JP5336122B2 - Water-retaining cement molding - Google Patents

Description

  The present invention relates to a water-retaining cement molded body, and more particularly to a water-retaining cement molded body that absorbs and holds supplied water and evaporates from the surface.

  In recent years, temperature rise in urban areas due to the heat island phenomenon has become a problem. As an example of a measure for alleviating this phenomenon, a measure using a water-retaining molded body having an effect of suppressing an increase in surface temperature is used for a building exterior material or a road pavement material. Such a water-retained molded body suppresses an increase in surface temperature by evaporating the water absorbed and retained inside from the surface.

Patent Document 1 discloses an example of a conventional water-retaining molded body. The technique of Patent Document 1 is a water-retaining concrete solidified body, and is characterized in that fine continuous voids of lightweight aggregate communicate with the surface. In the technique of Patent Document 1, during production, an aqueous solution containing a large amount of carbon dioxide gas is included inside the voids of the lightweight aggregate, and through holes are made in the cement paste (cement gel) by releasing carbon dioxide gas. A fine continuous void of lightweight aggregate is in communication with the surface.
JP 2001-158676 A [C04B 38/08]

  However, in the technique of Patent Document 1, since the through hole is formed in the cement paste by the release of carbon dioxide gas, the diameter of the through hole communicating with the surface is increased. When the diameter of the through-hole is large, the influence of gravity on the water in the through-hole is increased, so that the supply of water to the surface is delayed and the water is difficult to spread on the surface in a film form. For this reason, with the technique of patent document 1, the evaporation amount of the water from the surface decreases, and the surface temperature rise suppression effect cannot be exhibited appropriately.

  Therefore, the main object of the present invention is to provide a novel water-retaining cement molded body.

  Another object of the present invention is to provide a water-retaining cement molded body that is excellent in the surface temperature rise suppressing effect.

  The present invention employs the following configuration in order to solve the above problems. Note that reference numerals in parentheses and supplementary explanations indicate correspondence with embodiments described later in order to help understanding of the present invention, and do not limit the present invention.

The first invention is a water-retaining cement molded body containing a porous body, wherein the water-retaining cement molded body is selected by using a granular body obtained by pulverizing calcium silicate heat insulating material using a cutting machine as the porous body. A first capillary part is formed, which communicates the surface of the body with the inside and retains water in a pF range of pF 2.7 to 4.2. The first capillary part is formed inside the porous body. A water-retaining cement molded body formed by a first void that is a void and a second void that is a void formed between a porous body and a cement gel or between adjacent porous bodies .

In the first invention, the water-retaining cement molded body (10) includes a porous body (14), and evaporates the water absorbed and retained from the surface (12), thereby suppressing an increase in surface temperature. To do. By selecting and using a granular body obtained by pulverizing calcium silicate heat insulating material using a cutting machine as a porous body, the water-retaining cement molded body is opened at the surface and has a pF range of pF 2.7 to 4.2. Thus, a first capillary part for holding water is formed. The water held in the capillary in the pF region of pF 2.7 to 4.2, that is, the water held in the first capillary part is held with an appropriate force, so that it is easy to spread on the surface and is also supplied to the surface. Done quickly.

  According to the first aspect of the invention, since the first capillary portion that holds water in the pF range of pF 2.7 to 4.2 is provided, the water held inside can be appropriately supplied to the surface, and the surface temperature rise is excellently suppressed. The effect can be demonstrated.

  The second invention is dependent on the first invention, and the first capillary portion can hold water of 15% or more by volume water content.

  In 2nd invention, the 1st capillary part of a water retention cement molding (10) can hold | maintain 15% or more of water by volume moisture content. By retaining a large amount of water in the pF region of pF 2.7 to 4.2, the effect of suppressing the surface temperature rise can be exhibited for a long time.

A third invention is dependent on the first or second invention, and the calcium silicate heat insulating material includes a waste material.

In 3rd invention, the waste material of a calcium silicate heat insulating material is used as a calcium silicate heat insulating material.

  According to the fourth invention, the waste material of the calcium silicate heat insulating material that has been conventionally disposed of in landfills can be effectively used, and problems associated with landfill disposal such as disposal costs and securing of disposal sites can be solved.

According to a fourth aspect of the present invention, there is provided a water-retaining cement molded body including a porous body, wherein a granular body obtained by pulverizing calcium silicate heat insulating material using a cutting machine is selected and used as the porous body. By adding more water than the amount required for cement hardening during molding, the surface of the water-retaining cement molded body is communicated with the interior by forming voids by the action of the water retained in the porous body. And the 1st capillary part which hold | maintains water in the pF range of pF2.7-4.2, and the surface and the inside of the said water retention cement molding are connected, and in the pF range of pF4.2-5.5 A second capillary part for holding water is formed , and the first capillary part is a first gap that is an internal gap of the porous body, and a porous space between or adjacent to the porous body and the cement gel. The second gap, which is a gap formed between the masses. The second capillary part is formed in the cement gel, and the first void and the second void are continuously formed with respect to the third void that communicates with the surface of the water-retaining cement molded body. This is an adhesive cement molded body.

In 4th invention, the 1st capillary part which hold | maintains water in the pF area of pF2.7-4.2 is formed in the inside of a water retention cement molding (10) by the surface (12). At the same time, a second capillary portion is formed that opens at the surface (12) and retains water in the pF range of pF 4.2 to 5.5. Water held in the capillary in the pF region higher than pF4.2 is difficult to move in the capillary due to frictional force, etc., but by forming many second capillary parts in the water-retaining cement molded body, water-retaining cement molding The body can exert the effect of suppressing the surface temperature rise.

  According to the fifth aspect of the present invention, the water can be evaporated from the surface even after the water held in the first capillary portion is lost, so that the effect of suppressing the surface temperature rise can be exhibited for a long time.

  According to this invention, since it has the 1st capillary part which hold | maintains water in the pF range of pF2.7-4.2, the water hold | maintained inside can be supplied appropriately to the surface, and the outstanding surface temperature rise inhibitory effect is provided. Can demonstrate.

  The above object, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

  Referring to FIG. 1, a water-retaining cement molded body 10 (hereinafter simply referred to as “molded body 10”) according to an embodiment of the present invention includes a building outer wall material, a roof material, an exterior material and a covering material, and It is used as a pavement material for roads, parks, etc., and the water absorbed and retained inside is evaporated from the surface 12, thereby suppressing an increase in surface temperature. The molded body 10 is particularly preferably used as a substitute for conventional tiles and bricks, and cools the building directly by being attached to the outer wall of the building, for example.

  As will be described in detail later, the molded body 10 has a predetermined shape and dimensions (for example, 30 cm in length, 30 cm in width, A plate-like body having a thickness of 3 cm). The molded body 10 has a structure in which the porous body 14 is dispersedly arranged inside and on the surface of the cement gel 16 in which the cement is hardened, and the inside of the molded body 10 has innumerable openings that communicate with the surface 12. Capillaries are formed. The innumerable capillaries include the voids formed inside the porous body 14, between the adjacent porous bodies 14, between the porous body 14 and the cement gel 16, and inside the cement gel 16, or the like. A first capillary part which is a void formed continuously with each other and retains moisture in the pF region of pF 2.7 to 4.2, and a second capillary which retains moisture in the pF region of pF 4.2 to 5.5 Part.

  Here, the pF value refers to the strength (water potential) at which the capillary adsorbs and holds water as water column pressure (water column height), and the absolute value thereof is expressed as a common logarithm. The pF value is known as an index value representing the moisture state of the soil. In this embodiment, the pF value is an index for indicating whether or not the water retained in the molded body 10 is effectively used for surface evaporation. It is used as a value.

  FIG. 1 is a schematic diagram for easily showing the cross-sectional structure of the molded body 10, and does not strictly indicate the number, size, shape, arrangement, and the like of the porous body 14 and the capillaries.

  Various cements can be used as the cement used for the molded body 10, and an inorganic cement or an organic cement such as a synthetic resin may be used. As the inorganic cement, for example, ordinary Portland cement or alumina cement can be suitably used. Ordinary Portland cement is widespread and easy to obtain and inexpensive, so it is excellent in economic efficiency, and the molded body 10 formed using this has a high surface reflectance of light because it becomes white or pale. Surface temperature rise due to solar radiation is unlikely to occur. Further, if the molded body 10 is formed using alumina cement, a dense composition can be made, so that it is easy to form a thin capillary and excellent in corrosion resistance, cold resistance, heat resistance, and the like. Moreover, since the cement gel 16 which hardened the inorganic cement has hydrophilicity, the adhesive force of water is large. For this reason, since water easily moves in the capillary and water easily spreads on the surface 12 of the molded body 10, the inorganic cement is suitable for forming the molded body 10.

  In addition, a single cement can also be used for the molded object 10, and several cement can also be mixed and used. Moreover, an additive can also be mix | blended with cement, for example, an aggregate can be mix | blended with an inorganic cement and it can also be set as concrete or mortar. Furthermore, the inorganic cement can be fired or the like to form a ceramic.

  The porous body 14 is a granular body having a large number of fine voids (first voids 20) therein. The particle size of the porous body 14 is not particularly limited, but is preferably 0.5 mm to 2.0 mm, and in particular, those having a particle size of about 1.0 mm are preferable. This is because if the particle size is too large, the strength of the molded body 10 decreases. Further, if the particle size is not uniform, the porous body 14 having a small particle size may fill the gap between the adjacent porous bodies 14 or the arrangement of the porous body 14 may become uneven. This is because the second gap 22 described later may not be properly formed.

  Moreover, it is preferable that the magnitude | size (cross-sectional area) of the 1st space | gap 20 of the porous body 14 is a magnitude | size comparable as the diameter of the 2nd space | gap 22, and the 1st space | gap 20 is pF2.7 ~ A capillary that retains moisture in the 4.2 pF range is preferred.

  Specifically, calcium silicate heat insulating material, rock wool heat insulating material, diatomaceous earth calcined particles, zeolite, peat, charcoal, vermiculite, bentonite, perlite, activated carbon and the like can be used as the porous body 14. Further, organic or inorganic fibers rounded into a substantially spherical shape can be used.

  Below, the manufacturing method of the molded object 10 is demonstrated. First, a predetermined amount of the porous body 14 and cement are kneaded and mixed in a dry state, and then water is added and kneaded. Next, this kneaded mixture is put into a mold and the surface (upper surface) is smoothed, and then vibration is applied to remove air mixed during kneading to remove bubbles floating on the surface. Subsequently, after performing wet curing for 24 hours in a room kept at high humidity, the mold is removed, and further, the molded body 10 is obtained by curing in the air for 28 days in the room.

  In the production of such a molded body 10, a part of the water added to the mixture of the cement and the porous body 14 is used for hardening the cement, and the other part is the first void 20 of the porous body 14. Absorbed and retained. During curing, that is, when the cement hardens to form a cured product, water in the first gap 20 of the porous body 14 flows out and travels around the porous body 14 or the cement gel 16. Is discharged from the surface (upper surface) of the cured product to the outside. By discharging water through the periphery of the porous body 14, a second gap 22 is formed between the porous body 14 and the cement gel 16 or between adjacent porous bodies 14. The second void 22 appropriately joins the first void 20 and other second voids 22 of the adjacent porous body 14 and communicates with the surface 12. On the other hand, by discharging water through the cement gel 16, innumerable third voids 24 extending from the porous body 14 toward the surface 12 are formed in the cement gel 16. The third gap 24 also merges with the other gaps 20, 22, 24 as appropriate and communicates with the surface 12. In addition, since the 2nd space | gap 22 is formed along the circumference | surroundings of the porous body 14, and it is easy to merge with the other 2nd space | gap 22, it comes to have a wide cross section. For this reason, the diameter (cross-sectional area) of the second gap 22 is larger than the diameter of the third gap 24.

  The first gap 20, the second gap 22, and the third gap 24 form innumerable capillaries that communicate the interior of the molded body 10 with the surface 12. Among these, the capillary formed by the first gap 20 and the second gap 22 mainly functions as the first capillary section. Specifically, a capillary in which the first void 20 or the second void 22 communicates (opens) directly with the surface 12 by exposing a part of the porous body 14 to the surface 12, and another first void in the capillary. A capillary or the like in which 20 or the second gap 22 is continuously formed is a first capillary portion. In addition, the capillary communicating with the surface 12 through the third gap 24 mainly functions as the second capillary part. Specifically, a capillary or the like in which the first gap 20 and the second gap 22 are continuously formed in the third gap 24 communicating with the surface 12 is the second capillary section.

  However, among the first gap 20 and the second gap 22, a gap having a small diameter, for example, a gap in which the cement gel 16 enters the first gap 20 to reduce its cross-sectional area forms the second capillary portion. There is also a case. In addition, among the third gaps 24, a gap having a large diameter, for example, a gap in which the third gaps 24 merge to increase the cross-sectional area may form the first capillary portion.

  The mixing ratio of the cement and the porous body 14 is appropriately determined based on the type of the cement and the porous body 14, the intended use and required performance of the molded body 10, and the volume ratio (cement: porous The mass 14) is preferably in the range of 2: 8 to 6: 4. This is because if the proportion of the cement is too small, the molded body 10 cannot be produced because the shape is not constant, and if the proportion of the cement is too large, high water retention, which is one of the characteristics of the molded body 10, cannot be exhibited appropriately. Because there are cases.

  Further, as described above, the water added at the time of manufacturing the molded body 10 is used for hardening of the cement, and is once held in the porous body 14 (first void 20), and the second void 22 and the second void. 3 is used to form the void 24. Therefore, the amount of water added at the time of production is larger than the amount of water added at the time of producing ordinary concrete, mortar, etc., and the water / cement ratio at the time of producing the molded body 10 becomes high.

  In such a molded body 10, when water is supplied to the surface 12, the supplied water flows from the openings formed in the surface 12 due to capillarity, gravity, and the like to the respective voids 20, 22, 24 is absorbed. The water absorbed in the molded body 10 sequentially moves through the gaps 20, 22, and 24 by capillary action and gravity, and permeates the entire molded body 10, and is held in the gaps 20, 22, and 24. The

  And from the surface 12 of the molded object 10 which hold | maintained water, water evaporates suitably according to the surrounding environmental condition. In particular, when the temperature rises due to solar radiation, the water present on the surface 12 is actively evaporated. At this time, when the water in the vicinity of the openings of the gaps 20, 22, and 24 evaporates, the water held in the gaps 20, 22, and 24 existing in the vicinity of the evaporated water is caused by intermolecular force and capillary action. It is sucked up and spreads out from each opening to the surface 12. Further, as the water held in the vicinity of the surface 12 moves to the surface 12, the water held further inside the molded body 10 is sequentially sucked up by capillary action and appropriately passes through the gaps 20, 22, and 24. Through each opening to the surface 12. That is, with the evaporation of water on the surface 12, the water in the molded body 10 is sequentially supplied to the surface 12 through the gaps 20, 22, and 24 and is sequentially evaporated from the surface 12.

  Here, when the diameter of the capillary (void) is large, that is, in the case of a capillary holding water in a low pF region, the water held in the capillary is strongly affected by the downward force due to gravity. As the water moves slowly to the surface, it is difficult for the water to spread on the surface. On the other hand, when the diameter of the capillary is small, that is, in the case of a capillary holding water in a high pF region, the water held in the capillary is strongly affected by frictional force and the like. The water is difficult to spread. In other words, even if the pF region holding water is too high or too low, the area of water that spreads from the opening of one capillary to the surface becomes narrow, so a layer of water that spreads in a thin film on the entire surface is appropriately It cannot be formed and water cannot be quickly replenished to the surface when it evaporates.

  Therefore, the present inventors have been able to form a layer of water spreading in the form of a thin film over the entire surface, and as a result of earnestly examining the structure of the molded body 10 in which water is quickly supplied to the surface when the water evaporates from the surface. It was conceived that a capillary (first capillary part) that holds water in the pF region of pF 2.7 to 4.2 may be formed on the molded body 10.

  As described above, the first capillary part that retains water in the pF range of pF 2.7 to 4.2 adds more water than is necessary for the hardening of the cement when the molded body 10 is manufactured. It can be formed by forming voids by the action of water held in the porous body 14. In addition, by selecting and using the porous body 14 having innumerable voids that retain moisture in the pF range of pF 2.7 to 4.2, more first capillary portions can be formed in the molded body 10. it can.

  As described above, the first capillary portion that holds water in the pF range of pF 2.7 to 4.2 holds water with an appropriate force, so that the water spreads in the form of a thin film near the opening and the water evaporates. As the area increases and water evaporates from the surface 12, water is quickly supplied to the surface 12. That is, the water retained inside can be appropriately supplied to the surface 12. Thereby, in the molded object 10, since the state which the water has spread in the thin film form on the whole surface 12 is maintained, the evaporation amount of the water from the surface 12 increases, and the evaporation rate of water becomes quick. Therefore, the molded body 10 can exhibit an excellent surface temperature rise suppressing effect. Moreover, since the 1st capillary part hold | maintains water with moderate force, when absorbing the supplied water, it can absorb water quickly and the molded object 10 is excellent in water absorption.

  Below, the result of the evaluation experiment of the molded object 10 is shown. For the molded body 10 of this evaluation experiment, ordinary Portland cement (manufactured by Aso Lafarge Cement Co., Ltd.) is used as the cement, and the waste material of the calcium silicate heat insulating material is cut into the porous body 14 by a cutting machine (Hitachi Koki). A granular material pulverized to a particle size of about 1.0 mm using a cross-cut saw (C7RSH) was used. In addition, four types of molded bodies 10 in which the mixing ratio of the porous body 14 was changed, that is, Example 1-4, were prepared, and an evaluation experiment was performed on each of Examples 1-4. The ratio of porous body: cement in each example is volume ratio, Example 1 is 65:35, Example 2 is 70:30, Example 3 is 75:25, Example 4 Is 80:20.

  In addition, the calcium silicate heat insulating material is a heat insulating material used for piping equipment of a thermal power plant, and a large amount of waste material is generated during periodic inspection of the piping equipment. Conventionally, the waste material of the calcium silicate heat insulating material has been disposed of as industrial waste in landfill, but if it is effectively used as the porous body 14 of the molded body 10 in this way, problems associated with landfill disposal (for example, disposal costs and disposal) To secure a place). FIG. 2 shows the relationship (pF-moisture curve) between the pF value and the volumetric water content of the calcium silicate heat insulating material. The volumetric water content at each pF value was measured in the same manner as the measurement for the molded body 10 described later. As can be seen from FIG. 2, the calcium silicate heat insulating material has many voids that retain water in the pF region of pF 2.7 to 4.2, and in particular, the pF region of pF 3.0 to 4.0. Can hold about 50% water by volume.

  In FIG. 3, the pF-moisture curve of Example 1-4 is shown. The volumetric water content at each pF value was measured by referring to “Soil Standard Analysis / Measurement Method (edited by Soil Standard Analysis Method / Measurement Committee, supervised by Japanese Society of Soil Fertilizer, 1986 edition)”. Specifically, pF0 is a vacuum saturation method, pF1.5 is a sand column method, pF1.8 to 3.0 is a pressure plate method, pF3.8 to 4.2 is a centrifugal method, and pF7 is a heat loss. Each was measured by the method. In addition, when measuring the volumetric water content of each pF value, it arrange | positioned in the analyzer so that the surface 12 of each Example may become the lower side. This is because the molded body 10 evaporates water from the surface 12, so it is necessary to know how water is discharged from the surface 12.

  As shown in FIG. 3, in each Example 1-4, the volume water content in pF1.8 is 65 to 80%. In general, water in the pF region lower than pF1.8 naturally flows down from the molded body as gravity water, and water in the pF region of pF1.8 or higher is known to be retained in the molded body as capillary water. Therefore, it can be said that all the molded bodies 10 of Examples 1-4 have very good water retention.

  In any of Examples 1-4, the volumetric water content does not change much until pF2.7, and the volumetric water content rapidly decreases in a pF region higher than pF2.7. From this, it can be seen that in Examples 1-4, a large amount of water is retained in the pF region of pF 2.7 or higher. Further, the water content in the pF region of pF 2.7 to 4.2 tends to increase as the blending ratio of the porous body 14 increases, and the volume water content is 17.8% in Example 1. 2 is 19.9%, Example 3 is 24.4%, and Example 4 is holding 29.8% of water in the pF region of pF 2.7 to 4.2. Moreover, in any of Examples 1-4, 45 to 50% of water is retained in a high pF region of pF4.2 or higher.

  Furthermore, between pF3.0 and pF3.8, the relationship between the volumetric water content and the blending ratio of the porous body 14 changes. That is, in the pF region up to pF3.0, the volumetric water content increases as the blending ratio of the porous body 14 increases. However, in the pF region higher than pF3.8, the volumetric water content increases as the blending ratio of the porous body 14 increases. The rate is small. This suggests that the capillaries derived from the cement gel 16 become more involved in moisture retention as the pF range is increased.

  In FIG. 4-8, the test result which investigated the surface temperature rise inhibitory effect of Example 1-4 is shown. This test (moisture evaporation ability test) was performed according to the test method prescribed by the Interlocking Block Association, and was performed in a room kept at a constant temperature of 25 ° C. by an air conditioner. As the specimen, the molded body 10 of Example 1-4 formed into a plate-like body having a length of 30 cm, a width of 30 cm, and a thickness of 3 cm was used. Moreover, as a comparative example, the normal concrete molded object (comparative example 1) created in the same shape as Example 1-4 and the eco terrier ceramic tile (comparative example 2) by Sekisui Exterior Co., Ltd. which are commercial products are used. It was.

The specific test method of the water evaporation ability test is shown below. First, the specimen was immersed in water at 25 ° C. for 2 hours and 30 minutes, so that the specimen was sufficiently retained with water. Next, the surface (upper surface) was opened to the atmosphere, and the surface and the bottom surface were covered with a 30 mm thick foamed plastic heat insulating material, and the surface was irradiated with light having an irradiation intensity of 650 W / m ² using a 500 W halogen bulb. . And the time change of the surface temperature and back surface temperature at this time was measured using the temperature / humidity logger (made by Hioki Electric Co., Ltd.), and the weight change accompanying water evaporation was measured using the measuring instrument.

  FIG. 4 is a graph showing changes over time in the surface temperatures of Example 1-4 and Comparative Examples 1 and 2. As shown in FIG. 4, in Comparative Example 1, the surface temperature increased rapidly immediately after the start of the test, and became substantially constant at about 56 ° C. Further, in Comparative Example 2, although the increase in the surface temperature was suppressed as compared with Comparative Example 1, the surface temperature increased immediately after the start of the test as in Comparative Example 1, and became substantially constant at about 48 ° C. On the other hand, in Example 1-4, after maintaining the surface temperature of about 30 ° C. for 1000 minutes or more from the start of the test, the surface temperature gradually increased and became substantially constant at about 40 ° C. That is, in Example 1-4, the “low temperature maintenance range” that maintains a temperature lower by about 25 ° C. than Comparative Example 1 is higher than the low temperature maintenance range, but the temperature rise is alleviated. A “temperature rise relaxation region” that is about 15 ° C. lower than the comparative example 1 and a “transition region” that transitions from the low temperature maintenance region to the temperature rise relaxation region are confirmed. As a result, it can be seen that all of Examples 1-4 can exhibit a very excellent surface temperature rise suppressing effect for a long time.

  FIG. 5-8 is a graph showing changes over time in the surface temperature, the back surface temperature, and the weight for each of Examples 1-4. As described above, each of the surface temperatures of Example 1-4 reaches the temperature increase relaxation region through the transition region from the low temperature maintenance region. Here, looking at the weight change of Example 1-4, the weight decreases relatively linearly for a certain time from the start of the test, but then the inflection point comes and the slope of the weight change becomes gentle (that is, The evaporation rate of water becomes slower). This inflection point generally coincides with the starting point of the transition zone.

  Moreover, in the low temperature maintenance area | region of Example 1-4, surface temperature rises rapidly immediately after a test start, and the course where temperature falls gradually is reached immediately after reaching a change point. Using the pF-moisture curve shown in FIG. 3, when the corresponding pF value is determined from the volumetric water content of Example 1-4 at this change point, the pF value of Example 1-4 at this change point is Was about pF2.8. This is because, as described above, the water held in the capillary in the pF region up to pF 2.7 is strongly affected by the downward force due to gravity, so the movement to the surface 12 is slow and lost due to evaporation. This is probably because a loss occurs in the replenishment of the water surface 12. Moreover, when the pF value of the end point of the low temperature maintenance area | region of Example 1-4, ie, the start point of a transition area, was calculated | required similarly, all were about pF4.2. From these, it can be seen that in the low temperature maintenance region, water retained in the pF region of pF 2.7 to 4.2, that is, water retained in the first capillary portion is used.

  In the low temperature maintenance region, the maintenance time becomes longer as the blending ratio of the heat insulating material increases, that is, as the amount of water retained in the pF region of pF 2.7 to 4.2 increases (see FIG. 3). . That is, if the molded body 10 having a larger amount of water retained in the pF range of pF 2.7 to 4.2 is manufactured, the maintenance time in the low temperature maintenance range can be made longer.

  Moreover, the molded object 10 of Example 1-4 has a temperature rise relaxation area. When the pF region of water used in the temperature rise relaxation region is determined using the pF-water curve shown in FIG. 3, the water retained in the pF region of approximately pF 4.2 to 5.5, that is, the second capillary It was found that the water retained in the department was used. As described above, the water retained in the pF region higher than pF4.2 is strongly affected by frictional forces and the like, and thus hardly moves to the surface 12. However, in the molded body 10 of Example 1-4, since a very large number of second capillary portions are formed, the amount of water supplied from one second capillary portion to the surface 12 is small, but the temperature rise is alleviated. Demonstrates excellent surface temperature rise suppression effect in the region. By providing such a second capillary part, the molded body 10 can exhibit an excellent surface temperature rise suppressing effect for a long time even after the water held in the first capillary part is lost. In addition, although illustration is abbreviate | omitted, when the moisture evaporation capability test of the long time was further performed about the molded object 10 of Example 2, even if 60 hours or more pass after a test start, a temperature rise relaxation range may be maintained. confirmed.

  Further, as shown in FIG. 5-8, in Example 1-4, there is a difference between the surface temperature and the back surface temperature. From this, it turns out that the molded object 10 of Example 1-4 has the outstanding heat insulation. Further, as the moisture retained inside decreases with the passage of time, and the blending ratio of the porous body 14 increases, the heat insulating property of the molded body 10 increases. This is probably because the calcium silicate heat insulating material itself used as the porous body 14 exhibits high heat insulation. The thermal conductivity (kcal / m · h · ° C.) of Example 1-4 in the air-dried state is 0.276 in Example 1, 0.213 in Example 2, and 0.199 in Example 3. Example 4 is 0.175, which can be said to have a very low thermal conductivity compared to 2.30 of normal concrete.

  In addition, in the above-mentioned Example, after the surface 12 was leveled before curing, the molded product 10 was manufactured with the surface 12 left as it was. However, as another example, the molded body 10 can be formed with a large number of fine irregularities over the entire surface 12 by cutting the surface 12 thereof. The unevenness may be formed in a groove shape or a waveform that extends linearly in one direction and a flat surface inclined in the orthogonal direction is repeated, and the depth and pitch of the unevenness may be set to, for example, 1 to 2 mm. By forming such irregularities on the surface 12, the area of the surface 12 is increased, the apparent contact angle of water droplets on the surface 12 is reduced, and water is easily spread over the surface 12 in a thin and thin manner.

  Further, when the molded body 10 is manufactured, pressure may be applied to the surface 12. Since this pressure acts more greatly as the pressure is applied to the surface, the second and third gaps 22 and 24 closer to the surface 12 are compressed, and the second and second voids are compressed from the back surface of the molded body 10 toward the surface 12. The diameters (thicknesses) of the three gaps 22 and 24 are gradually reduced. Since the force that sucks up the water held in the capillary by capillary action increases as the capillary becomes thinner, the water held in the capillary moves toward the narrower side of the capillary. That is, if the thickness of the capillary is gradually reduced from the back surface of the molded body 10 toward the surface 12, moisture in the capillary can easily move toward the surface 12 of the molded body 10, and moisture from the surface 12. Evaporation is promoted.

  When pressure is applied when the molded body 10 is manufactured, the cement having high fluidity moves upward, and the proportion of the cement gel 16 in the vicinity of the surface of the cured product is increased. If the vicinity of the surface is cut, a large number of capillary openings can be reliably formed on the surface 12 of the molded body 10. Moreover, the diameter and number of capillaries can be controlled by appropriately adjusting the pressure applied to the mixture and controlling the flow direction and flow rate of the water that moves during compression dehydration.

  In the above-described embodiment, when the molded body 10 is manufactured, water is added after kneading the cement and the porous body 14, but the porous body 14 absorbs water in advance, You may make it knead | mix the porous body 14 containing, cement, and water.

It is a schematic diagram which shows the cross-sectional structure of the water retention cement molded object of one Example of this invention. It is a graph which shows the pF-moisture curve of the porous body (calcium silicate heat insulating material) used for a water retention cement molding. It is a graph which shows the pF-moisture curve of Example 1-4 of a water retention cement molding. It is a graph which shows the result of the water | moisture-content evaporation ability test of Example 1-4 and Comparative Examples 1 and 2 of a water retention cement molding. It is a graph which shows the result of the water evaporation ability test of Example 1 of a water retention cement molding. It is a graph which shows the result of the water evaporation ability test of Example 2 of a water retention cement molding. It is a graph which shows the result of the water evaporation ability test of Example 3 of a water retention cement molding. It is a graph which shows the result of the water evaporation ability test of Example 4 of a water retention cement molding.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Water-retaining cement molding 12 ... Surface 14 ... Porous body 16 ... Cement gel 20 ... 1st space | gap 22 ... 2nd space | gap 24 ... 3rd space | gap

Claims (4)

In a water-retaining cement molded body containing a porous body,
By selecting and using the granular body which grind | pulverized the calcium silicate heat insulating material using the cutting machine as the said porous body, the surface and the inside of the said water retention cement molding are connected, and pF2.7-4. Characterized in that the first capillary part holding water in the pF range of 2 was formed ,
The first capillary part is a first void that is an internal void of the porous body, and a second void that is formed between the porous body and the cement gel or between the adjacent porous bodies. A water-retaining cement molded body formed by voids .   The water-retaining cement molded body according to claim 1, wherein the first capillary part can hold water having a volume moisture content of 15% or more. The water-retaining cement molded body according to claim 1 or 2, wherein the calcium silicate heat insulating material includes a waste material. In a water-retaining cement molded body containing a porous body,
As the porous body, a granular body obtained by pulverizing calcium silicate heat insulating material using a cutting machine is selected and used, and more water than the amount necessary for cement hardening is added at the time of forming the water-retaining cement molded body. By forming voids by the action of water retained in the porous body, the surface and the interior of the water-retaining cement molded body are communicated with each other, and water is retained in the pF region of pF 2.7 to 4.2 And a second capillary part that communicates the surface and the inside of the water-retaining cement molded body and retains water in the pF range of pF 4.2 to 5.5. And
The first capillary part is a first void that is an internal void of the porous body, and a second void that is formed between the porous body and the cement gel or between the adjacent porous bodies. Formed by voids,
The second capillary part is formed in the cement gel, and the first void and the second void are continuously formed with respect to the third void that communicates with the surface of the water-retentive cement molded body . Cement molded body.

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