identifying lime putty vs. portland cement mortar on a brick chimney

[PSUengineer1]

Hello.

When I see large deflections on chimneys rather than brittle failure, I start to think that the mortar is a lime putty mortar vs. portland cement mortar. Short of doing a vinegar test, or scraping to identify white inclusions vs. white aggregate, can you tell just by looking at the mortar? I attached two photos. Are you able to tell if the photos show lime putty or portland cement mortar, and if so, please tell your opinion on which it is and why? Thank you.

 

[LittleWheels]

In the UK, historic buildings often use lime mortar.
I have found

https://cornishlime.co.uk/articles/the-difference-between-lime-cement-mortars/

and

https://www.turnbullmasonry.com/historic-lime-vs-cement-mortar-know-type-mortar/

to be useful guides.

 

[dik]

almost exclusively... it's much more 'plastic'.

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1679673731/tips/Historic_Brickwork_23-02-05_hchgoi.pdf[/url]

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-Dik