JPH0474163B2 - - Google Patents

Description

Detailed Description of the Invention The present invention relates to an addition to Patent No. 1647885 (Patent Application Publication No. 62366, 1990) relating to a method and apparatus for preparing a mixture of hydraulic substances such as cement. By adjusting the water adhering to the material to a highly efficient and uniform state, and adding and mixing powder of a hydraulic substance such as cement to the homogenized aggregate, the water-cement ratio can be made uniform on the surface of each aggregate. By forming a shell layer and making the strength development of the obtained mixture into the highest state and uniform, various advantageous molded bodies can be accurately produced, and the water adhesion treatment for the fine aggregate can be uniformized at all times. In addition to improving the durability of the processing mechanism, continuous operation over a long period of time can be smoothly realized.

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, even though the material, particle size, etc. have some influence, the adhering moisture value is also an important quality variation factor, and rather a decisive variation. This can be said to be a factor. In other words, it is possible to obtain approximately the same quality of material by using different materials depending on the production area, and it is generally more difficult to use various fine aggregates of completely different quality together, and also with regard to particle size. By using fine-grained sand, medium-grained sand, and coarse-grained sand separately, they can be prepared with approximately constant grain size, and even if there is a slight difference in grain size, the effect on the resulting product is comparatively small. Not very accurate. However, the amount of adhering moisture usually varies widely and widely; in other words, the sand is obtained from open fields such as riverbeds or beaches, and it is collected and transported in large quantities. Because of this, there are almost no special roofs or side walls where they can be stored, so they cannot be collected, transported, or stored without rivers or river water. The possibility of contact with rain and dew is extremely high.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 the surface.Moreover, the voids between these particles will also contain moisture. , so the adhering 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 is considered to be the same deposit, the specific amount of water adhering to it is different at the top and bottom, and the amount measured in the morning and the amount measured at noon are 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 pleating in any case, and is a major cause of a decrease in strength, while too little water content deteriorates moldability and pourability. 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 attached to the fine aggregate used for it is not as high as the above. The fact that the situation fluctuates and cannot be accurately grasped and managed means that it is virtually impossible to properly determine the above-mentioned relationship, and not only the W/C but also the S/C are concerned. As a result, desirable strength and molding work cannot be achieved. Of course, there are methods such as drying this fine aggregate to an absolute dry state or measuring it in water, but it is practically impossible to use when a large amount of sand is required, and the former method requires a large amount of heat. Energy and time are consumed, and the latter also requires man-hours to completely penetrate water into the sand grains and release air (according to JIS, 24-hour immersion is required) and then to drain the water contained. It bulks up significantly.

In view of the above-mentioned circumstances, the inventors of the present invention have made repeated studies and speculations, and have determined that at least part of the liquid (water) adhering to fine aggregate particles such as sand as described above is The proposed method is to apply a substantially uniform impact force that is greater than the adhesion force to the aggregate particles, and to add and mix hydraulic substance powder to the liquid-separated aggregate particles using this impact force (Patent No.
No. 1647885 (1990 Patent Application Publication No. 62366):
(hereinafter referred to as the original invention). That is, according to this original invention, the moisture attached to fine aggregate, etc. is removed using impact force, and depending on the impact force applied, the moisture attached to the aggregate particles becomes approximately constant, and therefore the impact force is uniform. By applying this, the adhering moisture after treatment becomes constant, and the fine aggregate etc. that are kept constant can effectively eliminate the disadvantages and problems of the prior art as described above.

However, as a result of repeated practical studies conducted by the present inventors regarding the original invention, the inventors have found that the above-mentioned fine aggregates are impacted with the velocity energy as described above. It is not always easy to ensure mechanical durability due to wear and tear on the impact surface, and it is also difficult to ensure mechanical durability when processing sand grains containing mud etc. In addition to adhering liquid, mud such as clay adheres to the impact surface, and the adhesion impedes the flow removal of moisture etc., and this adhesion acts as a buffer to stabilize the impact energy. This makes it difficult to obtain an accurate separation effect, and it becomes necessary to shut down the operation to remove such adhering materials, which is disadvantageous in that efficient processing cannot be carried out smoothly.

The present invention has been devised after further study to eliminate such disadvantages, and as described above, it develops and transports a group of fine aggregate particles to which liquid components such as water are attached, and at the same time, it A velocity energy imparting mechanism for imparting impact velocity energy greater than the adhesion force of the liquid is supplied, and the velocity energy imparting mechanism sequentially applies the fine aggregate particles to which the impact velocity energy has been imparted onto the circumferential surface of the rotating body. It is proposed that a liquid such as adhering water be separated by impact, and in this case, a means for wiping the liquid adhering to the circumferential surface of the rotating body is provided, It is proposed that the impacting function of the circumferential surface of the rotating body be constantly updated by a wiping means, and that particles imparted with impact velocity energy can be impacted.

That is, some of the apparatus for implementing the method according to the present invention are as shown in the attached drawings, and the overall structural relationship of the apparatus according to the present invention is as shown in FIG. A mixing mechanism B is provided therebetween. As this mixing mechanism B, any general mixer can be adopted, but as an example, a mixer equipped with an internal stirring piece as shown in the upper part of Fig. 1 is used, or a mixer shown in the lower part of Fig. 1 is used. As shown, a fairly long continuous mixing mechanism B is employed in which a stirring piece is rotated horizontally. In other words, it does not matter what type of mixing mechanism it is, but the additions to the mixing mechanism B include the input of aggregate by the conveyor F, the hydraulic substance powder addition mechanism C, and the addition of additives such as dispersants. Mechanism E, primary water addition mechanism D ₁ , and secondary water addition mechanism D ₂ are arranged as shown. However, in the case shown in the upper part of FIG. 1, only one of the water addition mechanisms D ₁ and D ₂ is used, and water can be added in accordance with each process by adjusting or stopping the addition amount using the valve.

However, in the impact moisture separation mechanism A, it is the same as the original invention that the fine aggregate particles are sequentially expanded and supplied to the hopper 5, and the hopper 5 is provided with velocity energy below the hopper 5 for imparting impact energy to the particles. As shown in FIG. 2 and below, a rotating body 2 with blades 9 disposed on its peripheral surface is provided as an additional mechanism.
It is configured to apply a predetermined impact velocity energy to the particles that are sequentially supplied. On the side of the velocity energy imparting mechanism 2, an impact body consisting of a series of rotating bodies 3, 3, 3, etc. in the one shown in Fig. 2 is arranged, and these impact surface members 3, 3, 3,... Impact surface members 3, 3 are rotated together with the rotating member 2 at a predetermined speed by a driving mechanism 1 provided on the fuselage A, and form a discharge port 6 below the fuselage A. , 3... is provided with a receiving part 1 for liquid, etc.
7 is formed with an inclined bottom surface, and the receiving portion 17 forms an outflow portion 18 outside the body A. Furthermore, a wiping means 4 made of hard rubber or the like is attached to the other side of each of the above-mentioned impact members 3, 3, 3... with its proximal end pivoted, and its own weight causes the wiping means 4 to wipe around the periphery of the member 3. It is configured to press against the respective surfaces and wipe off moisture etc. adhering to the peripheral surfaces. For this wiping means 4, the wiping performance for the surface of the member 3 can be adjusted by appropriately using an elastic material such as a spring. The fine aggregate reversely projected from the rotating impact surface member 3 is further subjected to impact separation at the fixed impact plate 12.

FIG. 3 shows another embodiment of the device according to the invention, i.e. in this embodiment the rotating bodies 3, 3, 3, . . . Another relatively large-diameter rotating body 3a is provided below the rotating body 2, and is similarly rotated by the driving mechanism 1. Similarly, a wiping means 4 is provided. Another receiving part 17a is formed below the rotating body 3a together with the receiving part 17, and its outflow part 18a is connected to the outflow part 18. In addition, instead of arranging the series of rotating bodies 3, 3, 3, etc., the one shown in FIG. 3 uses one rotating body 3 as shown in FIG. An intermediate rotating body 3b may be disposed between the rotating body 3 and the rotating body 3b.

As the rotating body 3, 3a or 3b, as shown in FIG. 5, a tire-shaped rotating body enlarged with an internal tube 13 relative to the drive shaft is appropriately adopted.

That is, in the case of a device using such a mechanism, the particles supplied by the velocity energy obtained by the velocity energy imparting mechanism 2 are generally blown in the tangential direction of the particle, and hit the rotating body 3, 3a or 3b located in the direction of flight. It is obvious that an impact is applied, and therefore adhering liquid, etc. (including mud) are removed on the rotating surfaces 3, 3a, or 3b. Third,
In the case of the one shown in FIG. 4, the rotating body 3a or 3b removes the liquid etc. by impact energy in this way, and its rotation gives velocity energy to the particles again to make them fly, and the next rotating body 3 or 3b A flight impact is applied to the aircraft, and adhering moisture is similarly separated. Rotating bodies 3, 3a and 3
It is clear that the moisture adhering to the surface b is subjected to the wiping effect of the wiping means 4 or 4a, and its function is constantly updated to receive the separation effect due to the impact energy, so that a uniform separation effect is always achieved. can get.

Examples of the present invention, which were specifically implemented using the above-described apparatus, will be described below.

Example 1 Separation of adhering water from river sand was carried out using the apparatus shown in Figure 2 of the attached drawings. In other words, river sand is medium-sized sand produced in the Oigawa River, Shizuoka Prefecture, and has an attached water content of 5 to 18%.
The supply rate was appropriately selected in the range of 400 to 950 Kg/mm, and the energy imparting mechanism 2 had eight vanes with a diameter of 500 mm and a height of 25 mm arranged at equal intervals on the circumference. The treatment was performed by rotating at a speed of 1500 rpm, and each rotating body 3 having a diameter of 300 mm and having a coating layer made of wear-resistant steel was rotated at 2500 rpm.

The amount of attached water in river sand after treatment is 4.23-4.54%
Even after 3 hours of continuous operation, the amount of water deposited was the same as long as the operating conditions were the same. The cement-to-sand ratio was 1:3, the water-cement ratio was 60%, 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 was mixed and adjusted by subtracting the amount of adhering water after treatment from the added amount, is as follows: initial shear stress yield value F ₀ is 5.26 g/cm, relative viscosity coefficient λ
is 0.75g/sec・cm ⁴ , relative occlusion coefficient ΔF ₀ is 0.015g/
cm ⁴ and separation bleeding is only slightly recognized as 0.2%, and the compressive strength after 7 days of a molded article formed using the mortar prepared in this way is 227 to 243 Kg/cm ² ( average 235
Kg/ ^cm2 ), and after 28 days it is 311-375Kg/cm2).
cm ² (average 353 Kg/cm ² ), and although some separation pleating 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-forming step, which was devised by the present inventors, was also carried out. In other words, the sand that has undergone the above-mentioned treatment first has a water landing volume of 6.6
%, and then Portland cement powder was added and mixed so that the W/C was 20%, and then secondary water was added to 192 Kg/m ² and a dispersant was added to 1% of the cement amount. The fluidity of a mortar with an S/C of 3 and a W/C of 60% is as follows: the initial shear stress yield value F ₀ is 7.9 g/cm ² and the relative clay coefficient λ is
1.55g・sec/cm ⁴ , relative occlusion coefficient ΔF ₀ is 0.025g/cm
⁴ , it is a mortar with favorable fluidity, and no separation breathing is observed, and the compressive strength of the molded product made with this mortar after 7 days is 244 to 265.
Kg/cm ² (average 256Kg/cm ² ), after 28 days it is
It has good and substantially uniform strength of 392 to 394 Kg/cm ² (average 389 Kg/cm ² ).

For these items, a part of the sand piled up in the same manner as above was used separately, and to this, water was added at 287 kg/m ³ and cement was added at 480 kg/m ³ in the same amounts as above. In the mortar mixed and kneaded at a ratio of m ³ , F ₀ , λ and ΔF ₀ were each unmeasurable, and the amount of separated pleating was 2.5%, which was extremely high. The compressive strength after 28 days is 207-208Kg/cm ² (average 207Kg/cm ² ), and after 28 days it is 306-296Kg/cm ² (average
305Kg/cm ² ), which was considerably inferior, and it was confirmed that the strength varied over a wide range.

Example 2 The same river sand as in Example 1 was treated using the apparatus shown in FIG.

The rotating body 2, which is the energy imparting means, has a diameter of
500 mm, and 16 blade plates 9 with a height of 25 mm are planted on the circumferential surface at equal intervals, and the rotating body 3
A has a diameter of 530 mm and is covered with a wear-resistant steel shock layer, and rotating body 3 has a diameter of 300 mm and is also covered with a wear-resistant steel shock layer, and their rotational speeds are It is as follows.

Rotating body 2...1300rpm Rotating body 3a...1300rpm Rotating body 3...2500rpm The measurement results for the amount of water attached to the river sand obtained after treatment were 3.1 to 3.05%, confirming that the amount of water attached was uniform. Ta.

The sand that has undergone this treatment has a sand-cement ratio of 1:1.3, a sand-to-gravel ratio of 44.5%, and a water-cement ratio of 1:1.3.
The fluidity of the concrete, which was mixed by adding water to make it 52% and dispersant to 1% of the amount of cement, has good fluidity with a slump of 7.2cm.
Separation breathing was slightly observed, and the average compressive strength after 7 days of a molded object formed using this concrete was 273.
Kg/ ^cm2 , and after 28 days it averages 382
Kg/cm ² and their coefficient of variation is 7.5%
It was a matter of degree.

On the other hand, a method of adding water and kneading in two stages according to the shell-forming method of the present inventors was also carried out, that is, after water separation treatment was performed as described above, first the amount of water attached was 6%. After adding primary water, add gravel at a rate of 1125Kg/ ^m2 , add and mix Portland cement powder so that W/C is 18%, and then add 101Kg of secondary water again. / ^m2
and a dispersant are added and mixed at a ratio of 1% of the amount of cement, S/C is approximately 3, S/A is 44.5, and W/C is 52%.
The fluidity of concrete that was assumed to be slump was 8.3.
cm, and the concrete had good fluidity.
However, the average compressive strength after 7 days of a molded body made of this concrete is 363Kg/cm ² , 28
After 1 day, it was 482 kg/cm ² and the coefficient of variation was about 0.6%, with no variation.

For these, we used the same Oigawa sand as mentioned above, measured its moisture content, corrected the moisture content, and then adjusted the composition per m ² to be the same as above: 294 kg/m ^{3 of cement, 153 kg/m 3} of water. ^m3 , sand 882Kg/
The concrete obtained from the mixer by mixing 1125 Kg/m ³ of gravel and 1125 Kg/m ³ of gravel has a slump of 10.2 cm, and the average compressive strength after 7 days of the compact obtained with this concrete is 234 Kg/cm ² , 28 308 days later
Kg/cm ² , and its coefficient of variation was 12.0%, which was not only poor in strength but also highly variable.

Example 3 In Example 2, the size and rotation conditions of the rotating body 2 and the rotary body 3 were all the same, and the processing was performed by rotating each of them in the apparatus as shown in FIG. 3 of the attached drawings mentioned above. Medium-grained sand with an attached water content of 3.05 to 3.10% was prepared.

Add primary water to the above sand so that the W/C for shelling is 16%, and add 344 kg of cement to 1217 kg/ ^m3 of sand.
A mixture of Kg/ ^m3 and gravel at a ratio of 641Kg/ ^m3 is sent by air pressure, and at the spray nozzle, 110Kg/ ^m3 of water and a quick-setting agent equivalent to 5% of the amount of cement are added and sprayed onto the inner surface of the tunnel. did. The W/C of the spraying work was 48%, the spraying speed was 6m ³ /hr, the amount of dust generated was 6.1mg/m ³ , and the rebound rate was 22%. The compressive strength after days is
It was 213Kg/cm ² and 258Kg/cm ² after 28 days.

In addition, the amount of water attached to the treated sand as described above is 11%.
After adding primary water so that the ratio is 20%, Portland cement powder is added and mixed so that W/C is 20%, then secondary water is added at 82Kg/cm ³ and dispersant is added at a ratio of 0.6% of the amount of cement. Addition and kneading with S/C of 1.75,
The fluidity of the mortar with a W/C of 41.3% is as follows: the initial shear stress yield value F ₀ is 0.79/cm ³ and the relative clay coefficient λ is
1.29g.sec/cm ⁴ , relative occlusion coefficient ΔF ₀ is 0.0051g/cm ⁴
, this mortar is flowed at a flow rate of 67 m/mm and the inner diameter is 2.
The water was pumped over a distance of 150 m using a 1.5-inch pipe, and the water landed on it as described above.
Add 5 to 15 mm of gravel to one part of sand adjusted to 3.10%.
A mixture of 0.83 parts and quick setting agent at a ratio of 4% to the amount of cement is pumped with compressed air and added at a ratio of 1:1 to the amount of kneaded mortar at a position 5 m before the tip of the spray nozzle. This was then 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 52.6%, and the amount of cement is 345
Kg/ ^m2 , but the rebound rate during spraying was 12
%, the amount of dust generated was 1.5 mg/m ³ , and the spraying with an average spraying thickness of 150 mm at the top of the tunnel was able to be carried out smoothly without flaking in general. Average compressive strength 7 days after spraying is 364
Kg/cm ² , after 28 days it was 420 Kg/cm ² , and its coefficient of variation was 1.8%, confirming that both the rebound rate and the amount of dust generated were reduced, making it a preferable spraying method.

In addition, in this spraying construction, the amount of water adhering to the sand is not adjusted and separated over the entire amount, but the moisture is corrected using a part of the sample, and this is compared with the case of spraying construction using the conventional wet method and 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 was confirmed that the amount of dust generated by the dry method is lower than that of either of them. is 20-30% for both wet and dry methods.
However, this can be reduced to a fraction of that. Moreover, the reaction of the nozzle during spraying is much smaller than with any conventional method, and the spraying volume is at least double the 3 to 4 m ³ /hr of the conventional method using a similar 2-inch pipeline. I learned that I could get it. Furthermore, in the case of this conventional method, the average strength of the sprayed material is about 60 to 75% of that of the present invention with the same composition, and the coefficient of variation is several times higher.

According to the present invention as described above, water and other liquids adhering to fine aggregate such as sand can be separated and homogenized relatively easily and at low cost. It is possible to accurately weigh the product, determine an accurate mixing relationship and adjust the appropriate mixture, and stabilize and uniformize the strength and other properties of the product by the mixture,
Moreover, since the separation operation of moisture etc. by the impact energy is performed on the circumferential surface of the rotating body, the grinding wear due to the impact of the fine aggregate does not occur concentratedly on a part of the impact surface, and the entire circumferential surface of the rotating body is removed. Therefore, water separated from the fine aggregate will not accumulate in the partially worn parts, which will reduce the separation effect in the fine aggregate that is sequentially subjected to impact. Furthermore, a wiping means can be employed on the circumferential surface of the rotating body to constantly update the separation performance on the impact surface, and by any of these, stable and uniform separation operation as described above can be ensured. Furthermore, the durability of the processing mechanism can be increased to enable efficient continuous operation, and this invention is industrially highly effective.

Additional Relationship The present invention relates to an addition to Patent No. 1647885 (1990 Patent Application Publication No. 62366 (original invention)), that is, it expands, transports and supplies fine aggregate with liquid such as moisture attached, and An impact force greater than the adhesion force of the liquid to the aggregate is applied sequentially to separate the adhering liquid and the resulting homogenization is used as a material for a hydraulic substance mixture such as cement and mixed, and an apparatus. However, the invention is the same as the original invention in that it employs a means for imparting velocity energy to fine aggregate, an impact surface member, and a mechanism for mixing fine aggregate and hydraulic material powder. By separating moisture, etc. using impact energy on the circumferential surface of the rotating body, the impact surface to which the removed moisture, etc. has been attached, is sequentially moved to perform impact separation on a new impact surface, and the impact surface is Partial damage occurs intensively, forming a concave damaged area on the impact surface, and the removed moisture remains in the concave damaged area, acts like a cushion, and attaches to the impact fine aggregate. By updating the function of the impact surface by wiping with the wiping means without disturbing the long-awaited separation and removal effect, it is possible to always ensure a favorable impact separation result, accurately achieve the processing purpose, and ensure sufficient durability of the mechanism. Therefore, the present invention relates to an improvement of the original invention.

[Brief explanation of drawings]

The drawings show the technical contents of the present invention, and FIG. 1 is an explanatory diagram showing the general relationship of the apparatus for carrying out the present invention, and FIG. 2 shows the main part configuration of an example of the water separation mechanism. 3 is a similar sectional view showing a modified example thereof; FIG. 4 is a partial side view showing a further modified example of the velocity energy imparting mechanism and rotating body portion; FIG. The figure is an explanatory view of the rotating body, showing both a side view and a sectional view. However, in these drawings, 1 is the driving mechanism, and 2 is the driving mechanism.
is a rotating body serving as a velocity energy imparting mechanism, 3,3
a, 3b are rotating bodies, 4, 4a are wiping means, 5 is a hopper, 6 is a discharge port, 17, 17a is a receiving part, 1
Reference numerals 8 and 18a indicate outflow portions, A indicates a water separation mechanism, B indicates a mixing mechanism, C indicates a hydraulic material powder addition mechanism, and D ₁ and D ₂ indicate water addition mechanisms, respectively.

Claims (1)

[Scope of Claims] 1. A part of the moisture attached to fine aggregate particles such as sand is applied with an impact force that is greater than the adhesion force of the moisture to the fine aggregate particles almost uniformly on the circumferential surface of the rotating body. The separated and attached moisture is sequentially wiped off on the circumferential surface of the rotating body, and after the attached moisture has been wiped off, separation is performed by the impact force on the circumferential surface of the rotating body. A method for preparing a mixture of hydraulic substances such as cement, which comprises using fine aggregate as a mixing material for a mixture of hydraulic substances such as cement. 2. A mechanism that applies velocity energy to fine aggregate particles such as sand, a rotating body mechanism that applies impact force to the fine aggregate particles charged with the velocity energy and removes adhering moisture to a uniform state; A moisture wiping mechanism that sequentially removes moisture adhering to the peripheral surface of a rotary body mechanism through its rotation, and adding water again to the fine aggregate particles that have removed the adhering moisture and adding hydraulic substance powder. A device for preparing a mixture of hydraulic substances such as cement, which consists of a mixing mechanism.