Abstract: This invention concerns a method for analysing the ageing stability of a bituminous binder, in particular by reference to its susceptibility to oxidation, by analysing a sample of the bituminous binder by means of electron spin resonance and measuring the integral of the signal of the carbon-centred stable radicals; accelerated ageing of the bituminous binder, comprising: i) heating the bituminous binder, followed by ii) heating the bituminous binder resulting from step i) under pressure; analysing a sample of the aged bituminous binder obtained from step b) by means of electron spin resonance and measuring the integral of the signal of the carbon-centred stable radicals; and comparing the integral of the signal of the carbon-centred stable radicals of the bituminous binder obtained from the first step and that obtained from the previous step.

Abstract: The invention describes a heteropolycompound constituted by a nickel salt of a lacunary Keggin type heteropolyanion comprising tungsten in its structure, with formula: Nix+y/2AW11-yO39-5/2y, zH2O wherein Ni is nickel, A is selected from phosphorus, silicon and boron, W is tungsten, O is oxygen, y=0 or 2, x=3.5 if A is phosphorus, x=4 if A is silicon, x=4.5 if A is boron, and x=m/2+2 for the rest, and z is a number in the range 0 to 36, in which said heteropolycompound has no nickel atom in substitution for a tungsten atom in its structure, said nickel atoms being placed in the counter-ion position in the structure of said compound.

Abstract: The invention describes a heteropolycompound constituted by a nickel salt of a lacunary Keggin type heteropolyanion comprising tungsten in its structure, with formula: Nix+y/2AW11-yO39-5/2y,zH2O wherein Ni is nickel, A is selected from phosphorus, silicon and boron, W is tungsten, O is oxygen, y=0 or 2, x=3.5 if A is phosphorus, x=4 if A is silicon, x=4.5 if A is boron, and x=m/2+2 for the rest, and z is a number in the range 0 to 36, in which said heteropolycompound has no nickel atom in substitution for a tungsten atom in its structure, said nickel atoms being placed in the counter-ion position in the structure of said compound.