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Concrete

Flatness

The flatness of concrete substrate should be below 2mm

Concrete Strength

Weak strength of substrate will leave the paint layers off.General requirement on concrete strength should be ≥25Mpa

Substrate Drying

Moisture exists in concrete and mortar floor,which will reduce the bonding strength between paint and substrate,also will cause paint bubbles and delamination. Judgment Method:

1)Moisture content meter to check the substrate water content,which should be below 6%.

2）In method of ASTM4263,put thin plastic film at size 45cm×45cm to the substrate surface,and seal the 4 sides with adhesive tape. After 16 hours,if the water appears under the plastic or the substrate turns black,the substrate is not dry enough for paint.

 3)Substrate drying time usually should be over 28 days.

Attachments

On the surface of substrate concrete, cement dust usually are attached,especially newly finished concrete surface,there are always cement particle mortar in loose condition without strength. Rust stains on steel sheet. All of these attachments will affect the bonding power between paint and substrate.So they must be grinded and removed before paint.

Environmental conditions

1)The whole area must be sealed to prevent paint quality problems like impurity,sinkhole,spongy surface

2)Temperature should be between 10～35℃，Relative air humidity ≤75%

3)Temperature and humidity transformation will affect the paint curing,leveling and appearance property.