How concrete alternatives like ferrock are dealt with? How it can be transported from the mixing plant to the building site, is transporting and mixing ferrock or other materials similar to concrete or not, are they easier than concrete to deal with?

Firstly, ferrock is concrete, just with a different aggregate make-up. It is applied like concrete, transported like concrete; it is concrete.

So, ferrock is concrete with a sizable content of waste iron and silica. The strength varies greatly depending on the proportions used, but, generally, it comes in at 5,000psi – 7,000psi at 7 days. This makes it equivalent to medium to high strength concrete. The likely ferrous content is believed to consume most of the CO2 produced by the cement.

In theory, it should be cheaper as you are dealing with waste products. But, if you want it at any scale then it comes from a concrete plant. Now the cost is wholly dependent on what it takes for them to get it for you. And even waste iron is likely to cost more than crushed rock.

Most designers, architects, and engineers tend to use it for ground applications. This is because it isn’t well established what problems it does have.

• It rusts. Specifically, it grows rust crystals as it is exposed to water. But, some examples don’t seem to. So, this will depend on the iron content and form in the mix.
• It can stain nearby materials. Again, this depends on the amount of iron and in what form it comes in.
• Efflorescence. It’s concrete so any salts that are in the mixture or form in the mixture will tend to leech out in the presence of water.
• Rebar. It isn’t clear how reactive to the rebar it is, so does the rebar need to be coated?
• Water. There are a lot of materials in this product that react in the presence of water.

This is a niche material using a waste product for aggregate. This means the chemicals present may not be known and may react with their environment. Using it for pavers or durable surfaces is probably fine but for a concrete replacement it has a long way to go. They need to be able to accurately predict the chemical processes that will result. A number of producers have gone to great lengths to solving many of these issues, but still, they haven’t been able to placate the fears of iron-water reactions. As such, most potential users of this material view it as another novelty brewed up by desert eco hermits. It may be great, but are you willing to test it?