Anchor assembly for a vertical formwork, said anchor assembly comprising - a front anchor element, and - a tie rod comprising a first end which is housed in said front anchor element, the first end of the tie rod comprising at least one grooved face and at least one planar face, the front anchor element and the first end of the tie rod being configured for fixing said front anchor element in different axial positions of the first end of the tie rod, - the front anchor element comprises a fitting part comprising a housing in which the first end of the tie rod is arranged, the housing of the fitting part comprising at least one grooved face (401, 402), - such that ∘ when the tie rod is arranged in a fitting angular position, in which the planar face of the tie rod and the grooved face (401, 402) of the fitting part are arranged facing one another, the tie rod can move axially with respect to the fitting part, and ∘ when the tie rod is arranged in a fixing angular position, in which the grooved face of the tie rod and the grooved face (401, 402) of the fitting part engage with one another, the tie rod cannot move axially with respect to the fitting part as a result of the grooved face of the tie rod and the grooved face (401, 402) of the fitting part engaging one another, the anchor assembly being characterized in that; - the front anchor element comprises blocking means configured for blocking the rotation of the tie rod with respect to the fitting part when the tie rod is arranged in the fixing angular position. - a front anchor element, and - a tie rod comprising a first end which is housed in said front anchor element, the first end of the tie rod comprising at least one grooved face and at least one planar face, - the front anchor element comprises a fitting part comprising a housing in which the first end of the tie rod is arranged, the housing of the fitting part comprising at least one grooved face (401, 402), - such that ∘ when the tie rod is arranged in a fitting angular position, in which the planar face of the tie rod and the grooved face (401, 402) of the fitting part are arranged facing one another, the tie rod can move axially with respect to the fitting part, and ∘ when the tie rod is arranged in a fixing angular position, in which the grooved face of the tie rod and the grooved face (401, 402) of the fitting part engage with one another, the tie rod cannot move axially with respect to the fitting part as a result of the grooved face of the tie rod and the grooved face (401, 402) of the fitting part engaging one another, the anchor assembly being characterized in that; ∘ when the tie rod is arranged in a fitting angular position, in which the planar face of the tie rod and the grooved face (401, 402) of the fitting part are arranged facing one another, the tie rod can move axially with respect to the fitting part, and ∘ when the tie rod is arranged in a fixing angular position, in which the grooved face of the tie rod and the grooved face (401, 402) of the fitting part engage with one another, the tie rod cannot move axially with respect to the fitting part as a result of the grooved face of the tie rod and the grooved face (401, 402) of the fitting part engaging one another, the anchor assembly being characterized in that; - the front anchor element comprises blocking means configured for blocking the rotation of the tie rod with respect to the fitting part when the tie rod is arranged in the fixing angular position.