JP6854624B2 - Water retention block - Google Patents

Description

The present invention relates to a water-retaining block laid on paving sand.

Conventionally, a concrete interlocking block (hereinafter referred to as ILB) is known as a water-retaining block in order to prevent the urban heat island phenomenon.
This is to evaporate the water stored in the block through the surface of the block to lower the temperature of the pavement surface, but the amount of water retained is 9 mm in a 60 mm thick block (indication of amount, not length, same as rainfall). (Same as below), and the evaporation duration is short. For this reason, it is necessary to artificially supply water through water supply pipes and sprinklers.

Therefore, the inventors have developed a firing block using an unused resource, Kira, which is a fine powder having a median diameter of 20 μm, in order to improve the amount of water retained (Patent Documents 1 and 2) .
The fired product of fine powder forms a large number of thin capillaries in the main body, has a large water storage capacity, and has a water retention capacity of 0.25 to 0.25 g / cm ³ .
The pavement surface on which this block was laid using appropriate crushed stone and paving sand had the effect of keeping the block surface moist even after 44 days of fine weather after rainfall in the summer.

In the evaluation of water retention, the water retention ILB is JIS A 5371 (Non-Patent Document 1), which defines the amount of water retention as water retention and the suction height after 30 minutes as water absorption. The water retention amount is obtained by immersing the block in water for 24 hours and dividing the water absorption amount by the volume, and the standard is 0.15 g / cm ³ or more. The suction height after 30 minutes is stipulated that the amount of water absorbed from the bottom of the block through the capillary tube for 30 minutes is 70% or more of the water retention amount, and the water absorption rate is required to have a certain speed or more. ing. All water is in a free state (gravity is applied, but capillaries are not restrained).

The evaluation of the water-retaining block is obtained by measuring the surface temperature of the laid block in the summer and the temperature difference (= temperature reduction effect) from the non-water-absorbing block, but it is an established test that can be evaluated only in the summer and can be evaluated throughout the year. There is no way. In addition, the relationship between this effect and JIS standards is unclear.

Delete

Delete

Delete

Utility Model Registration No. 3192252 Utility Model Registration No. 3202672

JIS A 5371 Precast unreinforced concrete products

The heat island phenomenon in the summer in cities is partly due to asphalt and concrete pavement that do not retain water, and water retention blocks are commercially available to prevent this. In ILB, there is a standard for water retention of 0.15 g / cm ³ or more, but with this level of water retention (for example, 0.2 g / cm ³ ), the duration of the temperature reduction effect in summer is extremely short. Most of the commercially available products have a water retention capacity of 0.22 g / cm ³ or less, water absorption from the lower part of the block laying, sand laying, etc. is slow, and the temperature reduction effect is small. In addition, the firing block using the unused resource Kira, which is a fine powder developed by the inventors, blocks due to the water absorption capacity from the lower part of the block laying even if the sunny weather continues for 4 days after rainfall in summer. The surface remains moist, and the surface temperature is 12 to 7 degrees Celsius at noon when the sunlight is strong, compared to a normal ceramic block that does not retain water. However, it does not eliminate the artificial supply of water.

In view of the above points, the present invention has a large amount of water retention (0.25 g / cm). ³ (Above) Moreover, the water absorption from the paving sand is sufficient, the surface of the block is as moist as possible, the evaporation from the surface continues for a long time (about 10 days after the summer rain), and the water retention block does not require an artificial supply of water. Is intended to provide.

The water-retaining block of the present invention is a water-retaining block laid on paving sand made from kira generated in the process of refining a ceramic raw material, and has a water-retaining amount of 0.25 g. Use the cake-like kira discharged from the filter press as it is so that the water absorption for 30 minutes is 3 mm or more with a ^{/ cm 3} or more, and if necessary, use clay, sand or chamotte. A product in which a glazed layer having a thickness of 1 mm or less having pores through which water vapor passes is provided on the surface of a water-retaining block in order to mix, form into a predetermined rectangular body, and fire it, and further suppress the evaporation of water in the block. Then, the predetermined test device stacks a lower container containing water, which is larger than the bottom surface of the water-retaining block for measuring water absorption from the bedding sand, and two upper containers containing the same 30 mm thick bedding sand. A block is placed on the upper container, and the water in the lower part is absorbed by the water absorption zone of the cotton cloth that connects the lower part of the sand in the upper container and the water in the lower container through the slit provided on the bottom of the upper container. It is characterized in that the block is made to absorb water in the bedding sand that supplies water to the bedding sand and is supplied by capillary water absorption, and the amount of water absorption from the bedding sand of the block is measured by the change in the weight of the block. ..

In order for the water-retaining block laid on the paving sand to prolong the temperature reducing effect of the surface by evaporation of water from the surface for a desired period of time, it is 0.25 g / cm ³ or more, and 30 in a predetermined test apparatus. It is necessary that the amount of water absorbed by the minute is 3 mm or more.
Water absorption from the bedding sand is related to the amount of evaporation on the surface, and the effect is not long-lasting if it is too fast or too slow. If it is too early, it will be difficult to use the water from the paving sand, and if it is too late, the supply will not catch up with the evaporation. All of these are due to the size of the capillary diameter. Therefore, it is sufficient to keep the capillary diameter within a range suitable for the temperature reduction effect, but it is not easy to measure the capillary diameter. In the present invention, it is specified not by the capillary diameter but by the property linked to the capillary diameter.

Although the results differ depending on whether water is absorbed from free water or water from the paving sand, it is important to understand the capillary diameter because the capillary diameter affects both. However, it is difficult to measure the capillary diameter. It can be seen with an electron microscope, but only a part of it can be seen, it is expensive, and it cannot be used on a daily basis. Therefore, instead of measuring the capillary diameter directly, it was a 3mm or more as a measure of the water absorption of 30 minutes from the sand laid at a predetermined capillary water absorption test device.

The inventors have conducted experiments by constructing various water-retaining blocks in order to prolong the effect of reducing the temperature of the surface, but in order to increase the amount of water absorption, it is necessary to increase the amount of water-retaining and reduce the diameter of the capillaries.
The block manufacturing method that satisfies this is not the conventional manufacturing method of granulating and molding kira, but a new manufacturing method that uses the kira that is discharged in the form of a cake from the filter press as it is in the process of refining silica sand and feldspar. It was found that this method reduces the diameter of the capillaries and reduces the cost. If the capillaries become too thin, the amount of water absorbed for 30 minutes becomes small. In such a case, it is effective to add a chamotte or the like for adjustment. Mix about 20% of the raw materials. On the other hand, if the amount of water absorbed for 30 minutes is large, evaporation will be large, so it is advisable to provide a glaze layer or the like to suppress evaporation on the surface.

As shown in FIGS. 2 and 3, the predetermined capillary water absorption test apparatus includes a lower container 1 containing water, which is larger than the bottom surface of the water retention block for measuring water absorption, and an upper container 2 containing 30 mm thick bedding sand. A block is placed on the upper container 2, and the lower water 3 is passed through the slit provided on the bottom surface of the upper container 2 to the lower part of the sand 4 on the upper container 2 and the water of the lower container 1. The water absorption zone 5 of the cotton cloth to be connected supplies water to the bedding sand 4, and the water in the bedding sand 4 supplied by capillary water absorption is absorbed by the block. It measures the amount of water absorbed from. The external dimensions of the containers 1 and 2 are 220 mm × 120 mm, and although not shown, the size of the slits is 5 mm × 50 mm provided along the side wall of the container. It is desirable that the amount of water in the lower container 1 has a depth of 20 mm to 30 mm in the container. Further, the size of the block placed on the upper part of the paving sand is a general one, and is 200 mm × 100 mm × 60 mm. The bedding sand is sand having a particle size of 4.75 mm or less and a 75 μm sieve passing amount of 5% or less.

With this capillary water absorption test device, the degree of water absorption from the paving sand was measured. As a result, the graphs shown in FIGS. 4 and 5 could be obtained, and the relationship between the water absorption time and the water absorption amount was clarified. The water absorption from the bedding sand was as follows.
(1) The water absorption rate may or may not be much slower than that of free water.
(2) Those that slow down are those with a large capillary diameter, and those that do not change are those with a thin capillary diameter.
(3) The amount of water absorption does not change, although there is a difference in time.
Thus, the results are not the same as from free water. The larger the capillary diameter of the block, the slower the water absorption rate. Of the three water-retaining ILBs examined for comparison, two were about 10% faster than when from water, one was extremely slow, and water absorption from water was 60 mm higher within one hour. It took three days from the paving sand to reach that point. Judging at 24 hours, it is the slowness at which it is judged that water is not absorbed. The inventor's block is about 50% to 60% of the water absorption rate from water. Water in the capillaries that separate the interface is easy to move from the thick side to the thin side of the capillary, but it is difficult to move from the thin side to the thick side. If the block has a large pipe diameter, the movement of the interface will be rate-determining, the water absorption speed will be slow, and if it is slow, the movement speed within the block will also be slow. On the other hand, if the block has a small pipe diameter, the water absorption rate does not change even if there is an interface in contact with the bedding sand. When the capillary is thick, the moving speed at the interface is rate-determining, but when the capillary is thin, the moving speed is originally slow, so the interface is not rate-determining and the speed is within the capillary. Therefore, if the quality of the block is judged from the result of water absorption of free water, the result of laying the block will be misunderstood. The types of blocks and the amount of water absorption (mm) for 30 minutes after the start of water absorption are shown in the table of FIG. It can be seen that there are differences depending on the type of block.

FIG. 7 shows how much the water absorption rate (water absorption amount per hour) from the paving sand is necessary. FIG. 7 shows whether or not the temperature reduction effect increases as the amount of evaporation increases for blocks that evaporate on the block surface, except for blocks such as ILB, which have a tube diameter that is too large to evaporate on the surface. I checked it. In the figure, the single units 1, 24, and 39 are the types of blocks.
After absorbing water by the water absorption test method from the paving sand shown above, the side surface of the block and the exposed paving sand surface are covered with aluminum tape (Fig. 10). As a result of investigating the relationship of the surface temperature around that time, it was found that the amount of evaporation affects the temperature when the amount of evaporation is 4 mm or less. It is an experiment in August in hot Nagoya. FIG. 7 of the experimental example is the data of three test specimens for 5 days. Therefore, the amount of evaporation needs to be 4 mm or more per day, and the effect does not change even if more than that is evaporated. This capillary water absorption tester can also measure the amount of evaporation in this way.

For this reason, it is necessary that the rate of rise of water from the paving sand and the amount of water moving near the block surface have the ability to exceed this evaporation amount of 4 mm. Even if it is 4 mm a day, it evaporates mainly for 8 hours in the daytime, so when considering the amount of evaporation per hour, it is necessary to have an evaporation capacity of 0.5 mm or more per hour in consideration of this point. .. The amount of water movement near the surface can be determined from the amount of water absorbed from the bedding sand for 30 minutes.

That is, the amount of water moving near the block surface is such that the amount of water absorbed from the paving sand has a functional relationship with the water absorption time, Y = aX ^1/2 (Y is the amount of water absorption, X is the water absorption time, and a is a constant by the block). As shown in FIG. 5, the amount of water absorption is proportional to the square root of the water absorption time. This is already known for water absorption from water, and since it was found that the inventor's block has this relationship even from the paving sand, the rising flow rate near the surface can be obtained from now on (differentiated). Using this, the flow rate on the surface when the amount of water absorbed from the paving sand for 30 minutes was 3 mm was calculated to be 0.6 mm / hr. Therefore, it is possible to cope with evaporation of 0.5 mm for 1 hour. Since the moving speed of capillary water near the surface can be estimated by obtaining the water absorption amount for 30 minutes from the bedding sand, conversely, the water absorption amount for 30 minutes from the bedding sand can be obtained from the required moving speed near the surface. , This can also be used as a reference. If the block thickness is the same, the moving speed (surface flow rate) near the surface is proportional to the square of the water absorption amount for 30 minutes and inversely proportional to the water retention amount.

The table of FIG. 8 shows the results of the water absorption amount mm (amount) for 30 minutes measured by this test apparatus and the temperature reduction effect of the block actually laid. Although the commercially available water-retaining ceramic block in the table is 3.6 mm, there is almost no effect because the amount of water retained is small and the capillary diameter is large, so evaporation is fast. The same can be seen in the graphs of FIGS. 9 and 10. The water retention amount is a value according to the JIS test method in which the block is placed on a water surface having a depth of 5 mm to 10 mm and the water absorption amount for 24 hours ^{is divided by the volume of the block (cm 3).} In addition, the temperature reduction effect is the temperature difference from the non-water-absorbing block (the block with the same shape and no water absorption) by laying the block by the usual construction method and measuring the surface temperature every day after noon after rainfall in summer. .. The larger the negative value, the greater the effect.

The amount of water absorbed for 30 minutes represents the amount of water absorbed. Therefore, the amount of water retained = the amount of voids in the capillaries affects as well as the size of the capillary diameter. If the pipe diameter is the same, the larger the number of capillaries, the larger the amount of water absorbed for 30 minutes. Water retention capacity of conventional products of the inventors is a 0.20~0.25g / cm ^3, which should be increased to 0.25 g / cm ³ or more. When the amount of water retained increases, the amount of water absorbed for 30 minutes increases, and the flow rate on the block surface linked to this increases. Even if more evaporation occurs than necessary, it can be adjusted with a glaze on the surface, so the temperature reduction effect can be prolonged.

As described above, the present invention is discharged from the filter press so that the water retention amount in the block is 0.25 g / cm ³ or more and the water absorption amount for 30 minutes is 3 mm or more in a predetermined test device. A glaze layer with a thickness of 1 mm or less that has pores that allow water vapor to pass through on the surface of the water-retaining block, which is made from cake-shaped glitter as a raw material , mixed with clay, sand, and chamotte, molded into a predetermined rectangular body, and fired. The movement speed of water in the block is superior to the evaporation rate, the amount of water stored is increased, the water absorption performance of water below the paving sand is increased, the evaporation is controlled by the glaze layer on the surface, and the temperature reduction effect on the block surface is provided. Has become sufficient.

In addition, the moving speed of water near the block surface can be estimated from the amount of water absorbed 30 minutes after the start of water absorption from the paving sand, and it is necessary to obtain the required moving speed near the surface from the amount of evaporation in summer. The amount of water absorbed 30 minutes after the start of water absorption from the bedding sand can be determined.

(Paragraph [0030] to paragraph [0033] at the time of filing)
Next, an embodiment of the water retention block of the present invention will be described.
The water-retaining block uses the cake-shaped glitter discharged from the filter press as it is in the process of refining the ceramic raw material, and if necessary, mixes clay, sand and chamotte, forms it into a predetermined rectangular body, and fires it. Manufactured by.
Next, with the capillary water supply test apparatus A shown in FIGS. 2 and 3, it is confirmed whether the water absorption amount 30 minutes after the start of water absorption is 3 mm or more.
That is, a lower container containing water and two upper containers containing 30 mm thick paving sand are stacked, a block is placed on the upper container, and the lower water is provided on the bottom surface of the upper container. The water absorption zone of the cotton cloth that connects the lower part of the bedding sand of the upper container and the water of the lower container through the slit supplies water to the bedding sand and absorbs the water in the bedding sand supplied by capillary water absorption to the block. Then, the amount of water absorbed from the paving sand of the block is measured by the change in the weight of the block.
The paving sand is sand having a particle size of 4.75 mm or less and a 75 μm sieve passing amount of 5% or less.
If the amount of water absorbed in 30 minutes is less than 3 mm, the desired effect cannot be obtained, and if the amount of water absorbed in 30 minutes greatly exceeds 3 mm, the moving speed and evaporation amount of water increase, and the effect increases, but it is necessary. The above evaporation amount is not necessary (Fig. 7), and adjustment is required in order for the effect to last for a long time.
This adjustment mixes the raw material (kira) with clay, sand and chamotte, and changes the firing temperature.
Comparing a water-retaining block that stores water in the block with a water-retaining amount of 0.25 g / cm ³ or more and a water-absorbing amount of 3 mm or more for 30 minutes with a predetermined capillary water absorption tester (2016). Measurement after rainfall of 34 mm in the summer of 2014), as shown in FIG.
According to this, the conventional water-retaining concrete product becomes ineffective on the second day (in this experiment, there is no effect from the first day), but the conventional water-retaining block developed by the inventor (conventional Moist Pave in the figure) Although the effect decreases after 7 days, the effect of the embodiment (glazed moist pave in the figure) lasts for about 10 days.
The effect of the glazed block lasts for a long time because water evaporates through the glazed surface (there are pores through which water vapor permeates), but the amount of evaporation is suppressed. The glazed surface also has the effect of preventing stains.

It is a micrograph of the water retention block of this invention. It is a perspective view which shows the structure for carrying out this invention. It is a structural sectional view which shows the capillary water absorption measurement of the water retention block of this invention. It is a graph which shows the water absorption time and the water absorption amount from the paving sand measured by the apparatus of this invention. It is a graph which shows the square root and the water absorption amount of the water absorption time from the paving sand measured by the apparatus of this invention. It is a table of the type of the execution block which explains this invention and the water absorption amount (mm) for 30 minutes after the start of water absorption. It is a graph which shows the evaporation amount and the surface temperature of the Example which explains this invention. It is a table which shows the water absorption amount for 30 minutes and the temperature reduction effect of the Example explaining this invention. It is a graph which shows the type of a block and the temperature reduction effect by the field test of the Example explaining this invention. In the figure, the term "moist pave" is the product of the present invention. It is a structural sectional view when this invention is used for the measurement of the amount of evaporation.

A Capillary water absorption test device 1 Lower container 2 Upper container 3 Water 4 Spread sand 5 Water absorption zone (cloth)

Claims (1)

A water-retaining block laid on paving sand made from kira generated in the process of refining ceramic raw materials, and has a water-retaining amount of 0.25 g / cm ³ or more and stores water in the block. The cake-shaped glitter discharged from the filter press is used as it is as a raw material so that the water absorption for 30 minutes is 3 mm or more with a predetermined test device, and if necessary, clay, sand and chamotte are mixed and molded into a predetermined rectangular body. In order to suppress the evaporation of water in the block, a glaze layer having a thickness of 1 mm or less having pores through which water vapor passes is provided on the surface of the water-retaining block. , A lower container containing water, which is larger than the bottom surface of the water-retaining block for measuring water absorption from the bedding sand, and two upper containers containing the same 30 mm thick bedding sand are stacked, and the block is placed on the upper container. The water in the lower part is supplied to the sand by the water absorption zone of the cotton cloth that connects the lower part of the sand in the upper container and the water in the lower container through the slit provided in the bottom of the upper container. A water-retaining block characterized in that water in the bedding sand supplied by capillary water absorption is absorbed by the block, and the amount of water absorbed from the bedding sand of the block is measured by the change in the weight of the block.

Images