You might be surprised to know that plants do not break through concrete. What they do is that they find cracks through the concrete that are already existing. Then, they tend to grow through this crack whenever they can. This however, does not suggest that plants happen to put extra pressure on the concrete so as to break it.
The plant seeds that are sometimes buried in the concrete happen to get more water than usual during the rainfall as the concrete does not soak up water as quickly as the plant. Hence, the plants grow through these gaps and cracks.