FR2541990A1 - POLYSACCHARIDES ALKYLSULFONES, MIXTURES OF MORTAR AND CONCRETE CONTAINING THE SAME, AND PROCESS FOR INCREASING THEIR FLOW SUFFICIENCY - Google Patents

Abstract

THE INVENTION RELATES TO A SUPERFLUIDIFYING AGENT FOR MORTAR OR CONCRETE. ACCORDING TO THE INVENTION, IT INCLUDES AN ALKYLSULFON POLYSACCHARIDE HAVING A DEGREE OF POLYMERIZATION OF UP TO 100 AND A DEGREE OF SULFONATION OF 0.2 TO 3.0; THE ATTACHED DRAWING GIVES THE NUCLEAR MAGNETIC RESONANCE SPECTRUM CORRESPONDING TO A TYPICAL WATER-SOLUBLE STARCH AND ITS SULFOETHYL DERIVATIVE OR ITS SULFOPROPYL DERIVATIVE. THE INVENTION APPLIES IN PARTICULAR TO CONSTRUCTION.

Description

The present invention relates to improvements

  has mixtures of mortar and concrete.

  More particularly, the improvement of the present invention consists in mixing mortar or concrete with a small amount of a fludifying agent such as alkylsulphonated polysaccharides. More particularly, the present invention is to improve the workability of mortar and concrete mixes to enable very low water / cement ratios. Mortar and concrete mixes are mixtures of a cementitious material and aggregates defined in the following. specifications

ASTM C 270 and C 125 respectively.

  It is known that in mortar and concrete mixtures, the initial weight ratio of water to cement, more commonly referred to as W / C ratio, is an important factor that regulates

  the workability of the cement mixture.

  The amount of water required for practical workability is much greater than would be required for full hydration of the hydraulic binder used to produce

The mixture.

  Excess water, especially in the case of high workability, can lead to serious handicaps both to the fresh mixture (segregation, excessive bleeding and others) and to the hardened mixture (excessive shrinkage, strong

  porosity, lower strength, and others).

  In order to obtain good workability of mortar and concrete mixtures at lower W / C ratios, particular materials have long been proposed,

  and a number of them have reached an important

commercial activity.

  Usually, such materials are referred to as fluidizing agents. More particularly, according to Italian standards for material testing (UNI), these materials are grouped in two classes, ie the fluidifying agents and the superfluidifying agents. The agent allows, in standard plastic mortars, a water reduction of not less than 6% (i.e.

V-

  lb VR VA 6% where V is the volume of water of the VR reference mixture and VA is the volume of water, including the fluidizing agent, of the mixture containing the fluidizing agent), then according to UNI 7102-72 the material is defined as a fluidifying agent. If, on the other hand, this material allows a water reduction of not less than 10% (ie VR VA R 9 10% o VR is the volume

VR R

  VR of water of the reference mixture and VA is the volume of water, including the fluidizing agent, of the mixture containing the fluidizing agent), then according to the UNI 8145 standard, the material is defined as a superfluidifying agent The fluidifying agents and superfluidifiers as defined above meet the conditions of concrete mixtures of types A and F

  specified in ASTM C 494-80.

  The known useful fluidifying agents are the

  lignin-sulfonates, gluconates and tannates.

  Some known industrial carbohydrates such as glucose syrups (see US Pat. No. 3,432,317) and modified starch hydrolysates (see Italian Patent Application No. 21680 A / 80 filed April 28, 1980) are commonly used in mixtures

  of cement both to improve the rhoological properties of

  blends as well as to improve their mechanical strength Their capacity for water reduction is, however, very limited and much lower than that of

superfluidifying agents.

  Industrially, the use of superflowing agents has only been important for

  have been in the last five years.

  The known superfluidifying agents are formed from polynaphthalene sulfonates (see, for example, US Patent No. 2,141,569, German Patent Application No. 1,238,831, Canadian Patent No. 993,901) and melamine resins.

  sulfonated (see for example Italian Patent No. 801,078).

  It has now been found that by sulfonating polysacchar -

  wrinkles with appropriate sulphonating agents, excellent superfluidifying agents with

  superior properties to all fluidic agents

known and superfluidifiers.

  The alkylsulphonated polysaccharide superfluidizing agents according to the invention are characterized by a degree of polymerization (DP) of up to 100, a degree of sulfonation (DS) as defined and determined herein, of between 0.2 and 3.0. more to be characterized by their fluidifying activity by the fact

  that the addition of 0.4% of the fluidising agent according to the

  vention may impart to the mortar to which it is added a flow increase of 6.5% to 130% if the value

  of D S is between 0.20 inclusive and 1.50 inclusive.

  Examples of polysaccharides useful for producing the superfluidifying agents according to the invention are, for example, cellulose, hemicellulose, starches and their hydrolysates. Examples of sulphonating agents for producing the superfluidifying agents according to the invention are, for example, chloromethylsulfonic acid, chloroethane sulfonic acid

  chloropropane sulfonic acid and 1,3 propane sultone.

  The preferred superfluidifying agents according to the invention are those produced from hydrolysed cellulose sulphonated with

  chloromethane or chloroethane sulfonic acid.

  The superfluidifying agents produced from

  molasses sulphonated with chloropropane

  and sulphonated starches with chloroethane or chloropropane sulphonic acid are

even better preferred.

  Currently, the most preferred superfluidifying agents according to the invention are those obtained from hydrolysates of water-soluble starch having a degree of polymerization equal to or lower than 100 and the acid

  chloroethanesulfonic acid as a sulfonating agent.

  It would seem that the fluidizing activity of the agents according to the invention is a function of the starting polysaccharides and the sulphonating agents used. This finding is supported by the data indicated in the following table.

TABLE 1

FLOW TESTING

FLOW

  : Thinner: Doses (b) (M refers to the product: single: 1) sulfopropylate: 0.6: + 12:: hemicellulose (a): 1.5: + 24:: 2) sulfopropylate: 0.3 : + 24:: starch (a): 0.5: + 35:: solfoethylate: 0.3: + 24:: soluble starch (a): 0.5: + 50:

  (a) prepared as in Examples 1, 2 and 3 respectively.

  (b) the doses are expressed as a percentage (dry to dry)

  the amount of cement in the mixture.

  As can be seen in Table 1, the fluidifying agents produced from starches soluble in water with a degree of polymerization up to and chloroethane sulfonic acid give the best results, never achieved before with any fluidifying agent. or superfluidifying agent The flow tests of Table 1 were made with plastic mortars according to the Italian standard UNI 8020, using Pt 325 cement (which is commonly used

in industry).

  The sulphonate groups of the fluidizing agents according to the invention can be either in the form of the acid

  free or they can be salified with a cation-

  of a Group IA and IIA metal, preferably sodium, potassium or calcium Other useful cations may be

  be chosen from ammonium or organic amines.

  When the cation is derived from an organic amine, the amine may be any suitable primary, secondary or tertiary amine such as, for example, hydroxyl group-containing amines. Primary, secondary alcohols

and tertiary are preferred.

  The superfluidifying agents according to the invention are

  easy to prepare by known methods.

  The following examples illustrate the super agents

  fluidifiers according to the invention, their method of preparation and their use in mortar mixtures

and concrete.

EXAMPLE 1

  Sulfopropylate of hemicellulose 100 g of a hemicellulose slightly soluble in water at room temperature, in suspension

  in 300 ml of water containing 75 g NaOH, 450 g of 1,3 propane-

  sultone and reacted for 16 hours at 50 ° C. with stirring.

254199 '0

  The reaction mixture is then allowed to stand for 48 hours at ambient temperature. The pH is then adjusted to 4 with sodium hydroxide and the product mentioned in FIG.

  Title is precipitated with methyl alcohol.

  The yield is 80% of the theory

substitution is 0.9.

Example 2

  Starch sulphate starch not soluble in water at room temperature in suspension in 250 ml of water containing 60 g of NaOH are added 350 g of 1,3 propane-sultone

  and reacted for 16 hours at 500 ° C with stirring.

  The reaction mixture is then allowed to stand for 48 hours at room temperature and the pH is adjusted to 4 with 2N NaOH. Finally, the title product is separated from the reaction mixture by precipitation with a mixture of 2.5: 1.5 of methanol / acetone, then this product is dissolved in water and dialyzed through a

  cellulose acetate membrane Dalton 3500.

  The yield is 45% of theory The degree

substitution is 1.1.

EXAMPLE 3

  Starch sulphoethylate soluble in water.

  1 g of starch, easily soluble in water at room temperature in suspension in 1000 ml of isopropyl alcohol, are added with 175 g of the sodium salt of 2-chloroethanesulphonic acid and a solution of 95 g of Na is reacted. In 100 ml of water, with stirring, for 15 min at 30 ° C. and then for 60 min at 80 ° C.

  The reaction is interrupted by cooling at the temperature

room temperature.

  After neutralization with acetic acid, the water phase is dialyzed through an acetate membrane.

Dalton cellulose 3500.

  The yield is 80% of theory The degree of

substitution is 0.6.

  As already indicated above, the fluidizing activity of the agents according to the invention seems to be a function of the starting polysaccharides and the agent

sulfonant used.

  It seems further that such activity also depends on the degree of sulfonation, i.e., the average number of alkyl sulfonic groups per repeating unit of

the polysaccharide chain.

  It was found that 0.2 was the minimum degree of sulpho

  nation needed to improve the fluidizing activity

  polysaccharide used according to the present invention.

  It has further been determined that in order to obtain a fluidizing agent having a remarkable activity (for example an activity greater than what is considered normal in the art), the degree of sulfonation

had to exceed

  The degree of sulfonation (also referred to herein as D S) of the sulfoalkyl polysaccharides tested according to the invention was determined by magnetic resonance spectroscopy.

nuclear 1 H RNM) -.

  The nuclear magnetic resonance spectra shown in FIG. 1 correspond to a typical water-soluble starch (a) and its sulfoethyl derivative (DS-0.5) (b) as well as to its sulfopropyl derivative (DSN 1 1) (c) The asteri identify signals corresponding to the CH 2 groups of the sulphoethyl and sulphopropyl substituents. These signals make it possible to determine the degree of sulphonation by relating their surface to that of the anomeric signals.

(H-1).

  Table 2 below shows the dependencies between

  the fluidifying activity and the degree of sulphonation.

Table 2

EFFECT OF DEGREE OF SULFONATION

  ::: Increase over:: D S: Flow (mm): to single product (mm):: Single: 72: =:

: 0.00 *: 70: 2:

: 0.20: 77 + 5

: 0.80 89 m + 17:

: 1,10: 139: + 67:

: 1.35: 151: + 79:

: 1.50: 165: + 93:

  * This corresponds to the raw material, that is starch

  soluble in unsubstituted or non-sulfoalkylated water.

  The sulfonated derivatives in Table 2 were prepared by subjecting a commercially available water soluble starch having a degree of polymerization of 80 to sulfonation with the sodium salt of chloroethylsulfonic acid according to US Pat.

method described in Example 3.

  The flow tests are performed with plastic mortars according to the Italian standard UNI 8020 and using a Pt 325 cement; the amount of the agent

  added plasticizer being 0.4% of the weight of the cement.

  The data in Table 2 show that the addition of 0.4% of a soluble starch in non-sulfoalkylated water to a mortar causes a slight decrease in the flowability of this mortar compared to the single product.

(or mortar not added).

  The fluidizing effect becomes remarkable after addition of a quantity of 0.4% of a superfluidifying agent according to

  the invention having a value of D S of 0.20 The effect of

  However, it is of little interest from a point of view.

industrial view.

  A fluidifying effect in the range of those obtainable with known fluidizing agents is obtained by adding 0.4% of a superfluidifier according to the invention, having

a value of D S of 0.80%.

  With the addition of 0.4% of a superfluidifying agent according to the invention having a DS value of 1.10, the fluidifying effect achieved is of the order of those which can be obtained with an equal quantity of agents. superfluidifiers marketed. Finally, the addition of 0.4% of a superfluidifying agent according to the invention, having a DS value of at least 1.35, gives a remarkable fluidifying effect, that is to say, much greater than fluidizing effect obtainable with

  an equal amount of any known superfluidifying agent.

  The possibility of thinning the mixture of mortar and concrete depends not only on the degree of sulphonation but also on the amount of the liquefying agent that is added thereto and it is even lower than the degree of

sulfonation is higher.

  According to the present invention, interesting results (with respect to the flowability are obtained with doses of between 0.1% and 0.4% (of the weight of the hydraulic binder) and higher values of the DS '. is to say

greater than 1.0.

  To obtain results of the same order of magnitude using fluidizing agents having an average degree of sulfonation, that is to say with D S values between 0.8 and 1.2, the dose of the fluidifying agent

  must be between 0.2% and 0.6%.

  When using fluidifiers having a low degree of sulfonation, for example having D S values between about 0.2 and 0.5,

  doses above 0.6% are required.

  In particular, when using starches

  water-soluble sulfoethyls (having a degree of polymerisation

254199 '

  <100), it has been found that with doses of 0.35% 0.55% (of the weight of the hydraulic binder) and a value of DS of the order of 0.8, the flowability Mortar and concrete mix were of the same order of magnitude as can be achieved using known fluidizers. When the value of D S of said starches is of the order of 1, then the flowability of the mortar and the concrete mixture is equivalent to that of a mortar and a mortar.

  concrete mixture having a known superfluidifying agent.

  Finally, using a sulfoethylated starch according to the invention having a DS value of the order of 1.3, the flowability of the mortar and of the concrete mixture containing it is greater than that obtained with any superfluidifying agent. known. Table 3 below shows the results that can be obtained with a commercialized soluble starch having a degree of polymerization of <100, at increased values of DOS, in comparison with the fluidizing agents according to the prior art.

TABLE 3

  COMPARISON OF SUPERFLUIDIFYING AGENTS ACCORDING TO

  INVENTION WITH FLUIDIFYING AGENTS AND

  KNOWN COMMERCIALIZED SUPERFLUIDIFIERS.

  FLUIDIFYING AGENT: FLOW: RESISTANCE TO

  : (mm) COMPRESSION at 7 DAYS *:: (10 Pa): Value referred to: Value referred to: 1 Sulfoethylate ba blproduced: t absodu it:: soluble starch asuesiabsoluepodue: in commercial water: (According to the invention :::: tion) DS 0,8: 89: + 17: 28,6: + 6,5:: 2 Crude liquor :::::: lignosulfonate :::::: calcium: 85 + 13: 25.5: + 3.3: 3 Mother liquor of :::::: sodium gluconate: 90: + 18: 24,8: + 2,6 ::: 4 Sulfoethylate ::: ::: soluble starch in :::::: marketed water :::::: (according to the invention) :::

: D.S. 1, O: 129: + 47: 2.35: + 6.2:

  : 5.Polynapthalene :::::: Sodium sulfonate: 120: + 38: 2-, 5 + 5.3

: 5.3:

  : 6 Melamine resin ::::: sulf Day: 115 + 33: 28.9: + 6.8: 7 Sulfoethylate :::::: soluble starch in :::::: marketed water :: :::: (according to the invention) 3 :: :::

: D.S. = 1130: 159: + 67: 26.2 + 4

  The following Table 4 shows the superior reduction in water demand that is obtained with commercialized water-soluble starch having a degree of polymerization and a DS value of 1.25, as compared to an commercialized superfluidifier known (polynaphthalene sulfonate).

TABLE 4

  : FLUIDIFYING AGENT: ml: W / C: ECOULE-: RESISTANCE:

: water:: MENT: AT THE COMPRES-

:::: SO, 7:

: SION A 7 6

  At :::: DAYS (10 P a: Single product: 225: 0 5: 85: 25.5:: Starch sulfoalkyl 6: 194: 0 43: 86: 35.1: Naphthalene sulfonate: 200: 0 44: 86: 33.55 According to the Italian standard UNI 8145, the reduction of water, as defined below, obtained with sulfoalkyl starch:

100 225-194 = 14%

  is superior to the water reduction obtainable with known superfluidifying agent (polynaphthalene sulfonate):

225-200 _ 11%.

225

  The tests summarized in Tables 3 and 4 are carried out with plastic mortar according to UNI 8020 standard using a

commercial cement Pt 325.

  The amount of the blowing agent that is added to the mixture is the same for all the samples, that is to say

  0.40% (referring to the weight of the hydraulic binder).

  Table 5 below shows the data obtained with concrete tests carried out according to Italian standards.

  (UNI 7163), using commercial Pt 425 cement.

TABLE 5

  : CEMENT TYPE: DOSE OF: W / C: VALUE: RESISTANCE TO:

:: CEMENT:: OF AFFAISCOMPRESSION:

  : kg / m 3:: SEMENT: (106 Pa): :::: (cm) ::: 425 Portland: 350: 0,55: 8: 3 days 7 days 28 jors:: same + polynaph :: : 22.633 39.2:: talenesulfonate: 350: 0.44: 8:38 44 57.9:: same + starch 350: 0.44: 10: 36.1 45, 1 59.35:: sulfoalkylated :: The alkylsulphonated polysaccharides according to the invention are

  useful for producing mixtures of mortar and concrete con-

  holding any type of hydraulic binder such as Portland cement and mixed cements (Portland-Blast Furnace Cement, Portland-Pouzzlane Cement or Fly Ash Cement, Slag Cement) The mortar or concrete mixture according to the invention may contain other additives such as hardeners, air entraining agents, plasticizers, accelerators and known retarders. It is convenient to note that the hydraulic binders used to produce the mortar and concrete mixtures according to the invention may already contain additives used in the clinker grinding process and / or in the process

  manufacturing of hydraulic binder.

  The superfluidifying agents according to the invention can be incorporated in the mixture of mortar and concrete by any practical method. Thus, they can be added directly to the mixture, advantageously in the form of a solution in water. Alternatively, the fluidizing agents according to the invention may be premixed with one or more of the ingredients of the mixture. If premixed with cement, the fluidifying agent

  must necessarily be in the dry state.

  The fluidizing agents according to the invention can

  also be added to the clinker during grinding.

  In this case, they can be mixed with known grinding auxiliaries such as, for example, alkanolamines and glycols. Although the present invention is advantageously applied to the production of any kind of mortar and concrete, it is particularly directed towards the field. additives that improve the workability of concrete used in civil buildings or public works constructions (such as bridges or roads) and for

manufacture of precast concrete.

i

Z 541990

Claims (10)

CLAIMS V E N D I C A T I 0 N S   1 superfluidifying agent for mortar or concrete   characterized in that it comprises an alkyl polysaccharide   sulphonated having a degree of polymerization which can reach   and a degree of sulfonation of between 0.2 and 3.0.   Agent according to claim 1 characterized in that   that the degree of sulfonation is between 0.2 and 1.5.   Agent according to Claim 1, characterized in that the alkylsulphonated polysaccharide is an alkylsulfone cellulose, a hemicellulose, hydrolyzed cellulose or   molasses or starch.   Agent according to Claim 1, characterized in that the alkylsulphonated polysaccharide is an alkyl starch sulfonated soluble in water.   Agent according to Claim 4, characterized in that the water-soluble alkylsulfonated starch is prepared by a process comprising the alkylsulfonation of a starch   soluble in water with chloroethanesulphonic acid.   Agent according to claim 4 characterized in that   that the degree of sulfonation is about 1.3 or more.   A hydraulic cement composition characterized by comprising a hydraulic cement binder and an alkylsulfonated polysaccharide having a degree of polymerization of up to 100 and a degree of sulfonation of 0.2 to 3.0. 8 Composition according to Claim 7, characterized in that the alkylsulfonated polysaccharide is present in an amount of 0.1% and 0.4% of the binder product and the degree of sulfonation is greater than 1.0.   9 Composition according to Claim 7, characterized in that the alkylsulfonated polysaccharide is present in an amount of 0.2% to 0.6% of the weight of the binder and the degree of sulfonation is 0.8 to 1.2.   Composition according to Claim 7, characterized in that the alkylsulphonated polysaccharide is present in an amount greater than 0.6% by weight of the binder and the   degree of sulfonation is 0.2 to 0.5.   Composition according to Claim 7, characterized in that the alkylsulphonated polysaccharide is a starch alkylsulfone soluble in water.   Composition according to Claim 11, characterized in that the alkylsulphonated polysaccharide is a water-soluble sulphoethylated starch which is present in an amount of from 0 035% to 0.55% by weight of the hydraulic binder and the degree of sulphonation is 0.8 to about 1.3. Process for increasing the flowability of a mortar or concrete mixture containing a hydraulic cement binder characterized in that it comprises the steps of incorporating into said mixture from about 0.1% to about 1.0% by weight, based on the weight of said binder, of   superfluidifying agent according to any of the claims cations 1 or 2.   Process according to Claim 13, characterized in that the alkyl sulphonated polysaccharide is a water-soluble sulphoethyl starch which is incorporated in the mixture in an amount of from 0.35% to 0.55% of the weight of the binder and has a degree of   sulfonation from about 0.8 to about 1.3.