It is unavoidable for concrete slabs to crack due to their rigid nature. Several factors can cause your slab to fracture, including uneven drying, shrinkage, and temperature change. So, whenever cracks develop, they need to be sealed immediately to prevent water seepage and further damage. But always make sure to use the high quality of the best concrete crack filler as sealants, and caulks are the most common products used to fill concrete cracks. Caulking guns can be used to apply them directly into the crack. They come in squeeze tubes.