High　viscosity　asphalt　(HVA)　is　a　kind　of　asphalt　modified　with　styrene-butadiene-styrene,　plasticizer,　and　crosslinker.　HVA　is　widely　used　in　porous　asphalt　pavements　around　the　world,　especially　in　China　and　Japan.　Most　previous　studies　have　focused　on　improving　the　performance　of　in-service　HVA　pavements　at　high　and　low　temperatures.　There　is　a　need　to　ensure　that　HVA　can　also　perform　well　at　high　temperature　during　construction　to　improve　the　workability　of　the　mixture.　The　purpose　of　this　study　was　to　use　warm-mix　additives　(WMA)　to　reduce　viscosity　during　construction　and　keep　acceptable　performance　at　high　and　low　temperatures.　To　accomplish　this　objective,　three　types　of　warm-mix　additives　(RH,　EC-120,　and　Sasobit)　with　three　different　contents　(2%,　3%,　and,　4%)　were　mixed　with　HVA.　An　HVA　without　any　WMA　was　used　as　a　control　sample.　Physical　tests　conducted　for　each　sample　included　viscosity　(135°C),　motive　viscosity　(60°C),　penetration　(25°C),　softening　point,　ductility　(5°C),　tenacity　(25°C),　and　toughness　(25°C)　before　and　after　short-term　ageing　(thin　film　oven　test).　The　test　results　show　that　the　WMA　additives　have　a　significant　effect　on　reducing　viscosity　135°C)　of　HVA　during　construction,　while　substantially　improving　motive　viscosity　(60CC)　with　the　addition　of　EC-120　and　Sasobit.　In　addition,　EC-120　improved　toughness　and　tenacity.　However,　WMA　had　an　adverse　effect　on　low-temperature　performance　due　to　the　reduction　on　ductility.　The　results　show　that　EC-120　is　considered　as　the　optimal　type　among　the　three　WMA　and　3%　is　suggested　as　the　best　content　of　EC-120　for　HVA.　©　2017Canadian　Society　for　Civil　Engineering.　All　rights　reserved.