ITRM950541A1 - AERATION MIXTURE - Google Patents

Abstract

An aeration mixture suitable in particular for use with cementitious compositions which comprises ash with high levels of residual carbon (ignition loss over 5%), which includes an active surface agent based on fatty acid; and a non-ionic surface active agent, the fatty acid-based surface active agent (a) being selected from the C12-24alkanoic acids and their salts of alkali metals, lower alkylamines and lower alkanolamines, and the surface active agent nonionic (b) being chosen from the materials of the formula Ph (R) -O- (CH2 CH2O-) nH where Ph (R) represents a phenyl group substituted with R, being R C8-9alkyl and n is from 1 to 50. An additional useful component is a salt selected from the group formed by the alkylsulfonated salts, alkylaryl sulfonates, sulphate esters of high and resinated alcohols.

Description

DESCRIPTION of the industrial invention entitled: "Mixture of aeration"

This invention relates to the introduction of air into cementitious compositions and compositions for the introduction of air and their use.

Cementitious compositions such as those of concrete, mortar and grout must be aerated, for example, to improve workability or to impart improved freeze-thaw durability. This is commonly achieved by incorporating in the fluid composition a mixture by introduction of air (hereinafter "Blend AE"). The act of mixing the cement compositions causes bubbles; these are stabilized with the AE blend. The same materials are described in ASTM C 260 and the subject of aeration is covered extensively in the literature (see, for example, "Concrete Admixtures Handbook", ed. Ramachandran (Noyes 1984) the descriptions of which are incorporated by reference). Examples of AE blends include surfactants, high alcohol sulfate esters and alkylsulfonates.

Although known AE blends provide excellent performance with some of the known cementitious compositions, they are nevertheless not universally effective. An example of reduced effectiveness is the use in conjunction with cementitious compositions which include ash. Ash is a pulverized residue from industrial coal furnaces and is widely used in cementitious compositions, for example, as a permeability reducer. The problem with ash is that it contains residual amounts of carbon (sometimes referred to as "unburned coal") that survive the combustion processes. It has been found that this residual carbon has the ability to absorb AE blends and therefore decreases their effectiveness. The problem is made more complex by two factors, (i) coal can originate from a wide variety of areas, meaning that the residual carbon content can change from batch to batch, making it difficult to eliminate the problem; and (ii) environmental pressures forced coal to burn at lower temperatures, and thus creating more and more residual coal in the resulting ash. Attempts have been made to overcome this problem by developing particular AE agents. However, these AE blends have reduced air-in properties or need a large amount to achieve their effect, or both of these problems.

It has now been discovered that a particular blend of materials provides an AE blend that not only has excellent qualities for introducing air, but that relatively low dosages can be achieved, even in the presence of the ash with residual carbon. Furthermore, according to the invention, an air introduction mixture is provided which comprises:

a) a fatty acid-based surface active agent, e

b) a non-ionic surface active agent the fatty acid-based surface active agent (a) being selected from the C2-24alkanoic acids and their alkali metal salts, lower alkylamines and lower alkanolamines, and the surface active agent non-ionic (b) being selected from the materials of the formula

where Ph (R) represents a phenyl group substituted with R, being R, C8-9alkyl and n is from 1 to 50.

In a preferred embodiment of the invention, the air introduction mixture additionally comprises (c) a salt selected from the group formed by the salts of alkylsulfonates, alkylaryl sulfonates, higher alcohol sulfate esters and resins.

The fatty acid-based surface active agent (a) can be chosen from any of the substances known to the state of the art. The fatty acid chain in the surface active agent (a) can be saturated or unsaturated, straight chain or branched chain. The fatty acid-based surface active agent (a) can be fatty acids, or preferably, they can be the salts of such fatty acids, preferably the salts of alkali metals or amines. The preferred alkali metal salts are those of sodium and potassium, and the preferred amine salts are preferably those of low molecular weight alkylamines or alkanolamines, preferably those of triethylamine or triethanolamine. Preferred surface active agents (a) include tall oil fatty acid soap, oleic acid soap, linoleic acid soap and palm fatty acid soap, fatty acid soap being particularly desirable. say tall oil.

The nonionic surface active agent (b), as defined above, can be selected from any of such materials. The substituent R on a phenyl group can be straight-chain or branched-chain, and is preferably C8 or C9 alkyl. Specific examples include nonylphenyl polyoxyethylene ether and octyl phenyl polyoxyethylene ether. The number n of oxyethylene units per molecule is in the range of 1 to 50. The value of n has been found to have an effect on the ability of the AE blends of this invention to cause sufficient intake of air in the presence of ash with a high proportion of residual carbon. For use with such a material, blends AE preferably comprise a surface active agent (b) with 20 to 30 oxyethylene units per molecule.

The salts of component (c) of the AE mixture according to the invention can be selected from a large variety of suitable materials.

The alkyl radicals of alkyl sulfonate and the aryl alkyl sulfonate are typically C9-C12 and can be straight-chain or branched-chain. The salts are preferably alkali metal salts, in particular sodium and potassium, or triethanolamine salts. Specific types include α-olefin sulfonates, benzene alkyl sulfonates and alkyl sulfates. Regarding the sulfates of high alcohols, the alcohols should have at least 12 carbon atoms. Ethylene oxide additives of such alcohols are also used, and typical examples include ether alkyl polyoxyethylene sulfates and ether phenyl alkyl polyoxyethylene sulfates. Typical resins include rosin soap obtained by saponification of pine resin with sodium hydroxide or potassium hydroxide, and the sodium, potassium, triethanolamine salts of abietic acid.

The weight ratios of the individual components are 10 to 90%, preferably 10 to 80% (based on the active material), of the surface active agent (a), 90 to 10% of the surface active agent non ionic (b) and not more than 20% of component (c) when this material is present. The mixture is used at a ratio of 0.001 to 0.1% by weight of the active ingredients with the weight of the cement plus the AE mixture. AE blends are generally used in the form of an aqueous solution. They can be used, together with other known state-of-the-art blends, such as water reducing agents, AE water reducing agents, high-end water reducing agents, high-end AE water reducing agents. range, fluidizers, waterproofing agents, anti-rust agents and shrink reduction agents.

The AE mixture according to the invention is useful for aerating the cementitious compositions. It is particularly useful when used in such compositions which include residual carbon material. It has been held, without limiting the invention in any sense, that the residual carbon conventionally absorbs the AE blends. Problems caused by materials such as ash are reported in JIS (Japanese Industry Standard) A 6201, which specifies that ash with a loss of more than 5% on ignition should not be used. Therefore, the AE blends of the present invention can be used with ashes with ignition losses of more than 5%. The invention also provides a process for preparing an ash-containing aerated cement composition, using an ash that has an ignition loss of more than 5%, including adding to the cement compositions that include ash a mixture for the introduction of air as described here. Further, the invention provides an aerated ash cement composition in which the ash has an ignition loss of more than 5%, comprising the composition an air intake mixture as described herein.

Furthermore, the invention is illustrated with the following examples.

Example 1

1) Test method

a) Concrete mixing method Fine aggregate, cement, and mixing water (comprising water reducing agent AE and the mixture AE according to the invention) are introduced into a mixer and mixing is carried out for 30 seconds. Crude aggregate is then introduced and mixing is continued for 90 seconds.

b) Changes in concrete as a function of time After measuring the consistency (JIS A 1101) and the air content (JIS A 1128) of the mix of the mix, the mix is transferred to a tipping-type mixer, and stirring is continued with an inclination angle of 15 degrees and the mixer rotation speed of 2 rpm. and the air content is measured at 30 minutes and at 60 minutes.

2) Materials used

to. Concrete

Ordinary portland cement (specific gravity = 3.16) formed in equal parts of ordinary portland cement from Onada, Sumitomo and Mitsubishi Material companies mixed together is used.

b. Cenerino

Commercial ash is used (specific gravity = 2.26, specific surface = 3410 cm <2> / g, ignition loss = 3.9%, methylene blue absorption = 0.9 mg / g).

c. Fine aggregate

Quarry sand from the Oi River basin is used (specific gravity = 2.64, fineness modules = 2.76).

d. Raw aggregate

Crushed stone from Ome, Tokyo is used (maximum size = 20 rom, specific gravity = 2.65, fineness modules = 6.63).

And. Mixing water

Tap water is used.

f. AE water reducing agent

An AE (Property Name "Pozzolith" (trademark) No. 70 water reducing agent is used, manufactured by NMB Ltd.

g. AE blend

The following AE blend is used.

As a fatty acid-based surface active agent (a)

tall oil saponified with potassium hydroxide.

As a non-ionic surface active agent (b): addition products of 10-, 20-, 25-, 30-40- and 50-moles of ethylene oxide to nonylphenol (hereinafter abbreviated to bl, b2, b3, b4 , b5 and b6, respectively).

As ingredient (c):

Sodium dodecylbenzene sulfonate (hereinafter abbreviated to cl)

Resin acid saponified with sodium hydroxide (hereinafter abbreviated to c2)

sodium sulfonate α-olefin (hereinafter abbreviated to c3)

sodium sulfate of nonylphenyl polyoxyethylene ether (hereinafter abbreviated to c4).

3) Proportions of the concrete mix and test results

The proportions of the concrete mix are determined with the aim of a consistency of 18 ± 2 cm and the aim of air content of 5 ± 0.5 percent, without adding ash and with an addition of ash to 20 percent of the total cement plus the little gray. The proportions of the mixture are given in table 1.

Table 1

W: water, C: cement, FA: ash, S: sand (fine aggregate), G: gravel (raw aggregate), AEWRA: air inlet and water reduction agent.

The concrete is manufactured according to these mixture proportions, and the air content and changes in the air content as a function of time are measured. The results are shown in Tables 2 and 3.

Experiments number 13 and number 17 to number 21 in Table 2 are cases where the number of oxyethylene units added to the nonylphenyl polyoxyethylene ether have varied, being 10 (b1), 20 (b2), 25 (b3), 30 (b4), 40 (b5) and 50 (b6), the constant surface active agent (a). A downward trend is observed for the dosage of the AE mixture when the number of oxyethylene units is reduced. Furthermore, since the non-ionic surface active agent (b) decreases with the reduction in the number of oxyethylene units, it is desirable for practical purposes that the number of added oxyethylene units is in the range of 20 to 30.

Experiments No. 1 to 7, are cases where no ash has been added, and where the addition ratio of the ingredient (b) has increased, a trend is observed that the dosage of the AE mixture needed to reach the target of the air content must be higher than in the case where no ingredient (b) was added (Experiment no. 1). However, in the cases of experiments Nos. 10 to 16, where ashy was added, the dosage of the AE mixture needed to reach the target of the air content, where the percentages of addition of the ingredient (b) are 10 to 90 percent, are lower than necessary in case the surface active agent (a) is used alone (experiment No. 10) and the non-ionic surface active agent (b) is used alone (experiment No. 16}. The lowest dosage is obtained when the ratio of ingredients (a) and (b) is 25: 75 by weight percentage. This can be seen with reference to Figure 1, a ratio diagram between dosage and composition.

Experiments No. 8 and No. 9 are cases where a commercial resin type AE mixture (c2) is used, and although the target of air content was achieved immediately after mixing, in the case of adding ash ( Experiment No. 9), the air content is greatly reduced with the passage of time.

Table 3 shows the results when sodium dodecylbenzene sulphonate (cl), saponified resin acid with potassium hydroxide (c2), sodium α-olefin sulfonate (c3), and sodium nonylphenyl ether polyoxyethylene sulfate (c4) are used in combination. added as (c) to ingredients (a) and (b). Experiments # 26 to # 31 in Table 3 are cases where ash is added, and AE blends using these ingredients show excellent properties at small dosages. Experiment No. 32 is a case where saponified resin acid with potassium hydroxide is used at a higher than desired mixing ratio of 25 weight percent and the air content decreases over time.

Example 2

1) Test method

to. Concrete mixing method - as for example 1.

The consistency (JIS A 1101) and the air content (JIS a 1128) are measured.

2 . Materials used

to. Concrete

Ordinary Portland cement (specific gravity = 3.16) is used, formed in equal parts of ordinary Portland cement from Onoda and Sumitomo and Mitsubishi Material companies, mixed together.

b. Cenerino

Eight batches (FI to F8) of ash of different ignition losses produced by the same power plant are used. The specific gravities, ignition losses and methylene blue absorption of these ashes are shown in table 5.

c. Fine aggregate

Quarry sand from the Oi River basin is used (specific gravity = 2.64, fineness modules = 2.76).

d. Raw aggregate

Crushed stone from Ome, Tokyo is used (maximum size = 20 mm, specific gravity - 2.65; fineness modules = 6.63).

And. Mixing water

Tap water is used.

f. AE blend

The AE mixes described below are used.

AE1

Somo mixed together saponified tall oil with potassium hydroxide as a fatty acid surface active agent (a) in a proportion of 50 percent by weight and a nonylphenyl polyoxyethylene ether additive having 25 oxyethylene units as a non-ionic surface active agent (b) in a proportion of 50 percent by weight.

EA2

They are mixed together saponified tall oil with potassium hydroxide as a fatty acid surface agent (a) in a proportion of 35 percent by weight, a nonylphenyl polyoxyethylene ether additive having 25 oxyethylene units as a non-ionic surface active agent ( b) in a proportion of 60 percent by weight, and saponified resin acid with potassium hydroxide in a proportion of 5 percent by weight.

AE3

An AE blend manufactured by NMB Ltd (proprietary name: No. 303A, with an alkylaryl sulfonate as the main ingredient).

AE4

An AE Blend for Ashy from Toho Kagaku Kogyo (proprietary name: "Cemerol" T-80, with polyoxyethylene sorbitan monooleate as the main ingredient).

3. Proportions of concrete mixing and test results

The dosage of the AE mixture is determined which has an air content of approximately 5 percent when using ashy F4 with an approximately average ignition loss. This dosage is used for other ash and fluctuations in the air content are measured.

The proportions of the mixture when ashy at 20 percent of the total weight of the most ashy cement is used, are determined by test mixes. The proportions of the mixture are shown in Table 4.

Table 4

W: water; C: cement; FA: ash, S: sand (fine aggregate), G: gravel (rough aggregate)

The test results are shown in Tables 5 and 6 As shown in Table 5, since the air content using AE1 is in a range of 3.7 to 5.2 percent with the coefficient of variation of 10.0 percent and 1 air contents using AE2 are in a range of 3.7 to 5.2 percent with the coefficient of variation of 9.8 percent, the contents of air using AE3 are in a range of 2.5 to 7.0 percent with the coefficient of variation of 35.2 percent, the contents of air using AE4 are in a range 2.7 to 6.4 percent with

the coefficient of variation of 25.0 percent. Furthermore, when AE1 and AE2 are used, the fluctuations in the air contents are extremely small and stable air contents are obtained with small dosages, although the loss on ignition of the ash varies. This contrasts with the results obtained when AE3 and AE4 are used, where the variations are much greater.

Table 5 on the last page.

Table 6

Note <1)> The dosage of the solids of the AE mixture in percentage weight of cement or of the total quantity of cement and ash.

Table 6 shows the test results in changes in the air content of concrete as a function of time using AE1, AE2, AE3 and AE4. The air contents of concrete using AE1 and AE2 show almost no reduction even after a period of 60 minutes. Furthermore, in the case of AE3, compared with AE1 and AE2, although the air can be introduced with a low dosage, the reduction of the air content after a time of 60 minutes is considerable. In the case of AE4, although the reduction in air content after 60 minutes is small, the required dosage is very high compared to AE1 and AE2.

Claims (10)

Claims 1. A mixture for the intake of air which includes: a) a fatty acid-based surface active agent b) a non-ionic surface active agent the fatty acid-based surface active agent (a) being selected from the C12-24 alkanoic acids and their alkali metal salts, lower alkylamines and lower alkanolamines, and the nonionic surface active agent (b) being selected from formula materials where Ph (R) represents a phenyl group substituted with R, being R C8-9alkyl and n is from 1 to 50. An air intake mixture according to claim 1, wherein the mixture additionally comprises (c) a salt selected from the group formed of alkyl sulfonate salts, alkylaryl sulfonates, high alcohol sulfate esters and resin. An air intake mixture according to claim 1, wherein the fatty acid surface active agent (a) is selected from the fatty acids, or salts thereof, preferably the alkali metal or amine salts. An air intake mixture according to claim 3, wherein the alkali metal salts are those of sodium and potassium, and the preferred amine salts are preferably those of low molecular weight alkylamines and alkanolamines, preferably those of triethylamine or of triethanolamine. An air intake mixture according to claim 1, wherein the substituent R is selected from the octyl and nonyl groups. An air intake mixture according to claim 1, wherein the number n of oxyethylene units per molecule is in the range of 1 to 50, preferably 20 to 30 oxyethylene units per molecule. An air intake mixture according to claim 2, wherein the additive (c) is an alkali metal salt, preferably sodium and potassium or triethanolamine salt. An air intake mixture according to claim 1, wherein the weight ratios of the individual components are 10 to 90% (based on the active material) of the surface active agent (a), 90 to 10% of the non-ionic surface active agent (b) and, when component (c) is present, not more than 20% of this. 9. A process for preparing an ash-containing aerated cement composition, using ash which has an ignition loss of more than 5%, including adding to the cement composition, which includes ash, an air intake mixture according to claim 1 or claim 2. An ash-containing aerated cement composition wherein the ash has an ignition loss of more than 5%, comprising the composition an air intake mixture according to claim 1 or claim 2.