3 ms·
From your link: Generally, one of the main problems with geopolymer binder is its poor workability: Alkali-activated fly ash has a much greater plastic viscosi
by bboygravity 3y ago
From your link:
Generally, one of the main problems with geopolymer binder is its poor workability: Alkali-activated fly ash has a much greater plastic viscosity than ordinary Portland cement[31] and is prone to fast setting. In a matter of minutes, it can produce “highly viscous, unmanageable concrete mixtures”.[32]
These problems were faced with Portland cement as well, leading to the development of mix designs and admixtures that increase workability; to a limited extent, those techniques can be applied to geopolymer binder.
- namibj 3y agoAnd in Roman times, concrete was laid in lifts like how foundation soil is handled today. Yeah, it's more effort than just pouring a thick soup into a vibrating mould, but e.g. precast slabs could handle a non-pourable paste. The side effect of rapid hardening would also be rather easy to handle and even allows shorter mould cycle times (and thus afford more expensive moulds). Another example would be railroad ties that could compression-mould. Those are produced in the millions per year.