Method to produce aggregates from unsettled cementitious mixtures, comprising the steps of (a) adding at least one pelletizing agent to an unsettled cementitious mixture, (b) mixing constantly the mixture of step (a) in a mixer to produce pellets, (c) discharging the pellets obtained in step (b) and (d) drying the pellets formed in step (c). The pelletizing agent is selected from the group consisting of cellulose, chitosan, collagen, polyacrylamide and co-polymers of polyacrylamide and polyacrylics, polyamines, polyvinylalcohols, polysaccharides, lactic acid, methacrylic acid, methacrylate, hydroxyethyl, ethylene glycol, ethylene oxide, acrylic acid, inorganic flocculants and inorganic coagulants.