Patent GB-431679-A (GB)
Title: Improvements in concrete and hydraulic cement
IPC: C04B24/22
Filed: 1933-11-07
Abstract: A cement-peptizing agent is incorporated in a structural concrete mix comprising cement, coarse aggregates and water, or in any of the constituents of the mix whereby reduction in water is permissible without diminution in plasticity or strength.  Tests for showing whether any given peptizing-agent peptizes cement are described.  The preferred agents are those which do not substantially reduce the surface tension of water or produce foam. Such compounds are water-soluble compounds, particularly sulphonic acids, their salts and derivatives, containing a number of aromatic nuclei directly attached to an aliphatic nucleus.  These can be prepared by sulphonation of a hydrocarbon or derivative thereof having the necessary configuration, e.g. dinaphthylmethane, or by reacting an aromatic sulphonic acid with formaldehyde or substance yielding the same, e.g. methylal, paraformaldehyde, or polyhydroxymethylenes, preferably in the ratio of 2 mols. of sulphonic acid to 1 mol. of aldehyde. Naphthalene sulphonic acids or their homologues or derivatives are preferred.  The initial condensation is believed to be followed by polymerization and best results are obtained by subjecting the product to a controlled polymerization.  The condensation product has a formula (A--R--A<1>) SO3M, A and A<1> being two or more aromatic groups, R a single alkyl group or a plurality of alkyl groups in straight or branched chain formation and SO3M at least one sulphonic acid group or the said group combined with a soluble salt-forming radical.  The b -naphthalene sulphonic acid condensation product may be prepared as follows: 100 parts by weight of naphthalene are added to 100 parts of concentrated sulphuric acid at 160 DEG  C.  The mass is stirred at 160 DEG  C. for 4 hours or longer till completely sulphonated.  It is cooled to 100 DEG  C., diluted with 44 parts of water, further cooled to 80 DEG C., and 12 parts of a 40 per cent aqueous formaldehyde solution added.  The mixture is stirred for 3 hours at 80 DEG  C., 12 parts more of formaldehyde solution being added at the end of each hour. The temperature is raised over 1 hour to 95--100 DEG  C. and is maintained for 18 hours with constant stirring.  The final heating period may vary according to the starting materials and conditions of reaction.  The product is cooled, neutralized with alkali, e.g. NaOH, and if desired dried. Alternatively it is diluted with 3 times its volume of water and neutralized with lime.  Calcium sulphate is filtered off, sodium carbonate added to the filtrate, calcium carbonate removed by filtration and the filtrate evaporated to dryness.  The sulphonation may be conducted in a cast iron vessel, the reaction with formaldehyde in enamelled or lead-lined apparatus. Sulphonic acids of benzene, diphenyl, phenanthrene, anthracene, or fluorene may be employed similarly.  Methyl, ethyl or other alkyl naphthalenes may replace the naphthalene, and other alkyl aromatic compounds such as xylene, cumene, or retene can be employed, but condensation products derived from such alkyl compounds are apt to reduce surface tension and cause foaming.  British Specifications 120,918, [Class 22], 263,571, 319,103, [both in Class 70], 361,094 and 392,246, [both in Group V], and U.S.A.  Specification 1,863,990 are referred to.  Reference has been directed by the Comptroller to Specification 391,582, [Group V].ALSO:A cement-peptizing agent is incorporated in a structural concrete mix comprising cement, coarse aggregates and water, or in any of the constituents of the mix, whereby reduction in water is permissible without diminution in plasticity or strength.  Tests for showing whether any given peptizing agent peptizes cement are described.  The preferred agents are those which do not substantially reduce the surface tension of water or produce foam. Such compounds are water-soluble compounds, particularly sulphonic acids, their salts and derivatives, containing a number of aromatic nuclei directly attached to an aliphatic nucleus.  These can be prepared by sulphonation of a hydrocarbon or derivative thereof having the necessary configuration, e.g. dinaphthyl methane, or by reacting an aromatic sulphonic acid with formaldehyde or substance yielding the same, e.g. methylal, paraformaldehyde, or polyhydroxy methylenes, preferably in the ratio of 2 mols. of sulphonic acid to 1 mol. of aldehyde. Naphthalene sulphonic acids or their homologues or derivatives are preferred. The initial condensation is believed to be followed by polymerization and best results are obtained by subjecting the product to a controlled polymerization.  The condensation product has a formula (A-R-A1)SO3M, A and A1 being two or more aromatic groups, R a single alkyl group or a plurality of alkyl groups in straight or branched chain formation, and SO3M at least one sulphonic acid group or the said group combined with a soluble saltforming radical.  The b -naphthalene sulphonic acid condensation product may be prepared as follows: 100 parts by weight of naphthalene are added to 100 parts of concentrated sulphuric acid at 160 DEG  C.  The mass is stirred at 160 DEG  C. for 4 hours or longer till completely sulphonated.  It is cooled to 100 DEG  C., diluted with 44 parts of water, further cooled to 80 DEG  C., and 12 parts of a 40 per cent aqueous formaldehyde solution added.  The mixture is stirred for 3 hours at 80 DEG  C., 12 parts more of formaldehyde solution being added at the end of each hour.  The temperatures is raised over 1 hour to 95-100 DEG  C. and is maintained for 18 hours with constant stirring.  The final heating period may vary according to the starting materials and conditions of reaction.  The product is cooled, neutralized with alkali, e.g. NaOH, and if desired dried.  Alternatively, it is diluted with 3 times its volume of water and neutralized with lime.  Calcium sulphate is filtered off, sodium carbonate added to the filtrate, calcium carbonate removed by filtration and the filtrate evaporated to dryness.  The sulphonation may be conducted in a cast iron vessel, the reaction with formaldehyde in enamelled or lead-lined apparatus. Sulphonic acids of benzene, diphenyl, phenanthrene, anthracene, or fluorence may be employed similarly. Methyl, ethyl, or other alkyl naphthalenes may replace the naphthalene, and other alkyl aromatic compounds such as xylene, cumene, or retene can be employed, but condensation products derived from such alkyl compounds are apt to reduce surface tension and cause foaming.  One to three parts of the agent are used per 100 parts of hydraulic cement.  It may be added to the latter conveniently in the form of a master batch in which it is mixed with ground cement or gypsum.  The master batch may be added to the clinker before entering the tube mill or to the ground cement. Alternatively, the agent is added to the gauging water. Concretes according to the invention may include the common admixtures such as diatomaceous earth, heavy metal stearates and oleates, and calcium chloride.  British Specifications 120,918, [Class 22], 263,571, 319,103, [both in Class 70], 361,094, and 392,246 and U.S.A. Specification 1,863,990 are referred to.  Reference has been directed by the Comptroller to Specification 391,582.