1) The compactness of subgrade construction base fails to meet the design requirements, resulting in uneven settlement;

2) The subgrade is in the soft foundation section, and there is no effective foundation treatment during construction;

3) The choice of pavement materials does not meet the requirements, and the flexural strength of concrete does not meet the design requirements;

4) Due to the lack of construction technology.

(a) Concrete mixing measurement is not allowed, and concrete cracks are caused by uneven concrete thickness. The solution is to mix concrete with an automatic metering mixer, make a standard metering bucket, control the amount of water added, and divide the dosage of each plate with a small scale in advance to ensure accurate metering.

(2) The solution to cracks in concrete due to untimely curing is: after the concrete is poured for 6- 12 hours (related to the temperature), it is covered with plastic film for curing, and most of the hydration heat and evaporation water in concrete are stored by using the impermeable characteristics of plastic film, so that the concrete can be cured by itself. When there is no floating water on the surface of concrete, water shall be sprayed in time for curing to keep the concrete moist all the time.

(c) In strong wind, scorching sun or weather conditions with excessive temperature difference between day and night, concrete is prone to crack. Solution: When there is wind and the temperature difference between day and night is too large, you can cover a layer of canvas on the plastic film, which can achieve better results. When exposed to the hot sun, you can avoid the construction at noon.

(d) If the cutting joint is not cut in time, it is easy to cause concrete cracks.

(e) Before the curing period, machinery walking on the concrete surface may cause concrete cracks. Especially, the machinery running on the concrete surface after concrete cutting and before asphalt pouring is more harmful to concrete.