Three　point　bending　fracture　tests　of　recycled　aggregate　concrete　beams　with　different　recycled　coarse　aggregate　replacement　ratio　(0%,　30%,　50%,　70%,　100%)　have　been　carried　out,　with　results　analyzed　by　digital　image　correlation　(DIC)　method　and　the　traditional　electrometric　method.　The　double-K　fracture　parameters,　crack-mouth-opening　displacement　(CMOD),　crack-tip-opening　displacement　(CTOD),　crack　extension　length　(Δa)　and　fracture　growth　path　were　obtained,　and　the　validity　of　DIC　method　was　verified.　The　results　show　that　when　the　replacement　rate　is　100%,　the　crack　initiation　fracture　toughness　and　unstable　fracture　toughness　of　recycled　aggregate　concrete　decrease　by　15.81%　and　15.39%,　respectively.　With　the　increase　of　the　replacement　rate　of　recycled　aggregate,　the　slopes　of　the　descending　sections　of　P-CMOD,　P-CTOD　and　P-Δa　curves　increase.　DIC　method　can　effectively　capture　the　fracture　propagation　process.　The　CMOD　values　measured　by　DIC　method　and　clip　type　extenometer　are　in　good　agreement.　The　variation　trends　of　DIC　measured　value　and　formula-calculated　value　of　CTOD　are　relatively　consistent.　Based　on　the　test　results,　the　estimated　values,　Δa,　of　specimens　with　different　replacement　rates　of　recycled　aggregate　under　different　loads　can　be　obtained　by　fitting　the　curve　between　P/Pmax　andΔa/Δac.　Copyright　©2022　Engineering　Mechanics.　All　rights　reserved.