JP2010024118A - Composition for water-permeable/water-retentive concrete or mortar, material obtained by solidifying the same and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide water-permeable/water-retentive concrete or mortar which is excellent in water permeability and water retentivity, particularly keeps excellent water retentivity even when dried and wetted repeatedly, exhibits an excellent temperature drop when sprinkled with water and keeps the dropped temperature for a long time and to provide a method for producing the same, and a composition becoming a raw material of the same. <P>SOLUTION: The water-permeable/water-retentive concrete or mortar is obtained by solidifying the composition containing fine aggregate obtained by milling original aggregate, cement a CMC aqueous solution having ≥100 mPa s viscosity and is used as a paving block, a roadbed block, porous concrete or a mortar product. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a water-permeable / water-retaining concrete or mortar composition that has excellent water permeability and water retention and can be used for pavement materials and the like, a water-permeable / water-retaining concrete or mortar obtained by solidifying the composition, and a method for producing the same.

Conventionally, water-permeable / water-retaining concrete or mortar (hereinafter sometimes simply referred to as water-permeable / water-retained concrete) has been used on sidewalks, rooftops of buildings, and the like to alleviate the heat island phenomenon. It is also used to maintain groundwater. As such water-permeable / water-retaining concrete, for example, Patent Literature 1 discloses water-permeable / water-retaining concrete as a pavement material using a high water absorption aggregate such as granulated slag, which is a porous material, and Portland cement. Has been proposed.
However, such a water-permeable / water-retaining concrete has a problem that the water absorption rate is lowered because the porous material is covered with cement hydrate.
Patent Document 2 discloses porous aggregates such as granulated slag, zeolite, and volcanic rocks, water-absorbing resins such as water-soluble polymers, fibrous materials such as polymer materials, and hardened materials such as Portland cement. A water-permeable / water-retaining concrete body has been proposed which is molded or constructed by kneading and solidifying in a state of 0 slump or low slump.
Such a water-permeable / water-retaining concrete body has improved bending strength due to the blending of the fibrous material, but it cannot be said that the water-permeable / water-retentive body is necessarily satisfactory.
JP-A-9-208290 JP-A-2005-314214

  An object of the present invention is excellent in water permeability and water retention, in particular, water permeability / water retention concrete or mortar, which maintains excellent water retention even by repeated wet and dry cycles, is excellent in temperature reduction due to watering, and has a long duration. It is in providing the manufacturing method and the composition for water-permeable and water-retaining concrete or mortar used as the raw material.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have crushed non-porous aggregates such as molten slag, and fine fine aggregates with adjusted particle sizes and particle diameters, and carboxymethyl cellulose. By using in combination with a water-soluble polymer aqueous solution with a specific viscosity or higher dissolved in water, the fine aggregate is covered with cement, and capillarity due to the gap between fine aggregate particles ensures and maintains an excellent water absorption rate. As a result, it was found that the strength of the cured body was ensured and the above problems could be solved, and the present invention was completed.

That is, according to the present invention, water-permeable / water-retaining concrete or mortar containing fine aggregate obtained by grinding aggregate, cement, and a carboxymethylcellulose (hereinafter abbreviated as CMC) polymer aqueous solution having a viscosity of 100 mPa · s or more. Compositions are provided.
Moreover, according to this invention, the water-permeable and water-retentive concrete or mortar which solidified the said composition is provided.
Furthermore, according to the present invention, there is provided a method for producing water-permeable / water-retaining concrete or mortar, which is characterized in that after the composition is driven into a molding or construction site, it is subjected to vibration and / or pressurization to cure and solidify. The

The water-permeable / water-retaining concrete or mortar of the present invention is, in particular, a fine-grained fine aggregate whose particle size and particle diameter are adjusted by grinding the aggregate, and a water-soluble polymer aqueous solution having a specific viscosity or higher in which CMC is dissolved. In combination, it is excellent in water permeability and water retention, in particular, it maintains excellent water retention even when it is repeatedly subjected to dry and wet, and is excellent in temperature drop due to watering and has a long duration. Therefore, the water-permeable / water-retaining concrete or mortar of the present invention is useful as a pavement material or a rooftop material of a building that alleviates the heat island phenomenon or the like.
The production method of the present invention can efficiently obtain the water-permeable / water-retaining concrete or mortar of the present invention.

The present invention will be described in detail below.
The composition of the present invention comprises fine aggregate obtained by grinding aggregate, cement, and a CMC polymer aqueous solution having a specific viscosity.
Examples of the aggregate include aggregates of non-porous materials such as molten slag, blast furnace slag, and steelmaking slag. These can be used alone or as a mixture of two or more.
The aggregate grinding process is performed by, for example, atomizing the porous aggregate by rubbing it with a rotating drum having a shape in which the upper part of the bottomed cylindrical body is opened and the central part protrudes upward. It can be performed using a commercially available grinder, specifically, a grinder manufactured by Nippon Casting Co., Ltd.

The conditions for the grinding treatment can be appropriately selected. In order to obtain the desired effect of the present invention with high accuracy, the coarse aggregate ratio of the obtained fine aggregate is 3.00 or less, preferably 2.70 or less. It is preferable to select conditions under which the volume ratio is 55% or more, preferably 65% or more, and the fine particle amount is 5 to 10%.
Here, the coarse grain ratio can be measured by JIS A 1102 “Aggregate Screening Test Method”, and the actual volume fraction can be measured by JIS A 1104 “Aggregate Unit Volume Weight Test Method”. The fine particle amount can be measured by JIS A 1103 “Aggregate fine particle amount test method”.
The above-mentioned fine aggregate generally refers to an aggregate having a particle diameter that passes through all of the 10 mm sieve and passes through the 5 mm sieve by 85% or more.
In the composition of the present invention, the content of the fine aggregate is usually 30 to 50% by mass, preferably 35 to 45% by mass based on the total amount of the composition. If it is outside the above range, the desired water permeability and water retention may not be obtained.

The cement is not particularly limited, and examples thereof include ordinary Portland cement, blast furnace cement, and early strength cement.
In the composition of the present invention, the content of cement is usually 10 to 30% by mass, preferably 15 to 25% by mass, based on the total amount of the composition.

The CMC polymer aqueous solution is an aqueous solution in which CMC is dissolved, and the viscosity thereof is 100 mPa · s or more, preferably 100 to 5000 mPa · s. If the viscosity is less than 100 mPa · s, water retention may be reduced. The concentration of the CMC polymer aqueous solution can be appropriately determined so as to achieve the above viscosity in view of the molecular weight of the CMC polymer.
The viscosity of the CMC polymer aqueous solution can be measured by the following method.
About 10 g of CMC is precisely weighed, 900 ml of distilled water is added, and it is stirred and dissolved with a stirrer (about 600 rpm). The amount of dissolved water is corrected so that the amount of sample intake x (99-water%), and the mixture is stirred for 3 hours to adjust the viscosity measurement solution. Next, the viscosity measurement liquid is put in a constant temperature water bath at 25 ° C. ± 0.2 ° C. to 25 ° C., and the viscosity is measured with a BM type rotational viscometer. Read the scale 3 minutes after the start of rotation of the rotor. The viscosity value can be obtained by multiplying the coefficient of Table 1 by the number of revolutions.

The weight average molecular weight of CMC is usually 25,000 to 500,000, preferably 50,000 to 400,000. When the molecular weight is small, it is difficult to prepare a water-soluble polymer aqueous solution having a predetermined viscosity or more, and the desired effect may not be obtained.
In the composition of the present invention, the content of the water-soluble polymer aqueous solution is usually 5 to 20% by mass, preferably 5 to 10% by mass, based on the total amount of the composition. If it is out of the above range, the desired water permeability and water retention may not be obtained.

In the composition of the present invention, in addition to the essential materials described above, other materials can be contained in order to obtain other desired effects without impairing the effects of the present invention. For example, coarse aggregate can be blended to increase strength and to make concrete. Further, in order to further improve the water retention, a polymeric fibrous substance having a water absorption property such as cellulose can be contained. Examples of the polymer fibrous material include “Ultrafiber 500” (registered trademark) manufactured by Bakay.
The content ratio in the case of containing these other materials can be appropriately determined according to the purpose.

  The water-permeable / water-retaining concrete of the present invention is obtained by solidifying the above-described composition of the present invention, and exhibits excellent water permeability and water-retaining properties, as shown in the examples described later. Even if it is applied, it has excellent water retention, is excellent in temperature drop due to watering, and has a long duration.

In order to produce the water-permeable / water-retaining concrete of the present invention, for example, the composition of the present invention is introduced into a desired mold and molded, or after being driven into a construction site, it is subjected to vibration and / or pressurization. It can be obtained by curing and curing.
The composition of the present invention can be usually mixed by a method in which components other than cement are kneaded in the above composition, and then cement is added and kneaded again.
Excitation and pressurization can be performed by a conventional method using a known apparatus used for the production of concrete.

The water-permeable / water-retaining concrete of the present invention can be used for pavement blocks, road surface blocks, porous concrete or mortar products.
The composition of the present invention can be used as a raw material for the above products, and can also be used for construction on the road in road pavement, ground and park pavement construction.

EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to these.
Example 1
A molten slag having a water absorption rate of 0.67%, a coarse particle ratio of 3.30, an actual volume ratio of 54.0%, and a fine particle amount of 0.9% is used as a grinding machine manufactured by Nippon Casting Co., Ltd. Was used to prepare a non-porous fine aggregate having a water absorption of 0.67%, a coarse particle ratio of 2.49, an actual volume ratio of 70.5%, and a fine particle amount of 8.96%. Further, CMC having an average degree of polymerization of 1400 and a weight average molecular weight of 330000 was dissolved in water to prepare a CMC aqueous solution having a viscosity of 3000 mPa · s.
The obtained pulverized non-porous fine aggregate (400 parts by mass) and CMC aqueous solution (80 parts by mass) were mixed, and 200 parts by mass of ordinary Portland cement was further kneaded to prepare a mortar composition. Next, the mortar composition was introduced into a predetermined mold, molded by vibration and pressurization, and cured and solidified to prepare a 4 × 4 × 16 cm test block.
The water absorption rate Q of the obtained test block is defined as the mass of the test block in an absolutely dry state (W _D ), the mass when the test block is absorbed for 24 hours (W _W ), and Q = (( It was calculated by (W _W ) − (W _D )) / (W _D ) × 100. As a result, the water absorption was 21.5%.

Comparative Example 1 and Reference Example 1
In place of the non-porous fine aggregate subjected to the grinding treatment, in Comparative Example 1, the water absorption ratio of 0.67%, the coarse grain ratio 3.30, the actual volume ratio 54.0%, and the fine particle amount 0. A test block was prepared in the same manner as in Example 1 except that 9% molten slag was used and spherical glass beads having a particle size of 0.99 to 1.40 mm (fine particle amount 0%) were used in Reference Example 1. The rate was calculated.
As a result, the water absorption of the test block of Comparative Example 1 was 9.0%, which was considerably lower than that of Example 1. Further, the water absorption of the test block of Reference Example 1 was 14.8%, which was lower than that of Example 1, despite using spherical glass beads having a uniform particle size.

Comparative Example 2
A test block was prepared in the same manner as in Example 1 except that a polyacrylic acid aqueous solution having a viscosity of 3000 mPa · s was used instead of the CMC aqueous solution, and the water absorption was calculated. As a result, the water absorption was 9.3% which was considerably lower than that of Example 1.
From the results of Comparative Example 1 and Comparative Example 2, it was found that the excellent absorptance in Example 1 was obtained by a combination of a ground fine porous aggregate and a CMC aqueous solution having a specific viscosity.

Comparative Example 3
The test was conducted in the same manner as in Example 1 except that instead of the CMC aqueous solution used in Example 1, a CMC aqueous solution having an average degree of polymerization of 100 and a weight average molecular weight of 17000 dissolved in water and having a viscosity of 80 mPa · s was used. A block was prepared and the water absorption was calculated. As a result, the water absorption was 11.8%, which was lower than that in Example 1.

Example 2
The test was conducted in the same manner as in Example 1 except that a CMC aqueous solution having a viscosity of 500 mPa · s, in which CMC having an average degree of polymerization of 800 and a weight average molecular weight of 174,000 was dissolved in water, was used instead of the CMC aqueous solution used in Example 1. A block was prepared and the water absorption was calculated. As a result, the water absorption was 14.8%, which was lower than that of Example 1, but a high water absorption comparable to that of Reference Example 1 using spherical glass beads having a uniform particle size was obtained.

Example 3
Viscosity of 300 mPa prepared by mixing 6000 parts by mass of non-porous fine aggregate subjected to grinding treatment prepared in Example 1, 40 parts by mass of CMC powder having an average degree of polymerization of 800 and a weight average molecular weight of 174,000, and 760 parts by mass of water. -800 mass parts of CMC aqueous solution of s was mixed, and 2000 mass parts of normal Portland cement was further kneaded to prepare a mortar composition. Next, the mortar composition was introduced into a predetermined mold, molded by vibration and pressurization, and cured and solidified to prepare a 4 × 4 × 16 cm test block.
(Confirmation test of water retention effect)
The absolute dry mass of the test block is (W _D ), the mass when the test block is absorbed for 24 hours is (W _W ), and the water absorption Q of the obtained test block is Q = ((( It was calculated by (W _W ) − (W _D )) / (W _D ) × 100. Then, it was left in a constant temperature and humidity room at a temperature of 20 ° C. and a humidity of 60%, and the mass was measured every 24 hours. The mass was (Wn), and the water absorption of the test block was determined for a total of 25 days from Q = ((Wn) − (W _D )) / (W _D ) × 100, and plotted on a graph. The results are shown in FIG.
(Confirmation test of repeated wet and dry effects)
The absolute dry mass of the test block is (W _D ), the mass when the test block is absorbed for 24 hours is (W _W ), and the water absorption Q of the obtained test block is Q = ((( It was calculated by (W _W ) − (W _D )) / (W _D ) × 100. Then, it was left in a constant temperature and humidity room at a temperature of 20 ° C. and a humidity of 60%, and the mass was measured every 24 hours. The mass was (Wn), and the water absorption rate of the test block was determined for a total of 25 days by Q = ((Wn) − (W _D )) / (W _D ) × 100. However, after absorbing water for 24 hours in the test block, the process was allowed to dry for 5 days in the constant temperature and humidity chamber, and then the process of absorbing water for 2 days was repeated, and the water absorption was measured while repeating the dry and humidified (water absorption) state. The results are shown in FIG.

Example 4
For testing as in Example 3, except that 4 parts by mass of cellulose ("Ultrafiber 500" (registered trademark), manufactured by Baccai)) was further added to the mortar composition as a polymeric fibrous material having water absorption A block was manufactured. Using the obtained test block, a water retention effect confirmation test and a wet and dry repetition effect confirmation test were conducted in the same manner as in Example 3. The results are shown in FIGS.

Comparative Example 4
Instead of the ground non-porous fine aggregate prepared in Example 1, Oikawa has a water absorption rate of 1.37%, a coarse particle ratio of 2.79, an actual volume ratio of 64.3%, and a fine particle amount of 1.7%. A test block was produced in the same manner as in Example 3 except that the fine aggregate (natural aggregate) was used. Using the obtained test block, a water retention effect confirmation test and a wet and dry repetition effect confirmation test were conducted in the same manner as in Example 3. The results are shown in FIGS.

Comparative Example 5
6000 parts by mass of the non-porous fine aggregate subjected to grinding treatment prepared in Example 1, 40 parts by mass of CMC powder used for preparing the CMC aqueous solution prepared in Example 3, and 760 parts by mass of water were mixed. Further, 2000 parts by mass of ordinary Portland cement was kneaded to prepare a mortar composition. Next, a test block was produced in the same manner as in Example 3. Using the obtained test block, a water retention effect confirmation test and a wet and dry repetition effect confirmation test were conducted in the same manner as in Example 3. The results are shown in FIGS.

From FIG. 1, it was found that the test blocks of Examples 3 and 4 containing the aggregate subjected to grinding treatment and the CMC aqueous solution having a specific viscosity had a large initial water retention effect and a water retention effect for about 3 days. At this time, it was found that Example 4 containing cellulose had a higher water retention effect than Example 3.
On the other hand, in Comparative Example 4 in which natural aggregate was used as the fine aggregate, the water retention effect was hardly obtained. Moreover, since the component of the used material was the same as that of Example 3, Comparative Example 5 was mixed with CMC in a powder state, so that excellent water retention as in Example was not obtained.
From FIG. 2, it was found that in Examples 3 and 4, even if water was lost due to drying, the water retention effect recovered to the same level as in the initial stage if water was replenished. In Comparative Example 5 in which CMC powder was mixed, the water retention effect was recovered, but the water retention effect itself was small.

Example 5
14000 parts by mass of the non-porous fine aggregate subjected to grinding prepared in Example 1 and 2400 parts by mass of a CMC aqueous solution having a viscosity of 300 mPa · s prepared by mixing 120 parts by mass of CMC powder with water, As a polymeric fibrous material having water absorbency, 60 parts by mass of cellulose ("Ultrafiber 500" (registered trademark), manufactured by Bakay) is mixed, and further, 14,000 parts by mass of Chichibu coarse aggregate and ordinary Portland cement 6000 are mixed. A mass composition was kneaded to prepare a concrete composition. Next, the concrete composition was introduced into a predetermined mold, molded by vibration and pressure, and cured and solidified to prepare a 50 × 50 × 6 cm test block.
The obtained test block was installed outside a room where the outdoor air temperature during the day was 30 ° C. or higher, and then watering of 10 liter / m ² was performed. The temperature of the test block before and after watering was measured and the behavior of watering temperature was observed. The results are shown in FIG.
Moreover, as a comparison, the temperature before and after watering was measured similarly about the commercially available water-permeable / water-retaining concrete block, lawn, natural soil, and asphalt, and the watering temperature behavior was observed. The results are shown in FIG.
From FIG. 3, it was found that the test block of Example 5 had a higher temperature before watering than a commercially available water-permeable / water-retaining concrete block, but the temperature after watering dropped sharply and its duration was long. .

It is a graph which shows the confirmation test result of the water retention effect performed in Examples 3 and 4 and Comparative Examples 4 and 5. It is a graph which shows the confirmation test result of the wet and dry repetition effect performed in Examples 3 and 4 and Comparative Examples 4 and 5. It is a graph which shows the result of the watering temperature behavior test done in Example 5.

Claims (6)

  A water-permeable / water-retaining concrete or mortar composition comprising fine aggregate obtained by grinding an aggregate, cement, and a carboxymethylcellulose aqueous solution having a viscosity of 100 mPa · s or more.   The composition according to claim 1, wherein the fine aggregate obtained by grinding the aggregate has a coarse particle ratio of 3.00 or less, an actual volume ratio of 55% or more, and a fine particle amount of 5 to 10%.   The composition according to claim 1 or 2, wherein the aggregate is a non-porous material such as molten slag, blast furnace slag, or steelmaking slag.   The composition according to any one of claims 1 to 3, further comprising a polymeric fibrous substance and / or coarse aggregate having water absorption.   Water-permeable / water-retaining concrete or mortar obtained by solidifying the composition according to claim 1.   5. A method for producing water-permeable / water-retaining concrete or mortar, wherein the composition according to any one of claims 1 to 4 is subjected to vibration and / or pressurization and curing after being molded or applied at a construction site. .

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