A method for producing aggregates from non-hardened cement compositions, in particular from concrete or residual concrete, which method includes adding a) a water-absorbing agent and b) a crystallization deactivator to a non-hardened cement composition and mixing until a granular material has formed. The method allows unneeded residues of still liquid concrete to be converted into a practical product, which can then be reused to produce new concrete compositions. The invention further relates to a granulated cement material that can be obtained according to a corresponding method, to the use of the granulated cement material as an additive for cement compositions, and to additive combinations for cement compositions, which additive combinations include a water-absorbing agent and a crystallization activator.

A method for producing aggregates from non-hardened cement compositions, in particular from concrete or residual concrete, which method includes adding a) a water-absorbing agent and b) a crystallization deactivator to a non-hardened cement composition and mixing until a granular material has formed. The method allows unneeded residues of still liquid concrete to be converted into a practical product, which can then be reused to produce new concrete compositions. The invention further relates to a granulated cement material that can be obtained according to a corresponding method, to the use of the granulated cement material as an additive for cement compositions, and to additive combinations for cement compositions, which additive combinations include a water-absorbing agent and a crystallization activator.

Provided by the present invention is a vinyl alcohol polymer crosslinked by a structure represented by the following formula (1) and/or a disulfide structure, in which the vinyl alcohol polymer is not completely dissolved in a mixture prepared by: adding the vinyl alcohol polymer to water so as to give a concentration of 4% by mass; and stirring at 95 C. for 3 hrs. in the formula (1), R.sup.1, R.sup.2 and R.sup.3 each independently represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group having 8 or less carbon atoms. Also provided include an additive for a drilling mud containing the vinyl alcohol polymer, a drilling mud containing the vinyl alcohol polymer as an additive, an additive for a drilling cement slurry containing the vinyl alcohol polymer, and a drilling cement slurry containing the vinyl alcohol polymer as an additive. ##STR00001##