Standard · Concrete
ASTM D4262
pH of concrete surfaces after chemical cleaning or acid etching.
ASTM D4262 checks that the rinse after acid etching or chemical cleaning has removed the chemicals. Acid or cleaner left in the pores of the concrete can spoil the bond of the coating.
Where it fits
Cleaning by broom, vacuum, water, detergent or steam (ASTM D4258) does not change the profile. Abrasion (D4259) or acid etching (D4260) creates a profile and removes weak laitance. D4262 follows the acid etch or the chemical cleaning.
Acid is hard to rinse out and neutralise fully, it does not remove oils, and its fumes etch nearby stainless steel and aluminium.
The procedure
Measure the pH of the rinse water itself. Then, straight after the final rinse and while the surface is still wet, measure the pH of the concrete surface at random places.
The trap
The surface does not have to reach pH 7. Unless the specification says otherwise, the surface pH is compared with the pH of the rinse water: it must not be much lower (acid left behind) or much higher. Cured concrete itself is alkaline, about pH 10 to 12. Many coating makers ask for a rinsed surface of pH 10 or more; that is a product requirement, not a value of the standard.
1 practice item in the members area mentions ASTM D4262 (CIP 2: 1).
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This page describes the subject of ASTM D4262 in our own words; it does not reproduce the standard. For the full text, buy the current edition from ASTM International. Checked on 2026-10-14; errors go in the corrections log. CoatMentor is an independent study aid. It is not affiliated with ISO, AMPP, SSPC, NACE International, ASTM or FROSIO.