GB2075502A

GB2075502A - Process for controlled degradation of liquid glucose syrups and cement additive therefrom

Info

Publication number: GB2075502A
Application number: GB8113010A
Authority: GB
Original assignee: Grace Italiana SpA
Current assignee: Grace Italiana SpA
Priority date: 1980-04-28
Filing date: 1981-04-28
Publication date: 1981-11-18
Also published as: ZA812687B; JPS5745129A; IT8021680A0; IT1141931B; AU546085B2; AU6977681A; CA1175045A

Abstract

A process for the preparation of a mixture of aldonates of glucose, maltose and malto dextrines comprises treating a concentrated liquid glucose solution in homogeneous phase with an oxidising agent and/or an alkali. The product of the process is used as an additive to cement mortars and concretes.

Description

SPECIFICATION Process for controlled degradation of liquid glucose syrups and cement additive therefrom The present invention relates to the controlled degradation or liquid glucose syrups in concentrated solution and to the use of the product as an additive to improve the physical and mechanical characteristics of mortar and concrete.

For the purposes of this invention the term "liquid glucose syrup" means the liquid product deriving from the acid and/or enzymatic and/or mixed hydrolysis of starch, obtained from any source such as, for example, maize, potatoes, rice, wheat, tapioca or other vegetable sources.

Oxidation of glucose to the corresponding aldonic acid (gluconic acid) is a classical reaction of carbohydrate chemistry and is amply described in the literature. The oxidizers most commonly used for this reaction are the halogens, e.g. iodine, bromine, chlorine and their derivatives, or the ferricyanides.

The most commonly described methods in the literature for the preparation of aldonic acids involve the use of hypoiodites or the electrolytic method using bromine. These methods, and in particular the 'electrolytic method using bromine, have also been applied to disaccharides and oligosacharides.

Although the abovementioned oxidations proceed in general with relative ease they are not free of disadvantages both in their analytical and preparative application. The chief disadvantages may be summarised thus: 1. The possibility of degradation of the starting compounds under the relatively drastic acidity conditions of the oxidation process using bromine and the alkalinity of the processes of oxidation using hypohalogenites.

2. The possibility of overoxidation which leads to the formation of keto-acids and di- and polycarboxylic acids even if there are still appreciable quantities of reducing carbohydrates present.

Both the aforementioned disadvantages invoive incomplete or unreproducible reactions and their minimisation requires a search for optimal experimental conditions in each case.

It is known that flucose, maltose and other malto-dextrines 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:

GLUCOSE GLUCONATE

MALTOSE MALTOBIOlTATE

DEXTRINE DEXTRINE ALDONATE The oxidation of liquid glucose syrups with hypohalogenites is known from carbohydrate chemistry (e.g. "The halogen oxidation of simple carbohydrates", J.W. Green, Advances in Carbohydrate Chemistry 3, 129, 1948). Nevertheless, on the basis of data in the literature, this oxidation is generally conducted in dilute systems and involves strong degradation of the nonreducing groups. It is also known from carbohydrates chemistry (e.g. W. Pigman and L.F.L.J.Anet "Action of acids and bases on carbohydrates", in W. Pigman and D. Horton, Eds., Vol. IA, p.165, 1972) that the reducing sugars are subjected to rapid degradation in an alkaline solution generating a variety of low molecular weight products according to the following diagram:

ÇH2 H H2OHOH ARABINONATE h H 9 RO T C00 2 SACCHARINATE OH I COO OH2OH RO OH CH 0 3 OH OH RO H OH H-COO FORMATE l < H-COO FORMATE CH3-COO ACETATE > CH3-tH-COO LACTATE OH The degradation illustrated above proceeds through the formation of highly unstable intermediate ketoenolics and is difficult to control. It usually proceeds even after neutralisation of the reaction mixture. All degradation methods, oxidative or with alkalis, for liquid glucose syrups known from the literature concern, as noted, dilute systems and mainly solutions of a single carbohydrate. It was therefore impossible to forsee the results of degradation, oxidative or with alkalis, performed on concentrated systems and consisting of a mixture of different carbohydrates such as those present in commercial liquid glucose syrups.

The fact that uniform results are 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 surprising.

The use of commercial liquid glucose syrups as additives for mortars and concretes has been long known. It is also known that the use of these syrups involves serious drawbacks which severely limit their use. In particular, these syrups have a strong retarding effect on the setting of cement mixes (mortars and concretes). Furthermore. the action of the syrups with a high reducing sugar content is not uniform and is therefore unpredictable. It often happens that the quantity of additive correct for 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 I shows the results obtained with three types of commercial liquid glucose syrups having the different weight ratios of monosaccharides, disaccharides and polysaccharides. The disadvantages resulting from the use of these syrups are clear from the compression resistance values of specimens of plastic mortar mainly after 24 hours.

TABLE I

E Compressive strength E E Kg/cm2 after: Sample %, E Kg/cmZ after: Addition rate Plain - 0.5 90 274 Liquid glucose syrup with D.E. 1.5 0.5 98 68 269 43 - 45 Liquid glucose syrup with DE. 1.5 0.5 101 67 272 49 - 53 Liquid glucose syrup with D.E. .5 0.5 105 45 258 36 - 37 It is certain that the delay in setting of 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 proportional to the dextrose equivalent (E.D.) of the syrup. The retarding effect of commercial liquid glucose 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 Cl 91-77.

TABLE II

Addition rate %O Type of liquid on the weight of glucose syrup cement Initial setting time Hours Minutes Plain ~ 2 40 D.E. = 36 - 37 | 1.5%. | 5 35 DE, = 43 - 45 1.5%fl 7 5 DE. = 49 - 53 1.5%o 7 50 Table Ill shows the disadvantages deriving from the use of syrups with increasing E.D. values as additives for mortars and concretes.

TABLE Ill

EE' Compressive strength o E Kg/cmZ after: X n a) 3 Sample \ z wic 1 day 3 days Plain - 0.5 90 115 259 D.E. 36 - 38 1.5%o 0.5 96 58 253 D.E.43-45 1.5%o 0.5 95 56 249 D.E. 58 - 60 1.5%o 0.5 97 54 240 To reduce the delay in setting of cement mixes the use was suggested of starch hydrolyzate (or liquid glucose syrups) having a low E.D. value and a relatively high polysaccharide content (see Italian patent No. 745 936 and U.S. patent No. 3 432 317).It was nevertheless immediately apparent that these additive compositions still have a considerable retarding effect on the setting of cement mixes so that it was proposed to add water-soluble amines (from 0.002 to 0.10%) and chlorides (from 0.005 to 0.90%): see Italian patent No. 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 799 page 5 (3) lines 6-13). The suggested method of this patent application is, first, uneconomical because the polysaccharides containing in the beginning carboxylic groups such as pectin, alginates, gums, chitin, inoline and so forth are expensive and therefore cannot be used with advantage as starting materials in the preparation of additives for cement mixes.In the second place, the entire description fails to show clearly the method to be used for converting the high molecular weight polysaccharides into polysaccharides having carboxylic groups with a molecular weight between 400 and 4,000.

Apart from the fact that it is not possible to repeat experimentally what was described in the above patent application it must be observed that even the abovementioned additives (consisting, 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)).

The main purpose of the present invention is therefore to 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 maltodextrins into the salts of the corresponding aldonic acids and/or the salts of lower molecular weight carboxylic acids (C1-C4) without substantially modifying the polysaccharidic components (extent of polymerisation > 3) of malto-dextrins, or depolymerising only partially said polysaccharidic components, by the use of simple oxidisers such as, for example, hypohalogenite or ferricyanides or an aqueous alkaline solution, with conversion of reducing sugars equal to or greater than 95% and very high reproducibility 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. There is not need of further additives such as, for example, chlorides, alkanolamines, salts of alkaline metals and alkaline-earth metals.

According to the present invention a mixture ofaidonates of glucose, maltose and maltodextrins is prepared by the controlled degradation of a concentrated liquid glucose solution in homogeneous phase by treatment with an oxidising agent, preferably a hypohalogenite, and/or an aqueous alkali.

If oxidation is done with a hypohalogenite, in accordance with a preferred procedure for conducting the 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, is reached. Then the solution is heated to 4060 , preferably 43--47 OC. The required quantity of hypohalogenite, preferably hypochlorite (with 10-1 5% chlorine), is added in between 1 and 3 hours, preferably between 1 1- and 22 hours, maintaining pH constant within 10.5 points by adding aqueous alkalis, and then neutralising by adding acid.The course of the controlled degradation process of this invention can be readily followed by IR and NMR spectroscopy as explained below.

According to a 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 1 1.5, preferably between 10.35 and 10.75 or between 11 and 1 1.5 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 60-800C, preferably 72-780C, maintaining temperature and pH within this range by heating or cooling and it necessary added aqueous alkalis for 50-1 20 minutes, preferably 55-80 minutes. The mixture is then neutralised with acid, preferably concentrated hydrochloric acid.The course of this alternative method of carrying out the process of this 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 (200C-300C) 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 of polymerisation between 1 and 10, on E.D. (equivalent dextrose) value above 30 and a maltose content above 10% (dry), preferably above 30%. For purposes of illustration a list is given below of several types of liquid glucose syrups in commerce whose chemical and physical properties are shown in Tables IV--IV: A) Liquid 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 B) Liquid 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, 8) 43 ZS, 9) 45 ZS, 10)43 ZF, 11)45ZN,12)43ZAL,13)45ZAL,14)43ADS,15)45ADS.

C) Liquid glucose syrups from FRAGD: GLOBE 10500. Oxidisers useful in the first of the alternative 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 hypochiorites are best. Other known oxidisers such as, for example, hydrogen peroxide, may be used but their practical use is limited by the high cost of the oxidiser. Among the alkaline agents useful in the second alternative form of the process of this invention may be mentioned in particular the aqueous solution of alkalis such as, for example, sodium hydroxide and potassium hydroxide.

TABLE IV PHYSICAL AND CHEMICAL CONSTANT OF LIQUID GLUCOSE SYRUPS SUPPLIED BY CARGILL (*)

Average Protein Colour composition Type of Water ASH % (Nx6.25) (% T of total Viscosity conversion D.E. T.S.% content % pH max max % SO2 ppm 390mm) solid % cps/ C 1. Acidic 36.0- 79.0- 21.0- 4.8- 0.4 0.08 max 40 min 80 D 16 () 80,000/30 39.0 80.0 20.0 5.2 M 12 11,000/40 Mt 10 4,000/50 P 62 1,600/60 800/70 2. Acidic 45.0- 81.0- 19.0- 5.0- 0.4 0.08 200- min 80 D 22 70,000/30 48.0 82.0 18.0 5.5 250 M 15 17,000/40 Mt 12 5,000/50 P 51 2,000/60 900/70 3. Acidic 58.0- 79.6- 20.4- 4.8- 0.5 0.08 max 20 min 80 D 29 14,000/30 and 61.0 80.6 18.4 5.2 M 43 3,500/40 enzymatic Mt 3 1,500/50 P 25 650/60 200/70 4. Acidic 60.0- 81.5- 18.5- 4.8- 0.5 0.08 max 20 min 80 D 39 27,000/30 and 83.0 82.5 17.5 5.4 M 32 9,000/40 enzymatic Mt 13 3,000/50 P 16 1,200/60 500/70 5. Acidic 62.0- 81.8- 18.2- 4.8- 0.5 0.08 250- min 80 D 38 32,000/30 and 65.0 83.0 17.0 5.4 350 M 33 6,000/40 enzymatic Mt 10 2,400/50 P 19 1,000/60 450/70 6. Acidic 39.5- 77.8- 22.2- 5.2- 0.4 0.08 20 min 80 D 18 30,000/30 42.5 78.8 21.2 5.6 M 14 7,000/40 Mt 12 2,300/50 P 56 1,100/60 500/70 TABLE IV (cont.) PHYSICAL AND CHEMICAL CONSTANT OF LIQUID GLUCOSE SYRUPS SUPPLIED BY CARGILL (*)

Average Protein Colour composition Type of Water ASH % (Nx6.25) (% T of total Viscosity conversion D.E. T.S. % content % pH max max % SO2 ppm 390mm) solid % cps/ C 7. Acidic 36.0- 78.0- 22.0- 4.8- 0.5 0.08 20 min 80 D 6 20,000/30 and 39.0 79.0 21.0 5.2 M 37 7,000/40 enzymatic Mt 11 3,000/50 P 46 1,500/60 700/70 * CARGILL B.V. Glucose Department, Lelyweg 31, 4612 PS BERGEN CP ZOOM Holland ) D = Dextrose M = Maltose MT = Maltotriose P = Polysaccharides TABLE V PHYSICAL AND CHEMICAL CONSTANTS OF LIQUID GLUCOSE SYRUPS SUPPLIED BY S.P.A.D. S.p.A. (*)

Type of conversion D.E. B.E.' BRIX % DX and Malt SO2 1) ACIDIC (Continue) 36-38 43 81#05 (14-16) (16-18) 50 ppm 2) " " " 45 81#1 " " " " " " 3) " " " " 45 " " " " " " 120-159 ppm 4) ,, ,, ,, ,, 43 81+05 5) " " " " 45 85#05 " " " " " " 6) " " 30 43 81#05 (12-13) (15-16) 50 ppm 7) ,, ,, 3638 46 87 " " " " | " 8) ACIDIC - enzymatic ,, ,, 43 81+05 ( 8-10) (25-30) 50 ppm 9) " " |" " | 45 | 85#05 | " " " " | " 10) ,, ,, ,, ,, 42 81#05 .. " .. .. 120-150 ppm 11) " " |" " | 45 | 85#1 | " " " " |80-100 ppm 12) ENZYMATIC 43-44 43 81#05 ( 4- 6) (50-60) 50 ppm 13) " " " 45 85#1 " " " " " " 14) ACIDIC-enzymatic 60#2 43 81#05 (25-28) (44-48) 50 ppm 15) " " " " 45 85#1 " " " " " " (*) S.P.A.D. S.p.A. = Society Piemontese Amidi e Derivati, Cassano Spinola, Alessandria.

TABLE VI PHYSICAL AND CHEMICAL CONSTANTS 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 - Density Kg/lt 1.422 - pH 5#0.5 - Colour light yellow Average composition of total solids: - Glucose 28 - Maltose 40 - Polysaccharides 32 (*) Fabbriche Riunite Amido Glucosio Destrina S.p.A., Milano.

The following examples illustrate the process of this invention.

EXAMPLE 1 To 30 g of glucose syrup with an E.D. value of 36-39, a 40% by weight aqueous solution of NaOH is added with constant agitation in a thermostat-controlled bath at 40 C + 50C until pH 9 is reached. During this period, which is approximately 5 minutes, the temperature of the solution rises to approximately 450C + 50C. Then, in a period of 2 hours, 50 mi of sodium hypochlorite solution (12% Cl) is added to the above solution while the pH is maintained nearly constant (9 + 0.5) by automatic addition of 40% by weight aqueous NaOH. 6-8 ml of NaOH solution in all are required. At the end of the reaction the temperature of the solution is approximately 430C. The reaction mixture is neutralised by adding 37% HCI. The final volume of the neutralised reaction solution is 85 ml.An iR and NMR spectroscopic check of the reaction solution shows that practically total conversion of the reducing sugars has been achieved (see Figure 1 a and Figure 2b).

-EXAMPLE 2 Example 1 is repeated using a syrup with an E.D. value of 43-45 instead of 36-39. The results obtained are practically equivalent to those of Example 1.

EXAMPLE 3 Example 1 is repeated using a glucose syrup with an E.D. value 58-60. The results obtained are practically equivalent to those of Example 1.

EXAMPLE 4 To 30 g of glucose syrup with E.D. 36-39, 70 ml of water and sufficient 40% by weight NaOH solution are added to bring the solution to pH 10.5. After holding the solution for about 1 hour at 750C, the mixture is cooled and neutralised with 37% hydrochloric acid.

An NMR spectroscopic check of the reaction solution (Figure 2c) shows that practically total conversion of the reducing sugars is achieved, indicating that the reaction mixture contains, in addition to the undegraded polysaccharides, the sodium salts of the carboxylic acids: formic, acetic, saccharinic and/or arabonic.

EXAMPLE 5 Example 4 is repeated except that the pH value of the reaction mixture is 1 1.25 instead of 10.5.

An NMR spectroscopic check of the reaction solution (Figure 2d) shows that practically total conversion of the reducing 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 Example 4 is repeated using a syrup with an E.D. value of 43-45. The results obtained are practically equivalent to those of Example 4.

EXAMPLE 7 Example 5 is repeated using a syrup with an E.D. value of 43-45. The results obtained are practically equivalent to those of Example 5.

EXAMPLE 8 Example 4 is repeated using a syrup with an E.D. value of 58-60. The results obtained are practically equivalent to those of Example 4.

EXAMPLE 9 Example 5 is repeated using a syrup with an E.D. value of 58-60. The results obtained are practically equivalent to those of Example 5.

IR spectroscopic examination of the aldonates produced by oxidation of the glucose syrups with hypohalogenites is based on the principle that the absorption of the carboxylate band at 1,598 cm-t is directly proportional to the concentration of the aldonate groups. Analysis is made in a D20 solution using sodium gluconate for reference in accordance with the following experimental procedure. 10 ml of the reaction solution are diluted with 50 ml of water. 2 ml of this solution (containing approximately 50 mg of carbohydrate) are evaporated to dryness in a rotary evaporator. The residue is dissolved in 2 ml of D20 (99.7%).The IR spectrum of the solution is then recorded in the 1,800-1,400 cm-1 region in a 0.050 mm CaF2 cell using as reference a similar cell filled with D20 in the reference beam.

The apparent aldonate content of the solution is calculated from the absorbance at 1,598 cm-' (line-base technique) with reference to a calibration curve obtained with sodium gluconate (1.0 to 4.0% by weight in D2O).

The true aldonate content is obtained taking into account the interference from the sodium formate determined with the NMR method (see below) and with reference to a calibration curve obtained with sodium formate in D20 (0.10.5%). As shown in Figure 1, the glucose (a) and the malto-dextrine (c) do not interfere with the analysis, especially if the absorbance values both in the calibration measurements and the analytical measurements are made with a base line drawn between the highest transmittance points on both sides of the analytical band.

Nuclear magnetic resonance (NMR) analysis of the oxidised glucose syrups is based on the following principle. The magnetic proton resonance spectra (1H-NMR) of the malto-dextrines in a D20 solution show the characteristic signals attributable to the anomeric protons (H-i) both of the reducing and the nonreducing groups.

Elimination of the reducing groups by oxidation with hypohalogenites or by alkaline degradation involves a substantial increase in the intensity ratio of nonreducing to reducing signals.

In addition, the characteristic signals of the products of oxidation or degradation (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. Figure 2a shows the spectrum of an unmodified glucose syrup. The doublets at 4.66 and 5.24 ppm (6 from the TSP internal reference standard) are due to H-1 of the reducing groups, respectively in the P and a configurations. The doublet at 5.36 a is due to H-1 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 5.24 â have practically disappeared; the signal at 4.22 S is due to Ha of aldonic acids; the doublet at 5.23 os is the signal of H-l of the nonreducing group of the aldobionic acid; the singlet at 8.48 a is due to the formic acid. Figure 2c shows the spectrum of the same syrup after treatment with NaOH as described in Example 4 with pH 10.5; Figure 2d shows the spectrum of the same syrup after treatment with NaOH as described in Example 5 with pH 1 1.25.

The analytical peaks are at 1.93 S for the acetic acid, at 1.39 a for the lactic acid, and at 8.48 a for the formic acid.

The experimental procedure followed is the following: 2 ml of reaction mixture are evaporated to dryness in a rotating evaporator and redissolved in approximately 2 ml of D2 (99.7%) and again evaporated. This procedure is repeated two more times for the purpose of exchanging 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 D2O (99.7%) containing 3% by weight of TSP as internal standard for anchoring the frequency to the magnetic field and 2% by weight of sodium terephthalate as internal quantitative standard.

The 'H--NMR spectrum of the solution is recorded at surrounding temperature in a spectrometer at 90 MHZ and the signals of interest are integrated. The areas of the analytical peaks are normally calculated by dividing their value by that of the sodium terephthalate signals and the concentration of each carboxylate type is calculated with reference to calibration curves obtained using solutions of 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 with cement mixes containing as an additive unmodified liquid 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 .5%o. But the amount of additive in accordance with this invention may vary within relativeiy broad limits depending on the type of cement to be used, surrounding conditions, and the result it is desired to reach. Ordinarily the useful amount is between 0.1 5%O and 4%O by weight of the cement.

TABLE VII

É Compressive Strength . > E Kg/cm' after: Sample " 2 w/c 8 1 day 3 days 7 days 28 days EL Plain - 0.5 88 115 266 362 465 DE. 43-49 1.5%o ,, 100 57 258 395 511 (unmodified) D.E.36-38 " " 101 57 262 412 528 (unmod if ied) D.E. 58-60 ,, ,, 99 52 253 389 506 (unmodif led) D.E. 36-37 , ,, 102 42 258 408 535 (unmodified) D.E. 49-53 ,, ,, 100 62 261 401 521 I (unmodified) TABLE VIII

Compressive Strength Sampl o E Kg/cm2 after: Sample 1 ~ 3 days ca ~ ~ ~ Plain - 0.5 89 118 274 363 463 D.E. 43-49 OX Example 2 1.5%o 0.5 97 147 299 409 537 D.E. 36-38 OX Example 1 ,, 0.5 98 148 297 415 552 D.E. 58-60 OX Example 3 " 0.5 97 145 296 402 523 D.E. 36-37 OX Example 1 ,, 0.5 97 137 285 421 558 D.E. 49-53 OX " 0.5 98 129 301 409 543 TABLE IX

s E Compressive strength E .~ B Kg/cm2 after: 08 S Sample \ ' w/c EL 1 day 3 days 7 days 28 days Plain - 0.5 92 109 245 355 459 D.E.49-53 1.5%, ,, 94 55 216 395 519 (unmodified) D.E. 36-37 " " 97 40 240 408 533 (unmodified) D.E. 58-60 " " 97 48 235 235 498 (unmodified) D.E. 37-38 77 " 96 54 236 409 525 (unmodified) D.E. 43-45 .7 " 95 58 250 402 501 (unmodified) D.E. 49-53 (OX) .. ,, 96 99 261 418 531 D.E 36-37 (OX) " " 92 93 271 419 543 Example 4 D.E. 58-60 (OX) " " 98 99 268 403 508 Example 8 D.E. 36-38 (OX) ,, " 94 101 264 412 539 Example 4 D.E. 43-45 (OX) " " 94 106 280 406 512 Example 7 TABLE X

Slump Compressive strength Type of Addition rate value Curing Kg/cm after: cement s/s w/c cm. conidtions 1 day 3 days 7 days 28 days Portland cement Plain 0.59 5 T 21 C U.R. > 90% 70 171 206 303 D.E. 49-53 0.555 4.5 51 188 235 335 1.5%# (unmodified) D.E. 36-37 55 185 261 246 1.5%# (unmodified) D.E. 58-60 52 179 270 335 1.5%# (unmodified) D.E. 36-38 " 77 77 49 184 268 330 1.5%o (unmodified) D.E. 43-45 55 178 273 351 1.5%# (unmodified) D.E. 49-53 78 197 267 352 1.5%# D.E. 76-37 68 200 275 344 " " " " 1.5%# OX Example 1 D.E. 59-60 75 203 282 358 " " " 1.5%# OX Example 3 D.E. 36-38 |" |" " | | 80 | 208 | 271 | 360 1.5%o OX Example 1 D.E. 43-45 77 210 280 352 " " " 1.5%# OX Example 2 For all practical tests with plastic mortar UNI provisions were followed (para. 2 sec. 1 art. 101) included in D.M. dated 3 June 1968 (Gazz.Uff. No. 180 dated 1 7/7/1968). The cement used was a Portland cement with the following mineralogical composition according to Bogue: CS 46%; C2S 27.6%; C3A 7.4%; C4AF 7.4%; CaSO4 5% ground to a fineness of 3500 cm2/g Blaine.

TABLE XI

Slump| Compressive Strenght Addition value Kg/cm2 after: Sample rate w/c cm. 1 day 3 days 7 days 28 days Plain - 0.51 10 85 183 218 331 D.E. 36-37 unmodified 1.5%# 0.478 9 58 198 251 363 D.E. 58-60 unmodified ., " 9 53 178 244 349 D.E. 43-45 unmodified " " 8 60 182 250 359 D.E. 36-37 OX Example " .. 9 93 215 288 389 D.E. 58-60 OX Example 3 ., " 11 88 211 279 380 D.E. 43-45 OX Example 2 " " 10 95 223 296 392 TABLE XII

Slump Compressive strenght Addition value Kg/cm after: Sample rate w/c cm. 3 days 7 days 28 days Plain - 0.733 12 95 143 258 D.E. 36-37 unmodified 1.5%# 0.702 11 97 161 279 D.E. 58-60 unmodified " " 12 84 157 267 D.E. 43-45 unmodified " " 11 99 159 283 D.E. 36-37 OX Example 1 " 0.702 13 121 178 297 D.E. 58-60 OX Example 3 " " 10 104 171 293 D.E. 43-45 OX Example 2 " " 12 118 187 301 TABLE XIII

Slump Compressive strength Addition value Kg/cm2 after: Sample rate w/c cm. 3 days 7 days 28 days Plain - 0.676 8 80 140 227 D.E. 36-37 unmodified 1.5%O 0.648 8 87 168 259 D.E. 58-60 unmodified " ,. 8 80 154 263 D.E. 43-45 unmodified ,. . " 9 91 166 248 D.E. 36-37 OX Example 1 " " 8 105 198 295 D.E. 58-60 OX Example 3 " | 0.648 9 100 186 283 D.E. 43-45 OX Example 2 ,. ., 9 108 197 299 For all the practical tests on concrete were used cements of the Portland and Pozzolanic types in an amount between 380 and 400 kg/m3.

The aggregate used in these tests was distributed according to the Fuller method and showed the following proportions: DIAMETER % BY WEIGHT mm 25-10 33 10- 7 10 7- 3 22 3- 0 35

Claims

1. A process for the preparation of a mixture of aldonates of glucose, maltose and maltodextrines which comprises treating a conncentrated liquid glucose solution in homogeneous phase with an oxidizing agent and/or an alkali.

2. A process according to claim 1 in which a liquid glucose syrup having an E.D. > 30 and a maltose content > 10% (dry) is treated with an aqueous alkaline solution until the pH is between 7.5 and 10 after which the solution is heated to 4O-600C and the hypohalogenite is added in a period of 1 to 3 hours while the pH is held constant within + 0.5 points, and the solution is then neutralized with acid.

3. A process according to claim 1 in which a liquid glucose syrup having an E.D. > 30 and a maltose content > 10% (dry) is treated with an aqueous alkaline solution until the pH is between 8.5 and 1 1.5, the solution is then heated to 60-80 C. and the temperature and pH are maintained at the above values for 50-120 minutes, after which the mixture is neutralized with acid.

4. Process according to claim 2 in which the aqueous alkaline solution is a concentrated solution of sodium hydroxide.

5. Process according to claim 2 or 4 in which the liquid glucose syrup is alkalized until a pH between 8.5 and 9.5 is reached.

6. Process according to any one of claims 2, 4 or 5 in which the solution of alkalized liquid glucose syrup is heated to a temperature between 43 and 470C.

7. Process according to any one of claims 2, 4, 5 or 6 in which the hypohalogenite is hypochlorite containing 1 0-1 5% chlorine.

8. Process according to any one of claims 2, 4, 5, 6 or 7 in which the hypohalogenite is added in a period between 1 hour 30 minutes and 2 hours 30 minutes.

9. Process according to claim 3 in which the liquid glucose syrup is alkalized until a pH between 10.25 and 10.75 is reached.

10. Process according to claim 3 in which the liquid glucose syrup is alkalized until a pH between 11.00 and 1 1.50 is reached.

11. Process according to claim 9 or 10 in which the alkalized solution is heated to a temperature between 72 and 780C.

12. Process according to any one of claims 3, 9, 10 or 11 in which the liquid glucose solution is held at the established pH and temperature for a period of 55 to 80 minutes.

1 3. Process according to any one of claims 1 to 12 in which the liquid glucose syrup is first subjected to partial hydrolysis of the maltose and the maltodextrines contained therein by treatment with an alkali at a temperature between 20 and 3O0C.

14. Process according to claim 1 substantially as described in any one of Examples 1 to 9.

1 5. Mixture of aldonates of glucose, maltose and maltodextrines obtained with the process of any of claims 1 to 14.

1 6. Additives for mortars and concretes comprising a mixture of aldonates of glucose, maltose and maltodextrines according to claim

1 5.

1 7. Mortar or concrete containing 0.1 5 SOo to 4%O by weight of the cement of a mixture of aldonates of glucose, maltose and maltodextrines according to claim 1 5.