In　order　to　improve　the　cement　use　efficiency,　a　concept　of　reverse　filling　is　proposed　and　applied　to　formulate　a　binary　system　of　limestone　powder-superfine　Portland　cement　based　on　dense　packing.　The　compressive　packing　model　and　the　minimum　water　demand　method　were　used　to　predict　and　measure　the　packing　density　of　the　binary　blends　containing　15%,　25%,　30%,　35%,　40%　and　50%　of　superfine　Portland　cement.　A　maximum　packing　density　can　be　achieved　at　a　low　content　of　superfine　Portland　cement　(similar　to　25%),　and　the　actual　water　to　powder　(cement　+　limestone　filler)　ratio　can　be　reduced　to　0.12　with　the　superfine　Portland　cement　content　between　25%　and　30%.　The　compressive　strength　at　90　d　reached　74.0　MPa　and　94.0　MPa　for　the　blends　containing　25%　and　30%　of　superfine　Portland　cement　respectively.　A　very　high　cement　hydration　degree　of　similar　to　93%　was　attained　for　the　blend　containing　25%　of　cement.　(C)　2019　Elsevier　B.V.　All　rights　reserved.