Their rate of use is decreasing and they are using more and more renewables. The US carbon footprint (all fossil fuels are not good) on a per capita basis is twice that of China.
I remember as a kid (before teens), seeing the burned warehouse across the street from my grandparents place. The beams were draped over the columns and some of the columns had collapsed. I don't recall what happened to the OPSJs. I was amazed at the sight.
Yes they can. If there has been a few days since the concrete has been cast, the location of the shrinkage cracks has likely been determined. Micro cracking has already occurred. You may have cracking occur between the new installed joints. You often find cracks form near sawcut joints...