CA1175045A - Process for controlled degradation in concentrated solution of liquid glucose syrups - product thus obtained and its use as an additive for mortars and concretes - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A process for the controlled degradation of liquid glucose syrups in concentrated solution snd in homogeneous phase wherein the reducing groups of glucose, maltose and maltodextrin are converted into the salts of the corre-sponding aldonic acids and/or into the salts of lower carboxylic acids (C1-C4) without substantially changing the polysaccharide components (degree of poly-merization > 3) of maltodextrin, or with only partial depolymerization of the polysaccharide components, by using simple oxidants such as hypohalogenites or ferricyanides, or aqueous alyaline solutions. The conversion of the reducing sugars is equal to or greater than 95% and a very high reproductibility of the desired results is obtained. The invention also concerns the product obtained by the process and its use as an additive to cement mortars and concretes The present invention concerns a process for the controlled degradation of liquid glucose syrups in concentrated solution. More particularly, the present inven-tion concerns a process for the controllod degradation of liquid glucose syrups in concentrated solution by elminating the reducing groups in the mono-, di-and oligosaccharides.

Description

1175~5 This invention concerns also the use o the resulting product of the process of this invention as an additive to improve the physical and mechanical characteristics of mortar and concrete.
For the purposes of this description the term "liquid glucose syrupl' means the liquid product deriving ~rom the acid and/or enzymatic and/or mixed hydrolysis of starch, obtained from any source such as for example mai~e, pota-toes, rice, wheat, tapioca or other vegetable sources.
Oxidation of the glucose to the corresponding aldonic acid (gluconic acid) is one of the most classical of the chemistry of carbohydrates and is amp-ly described in the literature.
The oxidizers most commonly used for this reaction are the halogens iodine, bromine~ chlorine and their derivatives, or the ferricyanides.
Preparation of aldonic acids with chemical methods given in the lit-erature, in subsequent periods, copy in general, even in the details, the methods perfected in preceding periods, in particular those with hypoiodites of Willstatter and Sch~del and of Goebel, and the electrolytic method using bro-mine of Isbell and Frush. These methods, and in particular the electrolytic method using bromine, have been applied also to disaccharides and oligosacchar-ides.
Although the abovementioned oxidations proceed in general with rela-tive ease they are not free of disadvantages both in their analytical and pre-parative application. The chief disadvantages may be summarized thus:
1. The possibility of degradation of the starting compounds under the relatively drastic acidity conditions of the oxidation process using bromine and alkalinity of the processes of oxidation using hypohalogenites.

2. The possibility of overoxidation which leads to the obtention of keto-acids and di- and polycarboxylic acids even if there are still appreciable . -1-ll'~S~4S

quantities of reducing carbohydrates present.
Both the aforementioned disadvantages involve incomplete or unrepro-ducible reactions and their minimization requires a search for optimal experi-mental conditions case by case.
It is known that glucose, maltose and other malto-dextrines with mol-ecular weights which are the normal components of liquid glucose syrups can be converted into the corresponding "aldonates" by oxidation of the "reducing"
(hemiacetal) groups in accordance with the following diagram:

H,OH ~; COO

OH H
GLUCOSE GLUCQNATE

HO ~ -O - ~ HO -OH OH Oll MALTOSE MALTOBIONATE

CH OH l CH20H - CH2H 1 ~H20H
l~o k o ko /1-o~l ¦ ~ ~ H,OH ~ ~ OO

H jn OH OH n OH

DEXTRINE FIG. 1 DEXTRINE ALDONATE

~1~75(~9 5 Th0 oxidation of l~qu~d glucose s~rups with hypohalogen~tes is known from carbohydrate chemistr~ (e.g. 'IThe halogen oxidat~on of simple carbohydrates", J. W. Green, Advances ln Carboh~drate Chem~stry 3, 129, 1948~.
Nev0rtheless, on the basis of data ln the literature, thls oxidation is generally conducted in dilute s~stems and takes wlth strong degradation of the nonreducing groups.
It is also known from carbohydrate chemis~ry (e.g. W. Pigman and L.F.L.J.
Anet "Action of aclds and bases on carbohdrates", in W. Plgman and D. Horton Ed.s., Vol. IA, p.l65, 1972) that the reduclng sugars are subjected to rapid degradation in an alkaline solution generating a variety of low molecular weight products according to the follow~ng diagram: C~H2HH
~ OH ARABINONATE
RO ~ COO

to~l SACCHARINATE
D ~01 1 C~l ~COO
C ~ H f RO \ ~ ~3 OH OH
H

H C~O FORMIATE

~ CH3-CIH-COO LACTATE

~17S~4S

The degradation illustrated above proceeds through the formation of highly unstable intermediate ketoenolics and is difficult to control. It usually proceeds even after néutralization of the reaction mixture.
All degradation methods, oxldatlve or with alkalis, for liquid glucose syrups known from the literature concern, as noted, dilute systems and mainly solution of a single carbohydrate. It was therefore impossible to foresee the results of degradation, oxidative or with alkalis, performed on concentrated systems and consisting of a mixture of different carbohdrates such as those present ln commercial liquid glucose syrups.
The fact that uniform results aTe obtained, i.e. that uniform qualitative and quantitative reaction mixtures of the products of degradation are obtained despite the disadvantages known from the technical literature, is surprlsing.
The use of commercial liquid glucose syrups as additives for mortars and concretes has been long known. It is also known that the use o these syrups involves serious drawbacks which severely limlt their use.
In particular, these syrups have a strong retardlng effect on the settlng of cement Mixes (mortars and concretes). Furthermore, the action of the syrups with a high reduclng sugar content is not uniform and is therefore unpredlctable. It often happens that the quantity of additive correct or a certain cement is not equally correct for another cement, to the point that hardening may completely fail even if the two cements may be considered of the same type from a commercial viewpoint. This lack of reproducibility is attributed mainly to the presence of weak alkali groups such as, for example, the hemiacetal groups ~aldehydo~ of the reducing sugars.
Merely as examples, Table 1 shows the results obtained with three types of commercial liquid glucose syrups having the different weight ratios of _ ~ _ ~7S~4S

monosaccharides, dlsaccharides and polysaccharldes. The disadvantages resulting from the use of these syrups are clear from the compression resistance values of specimens of plastic mortar mainly a~ter 24 hours.
TABLE I

~__ _ ~ - - _ \Compressive strength Kg/cm a~ter:
\ Add~tion Sample \ rate /OO w/c 3 \ ~ 1 day 3 days _ ~ _ _ ~ _ Plain - 0,5 90 120 274 Liquid glucose syrup 1 50,5 98 68 269 with D.E 49 - 53 ' 0,5lOI 67 272 Liq~id ,l~c ~yru~ 1,5 0,5 10 ~._ It is certain that the delay ln setting o~ the cement mixes is caused mainly by the simple sugars such as glucose and maltose present in the commercial liquid glucose syrups. The retarding effect is often proportlonate to the equivalent dextrose ~E.D.) o the syrup.
The retarding effect of commercial liquid gluco5e syrups as a : function of the E.D. value is given in Table II.
The results shown in this table were obtained in accordance with ASTM standards with method C191-77.

1~'75~ S

TABLE II

Type of liquid Addition rate /0O on Initial setting glucose syrup the weight of cement time l~ours Minutes Plain - 2 40 D.E. = 36 - 37 1 ~5/oo 5 35 D.E. = 43 - 45 1 ~5~/oo 7 5 D.E. = 49 - 53 1~5/oo 7 50 Table III shows the dlsadvantages deriving ~rom the use of syrups with increasing E.D. values as additives for mortars and concretes.
TABLE III
___ _ ~ ._ __ _ _ _~
\ ~ ~ Compressi~e strength Kg/cm2 after:
Sample \ ,~ ~ w/c 3 _ _ \ ~ ~ ~ 1 day 3 days _ ~
Plain - 0,5 90 115 259 D,E, 36 - 38 1~5/oo0,5 96 58 253 D.E. 43 - 45 1 ~5/oo 0~5 95 56 249 D.E. 58 ~ 60 1 ~5/oo 0~5 97 ~5~)~5 To reduce the delay in set~ing of cement m~xes ~he use was suggested of starch hydrolyzate (or liquld glucose syrups) having a low E.D.
value and a relatively high polysaccharide content (see patent IT 746 936 and pa~ent US 3 432 317). It was nevertheless immediately apparent that these additive compositions stlll have a considerable retardlng ef~ect on the setting of cement mixes so that it was proposed to add hydrosoluble amines (from 0.002 to 0.10%) and chlorides ~from 0.005 to 0.90%) see IT 746 936 page 22 and following and claim 7.
In DE-OS 2630799 mainly to avoid the addition of chlorides which corrode the reinforcing rods of cement structures an additive was proposed containing polysaccharides with carboxylic groups having a molecular weight between 400 and 4.000 and a portion of carboxylic groups between 2.5 and 25.0%
by weight.
The polysaccharides to be used in accordance with the invention may be produced, for example, by oxidative degradation of high molecular weight polysaccharides or by hydrolytic degradation of high molecular weight ; polysaccharides containing carboxylic groups ~see DE-OS 2630 79~ page 5 (3) lines 6-13).
The suggested method of the above patent application is, first, uneconomical because the polysaccharides containing in the beginning carboxylic groups such as pectin, alginates, gums, chitin, inoline and so forth can be found in trade at high prices and therefore cannot be used with advantage as starting products in the preparation of additives for cement mixes.
~n the second place, the ent~re description fails to show clearly the method to be used for converting the high molecular weight polysaccharides in~o polysaccharides having carboxylic groups with a molecular weight between 400 and 4.000.

~75(~

Apar-t from the fact that it is not possible to repeat experimentally wha~ was aescribed in the above patent application it must be observed that even the above-mentioned additives (con-sisting, as mentioned, of polysaccharides with carboxylic groups having a molecular weight between 400 and 4,000) retard the setting of cement mixes so that it becomes necessary to add accelerators such as, for example, salts of alkaline and alkaline-earth metals, alkanolamines, formates and so forth (see DE-OS 26 30 799, page 7 (5)).
In one aspect, the invention relates to a process for the preparation of a mixture of aldonates of glucose, maltose and maltodextrines containing formates and optionally acetates, lactates, saccharinates and arabinonates, characterized by control-led degradation in a concentrated solution of liquid glucose syrups and in homogeneous phase by the use of simple oxidizers selected from halogens, ferricyanides, hypohalogenites and peroxides or of aqueous alkaline solutions.
More particularly, this invention provide~ a process easy to apply industrially for the controlled degradation of liquid glucose syrups in concentrated solution and homogeneous phase to convert the hemiacetal groups of the glucose, maltose and malto-dextrins into the salts of the corresponding aldonic acids and/or the salts of lower molecular weight carboxylic acids (Cl-C4) with-out substantially modifying the polysaccharidic components (extent of polymerization > 3) of maltodextrins, or depolymerizing only partially said polysaccharidic components, by the use of simple oxidizers such as, for example, hypohalogenite or ferri-cyanides or an aqueous alkaline solution, with conversion of reduc-~ .
,,, " , ~ .

~75~S

ing sugars equal to or greater than 95% and very high reproduci-bility of the results, so as to be able to use directly the product derived from said process of controlled degradation as an additive for mortars and concretes.
Another purpose o this invention is to p:rovide an additive for mortars and concretes with uniform quality and capable of giving a very high rate of reproducibility of the results without the need of further additives such as, for example, chlorides, alkanolamines, salts of alkaline metals and alkaline-earth metals.
The intended purposes are reached by the process of controlled degradation in a concentrated solution of liquid glucose syrups and by the - 8a -~' ~75(:~5 product resulting from this process as set forth in the claims enclosed with this description.
According to this inventlon the controlled degradatlon in a concen-trated solution of liquid glucose syrups in homogeneous phase can be accomplished either by oxidation with simple oxid~zers, preferably with hypohalogenites, or b~ treatment wi~h aqueous alkalis.
If oxidation is done with hypohalogenite, in accordance with a presently preferred procedure for conducting ~he process of this invention, a liquid glucose syrup having an E.D. value between 20 and 85 is treated with an aqueous alkaline solution, preferably of concentrated sodium hydroxide, until a pH of 7.5 - 10, preferably pH 8.5 - 9.5, ls reached. Then the solution is heated to 40 - 60, preferably ~3 - 47C. Then the required quantity of hypohalogenite, preferably hypochlorlte (with 10 - 15% chlorine) is added in between 1 and 3 hours, preferably between 1~ and 2~ hours~ maintaining pH
constant within 0.5 points by addlng aqueous alkalis, then neutralizing by adding acid.
The course of the controlled degradation process of thls invention can be readily followed by IR and NMR spectroscopy as expla:Lned below.
According to the presently preferred alternative practice a liquid glucose syrup having an E.D. value between 20 and 85 is treated with an aqueous alkaline solution, preferably of concentrated sodium hydroxide~ to bring pH
to the desired value between 8.5 and 11.5, preferably between 10.~5 and 10.75 or between 11 and 11.5 depending on how it is desired to conduct the reaction, i.e. depending on the weight ratios of the final degradation products it is wished to obtain.
Then the solution is heated to 60 - 80C, preferably 72 - 78C, main*aining temperature and pH within this range by heating or cooling and if _ g _ :1~.7S045 necessary adding aqueous alkalis ~or 50 - 120 mlnu~es, preerably 55 - ~0 minutes.
Then neutralize with acid, preferably concentrated hydrochloric acid.
The course of this alternate method of carrying out the process of th~s invention may be conveniently followed by NMR spectroscopy as explained below~
When it is desired to reduce the molecular weight of the malto-dextrines present in the liquid glucose syrup to increase the quantity of the final product of degradation it is convenient to carry out a partial preliminary hydrolysis of the maltose and the malto-dextrines by treating the liquid glucose syrup with alkalis at the same pH values but at lower temperatures C20C - 30~C) before beginning the controlled degradation process according to this invention.
The liquid glucose syrups useful in the controlled degradation process of this invention have preferably a degree o~ polymerization between l and 10, an E.D. (equivalent dextrose) value above 30 and a maltose content ab~ve 10% ~dry), preferably above 30%.
~or purposes of illustration a list is given below of several types of liquid glucose syrups in trade whose chemical and physical properties are shown in Tables IV - VI:
A) Liquid glucose syrups from CARGILL: 1) G 36, 2) G 45, 3) G 58, 4) G 60/2, 5) G 62, 6) G 40/1, 7) CARGILL MALTOSE.

~ `` -- 10 -`

~750~5 B) Llqu~d glucose syrups from SPAD: 1~ 43 S,2) 45 S, 3) 45 L, 4~ 43 F, 5) 45 F,6) 43 SSP, 7~ 46 S, ~) 43 ZS,9) 45 ZS, 10) 43ZF, 11) 45 ZN,12) 43 ZAL, 13) 45 ZAL, 14) 43 ADS,15) 45 ADS.
C) Liquid glucose syrups from PRAGD: GLOBE 10500.
Oxidizers useful in the first of the alterna~e forms of the process of this invention belong to the class of halogen derivatives ~chlorine, bromine, and iodine) or the ferricyanides. It is preferable to use hypochlorites, hypobromites and hypoiodites or ferricyanides but hypochlorites are best.
Other known oxidizers such as, ~or example, hydrogen peroxide, may be used but their practical use is limited by the high cost of the oxidizer.
Among the alkaline agents useful in the second alternate form of the process of this invention may be mentioned in particular the aqueous solutions of alkalis such as, for example, sodium hydroxide and potassium hydroxide.

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Ln ~17S~45 TABLE V

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TABL~ VI
_ __ PHYSICAL AND CHEMICAL COSTANTS OF LIQUID GLUCOSE SYRUP
GLOBE 10500 F.R.A.G.D. S.p.A. (*) - D.E. 56 + 2 - Be 43 + 0,2 - Total solids % 80 * 0,5 - Denslty Kg/lt 1,422 - pH 5 0,5 - Color Light yellow Average composition of total solid:
- Glucose 28 - Maltose 40 -Polysaccharides 32 ~*) Fabbriche Riunite Amido Glucosio Destrina S.p.A., Milano~
The following examples illustrate better the process of this invention.
They do not constitute a limitation on the protection of thls invention because, as will be apparent to the technician of thls branch, the methods of carrying out the process of this invention can be varied as concerns the glucose syrups, the reagents, and the reaction conditions to better suit individual circumstances.
~.
To 30 g of glucose syrup with an E.D. value of 36 - 39 add an aqueous solution of NaOH at 40% by weight, agitating constantly in a thermostat-controlled bath at 40C ~ 5C until pH 9 is reached. During this period, approximately 5 minutes, the temperature of the solution rises to approximately 1~75~5 45C ~ ~C.
Then in a per~od of 2 hours add to the a'oove solutlon 50 ml of sodium hypochlorite at 12% Cl, maintaining pH nearly constant (9 0,5) by automatic addition of 40% NaOH by weight, 6 - 8 ml of NaOH total.
At the end of the reaction the temperature of the solution is approximately 43C. Then neutralize the reaction mixture by adding 37% HCl.
The ~lnal volume of the neutralized reaction solution is 85 ml.
An IR and NMR spectroscopic check of the reaction solution shows that prac~ically total conversion of the reducing sugars is reached (see figure la and figure 2b).
Example 2 Proceed as in Example 1 using a SyTup with an E.D. ~alue of 43 - 45 instead of 36 - 39. The results obtained are practically equivalent to those of Example 1.
Example 3 Proceed as in Example 1 using a glucose syrup with an E.D. value 58 - 60.
The Tesults obtained are practically equivalent to those of Example 1.
Example 4 To 30 g o~ glucose syrup with E.D. 36 - 39 add 70 ml of water and sufficient 40% NaOH by weight to bring the react~on solution to pH 10.5.
After holding the solution for 1 hol~r approximately at 75C cool the mixture and neutralize with 37% hydrochloric acid.
An NMR spectroscopic check of the reaction solution ~figure 2c) shows that practically total conversion of the reduclng sugars is reached, indicating that the reaction mixture contains, in addition to the undegraded ~ 16 -~L175~5 polysacchartdes, the sodium salts o~ carbox~llc acids: formlc, acetic, saccharinic and/or arabonic.
Example 5 Proceed as in Example ~ except that the pH value of the reaction mixture is 11.25 instead of 10.5. An MMR spectroscopic check of the reaction solution (figure 2d) shows tha~ practically total conversion of the reduction sugars is reached, indicating that the reaction mixture contains, in addition to undegraded polysaccharides, the sodium salts of the carboxylic acids:
formic, acetic, lactic, saccharinic and/or arabonic.
Example 6 Proceed as in Example 4 uslng a syrup with an E.D. value of 43 - ~5.
The results obtained are practically equivalent t~ those of Example ~.
Example 7 Proceed as in Example 5 using a syrup with an E.D. value of ~3 - 45.
The results obtained are practically equivaIent to those of Example 5.
Example 8 Proceed as in Example ~ using a syrup with an E.D. value of 58 - 60.
The results obtained are practically equivalent to those of Example ~.
Example 9 Proceed as in Example 5 using a syrup with an E.D. value of 58 - 60.
The results obtained are practically equivalent to those of Example 5.
* * * * * * * * * * * *
~R spectroscopic examination o~ the aldonates produced by oxidation of the glucose syrups with hypohalogenites is based on the principle that the absorption of the carboxylate band at 1,598cm 1 ls directly proportional to the concentration of the aldonate groups. Analysis is made in a D20 solutlon using sodium gluconate for reference in accordance with the following experimental ~175~5 procedure.
10 ml of the reaction solut~on are diluted with 50 ml of water.
2 ml of this solution ~containing approximately 50 mg o~ carbohydrate) are evaporated to dryness in a rotary evaporator. The residue ls dlssolved in 2 ml of D20 ~99.7%). The IR spectrum o~ the solutlon is then recorded in the 1,800-1,400 cm 1 region in a 0.050 mm ~aF2 cell using as re~erence a slmilar cell filled with D20 in the reference beam.
The apparent aldonate content o~ the solution is calculated from the absorbance at 1,598 cm 1 ~line-base technique) with reference to a calibration curve obtained with sodium gluconate ~1.0 to 4.0% by weight ln D20).
The true aldonate content is obtained taking into account the i~ter-ference rom the sodium formate determ~ned ~ith the NMR method (see below) and with reference to a calibration curve obtained with sodium formate in D20 ~0.1-0.5%).
As shown in figure 1, the glucose (a) and the malto-dextrine (c) do not interfere with the analysis, especially lf the absoTbance values both in the calibration measurements and the analytical measurements are made with a base line drawn between the hlghest transmlttance polnts on both sides of the analytical band.
Nuclear magnetic resonance ~NMR) analysis of the oxidated glucose syrups is based on the following principle. The magnetic protonic resonance spectra (lH-NMR) of the malto-dextrines in a D2~ solution show the characteristic signals attributable to the anomeric protons (H-l) both of the reducing and the nonreducing groups.
Elimination of the reducing groups by oxldation with hypohalogenites or by alkaline degradation invol~es a su~stantial increase in the intensity ratio of nonreducing to reducing signals.

11~5~45 In addition~ the characteTistic s~gnals of t~e products o~
oxidation or degradat~on ~aldonates or lower molecular weight carboxylic acids) make it possible to determine the content of these products in the reaction mixture. Figures 2a to d show typical spectra.
Pigure 2a shows the spectrum o~ an unmodif~ed glucose syrup. The doublets at 4.66 and 5.24 ppm ~ from the TSP internal reference standard~ are due to H-l of the reducing groups, respectively in the ~ and ~ configurations.
The doublet at 5.36 ~ is due to H-l of nonreducing groups.
Figure 2b shows the spectrum of the same syrup after oxidation with hypochlorite as given in Example 1 above.
The signals at 4.66 and 5.2~ ~ have practically disappeared; the signal at 4.22 ~ is due to H ~ of aldonic acids; the doublet at 5.23 ~ is the signal of H-l of the nonreducing group of the aldoblonic acid; the singlet at 8.48 ~ is due to the formic acid.
Figure 2c shows the spectrum of the same syrup a~ter treatment with NaOH as described in Example 4 with pH 10.5; figure 2d shows the spectru~ of the same syrup after treatment with NaOH as described in Example 5 with p~l 11.25.
The analytical peaks are at 1.93 ~ for the acetic acidJ at 1.39 for the lactic acid, and at 8.48 ~ for the forn~ic acid.
The experimental procedure ~ollowed is the following: 2 ml of reaction mixture are cvaporated to dryness in a rotating evaporator and re-dissolved in approximately 2 ml of D20 ~99.7%) and again evaporated. This procedure is repeated two more times for the purpose of exchanglng with deuterium the greater part of the "mobile" hydrogens belonging to water and to the residual hydroxylic groups of the carbohydrates. The residue is then dissolved in 2 ml of D20 ~99.7%) containing 3% by weight of TSP as internal standard for anchoring the frequenc-~ ~o the magne~ic field and 2% by weight of sodiumter~hthalate as 1:17~LS

internal quantitative standard.
The lH-NMR spectrum of the solution is recorded at surrounding temperature in a spectrometer at 90 M~lz and the signals of in~erest are integrated.
The areas of the analytlcal peaks are normally calculated by dividing their value with that of the sodium terephthalate signals and the concentration of each carboxylate type is calculated with reference to calibration curves obtained using solutionsof known concentration of these types in a D20 solution containing 2% of sodium terephthalate.
In Tables VII to X are gathered the results of several tests performed ~th cement mixes containing as an additive unmodified li~uid glucose syrups compared with cement mixes containing as the additive the product resulting from the process of this invention.
For all practical tests the amount of additive added to the mortar or concrete was maintained constant at 1.50/~D. But the amount o additive in accordance with this invention may vary within relatlvely broad limits depending on the type of cement to be used9 surrounding conditionsJ and the result it is desired to reach. Ordinarily the useful amount is between 0.15/o~ and ~O/DO
by weight of the cement.

- 2a-1~750~5 TABLE VII
__ \ .~ ~ Compressive strength Kg/cm after:
Sample \ ~ w/c o \ ¢ ~ ~ 1 day 3 days 7 days 28 days ~ _~ _ _ _.
Plain - 0,5 88 115 266 362 465 D.E. 43 - 49 ~unmodified) 1~5/oo " 100 57 258 395 511 D.E. 36 - 38 (unmodified) " " 101 57 262 412 528 D.E. 58 - 60 (unmodified) " " 99 52 253 389 506 D.E. 36 - 37 ~unmodified) " " 102 42 258 408 535 D.E. 49 - 53 ~unmodified) tl 11 100 62 26L 40~ 5.

- - 21 ~

11~75~4~

TABLE V~
\ ~ ~ ~
\ R ~ C~mpressive strength Kg/cm after:
Sample \ , w/c 3 ~ _ ~

Plain - 0,5 89 118 274 363 463 D E 36 - 38 OX " 0 5 98 148 297 415 552 D E 58 - 60 OX " 0 5 97 145 296 402 523 D E 36 - 37 OX " 0 5 97 137 285 421 558 , ~ 543 - 22 ~

TABLE lX

\ ~ ~ Compress~ve strength Kg/cm2 after:
Sample \ , ~ w/c o l l \ ~ g ~ 1 day 1 3 days ¦ 7 days 28 days ~ ~ _ _ I _ , _ Plain - 0,5 92 109 245 355 459 D.E. 49 - 53 1~5/oo ~I 94 55 216 395 519~unmodified) D.E. 36 - 37 " " 9~ 40 240 408 533 ~unmodified) D.E. 58 - 60 " " 97 48 235 325 498 ~unmodified) D.E. 37 - 38 " " 96 54 236 409 525 ~unmodified) D.E. 43 - 45 " " 95 58 250 402 501 (unmodified) D.E. 49 - 53 " " 96 99 261 418 531 D.E. 36 - 37 " " 92 93 271 419 543 Example 4 D.E. 58 - 60 ~OX) " " 98 99 268 403 508 Example 8 D.E. 36 - 38 (OX) " " 94 101 26~ 412 539 Example 4 D.E. 43 - 45 (OX) " " 94 106 280 406 512 Example 7 ._ __ _ . _ _ - 23 ~

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~lL175~45 For all practlcal tes~s with plastic mortar UNI provls~ons were followed (paTa. 2 sec. 1 art, lQl~ ~ncluded in D.M. dated 3 3une 1968 (Gazz.
Uff. No. 180 dated 17/7/1968~.
The cement used was a Portland cement with the following mineralogical compositlon according to Bogue:
C3S 46%
C2S 27.6%
C3A 7.4%
C4AF 7.4%
CaSO4 5%
ground to a fineness of 3500 cm2/g Blaine.

1~'750~5 TABLE XI

¦Additlon¦ ~Slump ¦Compressive strength Kg/cm2 after-San~ple rate w/c value cm.
1 day ¦ 3 days ¦ 7 days ¦ 28 days , , _ .
Pla~n - 0,51 10 85 183 218 331 D.~. 36-37 unmodified 1~5/oo Q~478 9 58 198 251 363 D.E. 58-60 I~ ~ 9 53 178 244 349 unmodified D.E. 43-45 ll ll 8 60 182 250 359 unmodified .
D.E. 36-37 OX ~ ll 9 93 215 288 389 Example 1 D.E. 58-60 OX 1~ I~ 11 88 211 279 380 Example 3 D.E. 43-45 OX tl ll 10 95 223 296 392 Example 2 5~5 TABLE XI~
-~ ¦AdditiOnI ¦S1UmP ¦COmPTe5SiVe str~ngth Kg/cm after:
Sample rate ~/c value cm.
~ _ 3 days ¦ 7 days ¦ 28 days Plain - 0,733 12 95 143 258 D.E. 36-371~5D/oo 0,702 11 97 161 279 unmodified D.E. 58-60 " " 12 84 157 267 unmodified D.E. 43-45 " " 11 99 159 283 unmodlfied D.E. 36-37 OX " 0 702 13 121 178 297 Example 1 D.E. 58-60 OX " " 10 104 171 293 Example 3 D.E. 43-45 OX " " 12 118 187 301 Example 2 ~7S~S

TABLE Xl~l _ _ Add~tion Slump Compressive strength Kg/cm af~er:
Sample rate ~/c ~alue cm _ ~ 3 days 7 days 28 days Plain - 0~676 8 80 140 227 D.E. 36-37 1,5/oo 0,648 8 87 168 259 unmodified D~E. 58-60 ~ ll 8 80 154 263 unmodified D.E. 43-45 I~ ~ 9 91 166 248 unmodified D.E. 36-37 OX 1~ ll 8 105 198 295 Example 1 D.E. 58-60 OX ll 0 648 9 100 186 283 Example 3 D.E. 43-45 OX ~l ll 9 108 197 299 ~75~:)4:~

~ o~ all the p~actlcal tests on concTete were used cements of the Portland and Pozzolan~c types in an amount between 380 and 400 kg/m3.
The aggregate used ln these tests was d~stTlbuted according to the ~uller method and used in the follow~ng proportions:
DIAMETER %BY WEIGHT
mm 7_3 22 3_0 35 30 ~

Claims (16)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for the preparation of a mixture of aldonates of glucose, maltose and maltodextrines containing formates and optionally acetates, lactates, saccharinates and arabinonates, characterized by controlled degradation in a concentrated solution of liquid glucose gyrups and in homogeneous phase by the use of simple oxidizers selected from halogens, ferricyanides, hypohalo-genites and peroxides, or of aqueous alkaline solutions.

2. A process according to Claim 1 characterized by treatment of a liquid glucose syrup having an E.D. > 30 and a maltose content > 10% (dry) with an aqueous alkaline solution up to a pH between 7.5 and 10 after which the solution is heated to 40 - 60°C and the required quantity of hypohalogenite is added in a period of 1 to 3 hours holding constant the aforesaid pH value within ? 0.5 points and then neutralizing the solution with acid.

3. A process according to claim 1 characterized by the treat-ment of a liquid glucose syrup having an E.D. > 30 and a maltose content > 10% (dry) with an aqueous alkaline solution up to pH
between 8.5 and 11.5 then heating the solution to 60 - 80°C and maintaining temperature and pH at the above values for 50 - 120 minutes, then neutralizing with acid.

4. Process for the preparation of a mixture of aldonates of glucose, maltose and maltodextrines containing formates and option-ally acetates, lactates, saccharinates and arabinonates, character-ized by the fact that before subjecting the liquid glucose syrup to the process according to any one of Claims 1 to 3, partial hydrolysis of the maltose and the maltodextrines contained in said liquid glucose syrup is performed by treatment with alkalis at the same pH stated in Claims 1 to 3 but at a temperature between 20 and 30°C.

5. Process according to claim 2 characterized by the fact that the aqueous alkaline solution is a concentrated solution of sodium hydroxide.

6. Process according to claim 2 characterized by the fact that the liquid glucose syrup is alkalized until a pH between 8.5 and 9.5 is reached.

7. Process according to any one of claims 2, 5 or 6 character-ized by the fact that the solution of alkalized liquid glucose syrup is heated to a temperature between 43 and 47°C.

8. Process according to any one of claims 2, 5 or 6 character-ized by the fact that the hypohalogenite is hypochlorite with 10 - 15% chlorine.

9. Process according to any one of claims 2, 5 or 6 character-ized by the fact that the hypohalogenite is added in a period between 1 hour 30 minutes and 2 hours 30 minutes.

10. Process according to claim 3 characterized by the fact that the liquid glucose syrup is alkalized until a pH between 10.25 and 10.75 is reached.

11. Process according to claim 3 characterized by the fact that the liquid glucose syrup is alkalized until a pH between 11.00 and 11.50 is reached.

12. Process according to claims 3, 10 or 11 characterized by the fact that the alkalized solution is heated to a temperature between 72 and 78°C.

13. Process according to any one of claims 3, 10 or 11 characterized by the fact that the liquid glucose solution is held at the established pH and temperature for a period of 55 to 80 minutes.

14. Mixture of aldonates of glucose, maltose and maltodextrines containing formates and optionally acetates, lactates, saccharin-ates and arabinonates obtained with the process of claim 1.

15. Additives for mortars and concretes characterized by the fact that they comprise a mixture of aldonates of glucose, maltose and maltodextrines according to claim 14.

16. Mortar or concrete containing 0.15°/oo to 4°/oo by weight of cement of a mixture of aldonates of glucose, maltose and malto-dextrines according to claim 14.