Two-component polyurethane structural adhesive composition (PU2K) consisting of an -NCO component, which contains one or more chemical entities carrying isocyanate end groups, and of a hardener component, which contains at least one chemical entity carrying a group which reacts with the isocyanate -NCO group, characterized in that : - the -NCO component and the hardener component each comprise from 0.1% to 40% by weight, based on the total weight of the corresponding component, of a thixotropic composition (A) comprising, based on its total weight: - from 1% to 40% by weight of a bis-urea (a) obtained by reaction of a primary aliphatic amine (a1) with a diisocyanate (a2) with a molar mass of less than 500 g/mol, and - from 60% to 99% by weight of a plasticizer (b) chosen from: - an alkyl phthalate, - pentaerythritol tetravalerate, - an ester of alkylsulfonic acid and of phenol, - diisononyl 1,2-cyclohexanedicarboxylate, - 3,3'-[methylenebis(oxymethylene)]bis[heptane], and - dioctyl carbonate; said thixotropic composition (A) being provided in the form of a suspension of solid particles of the bis-urea (a) in a continuous phase consisting of the plasticizer (b); and - at least one component, among the -NCO component and the hardener component, comprises from 5% to 40% by weight of alumina (B), based on the total weight of said component. - the -NCO component and the hardener component each comprise from 0.1% to 40% by weight, based on the total weight of the corresponding component, of a thixotropic composition (A) comprising, based on its total weight: - from 1% to 40% by weight of a bis-urea (a) obtained by reaction of a primary aliphatic amine (a1) with a diisocyanate (a2) with a molar mass of less than 500 g/mol, and - from 60% to 99% by weight of a plasticizer (b) chosen from: - an alkyl phthalate, - pentaerythritol tetravalerate, - an ester of alkylsulfonic acid and of phenol, - diisononyl 1,2-cyclohexanedicarboxylate, - 3,3'-[methylenebis(oxymethylene)]bis[heptane], and - dioctyl carbonate; said thixotropic composition (A) being provided in the form of a suspension of solid particles of the bis-urea (a) in a continuous phase consisting of the plasticizer (b); and - from 1% to 40% by weight of a bis-urea (a) obtained by reaction of a primary aliphatic amine (a1) with a diisocyanate (a2) with a molar mass of less than 500 g/mol, and - from 60% to 99% by weight of a plasticizer (b) chosen from: - an alkyl phthalate, - pentaerythritol tetravalerate, - an ester of alkylsulfonic acid and of phenol, - diisononyl 1,2-cyclohexanedicarboxylate, - 3,3'-[methylenebis(oxymethylene)]bis[heptane], and - dioctyl carbonate; said thixotropic composition (A) being provided in the form of a suspension of solid particles of the bis-urea (a) in a continuous phase consisting of the plasticizer (b); and - an alkyl phthalate, - pentaerythritol tetravalerate, - an ester of alkylsulfonic acid and of phenol, - diisononyl 1,2-cyclohexanedicarboxylate, - 3,3'-[methylenebis(oxymethylene)]bis[heptane], and - dioctyl carbonate; - at least one component, among the -NCO component and the hardener component, comprises from 5% to 40% by weight of alumina (B), based on the total weight of said component. <EOS>