Knowledge of "Roman cement" roughly speaking was never really lost.
How do you think the quay walls in medieval Dutch and Flemish harbours were built? The mortar was made with Trass [0], a natural puzzolanic from the Eifel, transported along the Rhine.
"Roman cement", also known as hydraulic lime [1] mortar, was in widespread active mainstream use in many places in Europe until the 1920's, and in some the 1930's. In Latvia for example, large scale Roman cement production only came to an end with the second world war flooding specific quarries.
The main problem with these hydraulic cements is they cure/set much more slowly. That's very much guaranteed to limit their use in speed focused modern construction.
There's still a market for hydraulic lime mortars. There's even a euro norm for it, EN-459. These products have excellent breathability and moisture resistance properties. The entire field is seeing a revival in monument restauration and ecological construction. Most straw bale construction in Europe for example is plastered using hydraulic lime plasters.
Some interesting products:
- natural hydraulic limes (NHL), like Saint-Astier from France
- formulated/artifical hydraulic limes (HL), often using blast furnace fly ash
- natural puzzolanic additives, like trass from the volcanic Eifel, has been used continuously since the Roman era!
I think it's worth pointing out that whilst hydraulic limes have good breathability compared to cement, they are still inferior to "air" lime based mortars (e.g. hot mixed or made with lime putty).
Although these have a slower set than hydraulic limes they are still in widespread use and a lot of straw bale construction will be using air lime as a superior alternative to hydraulic lime.
In what way are they inferior? There are a lot of properties of building materials, and correct selection is about the compromise based on what each has. Cure time is one consideration, cured strength is another, R value, mass/volume ratio - and those are what I as a lay person can come up with: I suspect someone with more knowledge as a longer list.
I guess the parent commenter meant to say hydraulic limes are inferior in terms of breathability compared to hydrated lime. Which is entirely correct.
As always, it's a trade-off. Anecdotally, we did the base plaster layer on our straw bale house using hydrated lime for better breathability. We'll probably make the top coat slightly hydraulic using trass.
I've been looking into straw bale construction just out of curiosity recently, do you have some good resources to learn more about construction and regulation?
One book I like is "Building with straw bales" [0], by Barbara Jones. It's mostly very practical. Reassuring also when it comes to using a less usual building technique. A tad bit to the eco hippie side for my taste, but only in minor details. All the important bits are very much grounded in sound practice.
If you want to gather practical experience, come help me fiddle with our straw bale house next spring or summer :-)
Regulation is going to be particular to your municipal or county government. Unless you’re in a major city, the permits desk will probably be approachable and will take the time to explain what you can and can’t do. They will probably entertain a variance unless you seem like you’re really out of your depth. They may be able to tell you about other bale construction in your area.
If language fluency would be the most important criterium - which it isn't-, the Dutch speaking 60% of Belgium are an even more logical choice. They're buried in that ranking below the less stellar English in the French speaking part of Belgium.
Flemish people might be an even more logical choice for the EU. Similar English, Dutch and basic German fluency, plus with most uni educated people there, pretty decent French.
And if you recruit me, you'll get fluent Latvian on top :-)
Are Latvians still learning Russian these days as well? In Georgia I noticed a big difference between the older (Russian) and younger (English) in their second language skills.
This is getting fairly off topic, but since you ask... My impressions about people born in Latvia post-1991 are numerous, but obviously anecdotal:
- Most native Latvian language speakers born in Latvia post-1991 will have low or non-existent Russian language skills, especially in the west (Kurzeme) or north. Very few native Russian speakers there. The situation in and around Riga is a little bit different. Try getting a customer-facing job in the private sector around Riga if you don't speak any Russian...
My significant other is young and speaks Russian fluently by accident. Native Latvian language, but raised in a "Khrushchevka" (Soviet apartment block) full of native Russian speaking families. Playing with the other kids meant learning Russian...
- Very very large differences amongst native Russian speaking youths in Latvia's three largest cities. A significant number hardly speak any Latvian. I've asked kids for directions that had trouble finding the words for "left" or "right". Which is somewhat surprising, given that officially, they're taking a significant part of their school in Latvian. Another group speaks both languages fluently. I've had chats over lunch with people I could hardly detect their native Russian background.
- Surprisingly, _a lot_ of young people in both groups speak abysmally bad English too.
In case of the land locked EU micro states, a blockade would be an obvious way.
Rather surprisingly, I can't seem to find a lot of historical examples of, say, German trade unions completely blocking Liechtenstein, demanding a fairer taxation system.
This does hit home. My significant other got a 600€/month pre-tax raise. Her net raise? 120€. She could actually go work 80% and hardly lose anything at all.
I did that for a while just because. Three day weekends are nice even without the rationale of progressive taxation.
Overall I'm not sure if a tax that encouraged it would be such a bad thing. It's obviously against the protestant work ethic which makes it seem almost unthinkable in America but it'd probably be healthier overall.
I'd say that depends on whether he wants his party to have official public mandates. Those certainly help, but they're not always strictly necessary when one's goal is to influence the political discourse...
From the archived ramenporn reddit comment thread at [0]:
> This must be incredibly stressful so for your sake I hope you sort it out quickly... but for the world's sake, I hope you fail and make the problem worse before jumping ship followed by every other engineer, leaving it to Zuckerberg to fix himself. But I still hope it's not too stressful for you!
How do you think the quay walls in medieval Dutch and Flemish harbours were built? The mortar was made with Trass [0], a natural puzzolanic from the Eifel, transported along the Rhine.
"Roman cement", also known as hydraulic lime [1] mortar, was in widespread active mainstream use in many places in Europe until the 1920's, and in some the 1930's. In Latvia for example, large scale Roman cement production only came to an end with the second world war flooding specific quarries.
The main problem with these hydraulic cements is they cure/set much more slowly. That's very much guaranteed to limit their use in speed focused modern construction.
There's still a market for hydraulic lime mortars. There's even a euro norm for it, EN-459. These products have excellent breathability and moisture resistance properties. The entire field is seeing a revival in monument restauration and ecological construction. Most straw bale construction in Europe for example is plastered using hydraulic lime plasters.
Some interesting products:
- natural hydraulic limes (NHL), like Saint-Astier from France
- formulated/artifical hydraulic limes (HL), often using blast furnace fly ash
- natural puzzolanic additives, like trass from the volcanic Eifel, has been used continuously since the Roman era!
[0] https://en.wikipedia.org/wiki/Trass
[1] https://en.wikipedia.org/wiki/Hydraulic_lime