What is the fine-grained topic of the following text: Edwin further commented that the 42.5 cement from Dangote achieves 42.5 MPA strength in 28 days setting time compared to 32.5 grade, which only achieves 32.5 MPA in the same period of time. Only return the topic.
Comparison of 42.5 and 32.5 cement grades from Dangote in terms of strength and setting time