Thirteen　one-dimensional　consolidation　tests　with　step　loading　were　performed　on　dredged　clays　reconstituted　at　different　initial　water　contents.　Both　vertical　deformation　and　pore　pressure　were　measured　during　primary　consolidation,　which　refers　to　the　time-dependent　compression　process　associated　with　the　dissipation　of　pore　pressure.　The　pore　pressure　changes　were　investigated　by　considering　the　maximum　and　the　residual　values.　The　development　of　compression　during　pore　pressure　dissipation　was　analysed　to　identify　the　change　patterns　in　volumetric　strain–time　curves.　Three　types　of　change　patterns　were　found　during　the　primary　consolidation,　and　the　remoulded　yield　stress　was　found　to　be　the　key　factor　in　classifying　the　change　patterns.　The　inflexion　point　is　absent　for　types　1　and　2,　indicating　that　the　end　of　primary　consolidation　cannot　be　determined　by　the　commonly　used　Taylor　and　Casagrande　methods.　Type　3　shows　an　inverse　‘S’　shape,　suggesting　that　the　end　of　primary　consolidation　determined　based　on　the　compression–time　curves　occurs　before　the　completion　of　pore　pressure　dissipation.　©　2015,　ICE　Publishing.　All　rights　reserved.