Pressure. Over time and constant pressure, it’s a fact that it will deteriorate to sand. The fact that the construction company has probably chosen some poor materials for the concrete blocks is also a bit disturbing. These are some of the foundation blocks that hold in the dirt around the houses. The street I’m walking on here is about 2 feet lower than the houses. The bits that are white have the parts that are starting to fall off first. There is even a chunk of the block on the ground (bottom, right corner). This is only one house, or one part of foundation, but all the houses here have this problem!