used. Also , more costly ,stainless rebar. If you are in a coastal location in certain parts of the world ,these products may be available.

Answered by blacksmith37 on June 11, 2021

How to prevent rebar from rusting in the ground?

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