The only reason that you see these deals being made is because the Chinese government is interested in Africa's natural resources [1], Chinese companies are competitive in construction (not really rocket science, plus slave labour certainly provides a financial advantage [2] [3]) and government officials stand to personally make money, as nothing gets done in Africa if you don't "properly compensate" the right government officials [4] [5] (european companies know this too, but bribery is sligthly more constrained by their governments).
The end product is usually low quality, with roads cracking open as soon as rain pours, but the goal was not to provide infrastructure in the first place, so no one is remotely concerned about any benefits nor about the impact on local communities, public safety, wildlife or the environment. Guess what happens to anyone that tries to protest on behalf of these issues. [6]
These deals are rarely rosy for the general population, who will still lack water, sanitation, food, jobs and education. Even the few that managed to survive outside of city centers will see their basic livelyhood (cattle, farming) disrupted by these "developments".
PS: I've worked in Angola, Kenya and Nigeria.
[1] http://www.newyorker.com/news/news-desk/china-in-africa-the-...
[2] https://www.theguardian.com/commentisfree/libertycentral/201...
[3] https://jamhuri-news.com/how-china-contractors-drove-kenyan-...
[4] https://qz.com/513090/in-south-africa-corruption-is-a-public...
[5] http://www.standardmedia.co.ke/article/2000175560/eacc-arres...
[6] http://www.reuters.com/article/us-angola-protest-idUSKCN0X70...