JP2011093759A - Lightweight water-retentive block - Google Patents

Abstract

The present invention provides a lightweight water-retaining block excellent in transportability, workability, and water retention performance that is effective in mitigating a heat island phenomenon.
Kneading water is added to a hydraulic composition containing cement, paper sludge ash, and pearlite, followed by pressure molding. Unit cement content of 190~220kg / cm ³ in the formulation, the unit paper sludge ash amount 80~120kg / cm ^3, a unit pearlite amount is 100~125kg / cm ^3, the short fibers alkali resistant natural cellulose 4～6Kg / Mix ³ cm.
[Selection figure] None

Description

  The present invention relates to a relatively low-strength lightweight water retaining block used mainly for the purpose of mitigating the heat island phenomenon.

  In recent years, the heat island phenomenon, in which the temperature in a city rises compared to the surrounding area, has become prominent. Along with this, a large amount of heat is accumulated on the roof of the building during the day, and it has been confirmed that the surface temperature is higher than the outside temperature and the temperature inside the building is higher even at night.

  Based on this, it is considered effective to improve the thermal characteristics of the rooftops of high-rise buildings and the like as a means to alleviate the deterioration of the thermal environment in cities. As one of the measures to embody this, there is a method of covering the roof of a building with a block having water retention, and it is necessary to develop a water retention block suitable for this method.

As a technique related to a water retention block for alleviating a conventional heat island phenomenon, for example, Patent Document 1 discloses a water retention block including cement, aggregate, water, and a water retention material, and the water retention material is an autoclave. consists granules curing the aerated concrete, and, the amount of the water-retaining material in the water retention block, water retention block is disclosed in which a 0.16~0.20m ³ / m ^3.

Patent Document 2 discloses that in a porous water retention block made of a hydraulic composition, the water retention amount per unit volume after the entire dry block is immersed in water and absorbed for 24 hours is 0.15 g. / Cm ³ or more, the percentage of the ratio of the block mass M ₃₀ after 30 minutes have passed after the bottom end of the completely dry block is immersed in water and the block mass M _cw when sufficiently wet (M ₃₀ / M _cw ) × 100%, the suction height is 70% or more, the bending strength is 3 N / mm ² or more, and it is heated from 100 to 110 ° C. until it becomes completely dry from a sufficiently wet state. A water-retaining block having a wet-dry time of 48 hours or more is disclosed.

In addition, as a specific blending example, the hydraulic composition is a super hard kneaded concrete blended with cement, pearlite litter and paper sludge ash, and the amount of paper sludge ash per unit of paper sludge ash is If the 100 to 300 / m ^3, if the unit pearlite scrap quantity for pearlite scrap 300 kg / m ³ or more, the unit cement content of 150 kg / m ³ or more, and a unit paper sludge ash weight of 100 to 300 / m ³ The case where it is is disclosed.

In addition, in Patent Document 3, cement, paper sludge incineration ash, and an aggregate made of at least a part of lightweight aggregate are used as an interlocking block for road pavement that aims to effectively use paper sludge incineration ash that is waste. Water-retaining block containing pumice crushed or pearlite grains as lightweight aggregate, unit cement amount is 250-450 kg / m ³ , unit paper sludge incineration ash amount is 30-700 kg / m ³ , unit lightweight bone The material amount is described as 150 to 700 kg / m ³ .

Japanese Patent No. 3535862 JP 2007-230827 A JP 2008-075270 A

Von Tan Van, Hiroshi Fujiwara, Akira Kawashima, “Study on Development of Lightweight Rooftop Water-Retaining Block”, 36th Kanto Branch Technical Research Presentation Presentation, March 2009

  In the inventions described in Patent Documents 1 to 3, the purpose is to alleviate the heat island phenomenon, and at the same time, the waste materials are effectively used, but the object is an interlocking block used on a road surface such as a sidewalk.

  For this reason, strength as an interlocking block is also required, and although the weight of the block is reduced by using lightweight aggregates, there are limits in terms of water retention and weight reduction.

  On the other hand, the present invention focuses on improving the mitigation effect of the heat island phenomenon due to water retention, for example, when installed on the roof of a building under conditions where the load conditions are loose, such as load, transportation cost, In view of workability, the object is to provide a water-retaining block that is lighter and has superior water retention performance.

The lightweight water-retaining block according to claim 1 of the present application is formed by adding kneaded water to a hydraulic composition containing cement, paper sludge ash, and pearlite and press-molding. 220 kg / cm ^3, a unit paper sludge ash weight 80~120kg / cm ^3, the amount of units pearlite is characterized in that a 100~125kg / cm ^3.

  As the cement, ordinary Portland cement can be used, but other cements may be used.

While the strength increases as the unit cement amount increases, the density of the block increases. In the present invention, considering the case where it is installed on the roof of a building, etc., it is aimed at a water retention block that is lightweight and excellent in water retention performance in terms of load, transportation cost, workability, and the unit cement amount is determined from each experimental result described later. 190 to 220 kg / cm ³ .

  Paper sludge ash (hereinafter referred to as “PS ash”) is ash that remains after incineration of paper sludge called paper sludge, which is the majority of the waste from the paper industry. It contains fine fibers that do not become paper among papermaking raw materials, fillers such as talc and kaolin, and foreign materials mixed with waste paper.

  Since it is porous, it is excellent in water retention, and it has been confirmed that water retention and water absorption performance can be imparted to concrete by using this PS ash. Since PS ash is lightweight and can be expected to have a pozzolanic reaction, it was thought that it was possible to develop a lightweight water-retaining block having the same strength as a general lightweight block while being lightweight.

From the viewpoint of the treatment and effective use of industrial waste, it is considered that it is used as much as possible, but large-scale use leads to an increase in density, and in each experiment described later, the present invention is reduced in terms of weight reduction and water retention performance. Since the expected effect was not obtained, the lower limit was set to 80 kg / cm ³ and the upper limit was set to 120 kg / cm ³ .

Perlite is very lightweight and has high water absorption, so it was used in the present invention. From each experimental result to be described later, the unit cement amount is 190 to 220 kg / cm ³ , and the unit paper sludge ash amount is 80 to From the relative relationship with 120 kg / cm ³ , when the unit pearlite amount was 125 kg / cm ³ or less, high water retention performance expected as a water retention block was obtained.

  The invention according to claim 2 is characterized in that the lightweight water-retaining block according to claim 1 further includes a fiber material.

  The fiber material in this case expects the role of reinforcing the water retention block and the water retention capability of the fiber material itself, and natural fibers are desirable from the viewpoint of the water retention capability.

The invention according to claim 3 is characterized in that, in the lightweight water-retaining block according to claim 1 or 2, the density in blending is 0.6 g / cm ³ or less.

The lightweight water-retaining block of the present invention is compacted by pressure molding, so that the actual density is generally larger than the blending density. However, in the present invention, the block compressive strength is 1 N / mm ² or more and the actual density is 1.0 g / cm. ^The target is about ³ or less, and in the experimental results described below, these targets are achieved when the density is 0.6 g / cm ³ or less in a blend containing cement, paper sludge ash, pearlite, etc. However, high water retention performance was secured.

  The invention according to claim 4 is the lightweight water retaining block according to claim 1, 2, or 3, wherein the pearlite is pearlite waste.

  As pearlite scraps, pearlite or other vitreous rhyolite is pulverized and then fired and foamed at high temperatures to produce pearlite that did not foam and became a product. can do.

  The product pearlite is very light, and when expanded, it has properties such as a porous structure, high water absorption, and heat insulation. Similarly, high water absorption has been confirmed for pearlite waste, and the effect of effective use of industrial waste can be obtained.

The invention according to claim 5 is the lightweight water-retaining block according to claim 1, 2, or 3, wherein the pearlite crushes the pearlite, adjusts the particle size, rapidly heats and foams, and the particle size is 2.5 mm or less. Density of 0.15 kg / m ³ , or crushing pearlite, adjusting particle size, rapidly heating and foaming, particle size of 50 mm or less and density of 0.17 kg / m ³ , or a predetermined ratio thereof It is characterized by being added in.

  These are commercially available as pearlite of the product, and the expected good water retention performance was obtained in the experimental results described below.

  The invention according to claim 6 is the hydraulic composition according to claims 1 to 5, wherein the fiber material is a short fiber of alkali-resistant natural cellulose extracted from wood.

  As a commercially available product, for example, there is a product name “Ultra Fiber 500” manufactured by Baccai Co., Ltd., and it is known that by adding it to concrete or mortar, it is effective in reducing cracks and can improve strength and durability. Yes.

  This product uses 100% alkali-resistant natural cellulose extracted from wood and has excellent dispersibility due to its short fiber length, small diameter, large number of fibers, and high apparent density. can do.

In addition, since the shape of the fiber is a conduit, it can retain about 80% of the moisture relative to the fiber mass, so it has a high affinity with cement and can be directly bonded to cement hydrate. Since it can do, the water retention of a block can be improved. In the case of “Ultra Fiber 500”, it is confirmed that high water retention is obtained in the range of ^{4 to} 6 kg / cm ³ .

  The lightweight water-retaining block of the present invention has low strength, but is very lightweight and has high water retention performance, so it has a very high effect on mitigating the heat island phenomenon when used under conditions where no load is applied or under low load conditions. It can be demonstrated.

  Moreover, since it is very lightweight, it is excellent in transportability and workability.

It is explanatory drawing of the apparatus made into the wet state used for the water retention test of Experiment 1. FIG. It is explanatory drawing of the water absorption test apparatus used for the water absorption test of Experiment 1. FIG. FIG. 6 is a Ci diagram at a unit cement amount of 220 kg / m ³ in the compaction test of Experiment 1. FIG. ⁴ is a Ci diagram at a unit cement amount of 270 kg / m ³ in the compaction test of Experiment 1. FIG. ⁴ is a Ci diagram at a unit cement amount of 320 kg / m ³ in the compaction test of Experiment 1. It is a 1 day intensity | strength comparison chart with the combination of No.18, No.19, and No.20 in the compressive strength test of Experiment 1, and a 14-day strength comparison figure. It is a density-compressive strength distribution map (material age 14 day series) in the compressive strength test of Experiment 1. It is a density-compressive strength distribution map (material age 1 day series) in the compressive strength test of Experiment 1. 6 is a density-water absorption distribution diagram for each cement amount in Experiment 1. FIG. 4 is a density-water absorption distribution diagram for each pearlite volume substitution rate in Experiment 1. FIG. 4 is a density-water absorption distribution map for each unit PS ash amount in Experiment 1. FIG. 6 is a density-water retention distribution diagram in Experiment 1. FIG. It is a wicking height distribution map in Experiment 1. 6 is a density-water absorption distribution diagram in Experiment 2. FIG. It is a water absorption rate comparison chart in Experiment 2. 6 is a density-compressive strength distribution diagram in Experiment 2. FIG. 6 is a density comparison diagram in Experiment 2. FIG. It is a water retention amount comparison diagram in Experiment 2. It is a density-water retention amount distribution map in Experiment 2. FIG. 6 is a drawing showing the suction height in Experiment 2. FIG. 10 is a comparison of compressive strength in Experiment 3. It is a water absorption rate comparison figure in experiment 3. FIG. 6 is a density comparison diagram in Experiment 3. FIG. 6 is a density distribution diagram in Experiment 3. 6 is a compressive strength distribution diagram in Experiment 3. FIG. It is a water absorption rate distribution map in Experiment 3. FIG. 6 is a density comparison diagram in Experiment 4. It is a compression strength comparison figure in experiment 4. It is a water retention amount comparison chart in Experiment 4. It is a suction height figure in experiment 4. It is a water absorption rate comparison figure in experiment 4. FIG. 10 is a diagram showing a test procedure in Experiment 5. It is a figure of the irradiation test apparatus in Experiment 5. It is a figure of the irradiation test surface temperature in Experiment 5. It is a figure of the irradiation test bottom face temperature in Experiment 5. It is a figure of the block moisture evaporation amount measurement result in Experiment 5.

  Hereinafter, experimental results including a preliminary experiment conducted for obtaining the formulation in the present invention and preferred embodiments will be described.

From past studies, when paper sludge ash (PS ash), which is a recycled material, is used as an admixture for concrete, it is determined by a pozzolanic reaction with silica (SiO ₂ ) and alumina (Al ₂ O ₃ ), which are the main components of PS ash. It has been confirmed that an increase in strength can be expected. Moreover, it has also been confirmed that by using PS ash having water retention, it is possible to impart water retention and water absorption to the block.

  The purpose of the present invention is to provide a block having high water retention that is installed on the rooftop, etc., and the performance required for this water retention block is a block that is installed on the roof and does not receive a load. It is considered that no problem occurs even if the compressive strength is smaller than that of general concrete.

  In addition to this, it is desirable to make the block weight lighter in consideration of a higher temperature reduction effect than a general one and a rooftop location and transportation / workability. Therefore, the temporary target value of the water retention block in the experiment was determined as follows.

1) Density 1.0 g / cm ³
2) 80% water absorption
3) Compressive strength 1N / mm ²

  In addition, by carrying out these experiments, a lightweight water-retaining block using recycled materials and reinforced natural fibers for concrete (trade name “Ultrafiber 500”, hereinafter referred to as “UF500”) of concrete is manufactured as a prototype.・ Understanding water retention characteristics.

[Experiment 1] Selection of cement and PS ash
(1) Overview

In order to develop a lightweight block with a density of 1.0 g / cm ³ , a water absorption rate of 80%, and a compressive strength of 1 N / mm ² , the temporary target values described above were increased in unit cement amount and unit PS ash amount in Experiment 1. It was decided to select the optimum value of the amount used, changing within the region, confirming the changing tendency of strength, water absorption and density.

(2) Materials used Table 1 shows the materials used in Experiment 1.

  In Experiment 1, in producing a target block, a natural material reinforcing fiber having recycled materials and water retention capacity was used.

(3) Blending conditions and formula blending In Experiment 1, the unit cement amount was 320 kg / m ³ , the unit water amount was 160 kg / m ³ , and the unit PS ash was based on the optimum blending based on the past research results on interlocking blocks. An amount of 200 kg / m ³ was used as a basic composition, and the other aggregates were replaced with pearlite waste in order to reduce the weight.

  Table 2 shows the basic composition.

Tables 3 and 4 show the composition of the 14-day series and 1-day series, respectively. Unit cement amount is 320, 270, 220kg / m ³ three levels, unit PS ash amount is 160, 200, 240kg / m ³ three levels, pearlite scrap-hard pearlite volume substitution rate for weight reduction and strength increase (Volume ratio) was tested for three levels of 100-0, 50-50, and 0-100, and a combined total of 27, and water absorption, strength, and density were confirmed. Here, the mixing amount of UF500 was set to 5 kg / m ³ which is the maximum addition amount with respect to the mortar.

  Note: No. 18 was subjected to a compression test at the age of one day.

However, the curing is the same as that performed at the product factory, and is as follows.
Preliminary time 1 h, temperature rise rate 10 ° C./h, maximum temperature 75 ° C. ± 5 ° C. held for 4 h, hereinafter natural descent.

  The strength was measured at the age of 14 days in accordance with the number of days until the shipment of the product at the product factory being about 14 days. In consideration of the progress of the test, Table 4 shows the experiment at the age of 1 day. went.

(4) Mixing method and specimen preparation method For mixing, an omni mixer with a nominal capacity of 10 L was used. In the kneading method, the material was kneaded for 30 seconds after the material was added, and the mixture was mixed for 1 minute after the water was added.

  The material after kneading was put into a base layer with a mold having sufficient rigidity, applied with vibration, and immediately demolded after curing for one day.

(5) Test items and test methods The test items are shown below.

(5) -1 Compaction test The compaction test was conducted in accordance with “JSCE-F 508 compaction test method”. The test method is shown below.

1. Adjustment of displacement meter: The zero point of the non-contact displacement meter is adjusted to a sample height of 200 mm.

2. Weighing of the sample: Based on the concrete composition of the concrete, weigh the sample corresponding to the 200 mm inner container (3.534 l) of the sample container correctly.

3. Sample input: Use a spoon for hand-mixing, pay attention to uniformity so that coarse aggregate does not concentrate, pack the sample into 3 layers while avoiding spills, and thrust each layer 10 times with a 16mm diameter stick. Then, level the surface of the sample with a stick so that it is almost flat.

4). Attaching the sample container: A sample container packed with the sample is attached to the shaking table and fixed, and the slide bar is slid to gently lower the mounting plate to the upper surface of the sample.

5. Input of initial data: Sample name, concrete unit volume mass, vibration conditions (acceleration, vibration frequency, amplitude, any two conditions necessary for controlling vibration of shaking table, measurement time interval and vibration time) input.

6). Start of measurement: Switch on and drive the data processing system and opportunity vibration system.

6. Data processing method The data processing program must drive the opportunity vibration system in response to an input of measurement start and capture an electrical signal of the displacement xi on the sample upper surface at a predetermined measurement time interval Δt.

8). The sample filling rate γ _ti at an arbitrary time ti is calculated by the following equation.
γ _ti = h / (h + x _i ) × 100
Where h: height at 100% filling rate of sample (= 100 mm)

9. Arbitrary compaction work _Eti is calculated by the following equation. However, the density m _ti of the sample is calculated from the unit volume mass obtained from the filling rate in the immediately preceding measurement time and the indicated composition.
E _ti = m _ti · α _max ² · t _i / (2π) ² f
Where E _ti : Compaction work (J / l), m _ti : Sample density (kg / l), α _max : Maximum acceleration of sinusoidal vibration (m / s ² ), t _i : Vibration time ( s), f: frequency (s ^-1 )

10. The compaction function approximates a set of data related to the filling rate and compaction work by the least square method to the following equation.
γ _t = C _i + (C _f −C _i ) {1−exp (−bE _t ^d )}
Where γ _t : filling rate (%) at compaction time t, Et: compaction work (J / l) at compaction time t, C _i : initial filling rate (%), C _f : achievable filling rate (%), B and d: experimental coefficient

11. The compaction efficiency Ce is calculated by the following equation as the gradient of the compaction function at the compaction work amount 1 J / l.
C _e = bd (C _f −C _i ) E ^(d−1) exp (−bE ^d )

12 The compacted work E98 is obtained by calculation as the compacted work when a filling rate of 98% is substituted into the compaction function.

(5) -2 Water retention test A water retention test was conducted to determine the amount of water retention. The water retention amount is calculated by the following equation by obtaining the wet mass, the absolutely dry mass, and the volume of the specimen.
Water retention amount (g / cm ³ ) = (wet mass (g) −absolute dry mass (g)) / volume of specimen (cm ³ )
here,

  Wet mass: After absorbing water in still water at 15 to 25 ° C. for 24 hours, the specimen is taken out and placed in a sealed plastic container as shown in FIG. 1 and drained at room temperature of 15 to 30 ° C. for 30 minutes, Mass when measured immediately after wiping visible water with a wrung wet cloth.

  Absolutely dry mass: The mass when dried to a constant mass in a dryer having a temperature of 105 ± 5 ° C. and then cooled to room temperature.

(5) -3 Water absorption test The water absorption test is to determine the water uptake for 30 minutes, and the test method is described below.

1. The block is dried to a constant mass in a dryer having a temperature of 105 ± 5 ° C., and then cooled to room temperature.

2. The block is installed in the water absorption test apparatus shown in FIG. The water level after installation is 5 mm from the bottom of the block, and the water is fresh water at 15 to 25 ° C. On the top surface of the specimen mounting base, use a material that allows water to turn around the bottom of the block, such as a wire mesh, or sandwich a water-absorbing sponge.

3. After 30 minutes, remove the block, drain the water to the extent that it does not drip, and wipe visible water drops with a squeezed waste cloth. The mass at this time is taken as the sucked mass after 30 minutes.

4). Wet the block and weigh the wet mass.

5. The suction height is obtained from the following formula.
Suction height (%) = (Sucked mass after 30 minutes (g) −absolute mass (g)) / (wet mass (g) −absolute mass (g)) × 100

  Table 5 shows the standard values of the products of each item according to the quality standards of concrete blocks for water retention pavement.

(5) -4 Compressive strength test The compressive strength test was conducted in accordance with “JIS A 1108 Compressive strength test method for concrete”. However, the specimen was molded by pressure vibration. The curing was steam curing, and the curing condition was that strength was measured at 14 days of age, according to the fact that the number of days until shipment of the product in the product factory was about 14 days. Moreover, the specimen size and mass were measured, and the apparent density was calculated.

(6) Test results and discussion
(6) -1 Results of compaction test Generally, when the amount of powder is too small, the achievable filling rate is 100% or less, and good compaction cannot be performed. However, the achievable filling rate C _f and compaction efficiency C _e of all 27 blends reached almost 100% regardless of the material used, and sometimes exceeded 100%.

This is thought to be due to the fact that the total amount of fine aggregate was powdered in order to reduce the weight in the basic composition. In addition, it is considered that the cause of the blending ratio exceeding 100% is that moisture was discharged to the concrete surface by vibration pressurization and removed from the mold when the test was performed.
The results of the compaction test are shown in FIGS.

  From previous studies, the initial filling rate (Ci) is the filling rate when a sample is packed in a container, and tends to increase as the unit water volume and the mortar aggregate void ratio increase.

In each of the unit cement amounts 220, 270, and 320 kg / m ³ , the Ci of the blend using the unit PS ash amount 160 kg / m ³ was relatively large. Therefore, it was found that compaction is easier when the unit PS ash amount is small. Further, in this experiment, many blends having an initial filling rate exceeding 90% were observed, and it was confirmed that the block compaction was easy in the blend used this time.

  The prototype block does not use the aggregate for general concrete, but uses a large amount of powdered fine PS ash and pearlite litter, so after compaction, the gap between the aggregates is small, It is thought that Ci became large because the organization became dense.

(6) -2 Block property test results.
The test results are shown in Table 6.

  The compressive strength at the age of 14 days all satisfied the target value.

  During the test, the strength of the 14th day of age was a large value that clearly exceeded the target value, so considering the progress of the test, if the target value is satisfied even in the strength of the 1st day of age, It is considered that the block performance can be sufficiently examined by measuring the strength of the material one day.

  Here, Table 7 shows the values measured for the 1-day strength and the 14-day strength in the formulations of No. 18, No. 19, and No. 20.

  The relationship between these strengths is shown in FIG.

From Table 7, it was confirmed that, in the strength of 3 blends, both the 1-day strength and the 14-day strength were 3 N / mm ² or more, greatly exceeding the target value. Since it can be expected that the 14-day strength is greater than the daily strength, the daily strength was measured later.

  Table 8 shows the test results of the blends whose daily strength was measured.

  The density and compressive strength distribution are shown in FIGS.

As shown in FIG. 7 and FIG. 8, the daily intensity was slightly smaller than the 14-day intensity, but it was confirmed that both the 1-day intensity and the 14-day intensity exceeded the target value of 1 N / mm ² . . The daily intensity was also three times larger than the target value.

This is because, in the present study, concrete was blended in the range of unit cement amount 200 kg / m ³ or more and unit PS ash amount 100 kg / m ³ or more and 300 kg / m ³ or less in the present study. It is considered that the compressive strength was increased because a large amount of calcium hydroxide was produced and the pozzolanic reaction was sufficiently generated by PS ash.

Since all 27 formulations were subjected to a daily curing with density, water absorption rate, water retention, and suction height test, the test results for all 27 formulations are shown in the graph at the same time in order to make it easier to grasp the change tendency of block properties. .
The density-water absorption distribution is shown in FIG. 9, FIG. 10, and FIG.

  FIG. 9 shows the density-water absorption distribution for each unit cement amount. FIG. 10 shows that the volume substitution rate (percentage) of pearlite scrap and hard pearlite is 100-0 (hard pearlite 0% with respect to 100% pearlite scrap), 50 The test results in the case of −50 (50% hard pearlite with respect to 50% pearlite waste) and 0-100 (100% hard pearlite with respect to 0% pearlite waste) are shown.

9 that the amount of the unit cement than when in the case of 220,270kg / m ³ of unit cement content 320 kg / m ^3, a high water absorption, it is understood density is small. It can be seen that the density at a unit cement amount of 320 kg / m ³ tends to be larger than the target value, and that the block density increases as the unit cement amount increases.

The water absorption rate was relatively inferior when the unit cement amount was 320 kg / m ³ . This is presumably because the voids included in the test specimen decreased due to the increase in density, and the water that could be included in the gaps decreased.

  From FIG. 10, when the volume ratio of pearlite litter and hard pearlite is 100-0, the block density satisfied the target value. Regarding the water absorption rate, when the volume substitution was 100%, the target value (80%) of the water absorption rate was not satisfied, but a good tendency was shown. This is thought to be because the water absorption rate of pearlite scrap is higher than that of hard pearlite.

Therefore, in the case of a combination in which the unit cement amount is 220 kg / m ³ and 100% pearlite waste is used, the density of the block tends to be small and the water absorption rate tends to be high. It is done.

FIG. 11 shows the density-water absorption distribution for each unit PS ash amount. A similar distribution is seen with unit PS ash amounts of 160, 200, and 240 kg / m ³ , and there is no significant change in the approximate line, so it is still difficult to select the unit PS ash amount within this range. it is conceivable that. In addition, since the water absorption rate of all 27 blends is 55% or less at the maximum, which is far below the target value, in the subsequent experiments, the tendency to affect the block properties by variously changing the amount of unit PS ash; did.

FIG. 12 shows the density-water retention distribution.
Maximum volume ratio of pearlite scraps and the hard pearlite (PA-PW) is in the case of 0-100, the maximum value of 0.45 g / cm ³ of water retention capacity, the minimum value of 0.33 g / cm ^3, also the density of the since the value is 1.52 g / cm ^3, the minimum value is 1.10 g / cm ^3, the difference between the maximum and minimum values is large, it is considered not good for the manufacture of the product.

  Conversely, in the case of hard pearlite 0% with respect to 100% pearlite scrap, the density is small and the water retention amount is large, and the difference between the maximum value and the minimum value is small, so the block is lightweight and has good water absorption and water retention. It was confirmed. Therefore, in the subsequent experiments, it was decided to use a blend using 100% pearlite waste.

In addition, all 27 formulations satisfied the standard value of water retention amount. This is probably because the recycled materials and concrete reinforcing fibers used this time are materials that have excellent water retention, and that this is because water retention was imparted to friend samples.
FIG. 13 shows a suction height-density diagram.

  As shown in FIG. 13, the suction height satisfied the standard value (70%) of the suction height, and a very good result was obtained. This is due to the use of recycled PS ash and pearlite scrap in this study and the introduction of reinforced natural fibers for concrete (UF500), which has a large number of fibers and approximately 80% of its own weight has water retention. Therefore, it is considered that the suction height has been improved.

[Experiment 2] Selection of perlite
(1) Outline From the results of selecting the amount of cement and PS ash in Experiment 1, the best results for both water retention and density were obtained when pearlite waste was mixed at a unit cement amount of 220 kg / m ^3. It was. However, the target value is not satisfied with the maximum water absorption rate of around 50%. Therefore, the kind of pearlite was further changed so that the water absorption rate reached 80% of the target, and the change tendency of the water absorption rate was obtained. In this section, we conducted experiments using three types of perlite, proposed a composition that satisfies the water absorption target, and grasped the lightness and water retention of the block.

(2) Materials used Table 9 shows the materials used.

The pearlite used here was hard pearlite (P5B) manufactured by Toko Perlite, pearlite fine (P2), and pearlite coarse (P3) manufactured by Taiheiyo Pearlite. P2 and P3 are pearlite crushed, adjusted in particle size, rapidly heated and foamed, and are lightweight and white pearlite for construction materials. It has excellent features such as light weight and water retention. P2 has a particle size of 2.5 mm or less and a density of 0.15 kg / m ³ , and P3 has a particle size of 5 mm or less and a density of 0.17 kg / m ³ . P5B is obtained by pulverizing glass rhyolite such as pearlite and then firing and foaming it at a high temperature. The particle size is 5 mm or less and the density is 0.20 kg / m ³ .

  These are very lightweight materials and also have high water absorption characteristics. For this reason, it is considered that development of a block having a higher water absorption rate can be expected by using these. In this chapter, we will experiment with each formulation, compare the properties of the prototype blocks, and select the formulation and pearlite type most applicable to this study.

(3) How to mix From the results of selecting the amount of cement and the amount of PS ash, a good result of density and water absorption is obtained in the combination of unit cement amount 220kg / m ³ and pearlite scrap 100%. Therefore, in the case where the unit cement amount is 220 kg / m ³ , three kinds of pearlite are changed, and the tendency to affect the properties is grasped, and pearlite capable of achieving the target value is selected.

In addition, since the PS ash did not show a tendency of a large change in the properties of the block from Experiment 1, the unit PS ash amount was changed to three levels of 160, 200, and 240 kg / m ³ . Therefore, 3 blends of PS ash, 9 blends of pearlite in combination of P2, P3 and P5B, and blends of unit PS ash amount 160 kg / m ³ , P2 and P3 were added 50% each. Experiments were conducted for a total of 10 formulations.
Table 10 shows the indication composition.

  * However, the curing was the same as in Experiment 1.

(4) Kneading method and specimen preparation method The same as in Experiment 1.
(5) -5 Test items Same as in Experiment 1.

(6) Test results Table 11 shows the test results. The compressive strength was evaluated based on the daily strength for the reason described in Experiment 1.

  FIG. 14 shows the relationship between density and water absorption, and FIG. 15 shows a comparison of water absorption in various pearlites. When P2 and P3 are used, the water absorption rate is close to the target of 80%. When P5B was used, neither the density nor the water absorption rate satisfied the target value. This is because P5B is harder than P2 and P3, and fine, so the material becomes dense by compaction and vibration pressurization, the void of the test specimen is reduced, capillary action is unlikely to occur, and it is difficult to suck water This is considered to be the cause.

  FIGS. 16 and 17 show the relationship between density and compressive strength, and density comparison among various pearlites.

  From FIG. 16, when P5B was used, the compressive strength was reduced as compared with the case where P2 and P3 were used. From FIG. 17, the density using P5B was higher than the density using P2 and P3. Since P5B is larger than the densities of P2 and P3, it is considered that the density of the test body using this is also increased. Therefore, it is considered preferable to use P2 and P3.

FIG. 18 shows the result of the water retention amount, and FIG. 19 shows a density-water retention distribution map.
From FIG 18, it formulated using P2, when water retention capacity becomes 0.52 g / cm ³ or more, compared to the formulation using P3 and P5B that at most does not exceed 0.50 g / cm ^3, good results Obtained.
Moreover, from FIG. 19, the water retention amount of all the blends exceeded the standard line.

  As for the wicking height, as shown in FIG. 20, the wicking height of all the blends exceeded 90%, and exceeded the standard value of 70%. It was confirmed that the water retention amount and suction height satisfied the standards.

  As described in Experiment 1, the prototype block did not use general concrete aggregates, it was a powder, PS ash with a fine particle size and water retention, and a large amount of pearlite waste and water absorption. It is considered that good results of water retention and water absorption were obtained because 80% natural fiber for concrete was mixed.

Summary of Experiment 1 and Experiment 2 As the unit cement amount increased, the block density also increased.

In this blending, the unit cement amount needs to be 220 kg / m ³ or less in order to satisfy various block property targets.

  The block water absorption rate using the recycled material of PS ash and perlite scrap was 50%.

A block with a compressive strength of 1 N / mm ² or more can be produced even in one day of material as long as it is within the strength increase level of unit cement amount 270 ± 50 kg / m ³ and unit PS ash amount 200 ± 40 kg / m ³ .

  By using recycled materials, if the strength level is low, the standard value of the water retention amount determined by the water block pavement concrete block quality standard can be satisfied, and more than twice the performance can be obtained.

  By using a recycled material, if the strength is low, it is possible to produce a block that sufficiently satisfies the standard values of water retention and suction height.

  By using a pearlite fine or pearlite coarse product, a block having a water absorption of about 70% can be produced.

[Experiment 3] Actual machine test
(1) Overview

  From the results of Experiments 1 and 2, a block having good properties could be produced although the target value of water absorption was not satisfied. Therefore, a product factory experiment was conducted from the results of these laboratory experiments.

  Here, in addition to the blends that were good in Experiments 1 and 2, various blends were selected and experiments were conducted in order to grasp the tendency due to the use of actual factory equipment.

(2) Materials used Table 12 shows the materials used.

(3) Blending conditions Table 13 shows the blending conditions.

  Based on the results of Experiment 1 and Experiment 2, an actual machine experiment was conducted for 5 formulations based on the formulation closest to the target lightweight water retention block property. In addition, in the same composition, a laboratory test was also performed and compared with the actual one. Curing was the same as in Experiment 1.

(4) Kneading method and specimen preparation method For this comparison, in addition to experiments on grasping various properties by making blocks on the actual product production line, a compaction test was conducted in the laboratory experiment. Since the mixing method is different in the laboratory experiment, it is described below.

  The mixer used was an omni-type mixer. After mixing cement and powder for 30 seconds, water and an admixture were added and kneaded for 1 minute.

Material after kneading is carried in a belt conveyor, sufficient stiffness to mold the table vibrator (amplitude 1.5 mm, frequency 90 Hz) having used, vibration of the press 30 kN / m ² (amplitude 0.3 mm, A frequency of 110 Hz) was added for 2 seconds after the base layer was added and 7 seconds after the surface layer was added for a total of 9 seconds. After the vibration was compacted, immediate demolding was performed.

  The prepared specimen is composed of a colorable surface layer portion having a planar dimension of 198 × 98 mm and a thickness of 5 mm and a base layer portion of 55 mm.

(5) Test items
(5)-Water retention test

A water retention test was conducted to determine the amount of water retention. The water retention amount was calculated by the following equation, as in Experiment 1, by obtaining the wet mass, the absolutely dry mass, and the volume of the specimen.
Water retention amount (g / cm ³ ) = (wet mass (g) −absolute dry mass (g)) / volume of specimen (cm ³ )

(5) -2 Water absorption test The water absorption test is to determine the water uptake height for 30 minutes, and the test method is the same as in Experiment 1.
(5) -3 Compressive strength test The test was conducted in accordance with “JIS A 1106 Concrete Compressive Strength Test Method”.

(6) Test results Table 14 shows the test results.

  Moreover, what put together the result of the compressive strength, the water absorption rate, and the density in a figure is shown in FIGS. However, from the experimental results of Experiment 1, since the water retention amount and the sucked height in all the blends satisfied the standard values, only the density of the target block performance, the compressive strength, and the water absorption rate were examined here.

  From FIG. 21, the compressive strength was larger than that of the laboratory test in almost all the formulations. This is thought to be due to the fact that the press in the actual machine test was larger than that in the laboratory test, and the specimen was compacted by compaction, so that the strength increased.

  From FIG. 22, the water absorption rate showed the same tendency between the actual machine test and the laboratory test. However, in all the formulations, the water absorption decreased from that in the laboratory test to 40% or less. As described above, this is considered to be caused by a decrease in the water content that can be contained in the voids due to a decrease in the voids because the specimens became dense. In addition, it is considered that one of the causes is that the capillary phenomenon has been hindered because the voids have decreased.

  From FIG. 23, the density of the actual machine test was larger than that of the laboratory test. As described above, it is considered that the density has increased because the specimens have become dense and the remaining voids have decreased.

  In addition, from the results shown in FIGS. 21 and 22, in all the formulations, the strength of the actual machine test was larger than that of the laboratory test, and the water absorption rate of the actual machine test was smaller than that of the laboratory test. The result of the test should be larger than that of the indoor test, but as shown in FIG. 23, the results of No. 2 and No. 3 were smaller than those of the actual machine. This is because pearlite (P2, P3) is a very fragile material, and when compacted, the pearlite is crushed by the actual press, the particle size of the pearlite changes, and the volume of the specimen increases. It is thought that it was because of.

(7) Change the molding machine test conditions and reproduce the actual machine test results
(7) -1 Outline In the actual machine test, the water absorption decreased to 40% or less compared with the laboratory test.

  It is considered that the properties of the blocks were different because the press conditions for compaction of the actual machine and the laboratory test were different. Here, in order to reproduce the conditions of the actual machine test even indoors, a simple block molding machine was used for 5 seconds. The test was performed by changing the press time for ˜30 seconds. From this, the various properties of the block are grasped, and the press time capable of reproducing the actual machine test is obtained.

(7) -2 Materials used
Same as (1) -2.

(7) -3 Mixing conditions

No. 2 in Table 13 showed the highest water absorption rate in both the actual machine test and the laboratory test. Therefore, here, a test was conducted at each press time for Formulation No. 2 with a unit cement amount of 220 kg / m ³ , a unit pearlite fine (P2) amount of 118 kg / m ³ , and a unit PS ash amount of 160 kg / m ³ . .

(7) -4 Kneading method and specimen preparation method

  For the compaction test, an omni mixer with a nominal capacity of 10 L was used. The material was kneaded for 30 seconds after the material was added, and mixed for 1 minute after mixing. The material after kneading was put into a base layer with a mold having sufficient rigidity, applied with vibration, and immediately demolded after curing for one day.

  The specimen is configured with a plane size of 198 × 98 mm and a height of 55 mm using a simple block molding machine (hereinafter referred to as a molding machine).

(7) -5 Test items and test method Same as those in Experiment 1.

(7) -6 Test results Tables 15 and 16 show the test results.

  FIG. 24 shows the density distribution. After adding 30 seconds of press time, the density result obtained was below the target value, but it was found that the approximate line was slightly tilted upward. Since the equation of the approximate line is monotonically increasing, it was confirmed that the density increased with increasing time. This is considered to be a phenomenon in which the specimen becomes denser because the amount of air contained in the fresh concrete gradually decreases by increasing the press time.

  From FIG. 25, these phenomena were confirmed about the compressive strength as well as the density. It is considered that the compression strength also increased because the amount of air decreased and the specimen became denser due to the increase in press time.

  FIG. 26 shows the water absorption rate distribution. By increasing the press time, the water absorption rate decreases and the recent straight line is inclined downward. This is presumably because the amount of air contained in the test body decreased and the test body became dense, so that the water that could be contained in the gap was reduced. In addition, it is considered that one of the causes is that the capillary phenomenon is less likely to occur because the voids are reduced.

From the experimental results so far, the density satisfied the target value of 1 g / cm ³ of this study, and the compressive strength also generally satisfied the target value of 1 N / mm ² of this study. Therefore, in order to find a solution for the reduction in water absorption rate in the actual machine test that became a problem, in the simple block molding machine that reproduces the actual machine test by using an approximate straight line from the result of the water absorption rate in the simple block molding machine test The press time will be determined provisionally.

It is considered that the press time necessary to obtain the water absorption value in the actual machine test can be obtained from the following function using an approximate line.
y = -0.1748x + 53.457
However,
y is the water absorption rate (%)
x is the press time (s)
Indicates.

  Here, the target value of the water absorption obtained from the actual machine test is 40.2 (%) as shown in Table 15. Therefore, if the press time which can obtain an equivalent water absorption rate is calculated using the above formula, the required press time can be obtained as 1 minute 15 seconds.

  This press time is an estimated value, but this time, a press that can tentatively produce a block with the same performance as the actual machine test result using a simple block molding machine indoors with this press time of 1 minute 15 seconds. Set with time. Under these conditions, a block performance improvement test was conducted in order to select a composition that would satisfy the target value of water absorption later.

(8) Summary In the actual machine test, because the press was large, the compressive strength increased compared to the laboratory test.
The density was also larger than the room, but it was confirmed that the target value was satisfied.
In the actual machine test, since the press was large, the water absorption rate was lower than that in the laboratory test.

  In a simple block molding machine test, it is possible to produce a block that satisfies the target values for both compressive strength and density.

  Temporarily, the press time of 1 minute 15 seconds was set as the press time that can produce a block having the same performance as the actual machine test result using a simple block molding machine in the room. Under these conditions, a block performance improvement test was conducted in order to select a composition that would satisfy the target value of water absorption later.

[Experiment 4]
(1) Overview

From the test results so far, it was found that when the unit cement amount is 220 kg / m ³ and pearlite fine (P2) or pearlite coarse (P3) is used, the performance of the specimen tends to be good. Experiment 2 also showed that the actual machine test could be reproduced indoors by setting the press to 1 minute 15 seconds.

  Therefore, in Experiment 4, the press was performed for 1 minute and 15 seconds, and an experiment was conducted to select a blend satisfying various block properties.

(2) Materials used Table 17 shows the materials used.

(3) Table 18 shows the formulation of indication.

PS ash has a higher density and lower water absorption than pearlite. This time, in selecting a composition that satisfies the target, we considered that the target value of the strength was satisfied, and that the material became denser and stronger than the laboratory experiment due to the press, and the unit PS ash amount was 100 kg / m ³ did. Further, P3 is coarser than P2, and by replacing this with P2 stepwise, the particle size distribution is changed, and the ratio of P3 with respect to P2 is selected in order to select the ratio that maximizes the capillary effect. Experiments were conducted on six formulations with the substitution rate varied from 0 to 100%.

  Curing was the same as in Experiment 1.

(4) Kneading method and specimen preparation method The same as in Experiment 1.
(5) Test items Same as in Experiment 1.

(6) Test results Table 19 shows the test results.

  From FIG. 27, it was confirmed that the density satisfied the target value for all the six formulations. In particular, when the pearlite rough substitution rate is 80% and 100%, the density is relatively small, and thus the lightness of the block can be further improved. This is because the particles of P3 are larger and harder than those of P2, so that when P2 is used in a large amount due to pressing in compaction, the remaining voids of the specimen are reduced and the volume is reduced. This is thought to be due to the increase in.

  Further, from Table 18 and Table 19, when the blending density calculated on blending and the actual density were compared, the actual density was larger than the blending density in all blends. This is considered to be due to the fact that the amount of air is 5% or less due to vibration pressure molding, and that PS ash and fibers have a high water absorption rate and absorb excess water.

  From FIG. 28, it was found that when the volume substitution rate of the pearlite crude P3 was 80% and 100%, the compressive strength was reduced compared to the case where P2 was used. As described above, it is considered that when P2 is used in a large amount, the strength of the specimen increased because the specimen became dense. In Formulation No. 1 which does not use P3 at all, by using P2, the specimen becomes denser than the press and the compressive strength should be the largest value, but the result is inferior as shown in FIG. Oops. This is presumably because P3 was not used at all, and the strength due to the hardness of P3 was not present.

  FIG. 29 shows a water retention amount comparison chart. From the above, it is considered that the use of P2 makes the specimen dense and the residual voids that can contain moisture decrease, so it is considered that the water retention amount is small, but as shown in FIG. 29, the tendency is not seen. It was. In all 6 formulations, the water retention amount and the standard value greatly exceeded. This is because PS ash and pearlite are used in a large amount, so that it is considered that a lot of water is contained.

  From FIG. 30, the sucked height exceeded 90% for all 6 formulations, which was a very good result. It is considered that the reason why this result was obtained was that a material excellent in water retention was used, and in addition, natural fibers for reinforcing concrete were used. Since the shape of the fiber is a conduit, it is considered that the specimen can absorb more moisture more quickly.

  From FIG. 31, although the water absorption rate was somewhat improved as compared with the result of Experiment 3, the result was not yet satisfied with 80% of the temporary target value. Among the blends not satisfying the target value of water absorption, the highest water absorption was obtained when the volume substitution rate of pearlite crude (P3) was 80%.

  This is because when P2 is used, the remaining voids are less than the compacted press pressure, so that it cannot contain a lot of moisture. Conversely, when P3 is used in a large amount, the properties of P3 particles are rough. This is considered to be due to the tendency of capillary action in the voids of the specimen. In the case of the blending No. 3 in which the volume substitution rate of P3 was 60%, the water absorption rate was inferior. This is because, as shown in FIG. 27, when the volume substitution rate of P3 was 60%, the density was the highest, so that the specimen became dense and the porosity decreased due to the press. it is conceivable that.

  From FIG. 27 to FIG. 31, in the case of No. 3 in which the volume replacement ratio of pearlite P3 is 40% among the blend Nos. 1 to 4 that satisfy the target value of compressive strength, the water absorption is relatively large. Because of the low density results, it is considered the most desirable formulation for the development of the targeted lightweight water retaining block.

(7) Summary

In the blending in which the amount of paper sludge ash was 100 kg / m ³ and the pearlite fine P2 was replaced with 40% pearlite crude P3, the density and compressive strength satisfied the target values.

When the amount of paper sludge ash is 100 kg / m ³ , the water absorption rate of the block can be improved by replacing the pearlite fine P2 with 40% pearlite coarse P3.

  Therefore, it was confirmed that the use of recycled materials and the natural fiber ultrafiber for reinforcing concrete can be applied to a lightweight water-retaining block by taking advantage of these characteristics.

[Experiment 5]
(1) Outline From the result of Experiment 4, it was confirmed that a relatively good result was obtained when the volume substitution rate of P3 was 40% although the target value of compressive strength was satisfied. Therefore, relative evaluation of the temperature rise performance (sample surface temperature) and moisture evaporation performance (moisture evaporation from the sample surface) of the prototype block was conducted, and an irradiation test was conducted to confirm whether the heat island phenomenon was effective. went.

(2) Specimen Table 20 shows the block formulation conditions.

  From the test results of Experiment 4, the block properties are shown in Table 21.

(3) Test method
(3) -1 Test procedure Figure 32 shows the test procedure.

(3) -2 Test equipment An irradiation test equipment with the structure shown in Fig. 33 is used. Table 21 shows the conditions of the irradiation test apparatus and the specimen.

(3) -3 Test chamber An irradiation test device is installed in a constant temperature and humidity chamber that can maintain an atmospheric temperature of 20 ± 3 ° C and an atmospheric humidity of 65 ± 15%.

(3) -4 Irradiation test method
(3) -4-1 Determination of lamp height (H) by means of a dense particle size asphalt specimen As shown in FIG. 33, a 20 mm long × 20 mm wide aluminum tape is stuck to the center of the surface of the dense-graded asphalt specimen. Leave a gap in the aluminum tape to insert the thermocouple.
2. The dense asphalt specimen is immersed in fresh water at 15 to 25 ° C. for 24 hours.

3. After removing the dense asphalt specimen and wiping the visible water film with a squeezed wet cloth, it is placed in a sealed plastic container as shown in FIG.

4). After removing the dense asphalt specimen and wiping the visible water film with a squeezed wet cloth, it is fitted into a heat insulating material as shown in FIG. An aluminum tape having a width of about 10 mm is attached to the gap between the surface of the specimen and the heat insulating material so that moisture does not evaporate from the gap.

5. Insert a thermocouple into the gap between the aluminum tape on the surface of the dense asphalt specimen and press the aluminum tape to bring the thermocouple into close contact with the specimen surface. Temperature recording is performed by sending temperature data to a personal computer.
6). An irradiation test equipment is installed with the center of the specimen aligned just below the center of the lamp.
7). Turn on the lamp and start irradiation. The surface temperature is recorded every 10 minutes from the start of irradiation.

8). The lamp height (H) is determined so that the surface temperature of the specimen becomes 60 ° C. or higher in the irradiation time of 2 to 4 hours. If the surface temperature exceeds 60 ° C. within 2 hours from the start of irradiation, or if the surface temperature is 60 ° C. or less even after irradiation for 4 hours, the procedure is repeated again, and the lamp height (H) is adjusted again.

(3) -4-2 Preparation of specimens and adjustment of irradiation test equipment 1 to 5 shall be the same as in the case of dense grained asphalt. However, the lamp height (H) is adjusted with the dense grained asphalt specimen. Adjust to the height you have done.

6). Immediately after installing a radiation clock on the thermocouple of the dense-graded asphalt specimen, turn off the lamp.

7． The lamp height (H) in the other specimens is adjusted so as to be the irradiance of the dense grained asphalt specimen.

(3) -4-3 Irradiation test Perform zero adjustment of the scale.

2. Turn on the lamp and start irradiation. The surface temperature is recorded every 10 minutes from the start of irradiation. The mass loss (that is, the amount of water evaporation) is recorded every 10 minutes from the start of irradiation.
3. In order to reproduce day and night sunshine, the lamp is turned on and off every 12 hours.

(4) Irradiation test results and discussion The irradiation test results are shown in Table 22 for the irradiation test conditions, and in FIG. 34, FIG. 35 and FIG.

  From FIG. 34, it was confirmed that the surface temperature in the prototype lightweight water-retaining block was lower than that in the other blocks. This is thought to be because most of the materials used in the prototype lightweight water retention block are excellent in water retention, unlike other blocks.

  By using paper sludge ash that is porous and has excellent water retention, water retention and water absorption performance can be imparted to the block. In addition, pearlite is very lightweight and, when expanded, has properties such as a porous structure, high water absorption, and heat insulation, so that the water retention of the block can be increased.

  Furthermore, since the strength of the block can be improved by using the natural fiber for reinforcing concrete, the shape of the fiber is a conduit shape, so that it can hold moisture of about 80% of the mass of the fiber. And the water retention of the block can be improved.

  Because these materials are used, the block can hold a large amount of water, the water evaporates due to the influence of the lamp light, the surface temperature of the prototype block is the lowest, and it can be kept below 60 ° C even for 3 days. It was. Due to the difference in the production method and the materials used, dense grained asphalt showed a value exceeding 90 ° C. for 3 days.

  This is probably because there was little water evapotranspiration because there was almost no water to hold. The normal block also had a higher temperature than the other blocks due to the small amount of water retained. Since the commercially available ceramic water-retaining block contains a large amount of moisture on the first day, the temperature is low, and the effect of reducing the surface temperature appears.

  However, if moisture was held only in the gap, it was glassy and the moisture was rapidly removed, and it was also confirmed that the temperature rose to nearly 90 ° C. after the second day. Therefore, it is considered that the prototype lightweight water retaining block has the most temperature reducing effect.

  From FIG. 35, the result of the bottom surface temperature was generally lower than the result of the surface temperature. This is probably because the bottom surface of the block does not receive heat directly and the water in the block concentrates on the bottom surface due to gravity. The dense grained asphalt and the ordinary block had little temperature reduction effect due to the small amount of water that could be retained.

  As for the commercially available ceramic water-retaining block, the result was low because moisture remained on the first day as well as the surface temperature, but since the water was completely released on the first day, the temperature rose from the second day, There was no temperature reduction effect and the result exceeded 80 ° C. In the trial light-weight water-retaining block, a large amount of retained water remained throughout the three days, and the temperature reduction effect was remarkably exhibited due to the evaporation of moisture, resulting in a low result of about 50 ° C.

  From FIG. 36, the amount of water evaporation during the surface temperature measurement did not show the effect of reducing the temperature of the surface temperature and the bottom surface due to the evaporation of water because the moisture was hardly retained for the dense asphalt and the ordinary block. . Regarding the commercially available ceramic water-retaining block, the amount of water retained on the first day was large, but since the water was lost after the second day, the temperature reduction effect was not seen as in the case of the dense grained asphalt and the ordinary block.

  The amount of water retained in the relatively light weight water retaining block is very large, and the water in the other blocks has almost disappeared for 3 days. However, a large amount still remains in the prototype light weight water retaining block.

  Therefore, as shown in FIGS. 34 and 35, the prototype lightweight water-retaining block exhibits a temperature reduction effect than other blocks and can retain moisture for a long period of time, so it is considered that a temperature reduction effect for a long period can be expected.

(5) Summary The effect of reducing the surface temperature was confirmed in the prototype lightweight water retaining block.

  Unlike the surface, the bottom surface of the block does not receive heat directly, and the moisture of the block concentrates on the bottom surface due to gravity, thereby indicating a lower temperature than the surface.

  Since the prototype lightweight water-retaining block can retain moisture for a long period of time, a temperature reduction effect can be expected for a long period of time.

  Prototype lightweight water retention block can be expected to maintain the effect of reducing surface temperature over a long period of time, and if it is in a state where moisture is supplied from the outside, it is considered that evapotranspiration will be possible for a longer period of time. It is.

(Combination adjustment)
Based on the above experimental results, the target value
1) Real density 0.9g / cm ³ or less
2) More than 50% water absorption
3) The composition was adjusted to determine the range of the unit cement amount, unit paper sludge ash amount, and unit pearlite amount in the blending, based on the blending in Table 20, replacing the compressive strength of 1 N / mm ² or more.

As a result, the unit cement amount 190~220kg / cm ^3, a unit paper sludge ash weight 80~120kg / cm ^3, be in the range of unit amount pearlite and 100~125kg / cm ^3, the new target value of the Was found to be almost satisfactory.

In this blending adjustment, UF500 was blended in the range of ^{4 to} 6 kg / cm ³ and its performance was confirmed.

Claims (6)

A hydraulic composition containing cement, paper sludge ash, and pearlite is added with kneaded water and subjected to pressure molding. The unit cement amount in the blend is 190 to 220 kg / cm ³ , and the unit paper sludge ash amount is 80 to 120 kg / cm ^3, weight water retention block unit amount pearlite characterized in that it is a 100~125kg / cm ^3.   The lightweight water-retaining block according to claim 1, further comprising a fiber material. The lightweight water-retaining block according to claim 1 or 2, wherein the density in the blending is 0.6 g / cm ³ or less.   4. The lightweight water-retaining block according to claim 1, 2, or 3, wherein the pearlite is pearlite waste. The lightweight water-retaining block according to claim 1, 2, or 3, wherein the pearlite crushes the pearlite, adjusts the particle size, rapidly heats and foams, the particle size is 2.5 mm or less, and the density is 0.15 kg / m ^3. Or pearlite is crushed, the particle size is adjusted and heated rapidly, the particle size is 50 mm or less and the density is 0.17 kg / m ³ , or these are added at a predetermined ratio Lightweight water-retaining block featuring   The lightweight water-retaining block according to any one of claims 1 to 5, wherein the fiber material is a short fiber of alkali-resistant natural cellulose extracted from wood.