This concrete garage floor is 3 years old. It has these quarter-inch wide sharp joints cut in every 12 feet. All settlement/curing cracks are in the joints, but I don't understand why they were cut so sharp and deep: All the depth and edge seem to accomplish is to collect dirt and provide a home for moisture and pests.
At this point is it OK to fill them in – at least partway to reduce the space available for dirt to accumulate? Or are they serving some other ongoing purpose?