JPH0262366B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for adjusting a hydraulic substance mixture mixed with aggregate and a device for the same, which is capable of controlling moisture attached to fine aggregate such as sand in a highly efficient and uniform state for each particle. By adding and mixing powder of a hydraulic substance such as cement to the aggregate that has homogenized the amount of adhering water, a kneaded product with a highly accurate cement ratio can be obtained, and the water-cement ratio can be adjusted on the surface of each aggregate particle. A uniform, strong, and stable shell layer is formed, and the resulting mixture exhibits the highest and most uniform strength, making it possible to accurately produce various advantageous molded products. .

River sand, mountain sand, and other fine aggregates are indispensable materials in today's various construction and civil engineering industries that utilize cement and other lime-based hydraulic substances, and have been commonly used since ancient times. However, when carrying out concrete construction work with such fine aggregate, although the material and particle size may have some influence, the attached moisture value is also an important quality variation factor, and is rather a decisive factor. This can be said to be a factor. In other words, it is possible to obtain approximately constant materials by using different materials depending on the production area, but it is generally more difficult to use various fine aggregates of completely different quality together, and also with regard to particle size. fine sand,
By dividing them into medium-grained sand and coarse-grained sand, they can be prepared with approximately constant particle size, and even if there is a slight difference in particle size, the effect on the resulting product is relatively small. However, the amount of adhering moisture usually varies and varies over a wide range, which means that the source of such sand is an open field such as a riverbed or beach, and it is collected and transported in large quantities. Because of this, there are almost no special roofs or side walls where they are stored, so their collection, transportation, and storage conditions do not allow access to rivers, river water, rain or dew. On the other hand, because of the fine grain size of this sand, it has an extremely large specific surface area, and it is inevitable that it will contain water adhering to its surface, and it also retains moisture in the voids between these particles. Therefore, the amount of attached moisture is always present, and moreover, it constantly changes depending on the weather conditions. For example, even if the sand is from the same production area and has the same deposit, the specific amount of water adhering to it will be different at the top and bottom, and the amount measured in the morning and the amount measured at noon will be different. The results are different, and the range of variation is quite large. However, when preparing a cement mixture using this fine aggregate, its water-cement ratio (hereinafter referred to as W/C), cement-sand ratio (hereinafter referred to as C/S), or when making concrete, the cement or The blending ratio of coarse aggregate G such as gravel (hereinafter referred to as S/G or C/G) to either or both of the sands determines the strength and fluidity (formability, workability) of the resulting compact. It is clear that excessive water content causes separation and breathing in any case, and is a major cause of a decrease in strength, while too little water content deteriorates moldability and injectability. Even if auxiliary treatments such as continuous vibration and compression are used together, a dense structure cannot be formed, which also results in a decrease in strength and other product defects. Therefore, although it is essential to properly determine the W/C as described above in order to obtain a desirable product and achieve smooth injection molding, the amount of water adhering to the fine aggregate used for it is not as high as the above. In fact, the above-mentioned relationship cannot be properly determined because the circumstances fluctuate and cannot be accurately grasped and managed, and not only the W/C but also the S/C are uncertain. As a result, desirable strength and molding work cannot be achieved. Of course, there are other methods such as drying this fine aggregate to an absolute dry state or measuring it underwater, but this method is practically applicable when a large amount of sand is required, and the former method requires a large amount of thermal energy. The latter also requires a significant amount of man-hours to completely penetrate the water into the sand grains and release air (according to JIS, 24-hour immersion is required) and to drain the water afterwards. Bulk.

The present invention has been devised after repeated studies and speculations in view of the above-mentioned circumstances, and is based on the above-mentioned liquid content (water) attached to fine aggregate particles such as sand.
At least a portion of the liquid content is applied to the aggregate particles by a rotating member, and an impact force greater than the adhesion force to the aggregate particles is applied substantially uniformly on the impact surface to perform a moisture separation process. However, it is proposed to add and mix hydraulic substance powder to the aggregate particles that have been separated from the liquid by utilizing this impact force.

In other words, the present inventors have made detailed studies regarding the uniformity of the adhering liquid content of aggregate particles, which varies widely as described above, but even if this adhering liquid content is simply water, thermal energy or air generated by wind can be generated. It is extremely difficult to achieve uniform separation and adjustment using a method that uses powder, and in particular, it is necessary to continue careful stirring operations in addition to thermal energy or air blowing until the treatment is completed.
Therefore, the present inventors came up with the idea of using impact force for such liquid removal, and conducted various studies. The amount of separation varies depending on the amount of attached moisture. However, it has been confirmed that the amount of water adhering to aggregate particles becomes approximately constant depending on the applied impact force, and therefore, it has been confirmed that if a uniform impact force is applied, the amount of adhering water becomes constant. In the present invention, the above-mentioned impact force uses velocity energy using centrifugal force due to rotation in order to discharge the separated water separately and to ensure smooth processing operation under appropriate working conditions. That is, the aggregate particles themselves are dispersed by applying velocity energy due to rotational force or centrifugal force, and the dispersed aggregate particles are made to collide with an impact surface to separate them. In other words, the present inventors have also considered applying velocity energy using wind power, but in this case, even if moisture separation is achieved by the impact, the discharged wind may damage the inside of the factory or equipment. There is a strong wind in the vicinity, and sand grains are scattered, making stable work impossible. In the case of rotational centrifugal force from a rotating body, smooth processing operations can be carried out under conditions with almost no such disadvantages.

However, even if it is not possible to completely remove water from the particles during the impact of the particles as described above, the amount of water remaining on the particles is generally inversely proportional to the impact force mentioned above, so it is necessary to adjust the degree of centrifugal force appropriately. It was confirmed that by selecting the appropriate amount of water, the amount of water adhering to the aggregate particles can be kept constant in a substantially stable and uniform state. That is, when the above-mentioned impact energy is applied, the amount of water adhering to fine aggregate particles that have been sieved in advance such as fine sand, medium sand, and coarse sand is generally relatively small. %, water separation will occur to a certain degree depending on the degree of impact energy. However, in a region where the amount of adhered water is, for example, 7 to 8%, the amount of adhered water exceeding a certain limit will be uniformly separated, and that limit is determined by the degree of impact energy. Therefore, if the fine aggregate is treated with impact energy as having adhering water above the above-mentioned limit, the adhering water on the fine aggregate becomes approximately constant according to the degree of impact energy. However, for this kind of fine aggregate, it is sometimes preferable to use one with as little adhering water as possible in terms of handling, and even if the amount of adhering water varies, for example, it is 2.5% to 18% rather than 3% to 18%, which varies widely. 6%
Naturally, it is preferable for the amount of water to vary within a narrow range to determine the amount of water to be added and the amount of cement to be mixed, and the merits of the present invention are fully present even in such cases. More preferably, even if there is a dry area on the surface of the particle, water moves during impact to properly wet the particle. In any case, if the amount of water adhering to fine aggregate such as sand becomes constant in this way, determine the amount of added water by appropriately understanding the W/C, C/S value, G/S, etc. as described above. It is clear that it is possible to stabilize the quality of the products obtained and obtain various cement products without variation.

Note that it is advantageous in terms of equipment and power to apply the centrifugal force to the sand grains using a rotating disk and have them collide with a stationary impact surface. The sand grains can be dispersed, spread out, and flown to allow for efficient processing. However, in this case, there is a certain amount of mud and clay attached to the sand grains as described above, and when such mud, etc. adheres to the impact surface along with water and the impact surface is in a stationary state, Such adhering mud etc. accumulate on the impact surface, and this adhering mud layer binds the impact aggregate as a sticky layer and becomes enlarged, and even if it is not so, it acts as a buffer layer and the impact fine particles are deposited on the impact surface. Even if fine aggregates have the same velocity energy, the amount of adhering water after impact treatment may vary due to the impact force of the aggregate. Therefore, in such a case, it is necessary to wipe the stationary collision surface, and such cleaning can be carried out as appropriate with water or by rotating a scraping piece. However, it is possible to remove mud and dirt stuck on the impact surface one by one by rotating the impact member and use its centrifugal force, and therefore the above-mentioned wiping operation is not required. The desired moisture removal process can be carried out with

In cold regions, it is natural for fine aggregates such as sand to be collected in a frozen state, and such frozen disc-shaped or large block-shaped fine aggregates cannot be treated to remove water as they are. In such cases, the material is thawed using water vapor, etc., and then processed after being dispersed. Further, fine aggregate obtained from the beach has salt etc. attached to its surface, and the liquid separation treatment of the present invention also functions as a treatment for removing salt etc. for such fine aggregate.

An overview of the apparatus for carrying out the method of the present invention is given in Part 1.
As shown in the figure, impact moisture separation mechanism A is designed to continuously supply fine aggregate using a conveyor, etc.
A mixing mechanism B is prepared for this purpose. Any general mixer can be adopted as the mixing mechanism B, but a preferred mixing mechanism is one that performs a continuous mixing operation, and generally includes a mechanism C that adds powder of a hydraulic substance and a water addition mechanism D. and a mechanism E for adding dispersants and other additives. The impact separation mechanism A and the mixing mechanism B do not necessarily need to be mechanically connected; in some cases, a tank may be interposed between the two mechanisms A and B, or a conveyor such as a truck or conveyor may be used. can be intervened. Once the liquid is separated by capping and using impact force, its moisture content will not change significantly unless it is directly exposed to rainwater, etc., and it can be stored in a tank for a considerable period of time, or transported and mixed. It may be supplied to mechanism B.

In the case shown in Fig. 1, water is added in two stages, and in the first stage, water is added by water spraying mechanism D ₁ to the water that has been separated by impact force, and the water is mixed and spread evenly over the surface of the fine aggregate. A water-adhesive state is formed on the surface, and a hydraulic substance powder is added and mixed from the addition mechanism C to this, and the added powder is uniformly adhered to the surface of the fine aggregate to form a shell made of the hydraulic substance. Then, the remaining water is further added and kneaded by a secondary water adding mechanism _D2 . As mentioned above, the entire peripheral surface of the particle is moistened by the impact,
On the surface of fine aggregate formed by adding and mixing powder of a hydraulic substance such as cement with primary water evenly adhering, the cement powder completely covers the circumferential surface of each particle. It has been confirmed that the resulting molded shell can be obtained as a stable product that does not peel off by subsequent addition of secondary water and kneading, and the kneaded product obtained in this way has a large strength development in the shaped product. . The intervention of the conveyance mechanism as described above can be taken in the process after addition and mixing of the hydraulic substance such as cement powder in the addition mechanism D.

However, as shown in Fig. 1, the present invention does not necessarily require dividing the added water into two parts and adding the hydraulic substance between them, but when water is added all at once. In other words, the fine aggregate whose adhering water content has been made uniform through the impact force separation operation is then added to accurately determine the amount of water to be added when preparing the kneaded material, and therefore the water-cement ratio ( W/C) and sand-cement ratio (S/
C) Other compounding conditions are determined rationally to reduce variations in strength of the resulting molded product and to increase its strength. Regarding the addition of coarse aggregate, the first
Although it can be added at any stage of each process as shown in the figure, a preferred embodiment is before the first addition of water and after the separation treatment by impact force.

There are various mechanisms for performing impact force separation processing in the present invention, and one example of a device that performs this impact processing operation using rotational centrifugal force is shown in FIGS. 2 to 5. That is, fine aggregate to be processed is charged into the hopper 5a,
The supply tube 2 integrally formed with the hopper 5a is directed toward the center of the rotary disk 4, and discharge ports 2a are provided on both sides of the lower end thereof. As shown in FIG. 4, the rotary disk 4 has blade plates 9 arranged radially so as to disperse and project the fine aggregate flowing out from the discharge port 2a. As shown in the figure or FIG.
As shown in FIG. 2, the side surface of 2 has an impact surface 12a formed on its inner surface that is inclined so as to expand downward, and is assembled onto the base frame body 17 with an appropriate gap 19. and the impact frame 12
A water receiving gutter 18 attached to the upper part of the base frame body 17 is positioned on the short side of the base frame body 17. The cylindrical portion 24 of the rotary disk 4 described above is rotatably attached to a support tube 22 provided at the center of the impact frame 12 via a bearing member 23 such as a bearing, and the upper end of the cylindrical portion 24 is pulley 25
is attached and rotated at a predetermined speed by a driving mechanism such as a motor.

That is, to explain the operation of what is shown in FIGS. 2 to 5, the fine aggregate dropped from the hopper 5a onto the rotary disk 4 is supplied from the discharge port 2a in a specific direction, and is thus delivered to the rotary disk 4 in a specific direction. Direction (in the case shown, the central part of the long side of the impact frame 12 in Figure 5)
By the rotation of the rotary disk 4, the fine aggregate supplied toward the impact frame 12 is mainly projected toward the short side of the impact frame 12, as shown in FIG. Considering the angular relationship between the projection direction and the impact surface on the long side, the projected fine aggregate will be guided to the short side, and therefore the treated fine aggregate will be below the impact surface on the short side. Obtained intensively. A part or most of the moisture attached to the fine aggregate that collided with the impact surface is detached from the particle surface due to the impact at the time of collision and transferred to the impact surface, and the moisture thus transferred to the impact surface is distributed as droplets on the short side. It flows down the side impact surface and falls into the water receiving gutter 18. Although a certain amount of mud and the like adheres to the surface of the fine aggregate, such mud is also removed by the impact and guided to the water receiving gutter 18 together with the water separated as described above. That is, in the case of the one shown in FIGS. 2 to 5, the fine aggregate particles dispersed around the entire circumference of the rotary disk 4 are collected intensively on the short side of the impact frame 12, so that they are dispersed around the entire circumference. There is less loss during impact treatment than in the case of unfolding, and recovery is also easy.

Another embodiment in which impact separation is performed using the centrifugal force of a rotating disk is shown in FIGS. 6 to 11 along with modifications of each part thereof. That is, FIGS. 6 to 8 show cases in which the impact frame 12b has an inverted conical shape and its impact surface can be replaced as appropriate, and the fine aggregate charged from the hopper 5b is collapsed. By impacting the conical impact frame 12b, the attached moisture is transferred to the impact frame 12b, but in this case, the fine aggregate acts in a grinding manner, resulting in significant wear on the impact surface. Therefore, as shown in FIG. 7, for the impact portion, a multi-divided impact plate 8 is adopted, and a packing material 8b is interposed and it is fixed at the impact position with a fastener 8e, and replacement can be done from the outside using the handle 8a. Opening 1 is made in impact frame 12 by tilting it appropriately.
It is designed to be attached and detached from 2c.
Note that a cleaning water storage tank 20 is provided around the outside of the hem 12d of the impact frame 12, and the cleaning water supplied from the inlet 20a is led out from the outlet 20b located above it. A small amount of cleaning water is constantly supplied to the inner surface of the hem 12d due to the head difference h between the opening 20a and the outlet 20b as shown in FIG.
This structure is designed to prevent mud and the like contained in the separated water discharged into the water receiving gutter 18 from stagnation on the inner surface of the skirt portion 12d.

Note that there is a possibility that fine aggregate may adhere to the inner surface of the base frame body 17 during actual operation, and in order to avoid this, a vibrator 21 is provided on the base frame body 17 to give a vibration effect. Particularly, since the part where the fine aggregate is significantly attached is the upper end of the base frame body 17, a mechanism for removing the adhered fine aggregate as shown in FIGS. 9 to 11 is appropriately employed for this part. In other words, FIG. 9 shows that an air cover 27 is installed inside a hard rubber plate 26 attached to this part, and as the air pressure of the air cover 27 is changed in a undulating manner, it adheres to the inner surface of the part. It is used to peel off fine aggregate, and Fig. 10 shows a method in which a hard rubber plate 26 is simply provided.
Even in this case, vibration is applied by the colliding fine aggregate, and the adhering particles are peeled off. In FIG. 11, a hard rubber plate 26a is provided with an appropriate gap 28 between it and the upper end of the base frame body 17. In this way, the hard rubber plate 26a is The vibrations are more pronounced, resulting in favorable peeling.

In the water separator according to the present invention, whether what adheres to the inner surface of the device is mud on the hem 12d or fine aggregate at the upper end of the base frame body 17, what adheres and stays there is caused by acceleration. Needless to say, it is preferable to prevent such deposits as much as possible, since this can lead to enlargement and obstruct the flow of moisture or fine aggregate in the area. In particular, in the case of a rotary disk 4 with blades, even if a suitable air flow is obtained along the wall surface and has the effect of removing such solid matter, the deposits once attached are removed. It also blocks airflow and grows rapidly.

An example of an apparatus capable of appropriately carrying out the impact treatment of the present invention without using the centrifugal force of the rotating disk as described above is shown in FIG. A mechanism 6 for receiving fine aggregate such as sand into a hopper 5 and cutting it out in a fixed amount
The blades 9 are dropped onto a rotating body 7 arranged radially through the blades 9, and the rotating body is driven by the motor 3 to impact the falling aggregate. Rotating body 7
At the front lower part of the
5 and 16 are provided, and these receiving hoppers 14 to 16 are provided.
Each of the chambers 16 is provided with a discharge damper 13 so that the processed material stored therein can be appropriately taken out.

That is, the first hopper 14 receives water and mud adhering to the fine aggregate, and the second hopper 15 and the third hopper 16 receive the fine aggregate. can accept relatively coarse and fine aggregate. Generally, the fine aggregate impacted by the lid rotating body 7 has a different scattering distance depending on its mass, and moisture adheres to the blade plate 9 of the rotary body 7, which causes centrifugation due to the rotation of the blade plate. The particles are collected at the ends by force and then released into the hopper 14 in the form of drops. Note that each of the hoppers 14, 15, and 16 as described above is provided with a cover on its upper part, and a partition plate 11 is provided between each hopper so that the degree of protrusion of the hopper can be adjusted appropriately. is as shown.

In the case shown in Figure 12, as is clear from the above, the fine aggregate is subjected to particle size classification at the same time as water separation. In view of the fact that the specific amount of adhering water varies depending on the impact energy depending on the particle size, this method is particularly significant when applied to fine aggregate with widely varying particle sizes. In other words, even if the particle size of the fine aggregate to be processed varies to some extent, classification will be performed together with the separation process, and therefore, the fine aggregate in each hopper 15, 16 obtained after the separation process will be divided according to its particle size. As a result, the moisture content becomes constant within a very narrow range, and the object of the present invention can be effectively achieved even with fine aggregate, which has large variations.

The impact treatment in the present invention is also shown in FIGS. 13 and 14.
It can also be implemented by a mechanism as shown in the figure. That is, in the system shown in FIG. 13, fine aggregate dropped from a hopper 5 is fed and sandwiched between two rubber tire-shaped rotating mechanisms 31, 31 which are driven at a rotational speed higher than the fine aggregate. The fine aggregate is projected downward through these rotating mechanisms, and is subjected to impact on the inclined impact plate 32 located in the fine aggregate projection direction, and the water adhering to the fine aggregate is separated and the fine aggregate is The water and mud are reversed and discharged from the discharge port 33, and the removed water and mud are received by the receiving gutter 34, and the bottom part below the impact surface 32 is drained from the head as in the case of FIG. 8 described above. Cleaning water is supplied using the difference. Note that this projection direction can be applied horizontally or in a downwardly inclined manner as the case may be, as in the case of FIGS. Two or more sets can be installed in parallel to achieve high-speed projection.

In the case shown in FIG. 14, fine aggregate falling from the hopper 5 is centrifugally projected from the end of the endless belt conveyor 35 onto an inclined impact surface 36 as in the case shown in FIG. 7 by the rapidly rotating endless belt conveyor 35. In addition, cleaning water is supplied to the hem below the impact surface to avoid condensation of dirt and the like. In other words, in systems that use such endless belt conveyors, velocity energy is imparted to the fine aggregate over a certain amount of time and distance, and accordingly, even if a considerable amount of fine aggregate is used, it is uniformly applied. You can gain speed energy. Note that when using this belt conveyor, if it is not preferable to drive the belt conveyor rapidly, as shown in FIG. Velocity energy can be imparted by the final centrifugal projection. In addition, when the belt conveyor 35 is driven at high speed, there is a tendency for fine aggregate to scatter on the conveyor, making it impossible to efficiently impart the necessary velocity energy. It is possible to carry out a water separation process with a high yield without causing the water to fall off. Also, regarding the projection direction from the conveyor 35, this 14th
As shown in the figure, if it is not preferable to make it horizontal because it goes against the direction of gravity, the above-mentioned 13.
It may be directed downward as shown in the figure, which is the 14th direction.
This is easy by using the rotating body 40 shown in Figure B.

It is clear that each of the devices described above applies a substantially uniform impact to the supplied fine aggregate, thereby separating water and other liquids adhering to the fine aggregate. . In other words, water adheres to the surface of aggregate particles with a certain degree of adhesion, but by applying an impact force that exceeds this adhesion force, it separates from the particles and the liquid moves to the impact surface due to inertia. , only the aggregate particles turn over and fall.

The apparatus shown in FIG. 13 described above can be implemented as shown in FIG. 15 by also taking into consideration the technique shown in FIG. 12. That is, in the one shown in FIG. 16, the rotating mechanism 31 is provided below the hopper 5, which is the same as in FIGS. Unlike the mechanism 31, it does not have the vane plate 9, but forms a flat cylindrical drum, which is rotated by the drive mechanism 3', and the bottom of the rotating body 31a is filled with water and dirt. A receiving plate 45 for receiving the fuel is attached, and a discharge port 46 is formed on the side of the fuselage. The rest of the structure is the same as that shown in FIG. 13, and an inclined impact plate 32, a storage tank 20, a discharge port 33, etc. are provided at the bottom of the body.

According to the structure of the cover shown in FIG. 15, the rotation mechanism 31
The particle material projected by the blade plate 9 is first impacted on the surface of the rotating body 31a as shown by the arrow g, so that the attached water is first attached to the rotating body 31a, and then The particle material receives the reversal action after the impact and the rotational force of the rotating body 31a, and is sent downward as indicated by arrow g', and is again subjected to the same adhering water separation action on the impact plate 32. The rotating body 31a is driven at a faster rotation speed than the general rotating mechanism 31, so that the rotating mechanism 3
It is possible to enhance the impact effect caused by the projection from 1, and also to make the impact effect on the fixed impact plate 32 more efficient.

The chart in FIG. 16 summarizes the results of specific water separation treatment using the separation device of the present invention as described above. Even if the rotating body is operated at different speeds, the amount of adhered water will vary to a certain degree, but if the amount of adhered water before treatment is above a certain limit, a substantially constant amount of adhered water will be obtained after treatment. Furthermore, as shown in the figure, even if the amount of adhering water before treatment is below a certain limit, removal can be achieved in approximately proportion to the initial moisture value. However, if the rotational speed of the rotating body is increased to increase the impact force, the moisture value after treatment will decrease, and on the other hand, if the rotational speed is decreased, the moisture value after treatment will increase. In any case, the state of the curve formed will be similar to that shown in the figure. Therefore, in order to make the moisture value after treatment approximately constant, water is further added to the fine aggregate which has variations, and the treated aggregate is treated with adhering water of 15% or more, for example.

Specific examples of the method according to the present invention as described above will be described below.

Example 1 In an apparatus as shown in Figure 12 of the accompanying drawings mentioned above, various types of water-containing Megawa sand produced in the northern Kanto region (brand name Omokawa: water absorption rate of 23
%, coarse grain rate 2.1) was supplied and processed.

As for the rotating body 3, the length from the axis of the blade plate 9 is
Use a 225mm one and run it at 1250rpm [393G: (G
The above-mentioned water-containing sand was fed from hopper 5 at a rate varying from 50 to 120 kg/min. It was also confirmed that the amount of adhering water in the hopper 16 was 6.4 to 6.8%, and that the amount of water was approximately equal in all cases. Note that hopper 16 should correspond to medium-sized sand.

Also, under the same conditions as above, the rotation speed of rotating body 3 is
At 1500 rpm (566G), the moisture content of hopper 15 is 5.6 to 5.9%, and that of hopper 16
is 5.2 to 5.4%, and furthermore, this rotation speed is
If it is 1750ppm, the one of Hopper 15 is
The moisture content was 3.9 to 4.2%, and the moisture content of Hopper 16 was 4.1 to 4.3%, and both had approximately equal moisture content.

The cement-to-sand ratio was 1:2, the water-cement ratio was 43%, and the dispersant was added at a rate of 1% of the amount of cement to the sand that had undergone the above treatment, and the amount of water added was as described above. The fluidity of the mortar, which is kneaded and adjusted by subtracting the amount of adhering water after treatment from the amount added, is such that the initial shear stress yield value F ₀ is 1.54 g/
cm ² , the relative viscosity coefficient λ is 0.86 g/sec.cm ⁴ , the relative occlusion coefficient ΔF ₀ is 0.0034 g/cm ⁴ , and the separation breathing is only slightly recognized as 0.05%. The compressive strength after 7 days of the molded object formed using the mortar adjusted by
438-452Kg/cm ² (average 447Kg/cm ² ), and after 28 days it is 521-545Kg/cm ² (average 534Kg/cm ² )
Although some separation breathing was observed as described above, the product had approximately uniform strength.

On the other hand, in addition to such a method in which water is added and kneaded all at once, a two-stage water addition method including a shell-shredding step, which was devised by the present inventors, was also implemented. In other words, the sand that has been treated as described above first reduces the amount of water attached to it by 10%.
Add primary water as follows, then add and mix Portland cement powder so that W/C is 20%, and then add secondary water at 153 kg/m ³ and dispersant at a rate of 1% of the amount of cement. S/C added and adjusted is 2
The fluidity of mortar with W/C of 43% is as follows: initial shear stress yield value F ₀ is 2.63 g/cm ³ and relative viscosity coefficient λ is
1.08g・sec/cm ⁴ , relative occlusion coefficient △F ₀ is 0.0072
g/cm ⁴ and is a mortar with good fluidity, and no separation breathing was observed, and the compressive strength of the molded product made with this mortar after 7 days was 521.
-545 Kg/ ^cm2 (average 533 Kg/ ^cm2 ), after 28 days it is 628-656 Kg/ ^cm2 (average 642 Kg/ ^cm2 ) with good and almost uniform strength.

For these items, a part of the sand piled up in the same way as above was used separately, and to this, water was added at 285 kg/m ³ and cement was added at 664 kg/m ³ in the same amounts as above. The mortar mixed and mixed at a ratio of m ³ has an F ₀ of 0.74 g/cm ³ and a λ of 1.37 g/cm 3 .
sec/cm ⁴ , △F ₀ is 0.014 g/cm ⁴ , separation breathing is 1.4%, which is quite high, and the compressive strength of the molded product obtained with this mortar after 7 days is 268 to 367 kg. /cm ² (average 332Kg/cm ² ), 28
After several days, the strength was 353 to 501 Kg/cm ² (average 397 Kg/cm ² ), which was considerably inferior, and it was confirmed that the strength varied over a wide range.

Example 2 Using the equipment shown in Figures 2 to 5 of the attached drawings, fine water-containing sand produced in Kisarazu, Chiba Prefecture (water absorption rate 2.8%, coarse grain rate
1.93) was treated by spraying and adding water at a rate of 30 min on the conveyor supplied to the hopper 5a. Rotating plate 4 at 1500rpm
(566G) to collect 360-450Kg of river sand.
The adhesion moisture of the treated sand obtained by changing the feeding rate within the range of min is 8.3 to 8.5%, which is approximately the same, that is, the treatment purpose can be appropriately achieved even if the feeding rate is changed slightly. It was confirmed.

The sand that has been treated in this way has a sand-to-gravel ratio of approximately 2 and a sand-to-gravel ratio of 38.5%, and water is added to the water-cement ratio to make it 43% after removing the adhering water after the above-mentioned treatment. , 1.2 of the amount of cement dispersant
The fluidity of the concrete added and mixed as 15.6 cm is good with a slump of 15.6 cm, and separation breathing is slightly observed.
The average compressive strength after 7 days of molding using this concrete was 285Kg/ ^cm2 ,
Also, after 28 days, it was an average of 412Kg/ ^cm2 ,
Moreover, their coefficient of variation was about 8.8%.

On the other hand, we also carried out a method of adding water and kneading in two stages according to the shell-forming method of the present inventors, that is, after the water separation process was performed as described above, first the amount of adhering water was 10 %, then gravel at a rate of 1150Kg/m ³ and Portland cement powder was added and mixed so that the W/C was 20%, and then secondary water was added again. 83Kg/ ^m3
and a dispersant are added and mixed at a ratio of 1.2% of the amount of cement, S/C is approximately 2, S/A is 38.5, and W/C is 43%.
The fluidity of concrete is slump 17.2.
cm, and the concrete had good fluidity.
However, the average compressive strength after 7 days of a molded body made of this concrete is 351Kg/cm ² , 28
After 1 day, it was 468 kg/cm ² and the coefficient of variation was about 5%, with no variation.

For these, we used the same sand from Kisarazu as mentioned above, measured its moisture content, corrected the moisture content, and adjusted the composition per m ³ to be the same as above: 360 kg/m ³ of cement, 155 kg of water. / ^m3 , sand 720
The concrete obtained from the mixer by mixing 1150 Kg/m ³ of gravel and 1150 Kg/m ³ of gravel has a slump of 12 cm, and the average compressive strength after 7 days of the molded body obtained with this concrete is 197 Kg/cm ² . 343 after 28 days
Kg/cm ² , and its coefficient of variation was 15.6%, which was not only poor in strength but also highly variable.

Example 3 The attached water was reduced to 3.8% using the apparatus shown in Figures 6 to 8 above.
Various types of hydrated coarse sand (water absorption rate 1.7%, coarse grain rate 3.35) produced in Fujikawa, Shizuoka Prefecture were treated in the range of ~26%.

When the rotary plate 4 was rotated at 1750 rpm (770 G) and the sand was fed from the hopper 5b at a speed range of 360 to 450 kg/min, the adhering moisture was 3.2 to 3.3%, which was a uniform moisture value. The amount of water attached
Add primary water to 14%, then add and mix Portland cement powder to a W/C of 20%, then add secondary water to 290Kg/ ^m3 and dispersant to 1.2% of the amount of cement. Add and knead at the ratio of S/C
1.5 and W/C is 38%, the mortar has an initial shear stress drop value F ₀ of 0.69 g/cm ³ , a relative viscosity coefficient λ of 0.35 g・sec/cm ⁴ , and a relative occlusion system number ΔF ₀ is
0.0032g/cm ⁴ and this mortar is 67m/min
It was pumped over a distance of 120 m through a pipe with an inner diameter of 2 inches at a flow rate of
Mix 0.95 parts of gravel with 0.95 parts of sand and sprinkle with cement powder.The sprinkled cement has a W/C of about 18% and is pumped with compressed air to the front of the spray nozzle tip. It was added at a rate of 106% of the amount of kneaded mortar at a position of 5 m from the tunnel and sprayed onto the inner surface of the tunnel.

The construction volume is approximately 8 m ³ per hour, the W/C in this shotcrete is 33.4%, and the amount of cement is 509
Kg/ ^m3 , but the rebound amount during spraying was 6.5
%, the amount of dust generated was 1.21mg/m ³ , and the spraying with an average spraying thickness of 120mm at the top of the tunnel was able to be carried out smoothly without flaking in general. Average compressive strength 3 days after spraying is 329
Kg/cm ² , after 28 days it was 603 Kg/cm ² , and its coefficient of variation was 3.2%, making the average strength 1.4 times higher than that of the conventional method with the same composition, and the coefficient of variation was 1/5. It was confirmed that the preferred method of spraying construction was reduced in the near future.

In addition, in this spraying process, the amount of water adhering to the sand is not adjusted and separated over the entire amount, but the water content is corrected using a part of the sample, and this is compared with the case where the water content is corrected using the conventional wet method and the dry method. The amount of dust generated by spraying is 2 to 5 mg/ ^m3 , and the amount of dust generated by the dry method is about 6 to 10 mg/ ^m3 , and it has been confirmed that the amount of dust generated is lower than either of those methods.On the other hand, the amount of rebound is less than that of the conventional method. is 20 to 30 for both wet and dry methods.
%, this can be reduced to a fraction of that. Moreover, the reaction of the nozzle during spraying is much smaller than that of any conventional method, and the amount of sprayed work can be at least doubled compared to the 3 to 4 m ³ /hr of a conventional method using a similar 2-inch pipeline. I knew.

Example 4 Using the apparatus shown in Fig. 6 of the attached drawings mentioned above, various water-containing sands from the Ishigawa River produced in the northern Kanto region (water absorption rate of 2.3%, coarse grain rate of 2.1) were prepared with various amounts of adhering water in the range of 3 to 15%.
processed. That is, in this case, water was added and supplied to the hopper at a rate of 32 kg/min on the conveyor, the rotating body was rotated at 1780 rpm (841 G), and the process was performed while feeding at 360 to 450 kg/min.
It was confirmed that the adhering water content of the obtained treated sand was 4.6 to 4.7%, and the amount of adhering water was adjusted to be uniform.

However, the amount of water attached to sand that has undergone this treatment is
Add primary water to 7.6% and then add gravel.
1196Kg/ ^m3 , Boltland cement W/C is 18
% and then transported by truck to the construction site over a period of approximately 2 hours. At the construction site, secondary water was added at a rate of 92.4 kg/m ³ and dispersant was added at a rate of 1.2% of the amount of cement. Add and mix so that S/C (sand:cement) is 2.34 and S/A
The concrete was made with a sand/gravel ratio of 38.5% and a W/C ratio of 46.8%. That is, the fluidity of this concrete was good with a slump of 12.5 cm, and no separation breathing was observed. However, the average compressive strength of the molded products made from this concrete after 7 days was 303 Kg/cm ² and after 28 days was 420 Kg/cm ² , and the coefficient of variation was 4.3%, which was a very small variation.

In other words, in the case of conventional ready-mixed concrete mixed using the same raw materials as above, the slump decreases in proportion to the transportation time and workability deteriorates, so mixing is continued during transportation.
As mentioned above, in order to transport the material for two hours and carry it to the site for construction, in some cases, water may be added after arriving at the construction site, which is an extremely reckless measure from the standpoint of obtaining the specified strength. It is well known that the compressive strength obtained due to the above-mentioned composition is 28 days.
It was approximately 300 Kg/cm ² and its coefficient of variation was approximately 15%, confirming that the product according to the present invention has excellent properties. Of course, there is no disadvantage in transporting the entire amount of blended water.

In addition to the above-mentioned embodiments, the present inventors have also studied precast concrete, prestressed concrete, preback concrete, etc., but the present invention, in which the moisture content of fine aggregate is fixed, is the best among them. In each case, the strength could be rationally increased and a product with less variation could be obtained, as in each of the above examples.

According to the present invention as explained above, the water adhering to fine aggregate such as sand is adjusted to a uniform state, and a uniform state of adhesion of water is formed on the entire surface of each particle to form this kind of cement mortar or It not only makes it possible to rationally adjust concrete and increase its strength, but also to obtain a high-quality product with little variation.Moreover, the process is relatively simple and can be carried out rationally and accurately. This invention has many effects and is industrially very effective.

[Brief explanation of the drawing]

The drawings show the technical contents of the present invention, and Fig. 1 is an explanatory diagram showing one example of the device according to the invention, and Fig. 2 is an explanatory diagram showing an example of the moisture adjustment mechanism for fine aggregate. 3 is a sectional view of its external appearance, FIG. 4 is an enlarged cross-sectional plan view of the rotary plate portion, FIG. 5 is a cross-sectional plan view thereof, and FIG. 6 is another implementation of this moisture adjustment mechanism. FIG. 7 is a perspective view of each impact plate portion, FIG. 8 is a cross-sectional view of the impact plate and cleaning water supply mechanism, and FIG. A cross-sectional view showing one example of a mechanism for removing condensation of mud and the like from below the plate, FIGS. 10 and 11 are cross-sectional views showing modified examples thereof, and FIG. 12 is another example of the moisture adjustment mechanism according to the present invention. 13 and 14 are sectional views showing further embodiments of this moisture adjustment mechanism, and FIG. 15 is a sectional view showing another embodiment of the moisture adjustment mechanism. FIG. 16 is a cross-sectional view of another apparatus for carrying out the method of the present invention, and FIG. 17 is a diagram summarizing the water removal status for one embodiment of the present invention. In these drawings, A is a water separation mechanism, B is a mixing mechanism, C is a hydraulic material powder addition mechanism, D is a moisture addition mechanism, E is an additive addition mechanism,
1 is a conveyor, 2 is a supply cylinder, 2a is its discharge port,
4 is a rotary disk, 5, 5a, 5b are hoppers, 7 is a rotating body, 8 is a multi-segmented impact plate, 9 is a blade plate, 1
2, 12b is the impact frame, 12a is its impact surface, 14
- 16 are each hopper, 18 is a water receiving gutter, 31 is a rotating body, 32 is an impact plate, 34 is a receiving gutter, 35 is a belt conveyor, 36 is an impact surface, 38 is a high pressure air pipe, 39
Reference numeral 40 indicates an impact plate and 40 indicates a rotating body.

Claims (1)

[Scope of Claims] 1. By applying a centrifugal force by a rotating member to the sand particles to which moisture has adhered, and causing the sand particles to collide with the impact surface one after another, an impact force greater than the adhesion force of the moisture is applied to the sand particles. It acts almost uniformly on the particles, and the uniform impact force separates a part of the adhering water from the sand particles, and also equalizes the amount of residual adhering water on the sand particles. A method for preparing a mixture of hydraulic substances such as cement, characterized by mixing substances. 2 Applying a centrifugal force by a rotating body to the sand particles to which moisture has adhered, and causing the sand particles to collide with the impact surface one after another, thereby applying an impact force greater than the adhesion force of the moisture to the sand particles approximately uniformly. , and the uniform impact force separates a part of the adhering water from the sand particles and equalizes the amount of residual adhering water in the sand particles, and mixes powder of a hydraulic substance such as cement with the sand particles. The powder is attached to the surface of the sand particles, and the remaining moisture required for kneading is added to the sand particles to which the hydraulic substance powder is attached, along with an auxiliary agent such as a dispersant, if necessary, and kneaded. A method for preparing a mixture of hydraulic substances such as cement. 3. A mechanism for sequentially applying centrifugal force to sand particles using a rotating member, an impact mechanism that uniformly removes adhering moisture by the impact force caused by the centrifugal force, and a mechanism for supplying the sand particles to the rotating member. and a mechanism for adding water again to the sand particles whose adhering moisture has been removed and homogenized by the impact mechanism, and a mechanism for adding and mixing hydraulic substance powder.