Composition comprising an amorphous calcium aluminate and associated production method

A composition comprising an amorphous calcium aluminate with a final lime to alumina molar ratio (RF) comprised within a range that extends between a lower limit (Ri) having a value greater than 0.01 and an upper limit (Rs) having a value less than 15, said lower limit (Ri) being different from the upper limit (Rs),

• wherein said amorphous calcium aluminate is a combination composed of at least:
• a first amorphous calcium aluminate with a first lime to alumina molar ratio (R1) that is lower than the lower limit (Ri) of said range, and
• a second amorphous calcium aluminate with a second lime to alumina molar ratio (R2) that is higher than the upper limit (Rs) of said range
• and wherein said combination comprises a first amount of the first amorphous calcium aluminate and a second amount of the second amorphous calcium aluminate, said first and second amounts being determined in such a way that the final lime to alumina molar ratio (RF) of the amorphous calcium aluminate, corresponding to the average of the first and second lime to alumina molar ratios (R1, R2) weighted by said first and second amounts, is within said range.