Key Points for Shot Blasting Concrete Floor (Preparation Before Epoxy/Polyurethane Flooring)
1. Pre-construction Inspection (Top Priority)
1. Concrete Strength and Age
The newly constructed floor must be properly cured, typically for at least 28 days, with a strength of ≥C25. Floors with insufficient strength, severe scaling, or powdering should not be directly shotblasted, as this will only make them more loose. Reinforcement treatment must be applied first.
Moisture Content Control: The moisture content of the epoxy floor base should be kept as low as possible, preferably ≤8%. Shot blasting is prohibited on damp surfaces, surfaces that have been recently wetted, or surfaces with returning moisture. Moisture can clog dust extraction filter bags and cause steel shot clumping, leading to subsequent floor blistering and delamination.
2. Base surface cleaning in advance
Remove oil stains, engine oil, old paint, sealants, adhesives, and markings. The oil-stained areas must be degreased, cleaned, and dried first; otherwise, oil may seep into the pores after shot blasting, leading to paint film adhesion failure later.
Remove protrusions, hollow spots, and loose patches in advance; mark cracks first, repair wide cracks before shot blasting to prevent loosening and enlargement of cracks.
