Abstract: The present invention refers to a modular framework used to mould concrete test blocks, composed of two identical modular semi-shells obtained from moulding suitable plastic materials, with each semi-shell being formed of two vertical borders positioned at 90°, built on the catheti of a lower horizontal triangular wall, each of them having vertical ribs in external position on the free edges, preferably provided with a lower tapered end; it being provided that two semi-shells can be joined by means of suitable rectilinear joints capable of being matched to the ribs.