Title: Hydraulic composition

Description: This invention relates to a hydraulic composition which not only can provide mortar or concrete of good workability by the addition of a relatively small amount of water but also makes possible the development of high strength after the cure of the mortar or concrete is completed.

As this type of hydraulic composition, that obtained by the admixture with the hydraulic substance of such additives as a polyalkylarylsulfonate or the lignosulfonate obtained from the sulfite pulp process, etc., has been known and is used with preference in many areas. However, these additives were not entirely satisfactory since the desired results were not developed by the use of these additives in small amounts and that, on the other hand, their use in excess results in the entrainment of an excessive amount of air in the mortar or concrete, retardation of the cure thereof, or an undesirable decline in the strength of the hardened product.

The object of the present invention is to provide an improved hydraulic composition by the discovery of a new additive not possessing the aforementioned shortcomings.

I found that a sulfosuccinic acid derivative obtained by the addition reaction of a compound selected from the group consisting of maleic acid ##EQU1## fumaric acid ##EQU2## citraconic acid ##EQU3## mesaconic acid ##EQU4## and the monoalkali metal salts, dialkali metal salts, alkaline earth metal salts, monoammonium salts and diammonium salts of these acids, with a compound selected from the group consisting of sulfurous acid, alkali metal sulphites, alkaline earth metal sulphites, ammonium sulphite, alkali metal hydrogen sulphites, alkaline earth metal hydrogen sulphites and ammonium hydrogen sulphite was an additive that could achieve the object of the present invention. Accordingly, there is provided in accordance with the present invention a novel hydraulic composition that consists of a hydraulic substance in which has been incorporated this additive.

Hydraulic substance, as used herein, denotes in accordance with the usual definition a substance which has the property of setting up a hydration reaction and hardening when mixed with water. As typical examples of hydraulic substances, included are portland cement, alumina cement, blast furnace slag and mixtures of quicklime and siliceous sand.

On the other hand, as specific examples of the aforementioned sulfosuccinic acid derivatives, mention can be made of sulfosuccinic acid and sulfomethylsuccinic acid as well as the salts of the alkali metals, such as sodium and potassium, the salts of the alkaline earth metals, such as magnesium and calcium, and the ammonium salts, of these compounds.

These sulfosuccinic acid derivatives are effective even when used in smaller amounts than in the case of the conventional additives. Moreover, even when these sulfosuccinic acid derivatives are used in relatively large amounts, there is no manifestation of any objectionable side effects amount - such as a decline in strength but, instead, they possess the excellent property of enhancing the effects that are had by their addition. Hence, no particular restrictions are imposed as regards the proportion in which these sulfosuccinic acid derivatives are admixed with the hydraulic substance in this invention. However, for usual purposes, the sulfosuccinic acid derivatives are suitably used in an amount of 0.01 - 5 parts by weight, and especially 0.05 - 1.0 part by weight, per 100 parts by weight of the hydraulic substance.

The hydraulic composition of this invention consisting of the hydraulic substance incorporated with the aforesaid sulfosuccinic acid derivatives excels not only in its workability when it is to be mixed with water but also when the resulting mortar or concrete is to be used. In addition, it is possible to impart the hardened mortar or concrete with a high degree of strength at an early stage. It is not known by what mechanism these effects are brought about in the hydraulic composition of this invention. However, it is presumed, in all liklihood, that this is ascribable to the fact that since the aforesaid sulfosuccinic acid derivatives are highly soluble in water, the solubility of the hydrated alumina or siliceous substance present at the surface of the particles of the hydraulic substance is increased, with the consequence that the hydration reaction is enhanced.

Needless to say, the invention hydraulic composition can contain the other known additives such, for example, as curing accelerators, retarders, waterproofing agents, shrinkage reducing agents, etc., in conjunction with the foregoing sulfosuccinic acid derivatives.

The following examples will now be given for specifically illustrating the invention.

EXAMPLE 1

Eight parts by weight of sodium hydroxide and 9.8 parts by weight of maleic anhydride are added to 100 parts by weight of water to obtain a homogeneous solution of disodium maleate. On addition of 10.4 parts by weight of sodium bisulfite to the foregoing solution and stirring, the reaction proceeds exothermically. After the evolution of heat has settled down, the stirring is continued for a further 3 hours at 60.degree.C. A rotary evaporator is then used and the water is removed from the reaction mixture to obtain 26.4 parts by weight of a white powder of trisodium sulfosuccinate.

A concrete test was conducted for determining the properties of the so obtained powder when used as a concrete additive. The results obtained are shown in Table 1.

The composition of the concrete used in the test was as follows: 300 parts by weight of portland cement, as coarse aggregate 1200 parts by weight of river gravel (heat loss = 0.1% by weight) of maximum particle diameter of 25 millimeters, and as fine aggregate either 760 parts by weight of river gravel (heat loss = 0.3% by weight) of maximum particle diameter of 2.5 millimeters (ratio of fine aggregate = 38.8%) when the additive was used or 800 parts by weight of the same river gravel (ratio of fine aggretate = 40%) when the additive was not used.

                                      Table 1
    __________________________________________________________________________
    Additive
                  Amount added
                           Water-  Amount
                                       Compressive strength
                  based on cement
                           cement
                               Slump
                                   of air
                                       (Kg/cm.sup.2)
    Experiment
          Class   (%)      ratio
                               (cm)
                                   (%) 7 days
                                            28 days
    __________________________________________________________________________
    Invention
          trisodium
          sulfosuccinate
                   0.125   0.45
                               6.5 1.6 256  359
    do.   do.     0.25     0.45
                               7.8 1.8 262  369
    do.   do.     0.5      0.45
                               7.5 1.7 274  374
    Control
          commercial
          lignosulfonic
          type additive
                  0.25     0.45
                               7.1 4.1 264  361
    do.   not added
                  --       0.53
                               6.5 1.4 218  322
    __________________________________________________________________________
     Note.
     The slump, amount of air and compressive strength were measured in
     accordance with the JIS Methods A1101, A1116 and A1108, respectively.

It can be seen from the results presented in Table 1 that the results obtained when the trisodium sulfosuccinate of the invention was added were comparable, if not superior, to the instance where the commercial lignosulfonic acid type additive was added, not to mention the instance where no addition was made.

EXAMPLE 2

The reaction is operated exactly as in Example 1 but using 11.2 parts by weight of citraconic acid anhydride instead of maleic anhydride to synthesize 27.8 parts by weight of trisodium sulfomethhylsuccinate. A concrete test was conducted for ascertaining the properties of the so obtained sulfosuccinate when used as a concrete additive. The results obtained are shown in Table 2. The composition of the concrete was the same as that of Example 1.

                                      Table 2
    __________________________________________________________________________
    Additive
                     Amount added
                              Water-  Amount
                                          Compressive strength
                     based on cement
                              cement
                                  Slump
                                      of air
                                          (Kg/cm.sup.2)
    Experiment
          Class      (%)      ratio
                                  (cm)
                                      (%) 7 days
                                               28 days
    __________________________________________________________________________
    Invention
          trisodium
          sulfomethylsuccinate
                      0.125   0.45
                                  6.7 1.6 254  360
    do.   do.        0.25     0.45
                                  7.1 1.8 257  366
    do.   do.        0.5      0.45
                                  7.6 2.0 279  381
    Control
          commercial
          lignosulfonic
          acid type
          additive   0.25     0.45
                                  6.7 4.2 257  350
    do.   not added  --       0.53
                                  6.5 1.6 208  305
    __________________________________________________________________________

It can be seen from Table 2 that the trisodium sulfomethylsuccinate of the present invention demonstrates exceedingly good performance when used as a water reducing agent.