JP5875858B2 - Air-entrained stable volume change inhibitor for cement composition and cement composition - Google Patents

Description

  The present invention reduces the shrinkage of a cement composition that requires durability, suppresses the generation of cracks, and ensures stable high-quality entrained air immediately after kneading to construction. The present invention relates to an entrained stable volume change inhibitor and a cement composition using the air entrained stable volume change inhibitor for cement composition.

  Generally, a cement composition shrinks due to self-shrinkage due to a hydration reaction or volume reduction due to dehydration during drying after setting. The shrinkage that occurs in this way is the main cause of cracks in the building, which lowers the strength of the building and has the problem that the water penetrated from the cracked part corrodes the internal reinforcing bars. As a means for solving such a problem, there is a method of suppressing shrinkage by adding an organic shrinkage reducing agent. Conventional organic shrinkage reducing agents are mainly composed of adducts of lower alcohol alkylene oxide (Patent Document 1), those based on polypropylene glycol (Patent Document 2), and alkylene having a chain hydrocarbon group. Those having an oxide as a main component (Patent Document 3), those having a glycol ether derivative whose hydrophobic group is a 2-ethylhexyl group as a main component (Patent Document 4) are known, and most of them are ethylene oxide (EO). ) And propylene oxide (PO) and other alkylene oxides added with an alkylene oxide as a main component.

  In general, shrinkage reducing agents are used in an amount of about 0.5 to 3% by weight with respect to cement, and are included in the chemical admixture for cement composition, which has a very large amount of addition. The effect on the amount and slump value) appears remarkably. The nonionic activator described above becomes water-soluble or water-insoluble, depending on the type of starting material to which EO and PO are added and the number of moles to which EO and PO are added. The amount of air that is entrained with foam increases and the nonionic active agent that becomes water-insoluble has a strong defoaming effect and lacks the amount of air to be kneaded. There was a problem that the quality of the product was not stable.

  As a means for solving these problems, an antifoaming agent is used when the air amount increases, and an air entraining agent (AE agent) is used when the air amount is insufficient. There is usually a method of adjusting to 4.5 ± 1.5%. For example, by combining a specific glycol-based shrinkage reducing agent with an antifoaming agent, a polycarboxylic acid-based water reducing agent, and an air entraining agent such as resin acid soap, alkyl sulfate ester, or alkyl phosphate ester, the air can be stabilized. Technology that can be introduced (Patent Document 5) and air entraining agents such as resin acid soaps, saturated or unsaturated fatty acids based on branched compounds having a branched structure containing three or more polyoxyalkylene chains in the molecule A highly versatile shrinkage-reducing agent (Patent Document 6) has been proposed by combining an antifoaming agent. Also, resin acid (rosin or rosin acid) with a specific particle size is used to improve the defect (air loss) that the amount of air decreases with time when using resin acid sodium salt as an air entrainer. Have been reported) (Patent Documents 7 and 8).

Japanese Patent Laid-Open No. 56-037259 JP 59-152253 A JP 2001-163653 A JP-A-2-124750 JP 2001-294466 A JP 2010-053025 A JP-A-1-270547 Japanese Patent Laid-Open No. 3-065547

  However, in the method of adjusting the air entrainment amount using an antifoaming agent, even if the air amount immediately after kneading can be adjusted, the air amount changes over time, and the air in the cement composition at the time of construction It is difficult to adjust the entrainment amount to an appropriate amount. In addition, when adjusting the amount of air using an air entraining agent such as sodium rosinate, it is necessary to use an amount that is tens of times the normal amount, leading to an increase in cost. The amount of air varies, and the amount of air to be entrained may vary greatly depending on the cement composition, making it difficult to determine the amount of addition. Moreover, the air entrained temporarily loses with time, and the present condition is that sufficient technique is not established about control of air amount, such as the appropriate air amount not being entrained at the time of construction. In the techniques described in Patent Documents 7 and 8, it is necessary to prepare rosin acid having a high melting point or a metal complex having a valence of 2 or more of rosin acid into fine particles having a particle diameter in a specific range, and fine powder or water. Because it is a suspension, it is inferior from the viewpoint of dispersibility in the cement composition. As a result, air entrainment is uneven, and an appropriate amount of air can be stably entrained from just after mixing until construction. There was no problem. In addition, the shrinkage reducing agents described in Patent Documents 1 to 4 correspond to dangerous materials according to the Fire Service Act and have the property of the fourth kind of flammable liquid, so that the standards for storage and handling, the standards for transportation and transport, etc. There was a problem that it was difficult to handle both manufacturers and handling users because they had to follow laws and regulations concerning dangerous goods. Further, the conventional shrinkage reducing agent has a problem that the shrinkage reduction effect varies due to the difference in aggregate or the cement composition having the same composition, and it is difficult to obtain a constant effect.

  As a result of intensive studies, the inventors have found that an air-entrained stable volume change inhibitor for a transparent liquid cement composition containing polypropylene glycol having an average molecular weight of 200 to 500, rosin acid, a specific polyoxyalkylene alkyl ether, and water. However, without using or reducing the amount of antifoaming agent or air entraining agent used in the past, a stable amount of air can be entrained from just after mixing the cement composition to construction, and the above-mentioned problems are remarkable. As a result, the present invention has been completed.

That is, the present invention
(1) Polypropylene glycol (A component) having an average molecular weight of 200 to 500, rosin acid (B component), a compound having a HLB value of 8 or less (C component) represented by the general formula (I), and water, and A Ingredients and B are in a weight ratio, A: B: 99.995-99.500: 0.005-0.500, and C is 0.005 to 0.00 of the total weight of A and B. 500% by weight, water is contained in a proportion of 5 to 50% by weight of the total weight of A component, B component, C component and water, and is a transparent liquid at 25 ° C. Stable volume change inhibitor,

(Chemical formula 1)
R-O- (AO) n-H (I)
(R is a hydrocarbon group having 8 to 18 carbon atoms, AO is an oxyalkylene group having 2 to 3 carbon atoms, and n is an integer of 1 to 10)

(2) A cement composition containing the air-entrained stable volume change inhibitor for cement composition according to (1),
Is the gist.

  The air-entrained stable volume change inhibitor for a cement composition of the present invention has good dispersibility in the cement composition, exhibits a stable and excellent air-entraining effect, and the amount of air increases or decreases over time. Therefore, the amount of air entrainment in the cement composition can be set to a target amount with little or no air entrainment agent or antifoaming agent added. In addition, the air-entrained stable volume change inhibitor of the present invention has a predetermined amount of each component and water in a transparent liquid state, and therefore can be treated as a non-hazardous material and is a shrinkage reducing agent designated as a hazardous material. Since it is not subject to such legal restrictions, it is very easy to handle during storage and use. Therefore, according to the air-entrained stable volume change inhibitor of the present invention, the air-entrained amount in the cement composition can be maintained at a stable amount from just after kneading until construction, and the air-entrained stable of the present invention. Cement composition using mold volume change inhibitor does not cause variation in shrinkage reduction effect due to differences in aggregates and preparation batches of cement composition, and shrinkage at the time of curing is reduced stably. Alternatively, neutralization of the cement composition of the present invention, suppression of crack generation after curing, and reduction of water permeability associated therewith can be achieved, and the durability of the structure by the cement composition of the present invention can be improved. In addition, due to the entrainment of air bubbles of stable quality, the cement composition using the inventive product exhibits a good bubble spacing coefficient, and the freeze-thaw resistance is also improved as compared with conventional shrinkage reducing agents.

  In the air-entrained stable volume change inhibitor for cement composition of the present invention, the polypropylene glycol as component A is, for example, an alkali catalyst such as sodium hydroxide or trifluoride starting from propylene glycol, dipropylene glycol or the like. It can be obtained by adding propylene oxide at 100 to 200 ° C. in the presence of an acid catalyst such as boron. In the present invention, polypropylene glycol having an average molecular weight of 200 to 500 is used, and an average molecular weight of 300 to 400 is preferable in view of shrinkage reduction performance and solution stability of the product. When the average molecular weight is less than 200, the desired shrinkage reduction performance cannot be obtained, and when it exceeds 500, the air-entrained stable volume change inhibitor for a transparent liquid cement composition that is uniform when water is contained. You may not be able to get it. The average molecular weight is calculated by the following formula from the measured value of the hydroxyl value (standard oil analysis test method 2.3.6.2_1996).

(Equation 1)
Average molecular weight = (56108 / hydroxyl number) × 2

  The B component rosin acid is mainly composed of acids with conjugated double bonds such as abietic acid, neoabietic acid, and parastrinic acid. It is also called rosin or resin acid, and it damages the pine tree trunk. Gum rosin obtained by steam-distilling the raw pine crab collected and removing the turpentine oil, wood rosin from which the pine root stock 10 years after cutting was extracted into a chip, and further distilled to remove turpentine oil, There is a tall oil rosin that is obtained by subjecting crude tall oil produced as a by-product to steam distillation under reduced pressure in a precision distillation tower in the process of pulping pine wood by the kraft method. The ratio of the component A polypropylene glycol and the component B rosin acid is a weight ratio of A component: B component = 99.995 to 99.500: 0.005 to 0.500, but 99.990 to 99.99. 750: 0.010 to 0.250 is preferable. When the ratio of rosin acid to the total amount of polypropylene glycol and rosin acid is less than 0.005% by weight, there is a possibility that sufficient air entrainment may not be exhibited, coarse air bubbles are entrained, cement Stable air cannot be entrained immediately after mixing of the composition until construction, and if it exceeds 0.500% by weight, the defoaming action becomes strong and the desired air entrainment cannot be obtained. Since a reaction product with rosin acid is formed, not only the air entrainment is too strong and excess air is entrained, but also agglomeration of cement occurs, and the fluidity is deteriorated, which may greatly affect the workability. Moreover, in order to obtain a desired air entrainment property, it is necessary to add another air entraining agent or an antifoaming agent. As a result, there is a possibility that stable air cannot be entrained immediately after the cement composition is mixed.

  The air-entrained stable volume change inhibitor for a cement composition according to the present invention is a compound of the above general formula (I), which is a C component, in an amount of 0.005 with respect to the total weight of the A component and the B component. The content is ˜0.500% by weight, preferably 0.010 to 0.200% by weight. When the C component is less than 0.005% by weight with respect to the total weight of the A and B components, the antifoaming action is weak, and coarse air and excess air are entrained, exceeding 0.500% by weight Has a strong antifoaming effect and does not entrain air in the cement composition, so that it is necessary to add a large amount of other air entraining agent or antifoaming agent in order to obtain the desired air entrainment property. There is a possibility that stable air cannot be entrained from immediately after kneading to construction, and as a result, the foaming interval coefficient increases and the durability index may decrease.

  In the compound represented by the general formula (I), the hydrocarbon group having 8 to 18 carbon atoms: R may be a linear hydrocarbon group or a branched hydrocarbon group, such as octyl, lauryl, myristyl, cetyl, stearyl, etc. In terms of handling, octyl and lauryl are preferable. C2-C3 oxyalkylene group: AO is formed by addition polymerization of alkylene oxide selected from ethylene oxide and propylene oxide, and the oxyalkylene group is composed of different alkylene oxides even if they are composed of the same alkylene oxide. If it is composed of different alkylene oxides, either block addition polymerization or random addition polymerization may be used. In general formula (I), n represents the average addition mole number of an oxyalkylene group, and is n = 1-10, Preferably it is 2-8, More preferably, it is 3-7. In the present invention, the compound represented by formula (I) is particularly preferably such that AO is an oxypropylene group and n is 3-6. When AO is an oxypropylene group and n exceeds 10, not only a uniform and transparent air-entrained stable volume change inhibitor can be obtained, but also the defoaming effect becomes stronger and the air-entraining agent necessary for air amount adjustment. Therefore, stable air cannot be entrained from immediately after mixing the cement composition until construction.

  The compound represented by the general formula (I) has a HLB value calculated from the Griffin formula of 8 or less. When AO in the general formula (I) is only an oxypropylene group, all the compounds represented by the general formula (I) have an HLB value of 8 or less. However, when AO contains an oxyethylene group (an oxyethylene group alone or an oxyethylene group) HLB may exceed 8 depending on the ratio of oxyethylene group and oxypropylene group and the number of n. When the HLB value exceeds 8, In addition to not being able to obtain the foam effect, there is a risk that coarse air bubbles may be entrained, and there is a possibility that stable air cannot be entrained immediately after mixing the cement composition until construction, so the starting material has 8 to 8 carbon atoms. It is necessary to adjust the average number of moles of addition of ethylene oxide and propylene oxide to 18 alcohols so that the HLB value is 8 or less. AO is preferably a combination of ethylene oxide and propylene oxide rather than ethylene oxide alone, and the HLB value is preferably 5 or less, and particularly preferably the ethylene oxide average added mole number is 2 or less.

  In the present invention, ethylene oxide alone or a combined compound of ethylene oxide and propylene oxide having an HLB value of 8 or less represented by the general formula (I) as the component C includes, for example, polyoxyethylene (2) -2-ethylhexyl ether, polyoxy Examples include ethylene (2) octyl ether, polyoxyethylene (2) polyoxypropylene (4) stearyl ether, and the like.

  The air-entrained stable volume change inhibitor for cement composition of the present invention contains water in a proportion of 5 to 50% by weight of the total weight of component A, component B, component C and water, and is a transparent liquid at 25 ° C. Although it exhibits, it is preferable to exhibit a transparent liquid also in 5-40 degreeC. The transparent liquid here means that the transmittance of visible light (550 nm) is 50% or more. The water ratio is preferably 10 to 25% by weight. If the proportion of water is less than 5% by weight, there is a risk of having a flash point, and flammable liquids are dangerous materials according to the Fire Service Act, and handling and storage are complicated from the viewpoint of work environment and safety, 50% by weight If it exceeds 1, the apparent amount added will increase, resulting in poor working efficiency and separation of the product without exhibiting a transparent liquid. There is a risk of not being able to.

  The method for preparing the air-entrained stable volume change inhibitor for cement composition of the present invention is not particularly limited. First, rosin acid as B component is dissolved in polypropylene glycol as A component while heating, and after cooling, C A method of preparing a mixture of ingredients and water is preferred.

  The cement composition of the present invention includes water such as cement paste (mixed with water and cement), mortar (mixed with fine aggregate and water) or concrete (added with coarse aggregate into mortar). The hard material can be prepared by blending the air-entrained stable volume change inhibitor of the present invention.

  When the air-entrained stable volume change inhibitor for cement composition of the present invention is added to a hydraulic material and kneaded, a rosin acid which is a hydrophobic substance of B component and a compound represented by the general formula (I) of C component are: Rough foam is removed or controlled, and then the alkali ions and rosin acid eluted from the cement composition react gradually to become soluble, and the amount of air that has been removed by entraining fine and stable air bubbles by stirring. It is assumed that an appropriate amount of air can be taken. In addition, the reaction product of alkali ions and rosin acid increases with time, but since the compound represented by the general formula (I) is blended in advance, an increase in the amount of air over time is suppressed in a well-balanced manner. From this, the air-entrained stable volume change inhibitor for cement composition of the present invention can entrain and maintain stable air from immediately after mixing the cement composition to the time of construction, as well as reducing shrinkage. In addition, it is possible to suppress neutralization associated with freeze-thaw resistance and crack suppression, reduce water permeability, and improve the durability of the cured cement composition.

  In addition to the air-entrained stable volume change inhibitor for cement compositions of the present invention, other chemical admixtures can be blended with the cement composition as necessary. Other chemical admixtures may be mixed with the air-entrained stable volume change inhibitor of the present invention and blended into the cement composition or separately, but the air-entrained stable volume change inhibitor of the present invention. It is necessary to use one that does not impair the effect. When other chemical admixtures are mixed with the air-entrained stable volume change inhibitor of the present invention, it is necessary to mix within a range in which the transparent liquid of the air-entrained stable volume change inhibitor is maintained. Other chemical admixtures include, for example, air entraining agents (air entraining components), antifoaming agents (antifoaming components, antifoaming components), water reducing agents (standard, delayed, accelerated), high performance AE water reducing agents (standard) Shape, delay type), high-performance water reducing agent, curing accelerator, fluidizing agent (standard type, delayed type), shrinkage reduction type (high performance) AE water reducing agent, setting retarder, accelerator, quick setting agent, foaming Agents, rust inhibitors, cold resistance promoters, adhesion mortar stabilizers, darkening inhibitors, thickeners, separation reducers, flocculants, self-leveling agents, antifungal agents and the like. These other chemical admixtures may be used alone or in combination of two or more.

  The cement in the cement composition is not particularly limited as long as it is a hydraulic cement. Examples of the cement include normal, low heat, moderately hot, early strength, super early strength, sulfate resistant portland cement, low alkali type of portland cement, blast furnace cement (type A, type B, type C), silica cement ( A type, B type, C type), fly ash cement (A type, B type, C type), eco cement (ordinary, fast setting), silica fume cement, white Portland cement, alumina cement, super fast setting cement, for grout Examples include cement, oil well cement, low heat cement, and cement-based solidified material. Examples of the powder that can be contained in the cement composition include silica fume, fly ash, fine coal stone powder, fine blast furnace slag powder, expansion material, and other mineral fine powder. That is, all hydrates that produce calcium silicate products are applied.

  Aggregates are classified into fine aggregates and coarse aggregates according to the particle size. Fine aggregates include river sand, mountain sand, sea sand, crushed sand, heavy aggregate, lightweight aggregate, slag aggregate, recycled aggregate, etc. Illustrated. Examples of the coarse aggregate include river gravel, crushed stone, heavy aggregate, lightweight aggregate, slag aggregate, recycled aggregate, and the like. Water that can be used for the cement composition is not particularly limited, and examples thereof include water supply water, water other than water supply water (river water, lake water, well water, etc.), recovered water, and the like.

  The blending ratio of the air-entrained stable volume change inhibitor for the cement composition of the present invention in the cement composition is not particularly limited, but usually 0.1 wt. % To 5.0% by weight, more preferably 0.5% to 3.0% by weight.

  There is no restriction | limiting in particular about the manufacturing method of a cement composition, a conveyance method, a setting method, a curing method, a management method, etc., A normal method can be employ | adopted.

  The effectiveness of the present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to the examples.

Synthesis of component A polypropylene glycol (PPG):
116 g of dipropylene glycol (MW = 116) and 1.25 g of caustic potash were introduced as starting materials into a 1 liter stainless steel container, and the reaction system was purged with nitrogen while the container was sealed and stirred, and the temperature was raised to 100 ° C. After reducing the pressure in the reaction system with a vacuum pump, the temperature was further raised, and when the internal temperature reached 120 ° C., the introduction of propylene oxide (PO) was started, the reaction pressure was 0.4 MPa, and the reaction temperature was 140 to 150 ° C. Then, a predetermined amount of PO was pressurized and introduced to cause addition reaction. After pressurizing and introducing a predetermined amount of PO, aging was carried out at the same temperature for 2 hours to completely add PO remaining in the reaction system, and cooled to 40 ° C. or lower. The reaction product was taken out from the container, and about 1% KYOWARD 600S (manufactured by Kyowa Chemical) was added to the reaction product, followed by adsorption treatment at 120 ° C. for 1 hour in a nitrogen atmosphere to carry out decatalysis. Using 5B filter paper (retained particles 4 μm), pressure filtration was performed to remove KYOWARD 600S, and five types of PPG having an average molecular weight of 150, 200, 350, 500, and 600 were obtained.

Synthesis of polyoxyalkylene alkyl ether of general formula (I) of component C (the number in parentheses is the number of repeating oxyalkylene groups):
(1) C component 1: Synthesis of polyoxypropylene (4) -2-ethylhexyl ether 134 g of 2-ethylhexyl alcohol (octanol OA: manufactured by Chisso Corporation) and caustic potash (reagent special grade: Kanto Chemical) in a 1 liter stainless steel container (Made by Co., Ltd.) 0.5 g was added, and the reaction system was purged with nitrogen while stirring and stirring the vessel, and the temperature was raised to 100 ° C. The inside of the reaction system was depressurized with a vacuum pump and dehydrated for about 15 minutes, and then the temperature was further raised. PO introduction was started when the internal temperature reached 150 ° C., reaction pressure 0.4 MPa, reaction temperature 175 to 185 ° C. Then, 4 mol of PO was introduced under pressure to cause addition reaction. After the introduction of PO, aging was carried out at the same temperature for 1 hour, and PO remaining in the reaction system was completely added and cooled to 40 ° C. or lower. The reaction product was taken out from the container, and 0.5 g of acetic acid (special grade reagent: manufactured by Kanto Chemical Co., Inc.) was added to neutralize caustic potash to obtain the target C component compound polyoxypropylene (4) -2-ethylhexyl ether. .

(2) Component C 2: Synthesis of polyoxyethylene (2) -2-ethylhexyl ether 2 mol of EO was added and reacted by the same synthesis method as polyoxypropylene (4) -2-ethylhexyl ether. C-component compound polyoxyethylene (2) -2-ethylhexyl ether was obtained. The HLB value calculated from the Griffin equation is 7.9.

(3) C component 3: Polyoxypropylene (3) Synthesis of lauryl ether 201 g of lauryl alcohol (Conol 20P: manufactured by Shin Nippon Chemical Co., Ltd.) was used as a starting material, and the above polyoxypropylene (4) -2-ethylhexyl was used. A 3 mol portion of PO was subjected to an addition reaction by the same synthesis method as that for ether to obtain a target C component compound polyoxypropylene (3) lauryl ether.

(4) C component 4: Polyoxyethylene (2) Polyoxypropylene (4) Synthesis of stearyl ether 270 g of stearyl alcohol (Calcoal 8098: manufactured by Kao Corporation) and caustic potash (reagent special grade: manufactured by Kanto Chemical Co., Ltd.) ) 0.5 g was added, and the reaction system was purged with nitrogen while the vessel was sealed and stirred, and the temperature was raised to 100 ° C. The reaction system was depressurized with a vacuum pump and dehydrated for about 15 minutes, and then the temperature was further raised. The introduction of EO was started when the internal temperature reached 150 ° C, the reaction pressure was 0.4 MPa, the reaction temperature was 175 to 185 ° C. First, 2 mol of EO was introduced under pressure to cause addition reaction. After completion of EO introduction, aging was carried out at the same temperature for 30 minutes, and then PO was introduced under pressure to cause addition reaction of 4 moles of PO. After the introduction of PO, the mixture was aged at the same temperature for about 1 hour to completely add PO remaining in the reaction system, and cooled to 40 ° C. or lower. The reaction product is taken out from the container, 0.5 g of acetic acid (special grade reagent: manufactured by Kanto Chemical Co., Inc.) is added to neutralize caustic potash, and the target C component compound is polyoxyethylene (2) polyoxypropylene (4) stearyl ether Got. The HLB value calculated from the Griffin equation is 3.0.

(5) Synthesis of C component 5: polyoxyethylene (7) polyoxypropylene (2) lauryl ether 201 g of lauryl alcohol (Conol 20P: manufactured by Shin Nippon Rika Co., Ltd.) was used as a starting material, and the above polyoxyethylene ( 2) Polyoxypropylene (4) Polyoxyethylene (7) polyoxypropylene (2) which is the target C component compound by addition reaction of 7 mol of EO and 2 mol of PO by the same synthesis method as stearyl ether ) Lauryl ether was obtained. Note that the HLB value calculated from the Griffin equation is 10.1.

Preparation of Air-Entrained Stable Volume Change Inhibitor Addition of B component rosin acid (Chinese rosin X: manufactured by Arakawa Chemical Co., Ltd.) to PPG of component A compound, and after dissolving uniformly and uniformly at 60 ° C, 40 ° C Cooled to: Next, the polyoxyalkylene alkyl ether of component C was added and dissolved uniformly, and then mixed with water to obtain the intended air-entrained stable volume change inhibitor. Table 1 shows the composition of each air-entrained stable volume change inhibitor and the appearance of the prepared air-entrained stable volume change inhibitor at 25 ° C.

Examples 1-2, Comparative Examples 1-2, Reference Example 1
Using an air-entrained stable volume change inhibitor (chemical) whose composition is shown in Table 1, based on the concrete mixing condition 1 shown in Table 2, three equal amounts of ordinary Portland cement (density = 3.16 g / cm ³⁾ ), Fine aggregates and coarse aggregates were produced in the room at an ambient temperature of 20 ° C. using the aggregate type 1 in Table 3.
The manufacturing method uses a forced biaxial kneading mixer, first uniform the cement and fine aggregate, then add water and chemical admixture and air-entrained stable volume change inhibitor, knead the mortar for 60 seconds, Coarse aggregate was charged and kneaded for 90 seconds to produce concrete. For concrete in Examples, Comparative Examples, and Reference Examples, AE water reducing agent (standard type Floric S: manufactured by Floric Co., Ltd.) is replaced with the water content of the concrete so that it becomes 1% by weight with respect to the cement weight. And added. The target slump value is set to 18 ± 2.5 cm, the target air amount is set to 4.5 ± 1.5%, and an air entraining agent (AE-4 (potassium rosin acid potassium salt type surfactant) as an air amount adjusting agent. : Made by Floric Co., Ltd.) and / or antifoaming agent (Trimin DF-325 (main component polyalkylene glycol fatty acid ester): made by Miyoshi Oil & Fat Co., Ltd.) Manufactured. The air-entrained stable volume change inhibitor was added in advance to the amount of water so as to be 1% by weight in terms of effective component with respect to the cement.
For the concrete in the above test, the mixer was washed for each type of air-entrained stable volume change inhibitor, and three batch concrete was continuously produced without washing the mixer for each batch. The first batch is made of concrete with an air-entrained stable volume change inhibitor added, the second batch is made with no air-entrained stable volume change inhibitor added, and the third batch is made up of the first batch In the same manner, the amount of air and slump value immediately after, 30 minutes, and 60 minutes after concrete mixing for each batch were measured. From the fresh concrete test results (air amount, slump value) immediately after concrete kneading, The effect was confirmed. The results are shown in Table 4.

Fresh Concrete Test As a fresh concrete test, the amount of air of the obtained concrete (immediately after kneading, after 30 minutes and 60 minutes) and the slump value were measured according to the following method.
Air volume: JIS A 1128: 2005
Slump: JIS A 1101: 2005

From the results of Table 4, in Examples 1 and 2, in the same test conditions (the same amount of air amount adjusting agent) regardless of the presence or absence of the air-entrained stable volume change inhibitor (chemical) for the cement composition of the present invention. There was no change in the air amount and slump value, and the results were the same as the results of the fresh concrete test under the same test conditions in the base concrete (Reference Example 1). On the other hand, in Comparative Example 1, since it is influenced by the chemicals added to the previous batch, the amount of air varies from batch to batch, and in order to obtain the target air amount, the amount of air entrainment agent or antifoaming agent added It can be seen that adjustment is necessary and control is difficult. In Comparative Example 2, even when 35A and a large amount of air entraining agent were added, the target air amount and the target slump value were not reached.
That is, the air-entrained stable volume change inhibitor for cement composition of the present invention is a transparent liquid non-hazardous material, and there is no risk of unevenness in air entrainment from the viewpoint of dispersibility, the amount of air per batch, Because it is not affected by the variation in the slump value and the chemicals added to the previous batch, it eliminates the need for manufacturing management, and the desired amount of air-entraining agent and antifoaming agent is the same as the base concrete. It was found that a cement composition having fresh properties could be obtained.

Examples 3-4, Comparative Examples 3-4, Reference Example 2
Using the above-exemplified air-entrained stable volume change inhibitor (medicine), based on the concrete mixing condition 2 shown in Table 2, three equal amounts of ordinary Portland cement (density = 3.16 g / cm ³ ), fine bone As the aggregate and coarse aggregate, one batch of concrete was produced by using the aggregate type 2 shown in Table 3 by the same method as described above. The mixer was washed every time for each type of air-entrained stable volume change inhibitor.
The amount of air immediately after the concrete kneading and the slump value were measured, and compared with the results of the fresh concrete test of Examples 1, 2, Comparative Examples 1, 2 and Reference Example 1 using the aggregate type 1, mixing condition 1. The effect of the difference in aggregate type and blending conditions was confirmed. The results are shown in Table 5 together with the results of the first batch of Examples 1 and 2, Comparative Examples 1 and 2 and Reference Example 1.

From the results of Examples 1 and 3 and Examples 2 and 4, the air-entrained stable volume change inhibitor for cement composition of the present invention has an effect on the air amount and slump value due to the difference in aggregate type and blending conditions. I was not able to admit. On the other hand, from the results of Comparative Examples 1 and 3, and Comparative Examples 2 and 4, the air amount and the slump value fluctuate significantly with changes in the aggregate used and the mixing conditions.
That is, the air-entrained stable volume change inhibitor for a cement composition of the present invention has a stable fresh property of the cement composition even if the aggregate and blending conditions used in the cement composition are changed. It was confirmed that the complicated work of determining the amount of addition of the antifoaming agent can be reduced.

Examples 5-10, Comparative Examples 5-12
Using an air-entrained stable volume change inhibitor (chemical) whose composition is shown in Table 1, based on the concrete mixing condition 1 shown in Table 2, three equal amounts of ordinary Portland cement (density = 3.16 g / cm ³⁾ ), Fine aggregate and coarse aggregate were produced in batches of concrete by the same method as described above using the aggregate type 1 shown in Table 3. The mixer was washed every time for each type of air-entrained stable volume change inhibitor.
The air-entrained stable volume change inhibitor was added in advance to the amount of concrete water so that it would be 0.5, 1.0, and 3.5% by weight in terms of effective component relative to the cement.
The amount of air and slump value were measured immediately after concrete kneading, after 30 minutes and after 60 minutes, and after the first batch of concrete kneading in Examples 1 and 2 and Comparative Examples 1 and 2 and Reference Example 1, after 30 minutes. Table 6 shows the air amount and slump value after 60 minutes.

From the results of Examples 1, 2, 5 to 10, the air-entrained stable volume change inhibitor for cement composition of the present invention has good air volume stability over time, and the associated slump loss is small. It is suppressed. On the other hand, with respect to the comparative example, the amount of air after the lapse of time increases or significantly decreases, the aging stability cannot be ensured, and the slump value fluctuates significantly with the lapse of time. Moreover, when rosin acid was compounded excessively (Comparative Example 5), aggregation occurred over time, the fluidity deteriorated, and the stiffness of the concrete was confirmed.
That is, the air-entrained stable volume change inhibitor for cement composition according to the present invention can maintain the air-entrained amount in the cement composition from immediately after kneading to the time of construction by entraining air bubbles of a stable amount and quality. Was recognized.

Examples 11-18, Comparative Examples 13-22
Using the concrete obtained in Examples 1, 2, 5 to 10 and Comparative Examples 1, 2, and 5-12, the bubble spacing coefficient measurement, the drying shrinkage test, and the freeze / thaw test were performed by the following methods. The results are shown in Table 7.

Foaming interval coefficient measurement The foaming interval coefficient was measured by the linear traverse method in accordance with ASTM C 457-98. Each concrete of Examples 1, 2, 5 to 10 and Comparative Examples 1, 2 and 5 to 12 after being discharged from the mixer was collected in a steel mold having a diameter of 10 × 20 cm and demolded after 24 hours of water injection. Immediately after demolding, the sample was immersed in water at 20 ° C. for 4 weeks, and the sample was cut from the height of 10 cm to 1 cm above and below. In general, when the foaming interval coefficient is 250 μm or less, the frost damage resistance is considered good.

Drying shrinkage test The drying shrinkage test was performed in accordance with JIS A 1129: 2001. Immediately after each concrete placement in Examples 1, 2, 5 to 10 and Comparative Examples 1, 2 and 5 to 12, a 10 × 10 × 40 cm specimen was prepared, and after 24 hours, the mold was removed, and the marking was made. After pulling, it was cured in water at 20 ° C. for 1 week, and then stored in a constant temperature and humidity chamber at 20 ° C. and 60% RH, and the drying shrinkage rate was measured. In addition, it is a shrinkage | contraction reduction rate (%) with respect to base concrete (reference example 3) in the dry material age 13 weeks of each concrete.

Freeze-thaw test (durability index)
The freeze-thaw test was conducted according to JIS A 1148: 2001 (Method A). Immediately after each concrete placement in Examples 1, 2, 5 to 10 and Comparative Examples 1, 2 and 5 to 12, a 10 × 10 × 40 cm specimen was prepared, and demolded after 24 hours. Curing was carried out in water for 4 weeks, a 300-cycle (c) freeze-thaw test was performed, and a durability index was obtained. In general, when the durability index of the cement composition is 60% or more, the frost damage resistance is considered good.

From the results of Examples 11 to 18, the air-entrained stable volume change inhibitor for cement composition of the present invention produces a concrete having a drying shrinkage reducing effect, a bubble spacing coefficient of 250 μm or less, and a durability index of 60% or more. It was recognized that it was excellent in frost resistance. On the other hand, with respect to the comparative example, it was confirmed that the bubble spacing coefficient was large and coarse air bubbles were entrained, and inferior in frost damage resistance from the durability index.
That is, since the air-entrained stable volume change inhibitor for cement composition of the present invention is entrained with stable quality air, the effect of suppressing volume change, a cement composition that is excellent in frost damage resistance is obtained. It was also found that cracking was suppressed and water permeability was reduced accordingly, and as a result, the durability of the structure could be improved with the cement composition of the present invention.

Claims (2)

Contains polypropylene glycol (component A) having an average molecular weight of 200 to 500, rosin acid (component B), a compound (C component) having an HLB value of 8 or less represented by formula (I), and water. A component: B component = 99.995-99.500: 0.005-0.500 by weight ratio, C component is 0.005-0.500% by weight of the total weight of A component and B component An air-entrained stable volume for a cement composition containing 5 to 50% by weight of water in the total weight of component A, component B, component C and water, and being a transparent liquid at 25 ° C. Change inhibitor.
(Chemical formula 1)
R-O- (AO) n-H (I)
(R is a hydrocarbon group having 8 to 18 carbon atoms, AO is an oxyalkylene group having 2 to 3 carbon atoms, and n is an integer of 1 to 10)   A cement composition comprising the air-entrained stable volume change inhibitor for cement composition according to claim 1.