As labor rates increase in China, much of that is going by the wayside. That being said, you might be right depending upon when these particular dams were built. Although it’s hard to believe such a large dam would use concrete blocks as we know them.
In 1987, My cousin, who was an engineer for the China Civil Engineering Construction Corporation (a quasi-government public works company), said the CCECC was about 20 years behind the times as far as the engineering profession. Even 20 years before that, the lateral force of that volume of water would require some interlocking and reinforced structure. Surprisingly, Chinese engineers were somehow getting Dutch, German and Canadian structural and civil engineering periodicals during the Cultural Revolution.
......Although it’s hard to believe such a large dam would use concrete blocks as we know them.......
I wasn’t very clear and perhaps mixed descriptions of two different types of construction. The dams are as you noted massive reinforced concrete.
My intention was to note that reinforced concrete surfaces are commonly stoccoed or parged to hide imperfections in the concrete. In the same manner, concrete block structures are stuccoed to hide the uneven block work.
I have never been to China but have traveled elsewhere in Asia and seen the poor block and concrete work.