You may notice, over time, that you see concrete driveway cracks in your driveway. There are a couple of reasons why this happens. One of the reasons you get cracks in your concrete driveway, is tree roots growing under your driveway are starting to get bigger, and push against the concrete. Another reason is that water gets into the concrete, and the expands when it freezes in the winter. This is why, if you do not seal your concrete driveway and it has small cracks in it, those small cracks expand out to bigger cracks every spring.