The cracks are wet or dirty，the crack repair glue is not easy to stick with wet cracks and unclean gap sidewalls.

Cracks are not grooved. In the formation process of cracks, the cracks exposed to the air, and has been loose aging, the complex structure, the most commonly lead to pouring glue sticking effect is not good, easy to fall off.

Poor construction conditions, rain and cold weather and cold weather.

The quality of the crack repair glue is poor.