JP2009161360A - High-fluidity mortar - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-fluidity mortar which is a high-fluidity mortar suited for use at a temperature as low as about 5°C, is a high-fluidity mortar being good in workability in laying at the low temperature and being capable of being defoamed within a relatively short time after laying, and is capable of performing laying at a temperature, e.g., ordinary temperature, higher than the low temperature without raising substantially no troubles of workability in laying and of the properties of an object on which it is laid. <P>SOLUTION: The high-fluidity mortar is one comprising a portland cement, an expanding material, a water-retaining and thickening admixture, a water-reducing agent, a defoaming agent, a fine aggregate (α) having a particle diameter of above 150 μm, and a fine aggregate (β) having a particle diameter of 150 μm or less wherein the (β)/(α) mass ratio is 0.8-3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a high-flowing mortar that can be used as, for example, a leveling adjusting material or a flooring material and is suitable for workability at a low temperature.

High-fluid mortar containing hydraulic components such as cement is used as a leveling material because it can easily form a horizontal surface when poured into a floor slab of a concrete structure, for example. When using high-fluidity mortar for leveling materials such as horizontal floors, it is important to set fluidity suitable for construction. It is also important to adjust various properties that are affected by fluidity manipulation. In order to obtain a mortar with a high fluidity, it is generally formulated with a large amount of kneaded water, so cracking during material separation and drying processes is likely to occur, and horizontal construction can be obtained, but construction with particularly good surface conditions. Things are difficult to get easily. In order to deal with such a problem, for example, a composition suitable for obtaining a horizontal surface in which various admixture components are mixed in cement as described below has been proposed. That is, sand (aggregate), lime-based expansion agent, dispersant, fly ash and cellulose-based water retention agent (refer to Patent Document 1), aggregate, dispersant, shrinkage reducing agent, setting like gypsum A blend of an accelerator, a thickener and an antifoaming agent (see Patent Document 2), an aggregate, a water reducing agent, an antifoaming agent, a coagulation regulator, and a water-soluble cellulose ether (see Patent Document 3). ) Etc. are known. Even in the case of high flow mortars with such countermeasures, the viscosity generally increases greatly as the temperature decreases, so if you try to use it at low temperatures, it will become highly viscous and fluidity will decrease, and workability will be reduced. Is significantly reduced. The tendency to increase the viscosity due to a decrease in temperature is more prominent for mortar containing a thickening component. Self-leveling cement-based mortars suitable for low-temperature construction are also known, but most of them use fast-hardening components. (For example, refer to Patent Documents 4 to 6.) Since these are mainly aimed at improving the setting / curability at low temperature, it is difficult to construct at higher temperature, or can be used at room temperature or higher. Even at low temperatures, condensation proceeds rapidly in a highly viscous state. In a highly viscous mortar, fine bubbles in the mortar caught during kneading are difficult to escape, which accumulates on the surface of the work piece, and remains in a broken surface, which tends to be a rough surface. As a measure for obtaining a low-viscosity mortar at a low temperature, it is known that a high fluidity suitable for a self-leveling material can be obtained at a low temperature when a dispersant containing a specific vinyl copolymer as an active ingredient is used. (For example, see Patent Document 7)
JP-A-56-84358 JP 7-267704 A JP 2006-56763 A JP-A-7-69704 JP 2000-211961 A JP 2006-16223 A JP-A-8-290955

  When general cement-based high-fluidity mortar is used at low temperatures, the workability of the construction is significantly reduced due to the increase in viscosity at low temperatures, and the surface becomes rough due to the residual bubbles entrained during kneading. On the other hand, mortars that exhibit high fluidity at low temperatures with the use of special dispersants, etc., may experience problems due to excessively low viscosity with increasing temperature, making it practically difficult to use at other temperatures. It was. The present invention is a high fluidity mortar suitable for use at a low temperature of about 5 ° C., has good workability at the time of low temperature, and can eliminate bubbles in a relatively short time after construction. It is a flow mortar that has a higher temperature than that, for example, at room temperature, etc., and it is an issue to provide a high flow mortar that can be used without substantially affecting the workability and properties of the work. To do.

  As a result of investigations for solving the above problems, the present inventor uses a fine aggregate having a particle diameter of more than 150 μm and a fine aggregate having a particle diameter of not more than 150 μm in a high-flowing mortar, and setting both to a specific content ratio The fluidity can be adjusted sufficiently by the method, and the adjusted fluidity is much less temperature-dependent than the fluidity adjusted mainly for thickening components. Even if the fluidity is such that workability can be obtained, the present invention has been completed since it can be used without any substantial trouble even at temperatures above room temperature.

  That is, the present invention includes Portland cement, an expansion material, a water retention and thickening substance, a water reducing agent, an antifoaming agent, a fine aggregate (α) having a particle diameter of 150 μm and a fine aggregate (β) having a particle diameter of 150 μm or less. It is a high flow mortar characterized by containing (β) / (α) in a mass ratio of 0.8-3. Moreover, this invention is the said high fluid mortar whose mortar flow in 5 degreeC is 250-300 mm.

  The high-fluidity mortar according to the present invention can exhibit high fluidity, for example, from a low temperature of about 5 ° C. to room temperature, and can easily express horizontality just by pouring. A construction having substantially no bubble marks on the surface can be obtained.

  The high flow mortar of the present invention uses Portland cement as a binder phase forming component. The type of Portland cement is not particularly limited. For example, in addition to various Portland cements such as normal, early strength, super early strength, moderate heat, low heat, etc. Mixed cement such as cement may be used. Two or more types of Portland cement may be used. Preferably, normal portland cement and early strength or very early strength portland cement are preferably used in combination, since the simminess during construction becomes good. When used in combination, it is appropriate to use an amount corresponding to 5 to 30% by mass of ordinary Portland cement used as early or very early Portland cement.

  Moreover, the high fluid mortar of this invention mix | blends and uses an expanding material. The expansion material is not particularly limited as long as it can be used for mortar and concrete. Preferably, an expansion material capable of causing volume expansion by a hydration reaction such as lime or ettringite is used. Examples of the lime-based expansion material include a clinker pulverized product in which free quick lime is co-generated, and a limestone calcined pulverized product as an active ingredient. The ettringite-based expansion material is not limited as long as it reacts with water to generate an ettringite phase, and examples thereof include those containing calcium sulfoaluminate as an active ingredient. Lime-based and ettringite-based expansion materials may be used in combination. The expansion material suppresses relatively large-scale shrinkage from the curing to the drying period, and can particularly prevent the occurrence of initial cracks. The blending amount of the expansion material is preferably 2 to 15 parts by mass with respect to 100 parts by mass of the cement content. If it is less than 2 parts by mass, shrinkage during curing cannot be sufficiently suppressed, and if it exceeds 15 parts by mass, there is a risk of expansion cracking due to overexpansion, which is not appropriate.

  Moreover, the high fluidity mortar of this invention mix | blends and uses a water retention and a thickening substance. Here, the water retention and thickening substance refers to a substance capable of imparting water retention and thickening to cement-based mortar, and is a single component substance (for example, a single compound) having both performances. Alternatively, a combination of both a water-retaining substance and a thickening substance (a mixture of a water-retaining substance and a thickening substance) may be used. Any of these can be used as long as it can be used for mortar and concrete. Examples of the former include water-soluble cellulose ethers, and more specifically, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose and the like are exemplified. Water-soluble cellulose ether suppresses material separation by thickening action. In addition, due to the water retention effect, for example, when applied to floors with unevenness, the drying period of the part where the construction thickness becomes thin and the part where the thickness becomes thick are matched, and cracks caused by the difference in the drying shrinkage time of the construction are suppressed. This contributes to maintaining the balance of moisture content in the surface layer and low layer during the drying process. The compounding amount of the water-soluble cellulose ether is preferably 0.08 to 0.5 parts by mass with respect to 100 parts by mass of cement. If the amount is less than 0.08 parts by mass, material separation and cracking cannot be sufficiently suppressed. If the amount exceeds 0.5 parts by mass, the viscosity may increase excessively and a desired mortar flow may not be obtained, which may reduce workability. Because there is, it is not appropriate.

  Moreover, a water reducing agent is mix | blended with the high fluid mortar of this invention. The water reducing agent can be used for mortar and concrete, and if it has a water reducing action, any of the so-called dispersant, high performance water reducing agent, AE water reducing agent, high performance AE water reducing agent or fluidizing agent can be used. Good and the ingredients are not limited. Among them, it is preferable to use polycarboxylic acid-based water reducing agents because good fluidity can be continuously expressed even at low temperatures. What is necessary is just to determine the compounding quantity of a water reducing agent suitably for every active ingredient, for example, when using a polycarboxylic acid type high performance water reducing agent, 0.4-1 mass part is preferable with respect to 100 mass parts of cement contents. In this case, if it is less than 0.4 parts by mass, it will be difficult to ensure fluidity suitable for construction at low temperature, and if it exceeds 1 part by mass, it will be easy to cause material separation.

  Moreover, the high flow mortar of this invention mix | blends and uses the fine aggregate ((alpha)) exceeding a particle diameter of 150 micrometers. The fine aggregate exceeding the particle diameter of 150 μm may be any fine aggregate, regardless of the content, as long as it can be used for mortar and concrete. Specific examples include natural fine aggregates of mountain sand, river sand, sea sand, crushed sand, and artificial fine aggregates obtained by firing raw materials mainly composed of mineral powder. The maximum particle diameter of the fine aggregate is preferably 2.5 mm or less, more preferably a fine aggregate having a maximum particle diameter of 1.2 mm or less. By using a fine aggregate having a particle diameter of more than 150 μm, the amount of shrinkage after construction is easily reduced.

  Moreover, the high flow mortar of this invention mix | blends and uses the fine aggregate ((beta)) with a particle diameter of 150 micrometers or less. By using this fine fine aggregate, fluidity suitable for construction can be stably expressed. In particular, in construction at a low temperature, even if the amount of water is not increased by the combined action with a water reducing agent, the increase in viscosity due to the temperature decrease is suppressed, and the desired fluidity can be easily obtained. The fine aggregate to be used is not limited as long as it does not substantially react with water and does not dissolve, and may be the same aggregate as the fine aggregate (α) except for the particle diameter. Preferably, inorganic fine aggregates are used. Specific examples include calcium carbonate powder and quartzite powder, but are not limited thereto. The amount of fine aggregate (β) having a particle size of 150 μm or less is correlated with the amount (α) of fine aggregate having a particle size of more than 150 μm, and (β) / (α) is 0 in terms of mass ratio. It may be set within a range of 8 or more and less than 3. When the mass ratio (β) / (α) is less than 0.8, the effect of blending fine aggregates with a particle diameter exceeding 150 μm cannot be obtained substantially, and it becomes difficult to stably obtain fluidity with good workability. In addition, material separation is difficult to suppress, which is not preferable. On the other hand, if (β) / (α) exceeds 3 in terms of mass ratio, the viscosity of the mortar becomes too large, and it becomes difficult to obtain desired fluidity. The total amount of fine aggregate (β) having a particle diameter of 150 μm or less and fine aggregate (α) having a particle diameter of 150 μm or more is preferably 1.3 to 2.5 parts by mass with respect to 100 parts by mass of cement. If the amount is less than 1.3 parts by mass, the amount of shrinkage is large, and cracks are likely to occur. Moreover, since the intensity | strength of a construction material will fall when it exceeds 2.5 mass parts, it is not suitable.

  Moreover, the high fluid mortar of this invention mix | blends and uses an antifoamer. Any antifoaming agent can be used as long as it can be used for mortar and concrete. The use of the antifoaming agent prevents the appearance of bubble blisters that are likely to be seen on the surface of the work due to the air entrained during the kneading of the high-fluid mortar, and makes it easier to obtain a smooth surface. As for the compounding quantity of an antifoamer, 0.05-1 mass part is preferable in conversion of solid content with respect to 100 mass parts of cement contents. If the amount is less than 0.05 parts by mass, it is difficult to remove the bubbles, and even if an amount of the antifoaming agent exceeding 1 part by mass is used, the blending effect is not improved and only the cost is increased, which is not appropriate.

  The high flow mortar of the present invention may contain components other than those described above as long as the effects of the present invention are not substantially lost. Examples of such components include shrinkage reducing materials that can be used in mortar and concrete, anti-whitening agents, fibers, setting modifiers, water repellents, pozzolanic reactive substances, gypsum, clay minerals, pigments, and the like.

  Moreover, the high flow mortar of this invention is a mortar whose mortar flow in 5 degreeC is 250-300 mm. If the mortar flow at 5 ° C. is less than 250, it is difficult to obtain a horizontal plane simply by pouring into a floor board or the like, and the workability of the work is also unfavorable. On the other hand, when the mortar flow exceeds 300, it is not preferable because cracks and the like are easily generated in the construction. Further, the blending amount of the high-fluid mortar kneading water of the present invention is not particularly limited and may be appropriately selected so that the mortar flow can be easily obtained. As a suitable example in the case of construction at 20 ° C., the amount of kneading water is generally 23 to 28 parts by mass with respect to 100 parts by mass of the high flow mortar. In this case, if it is less than about 23 parts by mass, fluidity suitable for good workability may not be obtained, and if it exceeds about 28 parts by mass, it will be difficult to improve the surface layer strength of the construction.

    Moreover, the compounding quantity of the kneading | mixing water of the high fluid mortar of this invention will not be restrict | limited especially as long as the said mortar flow is applied. The manufacturing method of the high fluid mortar of this invention is not specifically limited. For example, it can be produced by adding kneaded water to a kneading container, and then adding and mixing a compounding material other than kneaded water. Moreover, the construction method of this high fluidity mortar is not specifically limited, For example, the construction method of the cement type self-leveling material generally performed conventionally can be applied.

Hereinafter, the present invention will be described in detail by way of examples.
Using materials selected from A1 to F shown below, kneading water is first put into a kneading container so as to achieve the blending amount shown in Table 1, and then other materials are put together and kneaded for about 90 seconds. A fluid mortar was made. This mortar was prepared in the same manner in both environments of a temperature of 20 ° C. and a temperature of 5 ° C. However, only the amount of the kneaded water was changed depending on the temperature.
A1: Normal Portland cement (manufactured by Taiheiyo Cement Co., Ltd.)
A2: Early strong Portland cement (manufactured by Taiheiyo Cement Co., Ltd.)
B: Lime-based expansion material (trade name: Taiheiyo Expan, manufactured by Taiheiyo Materials Co., Ltd.)
C: Water-soluble methylcellulose-based thickener (trade name; Metroles 90SH-4000, manufactured by Shin-Etsu Chemical Co., Ltd.)
D: Polycarboxylic acid-based high-performance water reducing agent (trade name; Mighty 21P, manufactured by Kao Corporation)
E1: Fine aggregate (Yamagata silica sand No.6, No. 7, particle content 5% by mass with particle diameter of 150 μm or less)
E2: Fine aggregate (Yamagata silica sand No. 7, particle content of 51 μm or less with a particle diameter of 150 μm or less)
E3: Calcium carbonate fine powder (commercially available product, particle content 96 mass% with particle diameter of 150 μm or less)
F: Antifoaming agent (trade name; SN deformer AHP, manufactured by San Nopco)

  About the produced high fluidity mortar, the flow was measured according to the flow test method of the Architectural Institute of Japan standard JASS 15M-103 as fluidity | liquidity evaluation. As for the flow, the mortar prepared at a temperature of 20 ° C. is 20 ° C., and the mortar prepared at a temperature of 5 ° C. is 5 ° C. with respect to the high-flowing mortar immediately after the end of the kneading (when about 2 minutes have passed since water injection) Each was measured below. Moreover, the mortar produced at 5 ° C. was 5 ° C. so that the produced high-flowing mortar had a thickness of about 1 cm in a plastic container having an inner dimension of 13 cm, a width of 8.5 cm, and a height of 1.8 cm. The mortar produced at 20 ° C. was poured at a temperature of 20 ° C., respectively. As evaluation of material separability, the presence or absence of bleeding water generation on the surface of the construction left for 30 minutes was visually observed. Furthermore, as an evaluation of the surface condition of each construction after 1 day at 5 ° C. and 20 ° C. from the construction, it is visually confirmed whether or not there are bubbles bulging, pinholes or floating film formation on the surface. In the case where no occurrence of odor was observed, the surface condition was judged as “good”, and other cases were judged as “bad”.

  From Table 2, the high flow mortar according to the present invention stably exhibits a relatively high fluidity suitable for construction even at low temperature (5 ° C.) or at ordinary temperature (20 ° C.), and the surface condition is good after construction and material separation. It can be seen that there is no substantial occurrence.

Claims (2)

Contains Portland cement, expansive material, water retention and thickening material, water reducing agent, antifoaming agent, fine aggregate (α) with a particle diameter of 150 μm and fine aggregate (β) with a particle diameter of 150 μm or less. (Β) / (α) is 0.8 to 3, high flow mortar. The high flow mortar according to claim 1, wherein the mortar flow at 5 ° C. is 250 to 300 mm.