TRB’s National Cooperative Highway Research Program (NCHRP) Report 578: Evaluating Air-Entraining Admixtures for Highway Concrete explores a procedure for evaluating air-entraining admixtures used in highway concrete. The procedure involves the testing of non-air-entrained concrete and concrete containing the air-entraining admixture under simulated field conditions. The appendixes to the report have been published as NCHRP Web-Only Document 101.