MIT students fortify concrete by adding recycled plastic

[Nicodeamus]

Have you observed molecules of cement, fly ash or GGBS that are exposed on the surface of said concrete also leaching out? Especially when it rains?

That doesnt happen, fly ash ans ggbs actually binds with the concrete, it forms part of the silicate-hydrate matrix, hence we all them additives, usual plastic and steel in concrete makes it a composite material, the two are totally different in how they act.

 

[Nicodeamus]

Well, it does erode, so yes, I'm sure it does leach away over time. Now whether the composition of those molecules are bad is then the issue.

No it does not, what leeches out is pathogens that are in the water, we use fly ash for making dams, it still gains strength and react with water after over 30 years.

 

[Nicodeamus]

Exactly my point.

And yes the molecular constituents of concrete do leach. Especially when concrete is cracked. This is evident by the salt deposits visible along crack lines.

Concrete exposed to aggresive environments (sea, chemicals - especially sulphates and carbonates).

The constituents of concrete that do leach are as harmful, if not more harmful than the molecules in plastic.

That is simply false, sea salts only corrodes the steel in the concrete due to the redox reaction that it forms. Chemicals and sulphans in general can cause harm if they are acidic ( concrete has a ph of about 12). The issue of concrete cracking is 90% of the time due to exess water during mixing or loss of water during curing, mostly in SA this is the case, because idiots do not undress that concrete hardenes in the presence of water and and loses strength if you try and dry it out quickly.