BE553671A - - Google Patents

Description

       

   <Desc / Clms Page number 1>
 



   The invention relates to additional compositions for the incorporation into mixtures of hydraulic cements, for example, Portland cements or mortars and dry mixes for the manufacture of such concretes or mortars, as well as the resulting hydraulic cement mixtures containing the compositions. additional.



   For many years, much research has been directed to find suitable admixtures for modifying and improving the characteristics of hydraulic cement mixtures, to meet the widely varying technical and economic needs of the construction industries, and there has been much realized in this direction. Today, a large percentage of concrete used in the construction industries, including ready-mixed commercial concrete, sold to the public, contains one or more admixtures in order to obtain the desired physical properties and, in at the same time, keep the quantity of cement in the mixtures, and thus the cost price, to a minimum.



   Where concrete and mortars made entirely from hydraulic cement meet all the requirements with regard to physical properties, the objective was to lower the price by reducing the amount of cement needed in the mixes. When the requirements for physical properties exceed or differ from the results that can be obtained with simple mixtures containing moderate amounts of cement, the objective was to meet these requirements by keeping the amount of cement as low as possible. . Thus, in almost all cases, an essential aim was to obtain the desired technical results with a minimum quantity of cement, however modest or severe the technical requirements might have been.



   All other things being equal, the ultimate compressive strength can be increased, within limits, by increasing the amount of cement in a mixture. By the use of the so-called "plasticizers" or "water reducing agents" the final compressive strength can be increased without increasing the proportion of cement, or, what comes to the same, a given strength can be achieved with smaller amounts of cement. Thus, such agents have been widely employed where the compressive strength is large enough to affect the amount of cement present in a single mixture. Sulphite waste liquors or the solids contained therein have been widely used, with or without other additions, as "water reducers", in industry for the past few years.

   The most important active ingredient in waste sulphite liquors, or solids thereof, is lignosulfonic acid or a salt thereof. Hitherto no other satisfactory agents have been found for this use.



   The effectiveness of a "water reducer" in allowing the reduction of cement without loss of final strength is related to its influence on ease of work, for example, the degree to which it tends to increase fluidity of water. 'a mix. The lower the proportion of water in a mixture for a given cement content, the greater the final strength, but the mixture is more consistent and less workable. Thus, the proper use of a mixture limits the extent to which the quantity of water can be reduced, as an additional means, to decrease the cement content, necessary to obtain a determined final strength, since the Ease of use requires a certain degree of ease in the work.

   If the sand content of a mixture can be reduced from its content of coarse components, the total area to be wetted is reduced and thus less water is required to achieve the desired ease of work, and thus one. requires less cement due to the reduction in water obtained. Thus, a work reducer which improves

 <Desc / Clms Page number 2>

 to some extent the ease of working of a given mixture also allows a reduction in the amount of sand, in relation to the coarse components, and then a reduction in water without loss of ease of work. This, in turn, allows for a further reduction in cement content without loss of strength.



   One of the drawbacks in the use of "water reducers" (including waste sulphite liquors or their derivatives) has been their retarding effect on the setting and hardening rate of a cement mixture and its rate of setting. increase in compressive strength during the curing process. Slow setting delays the finishing of surfaces of floor tiles and the like and complicates production schedules. Slow curing delays the time when forms can be removed from solid structures and or loads may be placed on them in subsequent construction. These delay effects are particularly pronounced when working at low temperatures.



   The retardation effect on curing can be counteracted by the use of substantial amounts of accelerators, such as calcium chloride. But when a sufficient amount of an accelerator is used to overcome early retardation and avoid delays in finishing, the rate of cure can be so rapid, while the mass is in the right condition for finishing, that insufficient time remains to complete the finishing operations. In other words, the curve of the degree of cure as a function of time rises too quickly during and after the critical finishing period.

   Accordingly, the use of calcium chloride in an amount sufficient to effectively counteract the retarding effect of "water reducers" is believed to worsen the reaction between highly alkaline cements and reactive aggregates, causing the release of heat and excessive volume change during setting and increasing efflorescence of the hardened product. Little is known about the effects of accelerators other than calcium chloride.



   While considerable improvements in "water reducers" with regard to their retarding effects, have been achieved by modifying them in various respects such as purification and other treatments, and by combining other adjuvants, their effect. delay has never been satisfactorily overcome. When used in sufficient amounts to effectively reduce the amount of cement required for the desired final strength, their retarding effects are still quite pronounced compared to a simple mixture, prepared in the same way and intended to give the same final strength.



   Considering another problem concerning the construction industry, many types of jobs do not require considerable strengths of compressive strength, as is the case with the foundations of lightweight constructions, and lightweight slabs, but on the contrary a great fluidity and plasticity are sought to facilitate the casting operations and pour the concrete in the forms and on large and long surfaces enclosed in the forms. For these uses, minimum cement contents are used for reasons of economy and a high water content is employed, in order to obtain high fluidity.

   In this case, the lack of cohesion between the cement-sand mortar and the coarse components has been a serious problem and results in deposits, with the coarse components settling near the pour point and the cementable mortar separating in flowing towards more distant places. Although a number of "water reducers" appear to exert a favorable influence on cohesion, serious action has not been seen to correct this tendency of wet lean mixes to separate the mortar from the coarser components.

 <Desc / Clms Page number 3>

 



   When looking for resistant concrete, as for high construction or for roads, the characteristics dictate to limit the settlement as much as possible. This reduces the fluidity and plasticity of the mixes and increases the difficulty in placing them. Here again, the "water reducers" have a plasticizing effect which provides some improvement in plasticity and fluidity while allowing a lower water content to be used to achieve maximum strength. However, further improvements in plasticity and fluidity are desired with lower water contents, and the finishing details caused by the use of "water reducers" have been objected.



   For many years, the resistance of hardened concrete to freezing and thawing and to the crumbling effects of the salts used to melt ice has been increased by the use of agents which entrain the air. But it is recognized that the increased entrainment of air in a mixture causes a reduction in resistance. When seeking high strength, it was therefore customary to limit the amount of entrained air to a maximum, determined in advance, for example 5% or less in many cases, while a higher content air would have been preferred because of the need to greatly increase the cement content to maintain strength.

   Today there does not appear to be a known way to obtain the benefits of high air entrainment without a corresponding reduction in final strength for a mixture having a determined cement content. The problem has become more urgent recently, to achieve increased duration and resistance to shattering, and research carried out indicates that air contents of 7 or even 8% would be advantageous if adequate strengths could be maintained.



   The objects of the present invention, in the broadest sense, are to provide admixtures for hydraulic cements which possess superior properties as "water reducing agents" by allowing the use of lesser amounts of water and lower contents. cement for determined final compressive strengths, these admixtures having on the other hand little or no delay effects, also imparting a high degree of cohesion and fluidity without segregation for a given settlement, even in very lean ones having abnormally high water contents, and allowing increased air entrainment with less loss, if any, in resistance than has been possible heretofore.



   The "water reducers" of the invention maintain a cure rate approximately equal to that of a normal cement mixture of comparable compressive strength at normal or elevated temperature, and which accelerates setting at temperatures. very low which normally greatly delay the setting of normal mixtures.



   The admixtures, objects of the invention, of hydraulic cements further impart a higher degree of plasticity and fluidity to the cement mixtures than the known admixtures, to allow a reduction in the ratio of sand to coarse components and, thus, further. greater water reduction and as a consequence lower cement factors.



   Hydraulic cement admixtures also impart to cement mixes a greater degree of cohesion to prevent segregation of lean, high-settling mixtures, despite a high water content which normally causes segregation as such a mixture flows over great distances. in and over surfaces enclosed by forms.

 <Desc / Clms Page number 4>

 



   The water reducers of the invention, for hydraulic cement mixes, allow air quantities as high as 7, or even 8% to be entrained with a relatively small reduction in compressive strength and impart to mixtures containing 5 to 6% air a force equal or even greater than that the same mixtures would have with normal air contents.



   According to the invention, hydraulic cement mixes have all of the improved properties listed above, for example a lower cement content, and water content for a mixture of a given compressive strength, a hardening rate at normal or elevated temperature approximately equal to that of normal cements formulated to possess the same final strength, accelerated rate of hardening at low temperature, improved plasticity and fluidity, cohesion over a wide range of water contents and cement coefficients, ability to tolerate larger amounts of entrained air without appreciable loss of final compressive strength.



   To achieve the above objectives, the invention relates to an admixture for hydraulic cements characterized by a novel combination of four different additional compounds, in relatively small amounts relative to the amount of cement, and within certain limits of relative proportions one by one. compared to others., These four components are:
1) solids of residual sulphite liquors with or without separation of all or part of the carbohydrates, the main active ingredient being lignosulphonic acid or a salt thereof;

     2) a water soluble aromatic carboxylic acid, or a water soluble salt or ester thereof, having hydroxylic or amine substituents, or a water soluble salt thereof;
3) an accelerator, for example a metal chloride soluble in water or ammonium chloride; and
4) as accelerator a water soluble amine substituted or not.



   The invention also relates, as a new industrial product, to cements containing compositions in accordance with the preceding paragraphs or similar.



   The previous four classes of compositions or compounds have all been used already as additives in hydraulic cements and have certain recognized individual characteristics which modify the properties of cement mixtures. The third and fourth classes include compounds known in the art as accelerators, and so have been referred to above. But, for most purposes, they are used in accordance with this invention in such small amounts that. it is difficult to determine whether they actually react as accelerators or not in the combinations described and claimed here, as will be explained in more detail below.



   Commercial waste sulphite liquors are generally available only in a neutralized form, having been neutralized to convert acids to salts. The usual neutralizers are: calcium, magnesium, ammonium and sodium, calcium being the most common. The residual sulphite liquor solids referred to herein may originate either from the neutralized liquor or from the non-neutralized liquor and may either consist mainly of lignosulphonic acid alone or a salt salt, or comprise part or all of the other solids.

 <Desc / Clms Page number 5>

 liqueurs. It is preferred for the purpose of the present invention to use the solids of the neutralized liquors.

   But the same advantages are obtained whether the waste liquor used has been neutralized or not and whether the whole liquor or its solids only are used, although the results will differ as to their degree of effectiveness.



   It is desirable to remove from the recovered sulphite liquor or its solids which are to be used in cement mixtures, a substantial part of the carbohydrates contained therein.



  This can be achieved by removing fermentable sugars from the liquor prior to its use in cement and prior to recovery of residual solids. On the other hand, lignosulfonic acid can be separated from the liquor and used alone as a soluble salt.
The recovered sulphite liquor, from which the solids are derived, can also be treated with an ion exchange resin, preferably an anion exchanger, although a cation exchanger can be used. In addition, or according to another method, the recovered sulphite liquor can be treated with activated carbon.

   These treatments also serve to remove certain components or ingredients of liquors, such as some of the carbohydrates, which appear to adversely affect the properties of concretes or destroy the effectiveness of the lignosulfonic component of liquors.



   According to the invention, it is possible to use in liquid form or in the form of a solid residue, the solids of the untreated liquors, or the solids which remain in any liquor treated according to one of the methods described, above, or the Lignosulfonic component separates from any liquor, alone or together with other solids contained in liquors. For convenience, such solids, whether or not reduced to dryness or derived from the liquors from which they were obtained, all recognized in the art as "water reducers" or "plasticizers", are all herein referred to as "waste sulphite liquor solids".



   The general class of water-soluble aromatic carboxylic compounds, salts thereof, or their water-soluble esters comprises the second component of the combination according to the invention. Examples of effective compounds are: benzoic acid and its water soluble salts and esters, such as sodium benzoates or other alkali or alkaline earth metals, methyl benzoate, ethyl benzoate, water soluble hydroxybenzoic acids , alkoxybenzoics, etc. and their water-soluble salts or esters, such as salicylic acid, acetyl salicylate, acetyl-salicylic acid, methyl salicylate, syringic acid, sodium salicylate, calcium salicylate, magnesium salicylate. Because of the combined considerations of price, availability and efficacy, salicylic acid and sodium salicylate are preferred.

   For convenience such compounds forming the second component of the combination are referred to herein as "aromatic carboxylic compounds".



   As can be seen, the solubilities of some of the aromatic carboxylic acids in water are quite low, and the same is true of some of the other so-called water soluble compounds described here.



  However, all these compounds are used in very small quantities and the solubility of these quantities in a concrete or a mortar is that which is designated here by the expression "water-soluble".



   The accelerator chlorides forming the third component of the combination in accordance with the invention constitute a known class of compounds useful as accelerators for hydraulic cement mixtures. Included in this class are alkali and alkaline earth chlorides and ammonium chloride. Of these, calcium chloride was the most

 <Desc / Clms Page number 6>

 widely used for hydraulic cements and is most suitable for use in the present invention from the standpoint of availability and price. For convenience, the compounds of this class are all referred to herein as "accelerator chlorides".



   The water-soluble amines constituting the fourth class of the combination according to the invention are water-soluble amines, substituted or not, non-carboxylic as well as their water-soluble adducts with a mineral acid and the like, which give the amines in aqueous solution. Examples of such amines are: mono-di and tri-ethanolamines, tri-isopropylamine, amino-2-butanol-1-amine, n-methylglucamine mono- and trimethylamines, amino-1-methyl-2 -propanol-1-amine, and the like, with primary, secondary or tertiary alkyl or alkanol amines being particularly suitable, and triethanolamine being preferred from the standpoint of availability and price.

   For convenience, amino compounds of this class, including mineral acid adducts and the like which yield the desired amines in aqueous solution, are referred to herein as "water soluble amines".



   In connection with the previous definitions, it should be noted that the four compounds of the combination are all used in very small amounts in a cement mixture. By speaking of these compounds as being "water soluble", reference is therefore made to the solubility of these small amounts in water of the hydraulic cement mixture.



   It is known that various sulphite waste liquor solids have previously been used almost exclusively in cement mixtures as "water reducers" (previously generally referred to as "plasticizers" or "cement dispersants"). These residual sulphite liquor solids have generally been used in amounts of 0.25 to 0.5% by weight of the cement.

   Although these residual sulphite liquor solids are the only components of the new combination known to have appreciable water-reducing effects, considerably smaller amounts of this component of the combination than hitherto required are used in accordance with the regulations. invention to achieve the same functions of reducing the amounts of water and cement required for a mixture having a given settlement, ease of work and ultimate resistance to crushing.



   In combination with calcium chloride as an accelerator, in a range of about 1% up to 2 or even 3%, by weight of the cement, the delaying effects of the solids of waste sulphite liquors or their derivatives were reduced in measurement or resistances of 1 to 7 days are considered. However, damaging finishing relays during setup day have not been satisfactorily corrected, as explained above.



   Mono- and triethanolamines are also known to act as accelerators and to increase the final strength of hardened concrete or mortar, when used in hydraulic cement mixtures in amounts of 0.01% or more based on cement. It is known that the addition of such amines to a given simple mixture of cement, water and grit produces virtually no change in consistency, for example settling or ease of work. Other than that, very little is known about the effects of amines in cement mixes.



   Sodium salicylate has also been used as an admixture in hydraulic cement mixes to increase ultimate crush resistance. For this purpose, amounts greater than about 0.1% of the amounts of cement have been used, but at these amounts it has no effect.

 <Desc / Clms Page number 7>

 significant recognized on premature hardening or on strength gain, or on plasticity, fluidity, cohesion or water mixing requirements.



   In accordance with the present invention, the combination in a cement mixture of the four kinds of adjuvants defined above, each in lesser proportions than those which have been found effective up to now, produces all the advantages described above in the hydraulic cement mixes. These results are entirely new compared to prior knowledge on the four components used individually or in previously known mixtures with one or more other ingredients.



   The effect of the four component combination on the cure rate of cement mixes is different in nature from any effect of any of the components individually. Maintaining a cure rate near normal speed until a mixture has hardened beyond the finishing condition, for example avoiding abnormal acceleration or delay during the finishing period , is an effect which has not yet been achieved by the use of "water reducers", accelerators, or both. For example, the use of relatively large amounts of ordinary accelerators has the disadvantage, pointed out above, of accelerating too much cure during the finishing period.

   On the other hand, the amounts of accelerators preferably used in accordance with the invention are so small that they have little or no acceleration effect when used alone. Thus, their purpose in the builders of the invention is essentially to achieve the desired rate of cure and other advantages outlined herein.



   The acceleration of setting at low temperatures, compared to normal mixing, without appreciable acceleration during the finishing period at normal and high temperatures, is contrary to the known effects of prior admixtures for hydraulic cement mixes.



   The possible decreases in amounts of water and cement due to the four-component combination outweigh the similar effects of the same amount of the most effective known forms of waste sulphite liquor solids used alone, and none of the other three components were heretofore known to have some property which could explain these results.



   Although waste sulphite liquor solids and calcium chloride at relatively high concentrations are known to contribute to the cohesion of cement mixes to some degree, the other two components, individually, are not known to impart such an improvement. Nevertheless the combination of the four components, with concentrations of each lower than normal, impart to the cement mixes a degree of cohesion which far exceeds any degree that could be obtained with the individual components or with any. combination of them at any concentration.



  The resistance to segregation of lean mixtures with a high water content is particularly pronounced and quite revolutionary in character when the four-component combination is employed.



   The property of producing with 5 to 6 entrained air higher resistances than the resistances obtained hitherto with much smaller quantities of air is a completely new characteristic of quaternary combination. Even with known adjuvants, experience had shown that an increase in entrained air is accompanied by a corresponding reduction in final crush resistance.

 <Desc / Clms Page number 8>

 



   The above-described properties of the quaternary combinations of the present invention can only be attributed to some kind of synergistic effect in the combination, the explanation of which is currently impossible.



   The proportions of the four components to each other which are to be used in accordance with the invention do not have clearly defined limits and can vary over a considerable range realizing the advantages of the invention to varying degrees. . When unusual or particularly severe needs are encountered, the relative proportions of the four components may vary within the following fairly wide range:

     Parts
Residue sulphite liquor solids 5 to 50
Aromatic carboxylic compound 1 to 15
Chloride accelerator 0.5 to 40
Water soluble amine 0.5 to 10
The mixtures of the four components within the foregoing limits can be incorporated into the hydraulic cement mixes at a rate of between 45 to 340 g of mix per bag of cement, or 0.1% to 0.75% by weight of the cement.



   For the majority of applications the relative proportions of the four components should be within the following range:
Parts
Waste sulphite liquor solids 10 to 20
Aromatic carboxylic compound 2 to 6
Chloride accelerator 1 to 12
Water soluble amine 1 to 5
Likewise for the vast majority of applications, the mixtures of the four components should be incorporated into the hydraulic cement in the amount of approximately 115 to 340 g of mixture per bag of cement, or from 0.25 to 0.75 by weight of the cement. .



   The character and extent of the improvements accomplished by the present invention and the amounts and proportions of the four components which are preferably employed will be more clearly explained hereinafter in connection with the description of the various tests and illustrative examples of the preferred compositions.



   To illustrate the effects of the quaternary combination according to the invention on the crushing strengths of concrete mixtures after 1.7 and 28 days, the following Examples 1 to 4 are given in which the proportions of the four components of the admixtures are very varied. Each example compares a simple mixture of cement, sand and coarse aggregate to the same mixture containing the admixture, both being mixed at the same time from the same basic components with enough water to give the same settlement (so closely that the settlement can be practically determined from the consistency during mixing).

   The composition of the admixtures expressed in% of the weight of the cement contained in the final mixture, the settlement in cm (rounded to half cm), the coefficient of cement in kg per meter, the quantity of water in liters per meter, the quantity of air entrained in the mixture in% of the volume and the average crushing strengths

 <Desc / Clms Page number 9>

 in kg per square cm of a number of test cylinders tested at each age are given for each example in tabular form.

     Because of the possibility of uncontrollable differences in temperature and humidity, and because of small variations in the batches of cement, sand, gravel used in the examples carried out at different times, it should be noted that the values for each example can only be roughly compared to the values of each of the other examples.



  EXAMPLE 1.-
Normal mixture plus adjuvant Total adjuvant none 0.25
Residual sulphite liquor solids 0.10
Sodium salicylate 0.06
Calcium chloride 0.07
Triethanolamine 0.02 Settlement 9 7.5 Cement coefficient 225 225 Water content 110 100 Air content 2.1 3.5
Normal mixture plus adjuvant Strength after 1 day 35.7 51.8 Strength after 7 days 191 299 Strength after 28 days 324 399.7 EXAMPLE 2.-
Normal mixture plus adjuvant Total adjuvant none 0.35
Waste sulphite liquor solids 0.20
Sodium salicylate 0.06
Calcium chloride 0.07
Triethanolamine 0, 02 Settlement 7, 5 9.0 Cement coefficient 224 226 Water content 114 102 Air content 2 4.5 Strength after 1 day 31 47 Strength after 7 days 206,

  5,282 Resistance after 28 days 306,374

 <Desc / Clms Page number 10>

 EXAMPLE 3. -
Normal mixture plus admixture Total admixture none 0.38 Residual sulphite liquor solids 0.20 Sodium salicylate 0.06 Calcium chloride 0.10 Triethanolamine 0.02 Settlement 12.5 12.5 Cement coefficient 224 226 Water content 113 94 Air content 2 - 4.4 Strength after 1 day 31.5 63 Strength after 7 days 198 320.5 Strength after 28 days 316.5 420 EXAMPLE 4.



   Normal mix plus-adjuvant, Total adjuvant none 0.60
Residual sulphite liquor solids 0.25 Sodium salicylate 0.06 Calcium chloride 0.25 Tri-ethanolamine 0.04 Settlement 10 10 Cement coefficient 225 223 Water content 111.5 91.5 Air content 1.9 5.4 Strength after 1 day 31.5 52.5 Strength after 7 days 189,343 Strength after 28 days 326,420
The following example 5 is carried out in the same way as the previous examples and the same values are listed, but the two mixtures were carried out with different cement coefficients to show the strengths obtained by the quaternary admixture and 20% cement in less.



    EXAMPLE 5.-
Normal mixture plus adjuvant Total adjuvant none 0.25
Residual sulphite liquor solids 0.08
Sodium salicylate 0.06
Calcium chloride 0.09
Triethanolamine 0.02 Settlement 7.5 9 Cement coefficient 250 198 Water content 114 93.6 Air content 2 5.7 Strength after 1 day 38 46 Strength after 7 days 206.5 264 Strength after 28 days 319 3515

 <Desc / Clms Page number 11>

 
The following examples 6,

   74 8 and 9 were carried out over a period of a few days and should allow a direct comparison of the effects of using increasing amounts of aromatic carboxylic compound and water-soluble amine while keeping constant the amounts of residual sulphite liquor solids and calcium chloride at values generally used for these components without the other two components.



  As tests of a few days can only be compared summarily, each test includes a similar realization with a comparable simple mixture as a control and each test is given in a separate example, together with the corresponding realization of the simple mixture.



    EXAMPLE 6. -
Normal mixture plus adjuvant Total adjuvant none 0.27
Waste sulphite liquor solids 0.20
Sodium salicylate 0.01
Calcium chloride 0.05
Triethanolamine 0.01 Settlement 11.5 14 Cement coefficient 225 227 Water content 110.5 93.6 Air content 2 4.2 Strength after 1 day 36.5 57.5 Strength after 7 days 213 326 Strength after 28 days 343 434 EXAMPLE 7.-
Normal mixture plus adjuvant Total adjuvant none 0.33
Waste sulphite liquor solids 0.20
Sodium salicylate 0.05
Calcium chloride 0.05
Triethanolamine 0.03 Settlement 11.5 14 Cement coefficient 226 228 Water content 109 87.6 Air content 2 4.6 Resistance after 1 day 38.5 66 Resistance after 7 days 201.5 360 Resistance after 28 days 320,

  5 467

 <Desc / Clms Page number 12>

 EXAMPLE 8-
Normal mixture plus adjuvant Total adjuvant none 0.31
Waste sulphite liquor solids 0.20
Sodium salicylate 0.01
Calcium chloride 0.05
Triethanolamine 0.05 Settlement 9 9 Cement coefficient 228 228 Water content 107 86.6 Air content 2 4.8 Strength after 1 day 38 72 Strength after 7 days 212 364.5 Strength after 28 days 327.5 453.5 EXAMPLE 9.

   -
Normal mixture plus adjuvant Total adjuvant 0.39
Waste sulphite liquor solids 0.20
Sodium salicylate 0.05
Calcium chloride 0.05
Triethanolamine 0.09 Settlement 11.5 10 Cement coefficient 229 230 Water content 105 82.5 Air content 1.9 5 Strength after 1 day 38.5 59 Strength after 7 days 217 344.5 Strength after 28 days 350, 5,434
To illustrate the very rapid gain in resistance which can be obtained with the quaternary adjuvant of the invention in the unusual case where it is required, the following example 10 shows the effect of additions of increasing amounts of calcium chloride while the amounts of the other components remain constant.



  EXAMPLE 10.-
Adjuvants
A B C Total adjuvant 0.38 0.78 2.78
Residue sulphite liquor solids 0.20 0.20 0.20
Sodium salicylate 0.06 0.06 0.06
Calcium chloride 0.10 0.50 2.50 Triethanolamine 0.02 0.02 0.02 Settlement 14 12.5 12.5 Cement coefficient 224 225 223 Water content 93 92.5 92.8 Air content 5 5 5.2 Strength after 1 day 54 69.5 122.5 Strength after 7 days 308 339 366 Strength after 28 days 424 430 446

 <Desc / Clms Page number 13>

 
As is evident from Example 10, the amount of calcium chloride can be increased to a very high number compared to the amounts of the other three components of the additional mixture to obtain a rapid gain in initial strength,

   with little effect on final strength and consistency, as indicated by settlement and water values, and little effect on entrained air. Although not shown in the values indicated in Example 10, it should also be explained that such considerable variations in the amounts of chloride accelerator also have little influence on the great ease of work and excellent cohesion obtained with Quaternary builders, although high concentrations of chloride accelerators tend to accelerate cure during the normal finishing period to such an extent that it becomes unacceptable, except where a surface finish is not required, for example in the case of structures that have shapes that cover all surfaces,

   
There are no standard laboratory measurements for determining the finishing time of cement mixes * Efforts to present values for the time required for a mixture to set to finish state and the additional time available during which the finishing operations are completed, depend to such a degree on subjective judgment that they are quite unsatisfactory. Conclusions are therefore normally drawn from experience with a large number of uses under a wide range of current working conditions.



   Experiments carried out extensively with the use of the quaternary builders of the present invention in the field, with a wide variety of atmospheric conditions and basic concrete mix formulas, in parallel with specific hardening rate tests described above. Below, it becomes apparent that these adjuvants have highly favorable effects in solving the usual finishing problems described above.

   Over a wide range of proportions of the four components of the invention, working at normal or elevated temperatures, the cure rate approaches more closely that of a simple mixture than in the case of commercial "water reducers". allowing a faster finish and a longer period during which the finish can be completed for a determined degree of water and cement reduction, or strength increase, achieved by the various "water reducers".



   At low temperatures, at which the setting of a simple cement mixture is greatly retarded, the known "water reducers" cause even greater delay and often may not be properly used for this reason. The quaternary builders of this invention, on the other hand, presently accelerate setting to a finish condition during cold weather, compared to simple mixing.



  Thus, the invention makes the advantages of "water reducers" accessible to cold weather work where they could not be applied heretofore due to surface finish problems.



   As explained in the introduction to this specification, preceding the above examples, the action of the quaternary builders of this invention to reduce finishing times is new from what was known in the art. relates to the action of the four components used individually or in known combinations. As was also mentioned in this context, sodium salicylate was used alone as an adjuvant without being recognized to have a significant action on the rate of cure or on the rate of strength gain.



  Yet it was established by a recently established hardening test,

 <Desc / Clms Page number 14>

 and further described, a test which measures the rate of development of the bond strengths of cement mixes, that aromatic carboxylic compounds in small amounts act as accelerators in the onset of setting although they do not appreciably affect the strength the first. day. When used in the quaternary combination of this invention, the various aromatic carboxylic compounds have a retarding effect, particularly during the period when the mixture is in a surface finish state.



   This latter conclusion is based on tests carried out in accordance with a new method for measuring the initial rate of hardening of cement mixtures, which method is currently being considered as a standard test method.



   Briefly, the test method is to seal different 9mm stainless steel anchors to a depth of 125mm in a rectangular cement specimen, try to remove the anchors at regular intervals during the initial curing period of the mixture. , and measure the force required to remove each peg.



  The force required to remove a given anchor, divided by the area of the anchor in contact with the cement mixture, is the bond strength developed by the mixture at the time considered. Using this test method, the cure rate of the quaternary adjuvant can be compared directly with simple mixtures at the same temperature conditions.



   A correlation between the curing period during which finishing can be achieved and the bond strength as measured above was observed and all the tests carried out corroborated the previous conclusion that the aromatic carboxylic compound of the quaternary builders is responsible for the observed favorable curing rate. Until a few hours after placement, depending on concentrations and temperature, the presence or absence of this component does not appear to have a measurable effect on the rate of cure. Component omission, however, results in rapid curing afterwards, while the mixture is in a surface finish condition, often leaving insufficient time to complete a wide job.

   At preferred amounts, however, the component exerts the noted retardation effect during the finishing period, and this is accentuated when the proportion of this component in the quaternary adjuvant is increased, as indicated by the new test method. described. The same amounts of the same quaternary builder significantly accelerate the rate of low temperature cure, compared to simple mixtures. Since simple mixes are disadvantageously delayed at such temperatures, causing delays in finishing and mold release, the present invention serves to compensate for this disadvantage of simple mixes.



   Regarding the ease of work or the fluidity of the cement mixtures containing quaternary admixtures of this invention, visual observation has served as testimony, as there is no satisfactory test to measure the fluidity. All the evidence derived from outdoor observations indicated the substantial improvement in the workability of the mixtures containing the quaternary builders as compared to the "water reducers".

   For example, where settlements of 7.5 to 10 cm have been required up to now to achieve satisfactory working conditions for certain jobs, the substitution of the "water reducers" of the invention for those previously known has allowed the use of weaker settlements of about 2.5 to 5 cm with significantly lower water contents, while still obtaining the same

 <Desc / Clms Page number 15>

 ease of use, as far as can be judged from the actual working conditions in the open air.

   In other cases, the increased ease of work has been beneficial by allowing the use of less sand and less water, without loss in workability or reduction in settlement, while currently improving the cohesion of mixtures as in. demonstrates resistance to segregation and excellent mixing of coarse components with mortar. This is especially true for wet and lean mixes.



   Regarding the effect of air entrainment, the cement mixtures containing quaternary builders of the invention show considerable qualities. As is the case with most "water reducers" and especially those containing the solids of the waste sulphide liquors, the quaternary builders of this invention exhibit essential air entrainment characteristics. This characteristic of "water reducers" has heretofore limited their usefulness in large quantities for obtaining greater plasticizing action, because of the loss in resistance attributed to excessive entrainment of air as well as to the effects of excessive air entrainment. pronounced delays that result.

   In other instances where very moderate amounts of the known "water reducers" are used, special "air entrainers" have sometimes been used to improve the resistance of hardened concrete to freeze and thaw and to the chipping effects of water. salt used for thawing; but the amount of air purposely entrained for this purpose was often limited by the need to avoid the losses of strength occasioned by the higher air contents.

   But when employing the admixtures of this invention, air contents as high as 8% do not cause any significant loss in strength, compared to simple mixtures with cement coefficients 20% higher, which makes possible. the use of relatively large amounts of "water reducers" to achieve maximum cement savings with increased workability and the advantage of strong air entrainments without significant loss in strength.

   The above results obtained in accordance with the invention are illustrated by the following additional example EXAMPLE 11. -
Tests have been carried out with: @
A. a simple mixture (without additives)
B. a mixture containing a relatively large amount of a quaternary "water reducer" of the invention, plus an "air entrainment limiting agent" to limit entrained air for the water reducer, and
C. the same mixture as in B, but without the air entrainment limiting agent, in order to entrain a lot of air.



   The resulting air contents (% by volume) and the compressive strengths after 1, 7 and 28 days (kg / cm2) are shown in the following tables 1 and II in which the results of two series of tests are given. comparative trials. As in the previous examples, the additional ingredients are given as percentage by weight of cement, settlements in cm, cement factors in kg per meter, and water content in liters per meter. The air entrainment limiting agent of Mixture B was tributyl phosphate in all tests.

 <Desc / Clms Page number 16>

 



   TABLE I
Simple Mixture Mixture Mixture
A B C @
 EMI16.1
 
<tb>
<tb> Adjuvant <SEP> total <SEP> none <SEP> 0.75 <SEP> 0.75
<tb> Solids <SEP> of <SEP> liquor <SEP> sulphite <SEP> residual <SEP> 0.39 <SEP> 0.39
<tb> Salicylate <SEP> of <SEP> sodium <SEP> 0.09 <SEP> 0.09
<tb> Chloride <SEP> of <SEP> calcium <SEP> 0.21 <SEP> 0.21
<tb> Triethanolamine <SEP> 0.06 <SEP> 0.06
<tb> Agent <SEP> limiting <SEP> training
<tb> air <SEP> 0.0006
<tb> Settlement <SEP> 8.5 <SEP> 11.5 <SEP> 10
<tb> Coefficient <SEP> of <SEP> cement <SEP> 250 <SEP> 200 <SEP> 197
<tb> <SEP> content in <SEP> water <SEP> 108.5 <SEP> 86.6 <SEP> 80.4
<tb> <SEP> content in <SEP> air <SEP> 2.2 <SEP> 5.6 <SEP> 7.5
<tb> Resistance <SEP> after <SEP> 1 <SEP> day <SEP> 42 <SEP> 33.5 <SEP> 38
<tb> Resistance <SEP> after <SEP> 7 <SEP> days <SEP> 239.5 <SEP> 297,

  5 <SEP> 289
<tb> Resistance <SEP> after <SEP> 28 <SEP> days <SEP> 383 <SEP> 390 <SEP> 380
<tb>
 TABLE II
Simple Mixture Mixture Mixture
 EMI16.2
 
<tb>
<tb> A <SEP> B <SEP> c <SEP>
<tb> Adjuvant <SEP> total <SEP> none <SEP> 0.75 <SEP> 0.75
<tb> Solids <SEP> of <SEP> liquor <SEP> sulphite <SEP> residual <SEP> 0.39 <SEP> 0.39
<tb> Salicylate <SEP> of <SEP> sodium <SEP> 0.09 <SEP> 0.09
<tb> Chloride <SEP> of <SEP> calcium <SEP> 0.21 <SEP> 0.21
<tb> Triethanolamine <SEP> 0.06 <SEP> 0.06
<tb> Agent <SEP> limiting <SEP> air entrainment <SEP> <SEP> 0.0007
<tb> Settlement <SEP> 10 <SEP> 10 <SEP> 8.5
<tb> Coefficient <SEP> of <SEP> cement <SEP> 250 <SEP> 200 <SEP> 197
<tb> <SEP> content in <SEP> water <SEP> 108.5 <SEP> 85 <SEP> 80.6
<tb> Content <SEP> in <SEP> air <SEP> 2, <SEP> 2 <SEP> 6, <SEP> 0 <SEP> 8,

   <SEP> 0 <SEP>
<tb> Resistance <SEP> after <SEP> 1 <SEP> day <SEP> 40.5 <SEP> 23 <SEP> 32
<tb> Resistance <SEP> after <SEP> 7 <SEP> days <SEP> 238.5 <SEP> 303 <SEP> 297
<tb> Resistance <SEP> after <SEP> 28 <SEP> days <SEP> 375 <SEP> 396 <SEP> 382
<tb>
 
It will be observed from the values of Tables I and II above, that with quantities of entrained air as considerable as 7.5 to 8% the strengths obtained after 7 and 28 days with the mixture containing a quaternary adjuvant of the invention are little different from those obtained with the same mixture B containing 5.6% and 6% air and were substantially equal to or greater than the strengths obtained with the simple mixture A containing about 25% more cement.



   Thus, the builders of the present invention can be used in normal amounts in combination with air entrainers to achieve higher air contents without the strength losses seen heretofore in the art. The adjuvants of the invention can also be used, although they themselves entail appreciable quantities of air, for mixtures made with cements.

 <Desc / Clms Page number 17>

 entraining air without the loss of resistance one would normally expect.



   Although the foregoing description of the invention and its many advantages refer broadly to the use of a particular combination of four additional components, in mixtures of the nutrients, aggregates and water, it should be understood that one can to include still other adjuvants in the cement mixtures prepared in accordance with this invention for the purposes for which they are normally used. Such other adjuvants can be air entrainment agents, air entrainment limiting agents (see Example 11), pozzolanic materials, light ash, coloring materials, hydrophobic materials and the like.



   The quaternary builders of the invention can be added alone or as a mixture and added with such other builders, either to the cement, to the aggregate or to the water, or they can be incorporated into the complex cement mix, alone or together with other adjuvants, or in any other way.



   The presently preferred way of applying the invention consists in mixing the liquid amine with the accelerator with the dry chloride in powder form, then adding the solids of the residual sulphite liquor and the aromatic carboxylic compound in the form of dry powders to obtain the quaternary adjuvant in the form of a dry powder. This dry adjuvant, with or without other adjuvants, can then be incorporated into the cement mixture in any of the above-mentioned ways which would be most suitable. But the four components of the adjuvants of the invention can, if desired, be incorporated separately into the cement mixture, the liquid components preferably being incorporated into the mixing water before it is added to the components. dry in the mixture.



   With regard to the above, it should be understood that the expression "consisting essentially of" used in the summary below to define the combination of admixtures on which the invention is based, or a cement mixture containing the four components of the combination, does not prejudge the presence of other adjuvants which will individually produce their known effect which may be different and independent of the effect resulting from the application of the invention, or may be similar and additive in its character, or may to some extent prejudice the advantages of the invention.

   Furthermore, both in the foregoing description of the invention and in the summary, if the context is not expressly opposed thereto, it should be understood that all quantities of materials are expressed as percentages by weight, based on weight. hydraulic cement.



   While the invention has been described and illustrated herein with reference to various specific materials, methods and examples, it should be understood that the invention is not limited to those particular materials, combinations of materials or methods selected for this purpose. Many variations of such details can be used as will be understood by those skilled in the art.



   CLAIMS.

** ATTENTION ** end of DESC field can contain start of CLMS **.


    

Claims (1)

1. - Additional composition to be incorporated as an adjuvant in hydraulic cement mixtures, characterized in that it comprises 1 to 15 parts by weight of a water-soluble aromatic carboxylic acid or of one of its salts or water-soluble esters, of 0, 5 to 40 parts by weight of a water-soluble chloride accelerator, and 0.5 to 10 parts by weight of a water-soluble non-carboxylic amine, these ingredients being mixed or <Desc / Clms Page number 18> added to 5 to 50 parts by weight of residual sulphite liquor solids to complete the composition. 2. - Composition according to claim 1, characterized in that it is in the form of a dry powder and is capable of modifying the resistance, the cohesion, the ability to be allowed to work and the setting of hydraulic cement mixtures. . 3. - Composition in the form of a cement mixture containing a hydraulic cement, ingredients and water, characterized in that it comprises from 0.1% to 0.75%, by weight of the cement , an adjuvant comprising 5 to 50 parts, by weight of the total adjuvant, of residual sulphite liquor solids, 1 to 15 parts by weight of a water-soluble aromatic carboxylic acid or of a salt or ester salt water soluble, 0.5 to 40 parts by weight of a water soluble chloride accelerator, and 0.5 to 10 parts by weight of a water soluble non-carboxylic amine. 4. - Composition according to claim 3, characterized in that the adjuvant is incorporated therein in an amount of about 0.25% to 0.75% by weight of the cement. 5. - Composition according to any one of the preceding claims, characterized in that the sulphite liquor solids comprise the dried residue of neutralized waste sulphite liquor from which a large part of the carbohydrates has been removed. 6. - Composition according to any one of the preceding claims, characterized in that the water-soluble aromatic carboxylic acid, the salt or the ester comprises salicylic acid, or a salt or ester thereof. 7. A composition according to any one of the preceding claims, characterized in that the non-carboxylic amine comprises triethanolamine. 8. - Composition according to any one of the preceding claims, characterized in that the chloride accelerator comprises a soluble metal chloride. 9. - Composition according to any one of the preceding claims, characterized in that it comprises from 10 to 20 parts by weight of solids of residual sulphite liquor, from 2 to 6 parts by weight of the water-soluble aromatic carboxylic acid, or of a salt or ester thereof, from 1 to 12 parts by weight of the water-soluble chloride accelerator, and from 1 to 5 parts by weight of the water-soluble non-carboxylic amine. 10. - Additional composition in substance as described above. 11. - Cement mixture in substance as described above with reference to the examples cited.