Back to Basics: Why lime-surkhi mortar was used?

Engineering and Contracting, Volume 37 (1912) page 567:  records thus:
"At Periyar the use of commercial cements meant importation from Europe and long carriage through virgin jungle. "....
The method of making puzzuolan (locally made concrete) at Periyar, as described by Mr. A. T. Mackenzie,
Project Engineer, in his "History of the Periyar Project,"  is reproduced in the book thus: " Local limestone was burned in stone and clay kilns and after burning the lime was slacked and stored. Clay molded into flat tiles was under-burned in similar kilns. To manufacture the cement, the tiles roughly broken up were placed in a pan mills with a little water and ground to a fine powder. Lime was then added to this powder by degrees, with more water, and the grinding was continued until a thoroughly mixed and rather sloppy mixture resulted. This mixture was then combined with sand and stone to make mortar or concrete. "

The question is: Has not degradation of the lime-surkhi mortar used for the dam's construction 116 years ago weakened the dam's structure?

-Joseph Ponnoly

References:

Mackenzie, A.T. (1899)   History of the Periyar Project. Reprinted in 1963 by the Controller of Stationery and Print on behalf of the Govt. of Madras 

Chrimes, Mike, Ahead of the game – masonry dam design in the British colonies 1800–1900, part 2: 1872–1900,  Source: Dams and Reservoirs, Volume 19, Issue 4, pages 171 –183 , ISSN: 1368-1494, E-ISSN: 1756-8404.

J. Pennycuick. (1897) The diversion of the Periyar.. Min Procs ICE, 205