JP3547384B2 - Soil improvement material and pavement method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a soil improvement material using tap water sludge and a soil pavement method.
[0002]
[Prior art]
Natural clay such as red clay, Arakida clay, and Masago clay is widely used in clay courts, which are widely used for outdoor sports facilities and school grounds. By using natural soil in this manner, a clay coat having a natural feel can be formed at low cost.
[0003]
However, since such a natural soil is mainly composed of silt or clay, it has a drawback that it tends to be muddy or muddy when it rains, and that dust tends to rise when the weather continues.
[0004]
In order to cover the above-mentioned disadvantages while maintaining the merits of natural soil, the applicant of the present invention disclosed in Japanese Patent No. 1556916 (Japanese Patent Publication No. 1-041762) a soil pavement using clean water sludge (water purification plant generated soil). Suggest a way. According to this soil pavement method, soil pavement having preferable properties of natural soil and excellent in durability and water resistance can be performed, and the maintenance of the earth pavement surface does not require much labor. In addition, tap water sludge can be effectively used as a filler for general pavement soil materials that are becoming difficult to collect.
[0005]
[Problems to be solved by the invention]
By the way, in the soil pavement method using tap water sludge, it is necessary to pulverize tap water sludge into fine particles of fine sand or less. in this case,
(1) Drying of water sludge and crushing
{Circle over (2)} A method is considered in which tap water sludge is broken down into fine particles on a pavement foundation by pressurization with a tire roller or the like in a state of containing water (containing 30 to 60% of water).
[0006]
However, the water content of tap water sludge is usually high, and particularly in recent years, the water content is often 70 to 80%. Also, when a dewatered cake is prepared by a dewatering device, the moisture content thereof varies considerably. For this reason, the above method (1) is technically quite difficult and has a high cost for implementation.
[0007]
Also, if the degree of drying of water sludge is increased due to crushing, the water resistance performance based on the coagulant in the water sludge will be lost, and the water resistance and durability of the soil pavement surface will be weakened. There is. Then, once the water resistance is lost from the water sludge, the water resistance cannot be restored even if water is added thereafter.
[0008]
In addition, water sludge pulverized into fine particles of fine sand or less forms a solid pavement surface by tightly bonding with soil particles, but because the particles are fine, sufficient water permeability cannot be obtained, There was a problem that it easily became dust.
[0009]
On the other hand, in the above method (2), it is necessary to considerably repeat the pressurizing operation, and it is difficult to pulverize due to the variation of the water content of the soil material mixed with the water sludge and the limit of the performance of the mixing machine. In many cases, the mixing of the soil material and the water sludge is not uniform, and it has been difficult to stably secure the desired water resistance and durability. In addition, when tap water sludge having a high water content is used for a construction site, an unpleasant odor may be generated due to organic substances contained in the tap water sludge.
[0010]
The present invention has been made in view of such problems, and provides a soil improving material which is easy to manufacture and has high water resistance and high water permeability, and a pavement method using the soil improving material. The purpose is to:
[0011]
[Means for Solving the Problems]
First departureMing is, Soil improvement material,The water sludge obtained from the water purification plant is adjusted to a water content near its plastic limit, and then the water sludge isParticle size 0.425mm~4.75mmParticle size rangeBinder aggregate particlesBut50% by weight or moreGranulated, and then formed by drying treatment in a range where the water content in the water sludge does not fall below the minimum water content limit, and is mainly composed of binder aggregate particles having a particle size range of 0.425 mm to 4.75 mm. From a coarse-grained part and a fine-grained part below itBecome.
[0012]
Second departureMing is,In the first invention, the water content in the vicinity of the plastic limit is 75 to 95%, and after being adjusted to that state, it is granulated..
[0014]
No.3DepartureMing is,In the first or second invention, the minimum water content ratio limit is 50%..
[0015]
No.4DepartureMing is,In the first to third inventions, the soil improvement material is:After the drying treatment, water is added to adjust the water content to 60% to 120%.Stored.
[0016]
No.5DepartureMing is,This is a pavement method in which water sludge obtained from a water treatment plant is The binder is adjusted to a water content near the boundary, and in that state, granulation is performed so that binder aggregate particles having a particle size range of 0.425 mm to 4.75 mm are contained by 50% by weight or more. A soil improvement material comprising a coarse-grained portion and a fine-grained portion which are binder aggregate particles mainly having a particle size range of 0.425 to 4.75 mm and dried in a range not lower than the minimum moisture content limit, or It consists mainly of coarse and fine particles, which are mainly binder aggregate particles, which are stored by adjusting the water content to 60% to 120% by adding water after the drying treatment.The soil improving material is mixed with the soil material at a volume ratio of 20 to 50% with respect to the whole mixture, and a pavement surface is formed using the mixture.
[0017]
No.6DepartureMing is,In the fifth invention, a cohesive soil is used as the soil material,The soil conditioner is mixed with the cohesive soil at a ratio of 30 to 50% by volume to the entire mixture, and the mixture is used to form a pavement surface.
[0018]
No.7DepartureMing is,6In the invention, the soil improving material is,The water content was adjusted to 60 to 105%.
No.8DepartureMing is,In the fifth invention, a sandy soil is used as the soil material,The soil conditioner is mixed with the sandy soil at a ratio of 20 to 30% by volume to the whole mixture, and a pavement surface is formed using the mixture.
[0019]
No.9DepartureMing is,8In the invention, the soil improving material is,The water content was adjusted to 70 to 110%.
[0020]
No.10DepartureMing is,In the fifth invention, rock screenings are used as the soil material,The soil conditioner is mixed with rock screenings at a volume ratio of 20 to 40% based on the whole mixture, and the mixture is used to form a pavement surface.
[0021]
No.11DepartureMing is,10In the invention, the soil improving material is,The water content was adjusted to 60 to 120%.
[0022]
Function and Effect of the Invention
In the first invention, binder aggregate particles (particles in which sludge particles are aggregated) are formed in tap water sludge to obtain a soil improvement material. In this case, the binder aggregate particles having a particle size of not less than 0.425 mm and not more than 4.75 mm are contained in an amount of 50% by weight or more based on the whole water sludge, thereby acting as an aggregate when mixed with the soil material. The binder aggregate particles of the appropriate size to be used are sufficiently secured in the soil conditioner. For this reason, when the pavement surface is formed by mixing the soil improvement material with the soil material, the particles of the soil material are formed of a thin film composed of fine-grained portions (portions not converted into binder aggregate particles) in the soil improvement material. And the soil particles are strongly bonded to each other through this thin film, while the coarse-grained portion (binder aggregate particle portion) in the soil quality improving material is interposed between the soil particles to connect the soil particles to each other. At the same time as bonding, an appropriate gap is formed between the soil particles (acting as an aggregate supporting the soil particles). This allows the pavement surface to have excellent water resistance and water permeability without causing mud since water can quickly penetrate into the lower layer from the gap between the soil particles during water immersion.
Also, after granulation, the volatile organic matter contained in the water sludge is volatilized by performing a drying treatment so that the water content in the water sludge does not fall below the minimum water content limit. Offensive odors caused by organic substances are removed.
[0023]
In the second invention,In addition to the effects of the first invention,Since the water content of the water sludge is adjusted to 75 to 95% to form binder aggregate particles, the water sludge has an optimum plasticity at a water content near the plastic limit, and has a slight external force. Thereby, the binder aggregate particle structure can be effectively formed.
[0025]
Also,3In the invention ofIn addition to the effects of the first or second invention,Since the drying treatment is performed in a range where the water content of the water sludge does not fall below 50% (the minimum water content limit), the degree of drying of the water sludge is excessively increased, and the water resistance by the coagulant contained in the water sludge is increased. Will not be lost. Therefore, the completed soil improvement material has excellent water resistance, and does not expand and collapse even when immersed in water.
[0026]
Also,4In the invention ofIn addition to the effects of the first to third aspects,Since appropriate water is added after the drying treatment, when pavement is performed using the soil improving material, the pavement surface does not become too hard, and an appropriate degree of compaction can be provided. In addition, it is possible to prevent the water resistance ratio from dropping below 50% during storage and the water resistance is lost.
[0027]
No.5,6,8,10According to the invention, since the soil improving material and the soil material are mixed at an appropriate mixing ratio, a pavement surface having an appropriate compaction degree can be formed. In addition, since the mixing ratio of the soil improvement material to the soil material is 50% or less by volume, the amount of waste soil generated by replacing the soil with the soil improvement material does not become too large, and the burden of waste soil disposal is reduced. Small enough.
[0028]
No.7,9,11According to the invention, since the water content ratio of the soil conditioner is appropriately adjusted, a pavement surface having an appropriate compaction degree can be formed.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0030]
In the present invention, binder aggregate particles are formed in water sludge collected from a water purification plant to obtain a soil improvement material. Here, the binder aggregate particles are particles in which sludge particles of tap water sludge are in an aggregated state. It functions as an aggregate for supporting the soil particles so that a gap is formed between the soil particles.
[0031]
The formation of binder aggregate particles in tap water sludge is performed as follows.
[0032]
First, the water content of the water sludge is adjusted to a water content of 75 to 95% in order to make the water sludge into a state in which binder aggregate particles are easily formed. As a result, the water content of the clean water sludge is adjusted to a value close to the plastic limit, and the plasticity is in an optimal state, and the binder aggregate particle structure is easily formed by a small external force. Further, the formed binder aggregate particles also maintain a stable shape without breaking.
[0033]
For example, if the water content of the clean water sludge is 95% or more, the water is evaporated by heating and evaporating the clean water sludge. In this case, volatile organic substances contained in the water sludge are also volatilized. Heat evaporation is performed by solar drying, ventilation drying in a greenhouse, or the like. For example, in the case of sun drying, on the factory premises, tap water sludge is spread at a thickness of 5 to 30 cm, and the water is gradually evaporated by stirring with a tractor every hour. Such heating evaporation treatment is continued until the water content is adjusted to 75 to 95% while measuring the water content of the water sludge every hour. The measurement of the water content is performed, for example, by using a water content-bulk specific gravity relationship curve prepared in advance.
[0034]
The water sludge whose water content has been optimally adjusted in this way is passed through a sneader (crusher) to form granules of 19 mm or less. Further, the tap water sludge particles passed through the sneader are sieved through a 10 mm sieve so that binder water particles having a predetermined particle size range (0.425 to 4.75 mm) are contained in the tap water sludge in an amount of 50% by weight or more. Adjust to In this case, the content ratio of the binder aggregate particles is measured by a measuring method according to the particle size analysis test method of the Japan Society of Geotechnical Engineers (JSF T131).
[0035]
The water sludge obtained by the above method is further spread on the site of the factory with a thickness of 5 to 10 cm, and dried again by the sun while stirring every hour. The water is evaporated to a predetermined value of 50% or more. Due to this evaporation, the volatile organic substances contained in the water sludge are almost volatilized, and the ultraviolet rays contained in the sunlight perform a bactericidal effect, so that the odor due to the volatile organic substances in the water sludge is eliminated. Can be. This drying treatment (deodorization treatment) can be performed by ventilation drying and ultraviolet sterilization in a greenhouse.
[0036]
In any of the above treatments including the drying treatment, the water content of the clean water sludge is periodically measured and controlled so as to be kept at 50% or more (minimum water content limit value). By maintaining the water sludge at a water content ratio equal to or higher than the minimum water content ratio limit value, water resistance performance can be maintained.
[0037]
The details will be described below. In a water purification treatment at a water purification plant, an aggregating agent (for example, PAC) is added to precipitate a suspension quickly. These flocculants react with the water molecules while simultaneously generating a large amount of positive charge and combining with the negatively charged suspension to form large flocs. The flocs settle to the bottom due to gravity. As a result, water sludge, which can be said to be a combination of the suspension and the flocculant, is generated. The flocculant that has reacted with the water molecules is converted into an aluminum hydroxide substance that is insoluble in water, and the effect of the aluminum hydroxide substance causes the water sludge to have strong water resistance.
[0038]
However, once the aluminum hydroxide material is depleted of water, it cannot react with water molecules again, cannot re-associate with other negatively charged materials, and does not dissolve in water They lose their properties. For this reason, in order to maintain the water resistance of clean water sludge, it is necessary for the water to always have a certain amount of water or more, which is the minimum water content ratio limit. By performing various treatments within a range not to fall below the minimum water content limit, it is possible to appropriately perform moisture adjustment and deodorization treatment while securing the water resistance of water sludge, and to form a high quality soil improvement material it can.
[0039]
Since the soil improving material thus dried has a low water content, an appropriate degree of compaction cannot be obtained as it is. In addition, during storage, the water content may be reduced to 50% or less by drying. Therefore, after the drying treatment, water is immediately added again to the soil improvement material, the water content is adjusted to 60% to 120%, and then stored.
[0040]
In the pavement, the soil improvement material thus obtained is mixed with a general pavement soil material, and a pavement surface is formed with the mixture.
[0041]
In this case, the particles of the pavement soil material are covered with a thin film composed of fine-grained portions (portions not converted into binder aggregate particles) in the soil improvement material, and the soil particles are strongly bonded to each other via the thin film. . On the other hand, the coarse-grained portion (binder-aggregate particle portion) in the soil-improving material acts as an aggregate supporting the soil particles while interposing between the soil particles and binding the soil particles. , Forming appropriate gaps between the soil particles. This allows the pavement surface to have excellent water resistance and water permeability without causing mud since water can quickly penetrate into the lower layer from the gap between the soil particles during water immersion.
[0042]
In mixing the soil improving material and the soil material, the mixing ratio of the soil improving material may be in the range of 20% to 50%. By setting the mixing ratio of the soil improving material to the entire mixture to 20% or more, it is possible to secure a sufficient amount of the soil improving material to completely cover the soil particles of the soil material. Further, by setting the mixing ratio to 50% or less, it is possible to prevent the pavement surface from being excessively mixed with the soil improvement material in a large amount, thereby preventing the pavement surface from becoming too hard. When the mixing ratio of the soil improvement material is 50% or less, the generation of waste soil due to the replacement of the soil improvement material with the soil material (local soil) can be relatively reduced, and the burden of waste soil treatment can be reduced.
[0043]
In the concrete mixing of the soil improving material and various pavement soil materials, the water content of the soil improving material to be mixed is determined based on the properties of the soil material (such as water content, particle size distribution, surface area, and optimal water content). The content ratio of the binder aggregate particles and the mixing ratio of the soil material and the soil improving material are adjusted so as to obtain the optimum mixing effect. Here, the optimal mixing effect means that when both are mixed, uniformity of mixing is ensured, and at the same time, the water resistance and water permeability of the pavement surface can be maximized, and an appropriate degree of compaction is obtained. Say that you can. Specifically, when the soil material and the soil improvement material are mixed, by adjusting the mixture so as to have an optimum water content, an appropriate degree of compaction can be obtained on the pavement surface.
[0044]
The mixing of the soil improving material and the pavement soil material is sufficiently performed by, for example, plant mixing until the mixing becomes uniform throughout. Alternatively, it may be performed by central mixing at the construction site.
[0045]
FIG. 1 shows an example in which various pavement soil materials and soil improvement materials are mixed to obtain an optimum mixing effect.FigureIt is.
[0046]
FigureAs shown in (1), when the soil material is cohesive soil (for example, Arakida soil, red soil, black soil, etc.), the water content is generally high (5 to 25%). In addition, since the clay and silt content occupies 50% or more and the surface area is large, it is difficult to mix with the soil improving material. For such a soil material, a soil improvement material adjusted to a water content of 60 to 105% and a binder aggregate particle content of 65 to 75% by weight is mixed at a mixing ratio of 30 to 50%.(Hereinafter, it is referred to as a second embodiment).
[0047]
When the soil material is sandy soil (for example, masago, mountain sand, etc.), the water content is generally low (5 to 15%). In addition, particles equal to or greater than fine sand occupy 70% or more, have a small surface area, and are easily mixed with the soil improving material. For such a soil material, a soil improvement material adjusted to a water content of 70 to 110% and a binder aggregate particle content of 50 to 65% is mixed at a mixing ratio of 20 to 30%.(Hereinafter, a third embodiment).
[0048]
When the soil material is rock screenings (eg, green screenings, limestone dust, etc.), the water content may be low to medium. In addition, the equivalent of clay and silt is close to 30%, the composition is more than fine sand, and the surface area fluctuates greatly. Therefore, mixing with the soil improving material has many uncertain factors. For such a soil material, a soil improvement material adjusted to a water content of 60 to 120% and a binder aggregate particle content of 60 to 70% is mixed at a mixing ratio of 20 to 40%.(Hereinafter, it is referred to as Embodiment 4).
[0049]
As described above, depending on the type of soil material, by adjusting the water content of the soil improvement material, the binder aggregate particle content, and the mixing ratio with the soil material, the mixture has an optimal water content, An optimal mixing effect is obtained. The experimental results supporting this are shown in the figure.9belowFigureIt will be explained together.
[0050]
Next, a description will be given of experimental results which prove that the present invention achieves the effects of improving the water resistance and water permeability of a pavement surface and eliminating an unusual odor.
[0051]
FIG. 2 shows the results of a test performed to determine the optimum water content for forming binder aggregate particles.FigureIt is.
[0052]
In this test, 0.425 to 4.25 liters of tap water sludge (test Nos. 1 to 12) having various water contents were crushed into particles of 19 mm or less by a crusher and passed through a 10 mm sieve. The binder aggregate particle content of 75 mm is measured.Here, the test specimens of Test Nos. 7 and 8 having a water content of 94% and 75% are Examples 1 and 2 of Embodiment 1, the test specimens of Test Nos. 6, 9 and 10 are reference examples, and Specimens with test numbers are comparative examples.The content of the binder aggregate particles is measured by a measuring method according to the particle size analysis test method of the Japan Society of Geotechnical Engineers (JSF T131).
[0053]
Hereinafter, the test results will be considered. First, in the test specimens of Test Nos. 1 to 6 having a large water content (all of which have a water content of 95% or more), since the water contained in the water sludge is too large, a large lump is easily formed. Binder aggregate particles are not easily formed. Further, once the binder aggregate particles are formed, the shape is not stable, and the aggregates again become large. As described above, for the specimen having a water content of more than 120%, a sufficient amount of binder aggregate particles is not formed, and the larger the water content, the smaller the amount of binder aggregate particles formed.
[0054]
On the other hand, even in the specimens of Test Nos. 10 to 12 having a small water content (all having a water content of 65% or less), a sufficient amount of binder aggregate particles was not formed (at most 53% by weight of Test No. 10). ) Also, the formed binder aggregate particles are easily broken by external force. This is because the plasticity of the water sludge is low because the water of the water sludge is small.
[0055]
On the other hand, in the specimens of Test Nos. 7 to 9 having a water content of 75 to 95% near the plastic limit, binder aggregate particles are easily formed, and the content of the binder aggregate particles is 50 to 70%. It becomes.
[0056]
From the above, it is understood that the formation of the binder aggregate particles is most easily performed when the water content is adjusted to 75 to 95%.
[0057]
FIG. 3 shows the results of the water resistance test on the binder aggregate particles.
[0058]
In this test, 100 g of binder aggregate particles of 2 to 4.75 mm were taken out from the tap water sludge (7 types of tap water sludge having different production areas) on which the binder aggregate particles were formed, dried, and then used in a beaker. Water immersion test. In the water immersion test, the binder aggregate particles immersed in water are stirred with a glass rod for 1 minute, and left standing for 24 hours to observe the collapse of the binder aggregate particles. After 24 hours, the sample in the beaker is passed through a 0.425 mm sieve, the residue is dried, and after weighing, the disintegration rate of the binder aggregate particles is calculated. When the binder aggregate particles hardly disintegrate after 24 hours, it can be evaluated as having water resistance. For comparison, the same test was performed on spherical particles (aggregates) of Arakida soil.Here, the samples of test numbers 1 to 7 are Examples 3 to 9 of the first embodiment, and the sample of test number 8 is a comparative example.
[0059]
FigureAs shown in Table 2, the seven samples of binder aggregate particles collected from tap water sludge all had a disintegration rate of 3% or less after 24 hours. On the other hand, the spherical particles of Arakida soil gradually began to expand and collapse after being immersed in water and stirred, and the collapse ratio after 24 hours became 95%, and most of the spherical particles collapsed.
[0060]
From this result, it can be seen that the binder aggregate particles of the tap water sludge have a strong property (water resistance) to water. This is due to the action of the coagulant contained in the water sludge as described above. Due to this water resistance, the binder aggregate particles can serve as an aggregate supporting gaps between the soil particles when the soil improvement material is mixed with a general soil material, and improve the water permeability of the pavement surface. Work.
[0061]
FIG. 4 shows the results of the permeability test of the soil improvement material.FigureIt is.
[0062]
In this test, after the specimen is saturated with water for 24 hours, water is permeated from the upper part of the specimen, and the water permeation amount after a lapse of a predetermined time is measured. Based on this, the hydraulic conductivity is calculated.
[0063]
As the specimen, a mixture of naturally dried masago and a 30% by volume mixture of tap water sludge was adjusted to have a water content close to the optimum water content to form a cylinder having a diameter of 8 cm and a height of 8 cm. Used. The types of test specimens were prepared for five types of clean water sludge having different binder aggregate particle contents (test numbers 1 to 5), and prepared for clean water sludge pulverized to fine sand or less (test number). 6) and those prepared by replacing tap water sludge with Arakida soil (formed with spherical particles) and masago soil, respectively (test numbers 7 and 8).Here, the test pieces with test numbers 2 to 5 are Examples 10 to 13 of the first embodiment, and the test pieces with other test numbers are comparative examples.
[0064]
FigureAs shown in the above, the test piece composed of clean water sludge having formed binder aggregate particles (Test Nos. 1 to 5) was a test piece composed of Arakida soil (Test No. 7) or a specimen composed only of masago soil. (Test No. 8) has much higher hydraulic conductivity. For example, in the test specimen of Test No. 7, since the spherical particles of Arakida soil are very weak in water and collapse immediately after being immersed in water, they are used as aggregates that support between sand sand particles like binder aggregate particles. It has no effect and the permeability is very low.
[0065]
In addition, when comparing specimens made of tap water sludge with binder aggregate particles formed therein, the permeability increases as the amount of binder aggregate particles in the tap water sludge increases.
[0066]
Also, in the specimen using tap water sludge, the binder having no aggregate particles formed and the specimen consisting of tap water sludge pulverized to fine sand or less (Test No. 6) has a permeability coefficient of pure sand. The test specimen (Test No. 8) is lower than the test specimen. This is considered to be because water sludge below fine sand blocks the gaps between the particles of the mixed sand.
[0067]
From the above, it can be seen that the formation of binder aggregate particles in tap water sludge significantly improves the water permeability of a mixture of this and soil material.
[0068]
FIG. 5 shows the results of a water immersion test conducted to investigate the relationship between the water resistance effect of binder aggregate particles and the water content of water sludge.FigureIndicated by
[0069]
In this exam,Formed binder aggregate particlesAfter appropriate addition of water to the tap water sludge, it is filled into a mold (4 cm × 3 cm × 0.7 cm), compacted, taken out, and dried at 110 ° C. for 24 hours to obtain a specimen. This specimen is submerged and the change of the specimen is observed. Check the disintegration time of the specimen within 24 hours and the state of softening of the specimen after 24 hours. In this test, ten types of clean water sludge having different water contents are used as test specimens.Here, the test specimens of test numbers 1 to 5 are Examples 14 to 18 of the first embodiment, the test specimen of test number 6 is a reference example, and the test specimens of other test numbers are comparative examples.
[0070]
According to the results of the water immersion test, the test pieces (test numbers 1 to 5) having a water content of 50% or more exhibited substantially sufficient water resistance. Specifically, the test specimens of Test Nos. 1 to 3 hardly collapsed and did not soften even after 24 hours of water immersion. In addition, the test specimen of Test No. 4 (water content ratio 63%) softened slightly, and the test specimen of Test No. 5 (water content ratio 52%) softened, but none of them collapsed.
[0071]
On the other hand, in the test specimens having a water content of 50% or less (test numbers 6 to 10), sufficient water resistance was not obtained. Specifically, the test specimens of Test Nos. 7 to 10 completely disintegrated within 24 hours. Also, the test specimen of Test No. 6 having the highest water content (water content 43%) showed partial collapse after 24 hours.
[0072]
From the above results, it can be concluded that the moisture content needs to be 50% or more in order for the soil improving material to have a sufficient water resistance effect.
[0073]
Fig. 6 shows the results of the deodorization test by heating and drying the water sludge.FigureIndicated by
[0074]
This test was conducted to confirm whether the off-flavor of tap water sludge can be canceled by a simple heating and evaporation method.
[0075]
In the test, 500 g of tap water sludge having a water content of about 150% was used as a test piece and heated in a constant temperature furnace. The unpleasant odor before and after heating is checked by human odor, and the intensity of the unpleasant odor is classified. The test is performed by dividing the heating temperature into 10 stages from 20 ° C. to 110 ° C., and performing the heating for 4 hours, 6 hours and 8 hours, respectively. The classification of the intensity of the off-flavor was determined on the basis of the feeling of the person who performed the test in four stages: considerable, worried, not much worried, and hardly worried.
[0076]
The test shows the following trends: First, in the case of the same heating time, the higher the heating temperature, the greater the amount of odor removal. Next, at the same heating temperature, the longer the heating time, the greater the amount of odor removal. Specifically, in the case of heating for 4 hours, a heating temperature of 70 ° C. is required to make the off-odor less noticeable. On the other hand, in the case of heating for 6 hours, the temperature dropped to 50 ° C., and in the case of heating for 8 hours, the temperature further dropped to 30 ° C. That is, it was found that the same deodorizing effect can be obtained at a low temperature for a long time as the deodorizing effect obtained at a high temperature for a short time. The latter is also a simpler and more effective deodorizing method, which can save capital investment and energy.
[0077]
Further, as shown in the test results, when the off-flavor is reduced to a level that is not so noticeable, the water content of the clean water sludge is approximately between 42 to 63%. That is, when the water content is reduced to nearly 50% by heating evaporation, the off-flavor of clean water sludge can be substantially eliminated.
[0078]
From this test result, it can be concluded that when deodorizing clean water sludge, a considerable deodorizing effect can be obtained by reducing the water content to near 50% while maintaining the temperature of 30 ° C. to 50 ° C. for 8 hours or more.
[0079]
FIG. 7 and FIG. 8 show experimental results obtained by examining the relationship between the binder aggregate particle content in the soil improvement material and the water permeability.
[0080]
The soil is composed of sand, gravel, etc., but the permeability of the soil is considered to be greatly affected by the content ratio of coarse sand to fine gravel components. In this regard, the present inventor has confirmed that soil exhibiting high water permeability has a high content of coarse sand to fine gravel components by particle size analysis and water permeability test of various natural soils. Therefore, in the present invention, by adjusting the content ratio of binder aggregate particles having a particle size corresponding to coarse sand to fine gravel, that is, a binder aggregate particle having a particle size of 0.425 to 4.75 mm, a soil improvement material is obtained. Ensure that it has sufficient water permeability.
[0081]
In soil pavement, appropriate tightening is required at the same time as permeability, but in general soil materials, if the content of coarse sand and fine gravel increases and the content of clay and silt decreases, Tightening at the time tends to be worse. However, as described above, in the case of tap water sludge, the aggregates are bound by the action of the coagulant contained in the tap water sludge by forming the aggregate structure (binder aggregate particles), so that the sludge is tight. In this respect, sufficient quality can be obtained.
[0082]
FIG. 7 shows a test result of the relationship between the content ratio of binder aggregate particles in water sludge and the permeability coefficient.FigureIt is. FIG. 8 is a graph of the test result of FIG.
[0083]
In this water permeability test, the specimen was saturated with water for 24 hours, then permeated from the upper part of the specimen, and the amount of water permeation was measured after a lapse of a predetermined time. Based on this, the permeability coefficient at 15 ° C. was calculated. I do. As the test specimens, 10 kinds of water sludges having different contents of the binder aggregate particles were air-dried and then adjusted to a water content close to an optimum water content to obtain a cylindrical body having a diameter of 8 cm and a height of 8 cm. (Test Nos. 1 to 10) are used.Here, the test pieces with test numbers 6 to 10 are Examples 19 to 23 of the first embodiment, and the test pieces with other test numbers are comparative examples.
[0084]
FigureAs can be seen from the graph and in the graph, the untreated tap water sludge (test number 1) and the tap water sludge just crushed into fine sand (test number 2) have a low binder aggregate particle content (4. 6% by weight, 5.3% by weight) and low water permeability (1.04 × 10^-5cm / s, 6.87 × 10^-6cm / s). On the other hand, when binder aggregate particles are formed in tap water sludge (Test Nos. 3 to 8), the permeability increases as the content of binder aggregate particles increases, and in particular, the content ratio of binder aggregate particles increases. When the content reaches 50 to 60% by weight, a sharp improvement in the water permeability is observed. Specifically, in Test No. 5 (binder aggregate particle content = 43.2% by weight), the water permeability was 7.76 × 10^-4cm / s, but in Test No. 6 (binder aggregate particle content = 55.1% by weight), the water permeability was 1.74 × 10^-3cm / s, indicating sufficient water permeability.
[0085]
From the above, the binder aggregate particles were formed so that the binder aggregate particles having a particle size of 0.425 mm or more and 4.75 mm or less were contained in the water sludge by 50% by weight or more.MakeBy doing so, it is considered that the soil improving material (tap water sludge after forming the binder aggregate particles) can have sufficient water permeability.
[0086]
9 to 11 show the results of tests performed to examine the water resistance effect and the hardness of the pavement surface depending on the mixing ratio of the soil improvement material and the soil material.FigureIndicated by
[0087]
In this test, a test specimen having a diameter of 10 cm and a height of 6 cm, which has been subjected to tamping treatment with a rammer, is first air-cured for 4 days, and then the hardness is measured. Thereafter, the specimen is immersed in water for 24 hours, and the water resistance of the specimen is observed. If the shape of the specimen does not collapse after 24 hours, it is evaluated that there is a water resistance effect. Specimens were prepared by mixing soil improvement materials with three types of soil materials (masago, Arakida soil, green screenings), respectively, and the mixing ratio of the soil improvement materials was different for each soil material. Ten types were created respectively.
[0088]
The hardness measurement in this test was performed using a Yamanaka penetrator. Therefore,FigureIn, the hardness is represented by a hardness index. Here, the relationship between the hardness index (mm) and the bearing strength (Pa) is as follows.
Bearing strength = 100 × hardness index / ｛0.7952 × (40-hardness index)²｝
Thus, the bearing strength is determined by the hardness index (FigureThe larger the value in (), the larger the value.
[0089]
FIG. 9 shows the test results for a specimen in which the mixed soil material is a masago.Here, the test specimens of test numbers 5 and 6 are Examples 1 and 2 of Embodiment 3 shown in FIG. 1, the test specimens of test numbers 7 and 8 are reference examples, and the test specimens of other test numbers are It is a comparative example.
[0090]
FigureAs can be seen from the graph, when the mixing ratio of the soil improving material is less than 15% (Test Nos. 1 to 3), the test specimen completely collapses after water immersion, and it can be said that there is almost no water resistance. When the mixing ratio was 15% (Test No. 4), the test specimen collapsed after water immersion for the most part, but a certain water resistance effect was observed within 24 hours, and when the mixing ratio of the soil improvement material was insufficient. Conceivable. On the other hand, when the mixture ratio became 20% or more (test numbers 5 to 10), the specimen collapsed except that the surface of the specimen was slightly softened 24 hours after immersion in No. 5 with a mixture ratio of 20%. Was not observed, and it was confirmed that there was a water resistance effect.
[0091]
Next, when examining the hardness indices of these specimens, the specimens of Test Nos. 5 to 8 exhibited an appropriate hardness of about 32 mm. On the other hand, in the test specimens of Test Nos. 9 to 10, the hardness index increases to 34 to 35.5 mm, and it can be said that the ground used for general purposes is hard. From these results, it is found that when mixing the sand-improved soil and the soil-improving material, if the mixing ratio of the soil-improving material is set to 20% or more and 50% or less, the pavement surface can be appropriately hardened while maintaining water resistance. It is thought that it is possible to have.
[0092]
FIG. 10 shows the test results for a specimen in which the mixed soil material is Arakida soil.Here, the test pieces with test numbers 6 to 8 are Examples 1 to 3 of Embodiment 2 shown in FIG. 1, and the test pieces with other test numbers are comparative examples. FigureAs can be seen from the graph, when the mixed soil material was Arakita soil, the result was almost the same as that of the masago soil. However, since the particles of Arakida soil were fine, the mixing ratio of the soil improvement material was 20%. In the sample (Test No. 5), some disintegration was observed after 24 hours of water immersion, and the water resistance was not sufficient. Therefore, when mixing Arakita clay (cohesive soil) with a soil improvement material as a mixed soil material, it is considered appropriate to set the mixing ratio of the soil improvement material to 30% or more and 50% or less.
[0093]
FIG. 11 shows the test results for the test specimen in which the mixed soil material is green screenings.Here, the test pieces with test numbers 5 to 7 are Examples 1 to 3 of Embodiment 4 shown in FIG. 1, the test piece with test number 8 is a reference example, and the test pieces with other test numbers are comparative examples. It is. FigureAs can be understood from the above, in this case, the result was almost the same as that of the case of the masago. Therefore, when green screenings (rock screenings) are used as the mixed soil material, it is considered that the mixing ratio of the soil improvement material should be 20% or more and 50% or less as in the case of the masago.
[0094]
12 to 20 show how to adjust the content ratio of the binder aggregate particles in the soil improvement material in order to make the mixed soil of the soil improvement material and various soil materials sufficiently high in water permeability. This shows the test results of the examination.
[0095]
In these tests, naturally dried soil materials (sandy soil (mass sand), clayey soil, rock screenings (green screenings)) were used as soil improvement materials (binder aggregate particle content was varied for each sample). ), And adjust the water content to near the optimal water content to form a cylinder having a diameter of 8 cm and a height of 8 cm, which is used as a specimen. After the specimen is saturated with water for 24 hours, water is permeated from the upper part of the specimen, the amount of water permeated after a lapse of a predetermined time is measured, and the water permeability coefficient is calculated based on this. In addition, a particle size test was performed on the specimens that were subjected to the water permeability test, and the proportion of coarse sand fine gravel (particles having a particle diameter of 0.425 to 4.75 mm) in the specimens was examined.
[0096]
FIG. 12 shows the test results in the case where the mixed soil material was a sandy soil, a masago. 13 and 14 are graphs showing the test results.
[0097]
In this test, the ratio of coarse sand and fine gravel was 47.9% by weight and that of clay and silt was 23.8% by weight in the masago soil before being mixed with the soil improvement material. Permeability is 4.91 × 10^-5cm / s. A sample is prepared by mixing a soil improvement material with the masago at a mixing ratio of 20% and 30%. The upper limit and the lower limit of the mixing ratio are determined based on the conclusion that the mixing ratio of the soil improving material to the sandy soil is preferably 20 to 30% in the test of FIG. is there.That is, it is a test result obtained by variously adjusting the content ratio of the binder aggregate particles in the soil improving materials of Examples 1 and 2 of Embodiment 3 shown in FIG.
[0098]
First, when the specimens (samples 1 to 8) in which the mixing ratio of the soil improving material is 20% are examined, as can be seen from FIGS. 12 and 13, the binder aggregate particle content in the soil improving material in the test material is approximately equal. From around 50% by weight (samples 4 and 5), the water permeability significantly improvesdid. Further, even in the specimens (samples 9 to 16) in which the mixing ratio of the soil improving material is 30%, as can be seen from FIGS. 12 and 14, when the binder aggregate particle content of the soil improving material exceeds 50% by weight ( Samples 12 and 13), the permeability of the test specimen was significantly improveddid.
[0099]
From this result, when the soil improving material is mixed with the masago (sandy soil), the content of the binder aggregate particles in the soil improving material is set to 50 to 65% by weight in order to secure appropriate water permeability to the mixed soil. It can be concluded that it is appropriate to adjust to.
[0100]
FIG. 15 shows a test result when the mixed soil material is a viscous soil. 16 and 17 show the test results in the form of graphs.
[0101]
In this test, the ratio of coarse sand and fine gravel was 35.7% by weight, and clay and silt was 38.4% by weight as the clay soil before being mixed with the soil improvement material. Permeability coefficient 5.13 × 10^-6cm / s. This cohesive soil is mixed with a soil improvement material at a mixing ratio of 30% and 50% to obtain a specimen. The upper limit and the lower limit of the mixing ratio are determined based on the conclusion that the mixing ratio of the soil improving material to the clayey soil of 30 to 50% is appropriate in the test of FIG. .That is, it is a test result obtained by variously adjusting the content ratio of the binder aggregate particles in the soil improvement materials of Examples 1 and 3 of Embodiment 2 shown in FIG.
[0102]
First, when examining the specimens (samples 1 to 9) in which the mixing ratio of the soil improving material is 30%, as can be seen from FIGS. 15 and 16, the binder aggregate particle content of the soil improving material in the test material is approximately 65%. Permeability is remarkably improved from around the weight% (samples 5-6)did. Further, even in the specimens (samples 10 to 18) in which the mixing ratio of the soil improving material is 50%, as can be seen from FIGS. 15 and 17, when the binder aggregate particle content in the soil improving material exceeds 65% by weight. (Samples 14 and 15), the permeability of the test specimen was significantly improveddid.
[0103]
From this result, when mixing the soil improving material with the cohesive soil, it is possible to adjust the content of the binder aggregate particles in the soil improving material to 65 to 75% by weight in order to secure appropriate water permeability to the mixed soil. We can conclude that it is appropriate.
[0104]
FIG. 18 shows test results when the mixed soil material was green screenings, which are rock screenings. 19 and 20 are graphs showing the test results.
[0105]
In this test, as the green screenings before mixing with the soil improvement material, the proportion of coarse sand and fine gravel was 47.0% by weight, the content of clay and silt was 17.5% by weight, and the permeability was 6.78 ×. 10^-5cm / s. This green screening is mixed with a soil improving material at a mixing ratio of 20% and 40% to obtain a test specimen. This mixing ratio is based on the upper limit and the lower limit based on the conclusion that the mixing ratio of the soil improving material to the green screenings of 20 to 40% is appropriate in the test of FIG. is there.That is, it is a test result obtained by variously adjusting the content ratio of the binder aggregate particles in the soil improvement materials of Examples 1 and 3 of Embodiment 4 shown in FIG.
[0106]
First, when examining specimens (samples 1 to 7) in which the mixing ratio of the soil improving material is 20%, as can be seen from FIGS. 18 and 19, the binder aggregate particle content of the soil improving material in the sample is 60 to 60%. From around 70% by weight (samples 5 and 6), a noticeable improvement in the water permeability was observed. Also, in the test specimens (samples 10 to 18) in which the mixing ratio of the soil improving material is 40%, as can be seen from FIGS. 18 and 20, the binder aggregate particle content in the soil improving material exceeds approximately 60% by weight. (Sample 12), the water permeability of the specimen was remarkably improved.
[0107]
From this result, soil improvement materialGreen screeningsIt can be concluded that it is appropriate to adjust the content of the binder aggregate particles in the soil conditioner to 60 to 70% by weight in order to secure appropriate water permeability to the mixed soil when mixing with the mixed soil.
[0108]
If the content of the binder aggregate particles in the soil quality improving material is too large (for example, more than 75% by weight), the fine particles (particles of 0.425 mm or less) to be formed into a thin film when mixed with the soil material. Ratio is insufficient. For this reason, the content range of the binder aggregate particles in the soil improvement material is limited to 75% by weight or less.
[0109]
In addition, even if the soil material mixed with the soil improving material has a small amount of coarse sand fine gravel, and the soil improving material has an upper limit of binder aggregate particle content (for example, 75% by weight), the coarse sand fine gravel in the mixed soil can be reduced. If the ratio of the minutes does not increase sufficiently, it is advisable to adjust the particle size appropriately, for example, by mixing the soil material with another soil material having a large amount of coarse sand and fine gravel.
[0110]
FIGS. 21 to 23 show the results of tests for examining the relationship between the compaction degree of the mixture of the soil improving material and various soil materials and the water content of the soil improving material.FigureIndicated by
[0111]
The degree of compaction of the pavement surface has a significant effect on the hardness of the pavement surface, durability against use, feel during use, etc.It is an important point during construction that the degree of compaction is appropriate. Become.
[0112]
The degree of compaction is greatly affected by the water content of the soil material, and if the water content is low, water particles between the soil material particles bind to each other.AndSince it is weak, it does not compact sufficiently even when it is rolled. Conversely, if the water content is high, the water between the particles tends to move to the periphery due to the pressure during compaction, and eventually causes a problem such as a depression on the pavement surface. Also, after drying,crackCracks easily occur.
[0113]
As described above, the adjustment of the water content of the pavement material is extremely important for obtaining an appropriate degree of compaction. In particular, when a pavement surface is formed with a mixture of a plurality of materials as in the present invention, the water content of each material has a complex effect on the water content of the mixture, so it is necessary to pay particular attention to moisture adjustment. . From this viewpoint, this test was performed to find the optimal water content ratio of the soil improvement material for various water content conditions of typical pavement soil materials (masago, Arakita soil, green screenings). Things.
[0114]
In this test, first, for a mixture of a soil material and a soil improvement material, an optimum water content ratio (a water content ratio at which the degree of compaction is optimal) is determined by a compaction method. Using this optimum water content as a guide, the water content of the soil improving material relative to the water content of the soil material is adjusted so that the water content of the mixture is about 10% before and after the optimum water content. A specimen is prepared from this mixture, and the degree of compaction is checked.
[0115]
More specifically, the mixture was tamped with a rammer 25 times / 3 layers to form a cylindrical body having a diameter of 10 cm and a height of 12.7 cm, which was used as a specimen. A golf ball is dropped from the height of 1 m onto the specimen just after the preparation, and the surface of the specimen is checked for dents due to the fall of the golf ball, and the shrinkage of the specimen after drying is observed. The test is performed on a plurality of specimens in which the water content ratio of the soil material and the mixing ratio of the soil improvement material are different.
[0116]
FIG. 21 shows a test result when the mixed soil material is masago.
[0117]
For a mixture of 70% masago and 30% soil conditioner, the optimum moisture content is 25.8%. The masago is a sandy soil, in which the ratio of particles equal to or greater than fine sand occupies 70% or more, and the specific surface area is relatively small, so that the fluctuation range of the water content is narrow (5 to 15%). In accordance with this, specimens are prepared for the masago soil having a water content of 5%, 10%, and 15%. Further, the mixing ratio of the soil improvement material is set to 20% to 40% (see FIG. 9).That is, it is the result of examining the relationship between the compaction degree of the mixture of Examples 1 and 2 of Embodiment 3 shown in FIG. 9 and the water content of the soil conditioner. Then, among Test Nos. 1 to 6 in which the soil improvement material was mixed at 20%, Test Nos. 3 to 5 are Examples 1-1 to 1-3, and test pieces with other test numbers are comparative examples. Also, among Test Nos. 7 to 10 in which 30% of the soil improvement material was mixed, Test No. 8 was Example 2-1; Test No. 9 was a reference example; and test pieces with other test numbers were comparative examples. . Specimens of Test Nos. 11 and 12 containing 40% of a soil improving material are also comparative examples.
[0118]
When the mixing ratio of the soil improvement material is 20% (test numbers 1 to 6), when the water content of the soil improvement material is adjusted to 70% or more and 110% or less (test numbers 3 to 5), Provided a suitable degree of compaction. That is, no dent was formed by the drop test of the golf ball, and no shrinkage after drying occurred. The water content of these test specimens was around 26%, which was close to the optimum water content.
[0119]
On the other hand, in the test specimens (test numbers 1 and 2) in which the water content of the soil conditioner was adjusted to 120% and 150%, depressions occurred, and an appropriate degree of compaction could not be obtained. The water content of each of these specimens was higher than the optimum water content. Further, in the case of the test sample of Test No. 6 in which the water content of the soil conditioner was adjusted to 60%, the compactness of the mixture was poor because the water content was as low as 24%.
[0120]
From this result, when the soil improvement material is mixed with masago at a mixing ratio of 20%, the water content of the soil improvement material is adjusted to 70% or more and 110% or less to obtain a pavement surface having an appropriate compaction degree. It can be concluded that formation is possible.
[0121]
Next, the case where the mixing ratio of the soil improvement material is set to 30% is examined. In the test specimens of Test Nos. 8 and 9 in which the water content of the soil improvement material is set to 60% or more and 75% or less, an appropriate compaction degree is determined. The sample is hollowcrackNo cracking occurred. The water content of these specimens was 25 to 26%, which was a value close to the optimum water content.
[0122]
On the other hand, in the specimen of Test No. 7 in which the water content of the soil improvement material was adjusted to 85%, depression occurred even when the water content of the sand was 5%, which is the minimum. The water content of this sample was 29%, which was higher than the optimum water content. In addition, the specimen of Test No. 10 in which the moisture content of the soil improvement material was adjusted to 60% and the moisture content of the masago was adjusted to 15%, a depression was formed, and the moisture content of the mixture was 28.9%. .
[0123]
Therefore, it can be concluded that when the mixing ratio of the soil improving material is 30%, the pavement surface having an appropriate compaction degree can be formed by adjusting the water content of the soil improving material to 60 to 75%.
[0124]
Next, the case where the mixing ratio of the soil improvement material is set to 40% is examined. The test piece in which the moisture content of the soil improvement material is 60% while the water content of the sand is 5% at the minimum. For Test No. 12), an appropriate degree of compaction was obtained, but for the specimen (Test No. 11) in which the water content of the soil improving material was 70%, a depression was formed, and an appropriate degree of compaction was obtained. I couldn't. The water content of the test sample of Test No. 11 was 31%, which was higher than the optimum water content.
[0125]
Therefore, when the mixing ratio of the soil improvement material is 40%, the water content of the soil improvement material must be set to the minimum limit of 60% even if the water content of the sand is the lowest of 5%. It can be said that it is not easy to form a pavement surface having a high degree of compaction.
[0126]
From the above, when the soil improvement material is mixed with the sandy soil (for example, masago) at a mixing ratio of 20% to 30%, the water content is adjusted to 70 to 110% in order to obtain an appropriate compaction degree. It is necessary.
[0127]
FIG. 22 shows the test results when the mixed soil material was Arakida soil.
[0128]
In the case of a mixture of 70% of Arakida soil and 30% of soil improvement material, the optimum water content is 35.2%. Arakida soil is a cohesive soil, in which the ratio of clay and silty occupies 50% or more, and the specific surface area is large, so that the water content varies within a fairly large range (5 to 25%). Specimens are prepared for Arakida soil having a water content of 5%, 10%, 15%, 20%, and 25% in accordance with this fluctuation range. In this case, the mixing ratio of the soil improvement material is 30%, 40%, and 50% (see FIG. 10).That is, it is the result of examining the relationship between the compaction degree of the mixture of Examples 1 to 3 of Embodiment 2 shown in FIG. 10 and the water content of the soil conditioner. Then, among Test Nos. 1 to 6 in which the soil improvement material was mixed at 30%, Test Nos. 2 to 6 are Examples 1-1 to 1-5, and test pieces with other test numbers are comparative examples. Test numbers 8 to 11 are Examples 2-1 to 2-4 in Test numbers 7 to 12 obtained by mixing 40% of the soil improving material, and test pieces having other test numbers are comparative examples. Furthermore, among Test Nos. 13 to 16 in which 50% of the soil improvement material was mixed, Test Nos. 14 and 15 are Examples 3-1 to 3-2, and specimens with other test numbers are comparative examples.
[0129]
First, when the case where the mixing ratio of the soil improving material is 30% (Test Nos. 1 to 6) is examined, a specimen (Test No. 2 to 6) in which the water content of the soil improving material is adjusted to 60% or more and 105% or less. In), an appropriate degree of compaction was obtained. That is, no dent was formed by the drop test of the golf ball, and no shrinkage after drying occurred. Each of these specimens had a value close to the optimum water content.
[0130]
On the other hand, the specimen of Test No. 1 in which the water content of the soil conditioner was adjusted to 115% had a depression, and an appropriate degree of compaction could not be obtained. In this case, the water content of the Arakida soil was 5%, which was the lowest expected water content, but the water content of the test specimen was 38.3%, which was higher than the optimum water content. . Also,FigureAlthough not shown, when the water content of the soil conditioner is lower than 60%, the water resistance is lost, and the compactness of the mixture is deteriorated.
[0131]
From this result, when the soil improvement material is mixed with Arakida soil at a mixing ratio of 30%, the pavement having an appropriate compaction degree is adjusted by adjusting the water content of the soil improvement material to 60% or more and 105% or less. It can be concluded that a surface can be formed.
[0132]
Next, when the mixing ratio of the soil improving material is 40% (Test Nos. 7 to 12), the specimens (Test Nos. 8 to 11) in which the water content of the soil improving material is adjusted to 60% or more and 80% or less. No.), a suitable degree of compaction is obtained, and the specimencrackNo cracking occurred. The water content of these specimens was 35 to 36%, which was a value close to the optimum water content.
[0133]
On the other hand, in the test specimen of Test No. 7 in which the water content was adjusted to 90%, even when the water content of Arakida soil was the lowest of 5%, considerable depression occurred. After drying, some cracks occurred. The water content of this sample was 39%, which was considerably higher than the optimum water content. Further, in the test specimen of Test No. 12 in which the moisture content of the soil improvement material was 55%, the water resistance was lost.
[0134]
Therefore, it can be concluded that when the mixing ratio of the soil improving material is 40%, the pavement surface having an appropriate compaction degree can be formed by adjusting the water content of the soil improving material to 60 to 80%.
[0135]
Next, the case where the mixing ratio of the soil improving material was set to 50% was examined. In the test specimens of Test Nos. 14 and 15 in which the water content of the soil improving material was set to 60% or more and 65% or less, appropriate compaction was performed. Degree is obtained, and the specimen also has a hollowcrackNo cracking occurred. The water content of these specimens was 35 to 36%, a value close to the optimum water content.
[0136]
On the other hand, the specimen of Test No. 13 in which the water content was adjusted to 70% or more had a depression. The water content of this sample was 39%, which was higher than the optimum water content. When the water content of Arakida soil was set to 15% (Test No. 16), even if the water content of the soil quality improvement material was adjusted to the minimum of 60%, the specimens were dented and dried.crackAnd an appropriate degree of compaction could not be obtained.
[0137]
Therefore, it can be concluded that when the mixing ratio of the soil improving material is 50%, the pavement surface having an appropriate compaction degree can be formed by adjusting the water content of the soil improving material to 60 to 65%.
[0138]
From the above, when the soil improving material is mixed with cohesive soil (for example, Arakida soil) at a mixing ratio of 30% to 50%, the water content may be adjusted to 60 to 105% in order to obtain an appropriate compaction degree. is necessary.
[0139]
FIG. 23 shows the test results when the mixed soil material was green screenings.
[0140]
For a mixture of 70% green screenings and 30% soil conditioner, the optimum moisture content is 27.8%. The green screenings have a clay to silt ratio of about 30 to 35%, a specific surface area of medium, and a variation range of the water content of 5 to 15%. In accordance with this, specimens are prepared for the masago soil having a water content of 5%, 10%, and 15%. The mixing ratio of the soil improvement material is set to 20 to 50% (see FIG. 11).That is, 11 is a result of examining the relationship between the compaction degree of the mixture of Examples 1 to 3 of Embodiment 4 shown in FIG. 11 and the water content of the soil improving material. Then, among Test Nos. 1 to 6 in which the soil improvement material was mixed at 20%, Test Nos. 3 to 5 are Examples 1-1 to 1-3, and test pieces with other test numbers are comparative examples. Further, among Test Nos. 7 to 10 in which 30% of the soil improvement material was mixed, Test Nos. 8 to 10 are Examples 2-1 to 2-3, and test pieces having other test numbers are comparative examples. In Test Nos. 11 to 13 obtained by mixing 40% of the soil improvement material, Test No. 13 is Example 3-1 and specimens with other test numbers are Comparative Examples. Further, the test specimens of Test Nos. 14 and 15 in which the soil improvement material was mixed at 50% are comparative examples.
[0141]
In the test specimens of Test Nos. 3 to 5 in which the water content of the soil conditioner was adjusted to 80% or more and 120% or less, an appropriate degree of compaction was obtained, no dent was formed by the drop test of the golf ball, and after drying, No shrinkage occurred. The water content of these specimens was about 28%, which was close to the optimum water content.
[0142]
On the other hand, the specimen having a moisture content of 130% (test number 2) and the specimen having a moisture content of 150% (test number 1) of the soil improvement material had depressions, and an appropriate degree of compaction could not be obtained. . Their water content was 30-34%, higher than the optimum water content. The specimen of Test No. 6 in which the water content of the soil conditioner was adjusted to 70% or less had poor tightening and a low water content (26%).
[0143]
From this result, when the soil improving material is mixed with the green screenings at a mixing ratio of 20%, the pavement having an appropriate compaction degree is adjusted by adjusting the water content of the soil improving material to 80% or more and 120% or less. It can be concluded that a surface can be formed.
[0144]
Next, the case where the mixing ratio of the soil improvement material was set to 30% was examined. In the test specimens of Test Nos. 8 to 10 in which the water content of the soil improvement material was set to 60% or more and 80% or less, an appropriate compaction degree was determined. And the hollow of the specimencrackNo cracking occurred. The water content of these specimens was 27 to 28%, a value close to the optimum water content.
[0145]
On the other hand, the specimen of Test No. 7 in which the water content was adjusted to 90% or more, even when the water content of the green screenings was the lowest of 5%, dents were formed, and the water content was 31%, which was higher than the optimum water content. I was
[0146]
Therefore, when the mixing ratio of the soil improving material is 30%, the pavement surface having an appropriate compaction degree can be formed by adjusting the water content of the soil improving material to 60 to 80%.
[0147]
Next, the case where the mixing ratio of the soil improving material was set to 40% was examined. In the specimen of Test No. 13 in which the water content of the soil improving material was set to 60%, an appropriate degree of compaction was obtained. On the other hand, the specimens (test numbers 11 and 12) in which the water content of the soil improvement material was 65% or more had dents and the water content was 29 to 31%, which was higher than the optimum water content. Therefore, when the mixing ratio of the soil improving material is 40%, it is necessary to adjust the water content of the soil improving material to 60% in order to obtain an appropriate degree of compaction.
[0148]
Next, the case where the mixing ratio of the soil improving material is set to 50% is examined. Even if the water content of the soil improving material is adjusted to the minimum of 60% and the water content of the green screenings is adjusted to the minimum of 5% (test Nos. 14 and 15), when the specimens are dented or driedcrackAnd an appropriate degree of compaction could not be obtained. The water content of these specimens was 33-38%, which was higher than the optimum water content. Therefore, it is considered that it is difficult to obtain an appropriate degree of compaction when the mixing ratio of the soil improving material is 50%.
[0149]
From the above, when the soil improvement material is mixed with rock screenings (for example, green screenings) at a mixing ratio of 20 to 40%, the water content is adjusted to 60 to 120% in order to obtain an appropriate compaction degree. It is necessary.
[Brief description of the drawings]
FIG. 1 shows an example in which various pavement soil materials and soil improvement materials are mixed to obtain an optimum mixing effect.FigureIt is.
FIG. 2 shows the results of a test performed to determine the optimum water content for forming binder aggregate particles.FigureIt is.
FIG. 3 shows the results of a water resistance test of binder aggregate particles in tap water sludge.FigureIt is.
FIG. 4 shows the results of a water permeability test for confirming the water permeability improvement effect of water sludge formed with binder aggregate particles.FigureIndicated by
FIG. 5 shows the results of a water immersion test performed to examine the relationship between the water resistance effect of binder aggregate particles and the water content of clean water sludge.FigureIt is.
FIG. 6 shows the results of a deodorization test of tap water sludge by heating and drying.FigureIt is.
FIG. 7 shows test results on the relationship between binder aggregate particle content and water permeability in soil improvement materials.FigureIt is.
FIG. 8 is a graph showing a test result on a relationship between a binder aggregate particle content in a soil improvement material and water permeability.
FIG. 9 shows the results of a test performed to examine the water resistance effect and the hardness of the pavement surface depending on the mixing ratio of the soil improvement material and the soil material (masago).FigureIt is.
FIG. 10 shows the results of a test performed to examine the water resistance effect and the hardness of the pavement surface according to the mixing ratio of the soil improvement material and the soil material (Arakita soil).FigureIt is.
FIG. 11 shows the results of a test performed to examine the water resistance effect and the hardness of the pavement surface depending on the mixing ratio of the soil improvement material and the soil material (green screenings).FigureIt is.
FIG. 12 shows test results obtained by examining the relationship between the binder aggregate particle content of the soil conditioner and the permeability of the soil mixture of the soil conditioner and the masago soil.FigureIt is.
FIG. 13 shows the binder aggregate particle content of the soil conditioner and the mixed soil of the soil conditioner and masago (Soil improvement materialIs a graph showing the test results of examining the relationship between (a mixing ratio of 20%) and water permeability.
FIG. 14 shows the binder aggregate particle content of the soil conditioner and the mixed soil of the soil conditioner and masago (Soil improvement materialIs a graph showing a test result obtained by examining the relationship between the water permeability and the mixing ratio of (30%).
FIG. 15 shows test results obtained by examining the relationship between the binder aggregate particle content of the soil conditioner and the permeability of the mixed soil of the soil conditioner and the cohesive soil.FigureIt is.
FIG. 16 shows the binder aggregate particle content of the soil conditioner and the mixed soil of the soil conditioner and the cohesive soil (Soil improvement materialIs a graph showing a test result obtained by examining the relationship between the water permeability and the mixing ratio of (30%).
FIG. 17 shows the binder aggregate particle content of the soil conditioner and the mixed soil of the soil conditioner and the cohesive soil (Soil improvement materialIs a graph showing the test results of examining the relationship between (a mixing ratio of 50%) and water permeability.
FIG. 18 shows the test results of examining the relationship between the binder aggregate particle content of the soil conditioner and the permeability of the soil mixture of the soil conditioner and the green screenings.FigureIt is.
FIG. 19 shows the binder aggregate particle content of the soil conditioner and the mixed soil of the soil conditioner and green screenings (Soil improvement materialIs a graph showing the test results of examining the relationship between (a mixing ratio of 20%) and water permeability.
FIG. 20 shows the binder aggregate particle content of the soil conditioner and the mixed soil of the soil conditioner and green screenings (Soil improvement materialIs a graph showing the test results obtained by examining the relationship between the water permeability and the mixing ratio (40%).
FIG. 21 shows the results of a test for examining the relationship between the water content of soil improvement materials and soil materials (masago) and the degree of compaction of these mixtures.FigureIt is.
FIG. 22 shows the results of a test examining the relationship between the water content of soil improvement materials and soil materials (Arakida soil) and the degree of compaction of these mixtures.FigureIt is.
FIG. 23 shows the results of a test examining the relationship between the water content of soil improvement materials and soil materials (green screenings) and the degree of compaction of these mixtures.FigureIt is.

Claims (11)

Adjust the clean water sludge obtained from the water purification plant to a water content near its plastic limit,
Next, the tap water sludge is granulated so that binder aggregate particles having a particle size range of 0.425 mm to 4.75 mm are contained in an amount of 50% by weight or more ,
After that, the water content in the water sludge is formed by drying treatment within a range that does not fall below the minimum water content limit,
A soil quality improving material comprising a coarse-grained portion, which is a binder aggregate particle having a particle size range of 0.425 mm to 4.75 mm, and a fine-grained portion smaller than the coarsened portion . 2. The soil improvement material according to claim 1, wherein the moisture content near the plastic limit is 75 to 95%, and after being adjusted to that state, granulated . The soil improvement material according to claim 1 or 2 , wherein the minimum water content ratio limit is 50% . The soil improvement according to any one of claims 1 to 3, wherein the soil improvement material is stored after being adjusted to a water content of 60% to 120% by adding water after the drying treatment. Wood. The clean water sludge obtained from the water purification plant is adjusted to a water content near its plastic limit, and in that state, binder aggregate particles having a particle size range of 0.425 mm to 4.75 mm are contained in an amount of 50% by weight or more. Coarse-grained portion, mainly binder aggregate particles having a particle size range of 0.425 to 4.75 mm, which have been granulated and then dried so that the water content in the water sludge does not fall below the minimum water content limit, and A soil conditioner consisting of the following fine-grained portions, or a coarse-grained portion and a fine-grained portion, which are mainly binder aggregate particles, which are stored after being adjusted to a water content of 60% to 120% by adding water after the drying treatment. A pavement method comprising mixing a soil improvement material with a soil material at a volume ratio of 20 to 50% based on the whole mixture, and forming a pavement surface using the mixture. Claims using cohesive soil as said soil material, the soil improvement agent, the entire mixture was mixed with cohesive soil at the rate of volume ratio 30-50% relative, and forming a pavement with a mixture Item 6. The pavement method according to Item 5 . The pavement method according to claim 6 , wherein the soil improvement material is adjusted to a water content of 60 to 105%. Sandy soil is used as the soil material, and the soil improvement material is mixed with sandy soil at a volume ratio of 20 to 30% to the entire mixture, and a pavement surface is formed using the mixture. The pavement method according to claim 5, wherein The pavement method according to claim 8 , wherein the soil improvement material is adjusted to have a water content of 70 to 110%. Using rock screenings as the soil material , mixing the soil improvement material with rock screenings at a volume ratio of 20 to 40% with respect to the entire mixture, and forming a pavement surface using the mixture. The pavement method according to claim 5, wherein The pavement method according to claim 10 , wherein the soil improvement material is adjusted to have a water content of 60 to 120%.

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