A concrete-testing lab indicted for faking reports brazenly kept working on construction sites even after the city suspended its license, The Post has learned.

Stallone Testing Laboratories did strength tests on concrete at half a dozen buildings across town last month despite the Buildings Department ban on July 31, officials said.

The tests, to show if cement has been mixed properly, are required by law to make sure structures are safe.

Buildings officials caught Stallone working at a high-rise at 770 11th Ave. on Aug. 12 and promptly slapped the firm with an additional violation.

Department spokesman Tony Sclafani said follow-up tests would determine if the concrete was properly mixed there and at the other structures.