The invention relates to a composition for thermoplastic composite material comprising: 30% to 60% by volume, preferentially 35% to 50% by volume, of a thermoplastic matrix comprising from 50% to 100% by weight of a semi-crystalline polyamide polymer and from 0% to 50% by weight of at least one additive and/or of at least one other polymer, 40% to 70% by volume, preferentially 50% to 65% by volume, of long reinforcing fibers (or of long fibrous reinforcement), said thermoplastic matrix impregnating said long reinforcing fibers (or said long fibrous reinforcement), said semi-crystalline polyamide polymer being: a) a reactive composition comprising or consisting of at least one reactive polyamide prepolymer which is a precursor of said semi-crystalline polyamide polymer, or, as an alternative to a), b) a nonreactive composition of at least one polyamide polymer, said composition being that of said thermoplastic matrix defined above, and said reactive polyamide prepolymer of the composition a) and said polyamide polymer of the composition b) comprising or consisting of at least one BACT/XT copolyamide.