Cause analysis: the opportunity of pressing die has passed, and when concrete is too dry, there will be small cracks in pressing die. In summer construction, direct sunshine causes the surface of concrete to be too dry, while the interior of concrete has not yet solidified, so small cracks are easy to appear in the texture edges and corners when pressing moulds. Insufficient vibration, large stones floating on the surface, or air bubbles in the concrete are not completely discharged, may open small cracks on the surface of waste products. Failure to maintain in time can also lead to appearance cracks.
Preventive measures: According to the construction time and the parameters of concrete itself, the pressing die construction should be stopped strictly according to the time confirmed by the experiment. Avoid construction at noon in summer or set up a shade during construction to stop colored concrete work. Strictly follow the concrete construction technology to ensure the quality of concrete. Small cracks can be repaired with demoulding powder or strengthening agent before maintenance agent is applied.