Found by accident. Drew my attention immediately

In the Long Run We Are All Dead: Keynesianism, Political Economy, and Revolution (PDF, 362 pages) by Geoff Mann, 2017.

The heading on page 58: A General Theory of Civilization

Page 59:

Keynes became a Keynesian not to save capitalism or liberalism per se, but to save the “thin and precarious crust” of civilization itself. He was, to be sure, a capitalist, and he believed that something like capitalism—although in a more or less radically different form—would be a central pillar in the construction of more robust, peaceful, and secure social formation. But to read his commitment to capitalism as his priority is to misunderstand his politics and that of many elites of his time. He understood capitalism to be intimately interwoven with but not identical to civilization. His work, especially but not only The General Theory, is an attempt to do via “economics” what, since the French Revolution, others had tried to do through other modes of analysis—philosophical, political, even literary: to understand the ways in which modernity puts civilization at risk and to uncover the means by which we might rescue civilization from modernity’s self-destructive tendencies.

 

I find just two occurrences of the word "civilisation" in Keynes's General Theory: 

• in chapter 10:

  At periods when gold is available at suitable depths experience shows that the real wealth of the world increases rapidly; and when but little of it is so available, our wealth suffers stagnation or decline. Thus gold-mines are of the greatest value and importance to civilisation.

  but do read the whole paragraph;
  
  
• and in chapter 23, but here Keynes is quoting someone else, someone he disagrees with. (Recommended reading: the whole chapter.)
  

Keynes uses the word "civilisation" once in the book. Based on that one usage, it is clear that Keynes does see a strong link between civilization and the economy. But it would be a mistake to say The General Theory is a book about saving civilization. It is about fixing the economy.

It might not be wrong to say the book was motivated by the desire to save civilization (though I don't expect Keynes said any such thing). 

And it is certainly reasonable to look at all of Keynes's work (not only the GT) to see how he ties civilization and the economy together. This is what I think Mann is doing. But I need to see those quotes.