JPS622962B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing concrete and an apparatus thereof, and relates to quantitative changes in relative fluidity after mixing with water in a plastic fluid such as a kneaded product obtained by adding water and kneading powder of a hydraulic substance such as cement. By utilizing the newly confirmed facts, we aim to obtain a concrete product with excellent long-term strength by molding the kneaded material. Concrete is of essential importance in today's civil engineering and architectural fields, and has been extensively researched and considered in various fields both practically and theoretically. However, it is not easy to properly mix and form this concrete to achieve its purpose and also to obtain sufficient strength.In other words, if the amount of water mixed is increased, a kneaded product with excellent fluidity can be obtained. It is clear that both the kneading operation and the molding operation become easier,
It is generally known that such a kneaded product containing a large amount of water inevitably results in inferior strength of the resulting concrete product. In addition, when the amount of water mixed is large, the amount of breathing water that floats and separates on the surface after molding is also naturally large, so if this breathing water is not sufficiently separated after casting molding, the surface finish will be poor. It is not possible to carry out curing treatment, and the construction period for obtaining the desired product and completing the construction becomes longer. On the other hand, if the amount of blended water is reduced, the fluidity will be poor, making it difficult to knead and form into a dense structure, and the resulting product strength will also be insufficient. There is a tendency that this is not the case.
For this reason, in the conventional method, research has been carried out to improve these properties by adding various auxiliary agents such as water reducing agents and dispersants, and although some effects have been obtained, the basic fluidity etc. of cement Since properties have not been quantitatively measured by flow, slump tests, etc., product strength and other performance in relation to fluidity have not been fully elucidated. The prepacked method is known as one of the methods for obtaining such concrete. In other words, it is a method in which coarse aggregate such as gravel is filled into the forming area in advance, and then a kneaded material such as cement is poured into the molding area. This construction method has the advantages of being able to obtain homogeneous concrete without separation of aggregate and mortar, and the mixing operation is easy. However, when it comes to concrete using this pre-packed method, the priority is to accurately inject the above-mentioned kneaded material into the gaps between the pre-packed coarse aggregates, and if this injection cannot be achieved properly, the purpose is lost. This cannot be achieved, and in practice this injection must be extremely difficult. According to the conventional general pre-packed method, a large number of injection ports are arranged and the injection is carried out sequentially from each injection port. Since the injection process has to be injected into the body, it cannot help but become extremely complicated. In addition, in order to ensure the smoothness of such injection, it is important to specially select the shape and size of the prepacked coarse aggregate and to ensure that the kneaded material to be injected has sufficient fluidity. As is generally known, even if this method is used, it will be injected under conditions where the coarse aggregates come into contact with each other, so it will not be possible to obtain a preferable injection, and the resulting product will not be sufficient. Since it is not easy to obtain sufficient strength, the practical application of ordinary concrete construction methods has been limited to applications such as underwater concrete construction, where it is impossible or extremely difficult to apply. However, the present inventors have conducted a lot of practical research and speculation regarding such prepacked concrete, and have developed a special technique that utilizes reduced pressure conditions for pouring the prepacked concrete. Although we have succeeded in discovering particularly new behaviors and establishing new construction methods that utilize these to their advantage, we have achieved remarkable progress and improvements in terms of injectability, but there is still a tendency for the strength to be insufficient. It remains. In general, the factors that determine the strength of concrete are the water-cement ratio, voids caused by latent air, water voids caused by separation breathing that occurs on the bottom surface of aggregate, unit cement amount, coarse aggregate to fine aggregate ratio, as mentioned above. However, the factors that greatly affect the strength development of these medium-prepacked concretes are the water-cement ratio, water gaps caused by separated breathing water, and the fact that the coarse aggregate and cement are not directly kneaded. This is thought to be due to a decrease in adhesion elements. Therefore, in conventional prepacked concrete, fly ash is added to improve the fluidity of the poured mixture, water reducers are added to reduce the water-cement ratio, and the adhesion of coarse aggregate and mortar is strengthened. Additionally, in order to increase mortar strength and improve breathing water separation, etc., aluminum powder is added singly or in combination. In particular, when adding aluminum powder, by reacting it with cement, it is possible to generate hydrogen gas and increase the internal pressure, and this increase in internal pressure is extremely important for developing strength. In some cases, it is considered essential in the case of the prepackaged method.
However, even with this method, it has not yet been possible to obtain a preferable strength in the case of the prepacked method.In other words, the strength of prepacked concrete is generally determined by the fact that the strength of prepacked concrete is the same as that of the mortar used in it. The compressive strength is around 60% of the compressive strength of concrete made by conventional methods, and this makes it difficult to obtain accurate pouring as mentioned above, and despite the advantages of the prepacked method mentioned above, it is not widely used. This is one of the reasons why. Regardless of which method is used, another problem in obtaining such concrete products is that a considerable amount of time is required between charging and filling the formwork and demolding. In other words, simply leaving it at room temperature and pressure after filling the mold would generally require 3 to 7 days or more, so it is necessary to speed up such demolding as much as possible. increases the rotation rate of the formwork,
This is the reason why efficient production can be carried out without preparing a huge amount of formwork, and advantageous production can be carried out with a relatively small number of man-hours and equipment. Therefore, great efforts have been made in various fields for such early demolding, and instead of the usual method of curing at room temperature and curing in water, forced curing by adjusting temperature and pressure conditions, etc. Many studies and efforts have been made to achieve early demolding, and today many techniques have been completed and announced that enable demolding within a few hours. However, when trying to remove the mold quickly, even if it is possible to remove the mold within a short period of time as described above, an unfavorable fact arises. If initial strength is achieved and early demolding is attempted, the long-term strength of the concrete will decrease even if standard heat curing specified by JIS etc. is performed. When the initial strength required for early demolding is obtained by capping and forcibly curing as described above, the long-term strength, which is the strength of the final product of the concrete, will decrease. To be more specific, as mentioned above, the long-term strength of forced curing to increase the formwork rotation rate, etc. and early release from the mold is the long-term strength of long-term compression even if left to cure at normal room temperature and cured in water. It is generally accepted in the industry that the strength decreases by around 20% compared to other factors. Therefore, even if early demolding is significant as mentioned above, if you consider it from the viewpoint of long-term strength, which is important for this type of concrete product, it is completely the opposite and cannot help but be a major disadvantage. It is. The inventors of the present invention have conducted extensive research into overcoming these technical bottlenecks, and in 1972, they filed a patent application.
He proposed a technique such as No. 20682 (Japanese Patent Application Laid-Open No. 110713/1983; hereinafter referred to as the first prior invention). That is, when using the first prior art of the present inventors, it is possible to demold the mold as early as about 3 hours, and its long-term strength can be maintained sufficiently high, making it industrially viable. This can be said to be an extremely significant technology. In addition, the present inventors have conducted many practical and theoretical studies regarding the prepacked method described above, elucidated the technical reality regarding its fluidity, and established an accurate method regarding injection operation conditions. He also made improvements to formwork and other prepacked molding equipment, and made many proposals regarding the adjustment conditions and other aspects of the various materials used in this prepacked construction method, and also conducted on-site research and practical application of these proposals. We have come up with some ideas for this. The present invention further develops and improves the series of prior art, and enables smooth injection molding by various methods including pre-packed methods, and accurately produces products of excellent purpose without significantly reducing long-term strength. It was designed to make it more profitable. Further, according to the present invention, early demolding, which is advantageous in terms of equipment and construction period, can be more appropriately achieved, and the above-mentioned strength can be sufficiently obtained. To begin with, the basic discovery of the present invention will be explained. In the series of technological development processes described above, the present inventors discovered that a plastic fluid such as this type of cement kneaded material was injected into a prepared structure. In order to accurately clarify the injection characteristics when filling, we confirmed that conventional methods such as P funnel and rotational viscometer are inappropriate and that a new measurement method that emphasizes relative fluidity should be used. , Patent Application No. 157452 (1975)
No. 157452) "Method for measuring fluidity of plastic fluid, method for adjusting plastic fluid, method for injecting plastic fluid, and apparatus thereof" (hereinafter referred to as the second prior invention). However, if the new technology of the second prior invention is used, it is possible to obtain preferable measurement values according to the actual situation with respect to the pre-packed construction method as described above, and by operating using this, it is possible to obtain the measurement values as described above. It is possible to smoothly and stably perform injection using the difficult pre-packed construction method, for example, even with an injection distance of several meters, and even with a plastic fluid of a kneaded product with a low water-cement ratio (W/C). What is possible is as disclosed in the earlier application, and thereby the prepackaged construction method can be dramatically developed. By the way, in accordance with such an effective plastic fluid injection fluidity measurement technique, the present inventors have investigated the relationship between the passage of time and fluidity after water injection and kneading for kneaded products based on pastes of various cements, which are the basic materials of mortar and concrete. As a result of careful testing and measurements, we discovered a new fact that does not exist in conventional theory. The new discoveries of the lid are summarized in Figures 1 to 4 of the attached drawings, and Figure 1 shows the relationship between the time elapsed after injection and mixing of cement paste and the injection flow characteristics. The relative initial shear stress yield value (Fo: g/cm ³ ) disclosed in the second prior invention was typically adopted as the flow characteristic value, but in any case, up to a certain time after water injection and kneading. It is clear that the Fo value becomes smaller (in the case of adding a dispersant, it remains flat after that), that is, the injection fluidity becomes good, which is because the injection fluidity conventionally deteriorates as the water injection kneading time elapses. This is a new fact that is completely contrary to what is understood. In addition, in this figure 1, the case of only portland cement (plain) is representative.
The results are shown for the addition of a non-retarding dispersant and the alumina cement paste.
Each sample was kneaded (2
Although the above-mentioned dispersant was added at the time of this secondary kneading, it is also the case that concrete materials such as blast furnace cement and early strength cement, which are not shown in Fig. 1, are used. Similar trends are observed even if there are some differences in the numerical values (time at which Fo decrease is recognized, and the Fo value).
That is, it was confirmed that the injection fluidity was good until a certain time was reached, after which the injection fluidity changed, the Fo value increased, and the fluidity deteriorated. In particular, as shown in the figure, alumina cement shows a tendency for the Fo value to decrease (improvement in fluidity) even after 180 minutes after water injection and mixing, which can be said to be a surprising new fact.
As shown in the figure, in the plain case and in the case of adding a dispersant, the addition of a dispersant allows for a smaller W/C, lowers the Fo value, and lengthens the inflection point of the injection flow characteristics. Generally 1%
It can be seen that the amount is doubled by adding a certain amount of dispersant. Next, use the paste as shown in Figure 1 above,
Figure 2 shows the results of measuring the 4-week strength of the products obtained by molding the kneaded products after 30 minutes, 60 minutes, and 90 minutes of water injection and kneading. According to this Figure 2, in the case of plain paste shown by the dotted line, the kneading time is
It is clear that the strength gradually increases until about 60 minutes, and then decreases, and in the case of adding a dispersant, as shown by the solid line, the strength increase period due to the kneading time as described above is longer than in the case of plain, which is 100 minutes. It will be about. In particular, in the case of alumina cement (indicated by the dashed line), the strength increase was remarkable, and within 120 minutes
It was confirmed that a high strength of 900Kg/cm ² could be obtained and that the strength would last for a long time. Furthermore, Figure 3 shows the hydration over time for Portland cement, alumina cement, blast furnace cement, and early-strength cement with mixing times of 0 minutes, 60 minutes, and 180 minutes (including 30 minutes for Portland cement). This shows the state of heat generation, but compared to the one with a kneading time of 0 minutes (no secondary kneading), the one with the above-mentioned kneading time and the second kneading has a shorter hydration heat generation peak point. As shown in the figure, the situation and amount of generation can be changed in this manner, and the changes are particularly remarkable in the case of alumina cement. In other words, it is estimated that such a change in the state of heat generation of hydration is manifested as a change in the four-week strength as shown in Figure 2, and in fact, the larger the change in the shape of the change in Figure 3, the greater the intensity in Figure 2. The increase is also increasing. Figure 4 shows the results of measuring the state of heat of hydration generated by the addition of an alkyl sulfonic acid dispersant (trade name: Mighty) produced and sold by Kao Soap Co., Ltd., which is called a non-retarded dispersant (water reducer). However, it is clear that even a dispersant that is said to be non-retarding has a certain retarding effect on the generation of heat of hydration depending on the amount added, and this shows that It is recognized that this is consistent with the fact that, as shown in Fig. 2 described above, the strength still shows a tendency to increase even after the kneading time is 90 minutes. The present invention is based on such a series of new discoveries and uses these relationships to advantage to achieve the above-mentioned special technical objectives. Establishing a new technical method by utilizing the relationships shown in Figures 3 to 3.
Furthermore, by combining this with relationships such as those shown in FIG. 4, it is attempted to obtain the characteristics in a more favorable state. First of all, the above-mentioned 1~
If we consider the relationship shown in Figure 3 in detail, we can see that when Portland cement comes into contact with water, it swells due to capillary water adsorbed on the cement particle surface, and gypsum and other components dissolve in the capillary water. The resulting etrigite is precipitated to prevent rapid setting of 3CaO.Al ₂ O ₃ . After that, various crystals such as tobermolite are grown, and the secondary kneading is performed at the point when such swelling and crystal growth have been appropriately obtained (around 30 minutes or after) to form these swollen cement particles. It promotes grain refinement by peeling off the surface layer and fragmentation by dividing crystal grains, and as they are dispersed in the slurry water, it eliminates unevenness in partial concentration and improves fluidity. It is recognized that swelling and crystal growth occur on the surface of the new cement particles after the swelling surface layer is peeled off, and in any case, such phenomena reduce the Fo value as shown in Figure 1 above. In addition, the strength of the finished concrete is increased by the paste itself, and even when fine aggregate or coarse aggregate is mixed with it, the cement components and crystals are enriched on the surface of the inert aggregate as described above. The resulting water film is covered, and this also increases the strength of the concrete. Of course, the above-mentioned decrease in Fo value improves the injection properties when carrying out the prepacked method aimed at in the present invention, resulting in smooth injection and the formation of a dense injection structure. Alternatively, in the process of injecting and flowing mortar between prepacked inert aggregates, the Σ effect and lamination may occur, and there is an element in which low-concentration slurry water forms a thin layer on the coarse aggregate surface. The presence of a high concentration of fine active crystals obtained by the above-mentioned secondary kneading in the slurry water increases the specific surface area and reduces separation and breathing, making it easier to flow the highly concentrated slurry prepared in this way. As shown in Figure 3, the injection changes the state in which the hydration reaction occurs, resulting in a faster and more vigorous hydration reaction, and is the same for all types of cement. The change is particularly remarkable in the case of alumina cement, which has a long period of Fo value reduction due to mixing, as shown in Figure 1. However, it is clear that achieving a more vigorous hydration reaction earlier in this way contributes to at least an increase in initial strength (strength for demolding), and such a relationship is shown in Figure 2. The results showed that compared to the 0 minute kneading time (therefore no secondary kneading), the ones with a 30 minute and 60 minute kneading time and secondary kneading had higher initial values. The strength of alumina cement with a mixing time of 120 minutes is 200 kg/cm ² compared to that of 0 minutes.
An initial strength increase close to that of the previous one was obtained. That is, in the present invention, these relationships are utilized,
Specifically, for at least 30 minutes or more, the above Fo value and ΔFo should be maintained in relation to the intended injection area.
(relative occlusion) value, λ (relative flow viscosity coefficient) value,
It is proposed that the mixing time be within a range that can ensure the relative fluidity required by the injection speed and the properties of the pre-packed aggregate, and that the secondary kneading should be injected. The lower limit of the aging time can be easily understood from the situation in Figure 1, and the upper limit is the point just before the generation of each heat of hydration draws the steepest curve as shown in Figure 3. For example, it takes about 4 hours for Portland cement, 6 to 7 hours for blast furnace cement under such conditions, and about 6 hours for alumina cement. Note that the specific kneading time does not necessarily require that the entire amount of the kneaded material remains for a certain period of time; for example, in Fig. 1, the kneading time is the same whether the dispersant is added or not for 30 minutes or 60 minutes;
In the figure, the mixing time to obtain substantially the same compressive strength can be determined, for example, in the range of 60 to 90 minutes, and in the case of Portland cement, the mixing time in the range of 30 to 60 minutes in Figure 3 shows that It can be seen that there is no significant change in the kneading time, and the kneading time can be appropriately selected within a range that does not cause such a substantial change. The secondary kneading, which is carried out by taking a kneading time exceeding the above-mentioned upper limit, is carried out at the point when the tobermolite crystal products that have been generated and grown as described above have become entangled to a certain extent. Therefore, even if such a secondary kneading operation is added, the strength will be reduced. It is also clear that the active hydration reaction cannot be fully utilized to develop the strength of the molded product; in any case, demolding becomes difficult in a short period of time, and sufficient long-term strength cannot be obtained. In the present invention, it is a matter of course that river sand or the like may be mixed into the cement-containing fluid as described above for the purpose of preparing a well-known mortar. Powdered auxiliary materials such as fly ash, water slag or other slag powder, gypsum powder, or fibrous materials can be added. These materials have a diameter of 0.15 mm or less, and by appropriately interposing such auxiliary materials between cement particles, it is possible to reduce the amount of cement and to achieve preferable strength. For the case of plain training as described above, the fourth
When a dispersant as shown in the figure and also shown in Figures 1 and 2 is added, the arch action of cement particles or the inclusion of water between adsorbed water particles, which is expected in the case of plain cement particles, occurs. Slurry water reduction that contributes to flow due to flow is avoided, making it possible to reduce the water-cement ratio for the same flow, especially when using high-performance dispersants such as those mentioned above. The particles repel each other due to the zeta potential, etc., and the water contained between the particles is reduced to a certain extent, and such an effect can be effectively obtained by adding it at the time of secondary kneading, which is preferable. By effectively obtaining injection fluidity, as shown in Fig. 1, there is a longer Fo value reduction period than in the plain case, and as shown in Fig. 2, excellent initial strength is achieved. results in an increase in The results shown in FIG. 4 correspond well with the situation shown in FIG. By appropriately blending the seeds or more, the amount of water required to prepare the paste or mortar can be reduced and favorable fluidity can be obtained. Due to the above-mentioned circumstances, such dispersants and penetrants are generally added during the secondary kneading, and at least the total amount of these auxiliary agents to be added is added during the primary kneading. investment should be avoided. In other words, according to the results of studies conducted by the present inventors, those in which these kneading aids were added during the first kneading were inferior in strength to those added during the second kneading, and even under the same mixing conditions. In this case, it is not possible to advantageously obtain excellent strength as the object of the present invention. However, it is possible to use some of these kneading aids in the primary kneading, and in this way some of the kneading aids used in the primary kneading can be used in the primary kneading. In this way, the kneaded product prepared with a relatively small amount of water reduces the amount of water film interposed between cement particles that have fluidity higher than the capillary region. At the very least, try to generate tobermolite crystals with high concentration. In addition, in the present invention as described above, the first
It is preferable that the amount of water added during each of the subsequent and second kneading processes is selected within a specific range. In general, regarding the relationship between cement particles and other solid particles and the amount of water, there are differences between the absolute dry state and the slurry state in which particles are suspended in the water, and also between pendular and funicular. ) and capillary can be considered separately, as published in the literature, etc.
Also, depending on whether or not the intervening air is continuous, the state of the funicular can be divided into the state of the funicular F ₁ where the air is continuous and the state of the funicular F ₂ where the air is not continuous. However, in the present invention, in such various states between particles and moisture, the liquid forms a liquid film on the particle surface without substantially air existing between the liquid and the particles. The particles are substantially separated from each other by this liquid film, and the mixture of liquid and particles has a fluidity higher than that of the capillary region where plasticity is observed, and the amount of breathing in this mixture is substantially zero. Another feature of the present invention is that a specific water content range is selected as shown, and the water content is limited. It must be understood that when the amount of water mixed in the lid is such that the amount of breathing becomes substantially zero, the flowability is generally poor and it is not possible to obtain a desired charging molding in the mold. However, based on the above-mentioned new discovery by the present inventor, by utilizing the fact shown in Figure 1, the relative fluidity can be improved. Concrete construction using this method allows for appropriate injection and filling even in the forming area where coarse aggregate and reinforcing materials are pre-packed, for example. Moreover, in this case, the secondary kneading shortens the hydration reaction heat generation peak period as shown in Figure 3, so that the concentrated kneaded product does not substantially generate breathing water as described above. The hydration reaction progresses rapidly under conditions where the mold is densely injected and filled, which inevitably results in rapid internal demolding and high strength. Thus, the characteristics of the present invention that cannot be found in the prior art are extremely clear. That is, in the present invention, by organically combining the above-mentioned new discoveries, mold removal can be achieved in a short time, such as within 2 hours, and the compressive strength is 700 to 800 kg/cm ² or more. In terms of long-term strength, it is almost as good as that of a combination of curing at room temperature and curing in water, and in some cases it is possible to accurately obtain a product that exceeds that. In the present invention, the amount of added water used during secondary kneading that does not substantially produce breathing water as described above and exhibits fluidity above the capillary range depends on the composition of each kneaded product, the sand and other compounds used. The specifics will vary depending on the properties and other factors. The cement used also has an effect, but according to the actual study conducted by the present inventors using the W/C value, a minimum of about 28% is necessary, and the maximum amount of water to be mixed is W/C.
It is 40%. Although it is true that the entire required amount of water may be added during the primary kneading, similar to the divided addition method described above for adding a dispersant, Do not add the entire amount of water required, but leave some of it behind.
It is more preferable to add this during secondary kneading. That is, by reducing the amount of water used in the primary kneading in this way, the thickness of the water film formed between cement particles is reduced, resulting in a highly concentrated hydration reaction and crystal formation. In particular, when the kneading time is taken in the conveyance process on the belt as described in the embodiment described later, the small amount of kneading water causes the kneading water to be loaded and conveyed in a non-flowing state on the belt. It is suitable for charging the material discharged from the bottom of the kneading machine to the top of the secondary kneading machine in an inclined manner, and the amount of adhesion on the belt is also small. In addition, in the present invention, the material after the first kneading is left to stand for a period of time commensurate with the hydration reaction stagnation period, and the crystals such as dicalcium alpha hydrate or aphelite are suitably heated to 35°C or higher to substantially remove crystals such as dicalcium alpha hydrate or aphelite. Maintain temperature conditions that do not cause overheating. Preferred specific temperature conditions are generally 50℃ or higher, and the upper limit temperature varies in each case depending on the quality of the cement used, but in any case, a heating increase exceeding 115℃ is recommended. The temperature is controlled so as not to occur throughout the entire process of the hydration reaction. The inventors of the present invention have repeatedly conducted practical studies on many concrete materials over many years.
During such a hydration reaction process, if the temperature is increased above the above-mentioned limit even for a short period of time, crystals such as dicalcium alpha hydrate or aphelite, which have an undesirable effect on strength development, will be generated, resulting in a decrease in strength. This will result in some loss of sexuality. Heating above 35°C but below the above-mentioned limits promotes the hydration reaction to some extent. In this case, applying mechanical vibration or ultrasonic waves causes particles to be dispersed, and is therefore effective to some extent. Such heating during the mixing time and the addition of a retarder as described above are contradictory in nature, but they are used by appropriately discarding them during actual construction pouring. It is clear that the invention according to the above-mentioned method exhibits excellent effects and exhibits its technical characteristics especially when adopted in the pre-packed construction method described above. As mentioned above, the invention is based on the elucidation of the behavior of cement paste, which is a basic substance in this type of concrete, after adding water, and several new discoveries, and therefore does not rely on such a pre-baked method. It can also be fully utilized in concrete. For example, as mentioned above, by selecting a limited amount of mixed water that exhibits fluidity higher than the capillary range and does not substantially cause breathing, the W/C of conventional general concrete can be reduced to 60.
% or higher, it is clear that the thickness of the water film formed between cement particles is reduced, resulting in a highly concentrated hydration reaction and crystal formation, and moreover, if an appropriate kneading time is Since the relative flow characteristics can be improved by secondary kneading after mixing, it is possible to easily achieve concrete placement with a dense packing structure by using a kneaded material with a sufficiently low W/C. And, by doing this, the relationship that initial strength for demolding can be obtained within a short time and the relationship that sufficient long-term strength can be obtained are all the same as in the case of the prepacked construction method. Even if it is not possible to fully achieve the effects of making it possible to arrange the coarse aggregate in the highest proportion and reducing the shrinkage rate, which is unique to pre-packed products, most of the other effects unique to the present invention can be achieved by this pre-packed product. This can be obtained even in the case of general concrete forming or pouring that does not require In particular, in the case of the present invention which employs primary mixing and secondary mixing, in the case of a general concrete forming or pouring method that does not use this prepacked method, the primary mixing and subsequent mixing time In the process of mixing, it is possible to add water and mix only cement or cement mixed with fine aggregate such as sand, and by adding gravel or gravel and sand in the second mixing process. Thus, while fully obtaining the above-mentioned characteristics of the present invention, the equipment for the primary kneading and subsequent kneading processes can be made sufficiently compact and the driving force thereof can be reduced. The amount of covered gravel or gravel and sand that is not mixed is extremely small, which necessitates miniaturization of the equipment, and the kneading driving force is also light, making it difficult to mix equipment and Only the secondary kneading requires something similar in terms of driving force, and the equipment for taking the time for kneading can also be small, so even if the process is duplicated, the equipment and driving force will be reduced. Therefore, the technology of the present invention can be advantageously used in the field of concrete production that does not involve prepacked methods. In any of the above-mentioned cases, the present invention can obtain initial strength within a short period of time, which increases the rotational efficiency of formwork in the continuous industrial production of concrete products of this type. This means that it is possible to mass-produce concrete products by greatly reducing the number of formworks that need to be prepared, but what is even more preferable is the reduction in the factory area or scale required to manufacture such concrete products. The goal is to significantly reduce the For example, it has traditionally been said that factory equipment for producing such concrete products requires at least tens of thousands of square ^meters , and desirable concrete products cannot be produced until the respective equipment is installed on such a vast site. can be manufactured. However, according to the present invention, it is possible to remove the mold in about 2 hours as described above, and especially if the molds are treated as a layered state for curing, it is possible to remove the mold either vertically or horizontally. Therefore, such a continuous production facility can be significantly downsized and can be operated easily. In the case of continuous production by stacking formwork horizontally with a lid on, it is necessary to move a large number of stacked formworks up and down using jacks or other means, and it is also necessary to stack formwork vertically. Even in the case of continuous production, it is necessary to move a large number of stacked formworks horizontally in order to charge and cure materials using stationary equipment. In these cases, the amount of time it takes to obtain the initial strength that allows demolding is proportional to the operating force for moving the mold, and the operating force for moving the mold greatly influences the operability and the design of specific equipment. For example, if formwork is fed in sequentially in 15-minute increments and the curing period is 3 hours to obtain initial strength that allows demolding, it will be necessary to move and operate a stack of 12 or more formworks. On the other hand, if the curing period to obtain the initial strength is 2 hours, it will be necessary to move about 8 pieces of laminated formwork, and if it is 1.5 hours, it will be necessary to move and operate 6 pieces of laminated formwork. It's enough. However, the equipment design for moving and operating 12 or more laminated formwork without affecting the internal moldings, such as curvature or distortion, requires less acceleration compared to that for 8 or 6 laminated formworks. It is inevitable that the difficulty will increase and it will become huge. The present invention, which achieves initial strength within a short time while ensuring long-term strength as described above, adopts the curing treatment in the stacked state of the formwork as described above,
Furthermore, handling operations that do not affect the internal molded body of the laminated formwork can be accomplished with relatively simple and compact equipment. As a result, the production of this type of concrete, which in the prior art generally required at least tens of thousands of square ^meters of land and equipment as mentioned above, can now be produced satisfactorily in a mobile plant, and in particular does not require any land at all. It is possible to make stable production possible even on a ship floating on the water without being exposed to water. In continuous production using stacked formwork as described above, the curing effect after molding within the formwork can be enhanced by creating a space between the stacked formworks through which steam can pass. When carrying out such heat curing, the filling material (kneaded material) in the formwork in the layer above or below the steam passage part functions as a heat insulator, that is, the appropriate temperature is maintained above and below the heating curing area by steam passage. Continuous production, including heat curing, is carried out by ensuring that the insulating layer formwork, which adopts a sloped relationship, is stacked and positioned. In particular, as mentioned above, the laminated formwork in which the materials and kneaded material are tightly packed is individually tightened to achieve restraint curing, and in addition, new material is successively accommodated at one end of the laminated formwork. The above-mentioned restraint curing, in which the frame can be resupplied and connected, and the products can be taken out from the form by sequentially taking out the already cured items from the other end, is something that should be generally followed in the curing process. This eliminates the constraint that the product must be heated and cured at a temperature gradient of 15°C/hr or less (otherwise, the long-term strength of the product will be lost), and it is possible to achieve a more rapid temperature rise. It makes it possible to carry out heat curing at high temperatures, and there is almost no loss in long-term strength. Replenishing new formwork from one end and sequentially taking out cured formwork from the other end allows the advantageous operations described above to be carried out continuously and smoothly with little thermal energy loss. In explaining specific embodiments of the present invention, first, an apparatus designed to carry out a series of steps by adding the present invention to the inventions of the present inventor's earlier applications as described above. The outline of this is as shown in FIGS. 5 and 6, and a primary kneading machine 1 is installed on one side of a machine stand 50 placed on a foundation 5, and above the primary kneading machine 1. is equipped with a fine aggregate (sand, etc.) measuring machine 11 and a cement measuring machine 12, and the raw materials weighed by these measuring machines 11 and 12 are fed into the primary kneading machine 1, which is equipped with a flow meter 13. Kneading is performed under conditions in which a predetermined amount of water is added from the pipe 14. Cement weighing machine 1
Regarding 2, since Portland cement etc. are almost completely dry, normal measuring methods are sufficient, but regarding the fine aggregate weighing machine 11, it is practical that sand etc. can be obtained in an absolutely dry state. There are no
Moreover, it is clear that the amount of attached water will greatly affect the measurement results, regardless of whether the weight method or the volumetric method is used.Also, the amount of attached water will fluctuate considerably. Even if the pile is the same in a yard, there will be significant variations between the surface and inner layers (weather conditions, etc. are also taken into consideration). Therefore, in order to avoid such measurement errors, the present inventors adopted an underwater measurement method and also adopted vacuum conditions for this underwater measurement.The details of this technique are described in Patent Application No. 1977. No. 147180 (Unexamined Japanese Patent Publication No. 1983-
No. 71859: hereinafter referred to as the third prior invention), by adopting vacuum conditions for instant underwater measurement, air between fine aggregates and their structures is removed, and the air can be removed within a short time. To create underwater measurement conditions in which no residual water remains, and to facilitate the separation and discharge of water remaining in fine aggregate particles after measurement, thereby restoring the overall condition to an even and appropriate state of adhering water content within a short period of time. Furthermore, by utilizing the pressure difference between the vacuum condition and the atmospheric pressure condition, it is possible to smoothly fill and drain water into the weighing machine 12 formed in the shape of a closed tank. A connecting port 17 is formed at the top of the lid weighing machine 12 to be connected to a fine aggregate charging port 16 by a conveyor 15 like a vacuum tank, so that the inside of the weighing machine 12 can be depressurized. It's on. The primary kneader 1 is of a horizontal drum type, with a horizontal shaft 18 suspended horizontally, and by driving stirring blades disposed on the horizontal shaft 18, mixes cement and fine powder contained in the horizontal drum. Stir aggregate efficiently. An endless belt type conveyor 20 is provided between the lower part of the primary kneading machine 1 and the charging port of the secondary kneading machine 2 set in the middle part of the machine stand 50. This can be replaced by a conveying means such as a bucket conveyor, and in any case, it is an important mechanism that takes the above-mentioned kneading time in the present invention. The kneaded materials are received one after another and sent to the secondary kneader 2, and in this transfer process, a necessary kneading time is allowed for each kneaded material. The kneading time is preferably taken by stopping the conveyor 20, that is, the entire amount obtained in the primary kneader 1 is received by the conveyor 20 and stopped, and after the kneading time has elapsed, it is charged into the secondary kneader 2. This is preferable in terms of taking a constant kneading time. Furthermore, the compositional factors of the kneaded product, such as water-cement ratio and cement-sand ratio, between the pre-kneaded product in the primary kneader 1 and the subsequent kneaded product performed after discharging this pre-kneaded product do not always match; These factors cause large fluctuations in the characteristic values of injection molding performed after secondary kneading and the characteristic values of the resulting product, so it is important to accurately distinguish between the pre-kneaded product and the subsequent kneaded product. It is preferable to transport the For this reason, in the present invention, the conveyor 20 is provided with horizontal partition walls 21 as shown in FIG. 6, and the kneaded material is received between these partition walls. Separate things appropriately. Of course, separating the preceding kneaded product and the subsequent kneaded product in this way is also the reason for giving each kneaded product an accurate kneading time. In the secondary kneading machine 2, a horizontal shaft 22 is installed horizontally,
It is driven by a motor 36 as in the primary kneading machine 1, but a dispersant metering device 25, a retardant metering device 26, and a flow meter 28 are connected to the lid 24 provided on the charging port. A water injection pipe 27 having a water injection pipe 27 is disposed, respectively, for injection of the additives and supplementary water. Also, the secondary kneading machine 2
A discharge port 29 is provided at the bottom of the container, and a sieve member is appropriately incorporated into the discharge port 29 so that lumps larger than a certain size are screened out. A fluidity tester 4 for the kneaded product is installed on the side of the secondary kneader 2, and is used to appropriately test the Fo value and other properties of the kneaded product in accordance with the second prior invention as described above. The measured value is used as a factor in injection molding work as described later, and also as a factor in kneading adjustment in the secondary kneader 2. Further, the motor 36 is driven via a transmission 23, so that the specific kneading speed can be changed as appropriate. The discharge port 29 is connected to the supply port 30 of the injection mechanism 3 shown on the right side of the machine base 50 by a conduit, and a strainer 4 is connected to such a conduit.
5 and supplied as a sieved kneaded material. The injection mechanism 3 is set on a trolley 31, and is moved to a suitable position for injection into a group of molds prepacked with coarse aggregate and assembled therein. In addition, this injection mechanism is in the form of a closed tank to be suitable for injection using reduced pressure conditions as a pre-packed construction method developed by the present inventors. The injection is performed appropriately under the reduced pressure conditions. When the mechanism shown in FIGS. 5 and 6 is used, the conveyor 20 portion as described above is appropriately covered, and a heating means is suitably used, especially for the purpose of heating during the kneading process as described above. It is easy to transport the product within a cylindrical shield provided with molding, making it possible to carry out a series of processes from kneading to injection molding under at least enclosed conditions, and moreover, the injection work conditions It is clear that it is possible to properly manage and smoothly implement under rationally determined conditions, and to operate according to an accurate production control system. In the illustrated apparatus according to the present invention as described above, a substantially completely closed system is adopted, and although the upper surface of the belt conveyor in the conveyance mechanism is slightly open, there is virtually no room for dust or other particles to be generated. Therefore, it is clear that suitable concrete products can be obtained without causing pollution. It is also possible to appropriately cover the top surface of the belt conveyor mentioned above, and by appropriately heating the belt conveyor during the covered conveyance process, it is possible to reduce the amount of dispersant added and achieve preferable relative fluidity. Obtainable. The apparatus shown in Figs. 5 and 6 is designed to be applied to the prepacked method and does not have a coarse aggregate charging system in the second kneading mechanism, but the present invention is applicable to the prepacked method. 2 as mentioned above applies in cases where there is no
The next kneader 2 may be provided with a coarse aggregate charging system that also includes a weighing mechanism. Furthermore, the apparatus shown in Figs. 5 and 6 is designed to perform completely continuous operations, with the primary kneader 1 performing only the primary kneading and the secondary kneading machine 2 performing the primary kneading. Only secondary kneading is performed, and the materials and kneaded materials are transported in an orderly manner in one direction. However, the present invention is not necessarily limited to such a method; for example, if there is only one kneading machine due to equipment limitations, it may be carried out using that single kneading mechanism. It is clear that in the configuration shown in Figures 5 and 6, in order to perform both the first primary kneading and the secondary kneading with a single kneading mechanism, the conveying mechanism should be moved between the two figures. The intermediate kneaded material is formed long or wide enough to receive the kneaded material, and the intermediate kneaded material sent from the single kneading mechanism is received on the conveying mechanism and the kneading time as described above is taken, and this kneading time is While the mixture is being taken on the conveyance mechanism, the kneading mechanism performs primary kneading using the next second material, and then similarly sends it to the kneading mechanism, and after sending out the second intermediate kneaded material. After the kneading time has elapsed, the first intermediate kneaded product is charged again into the kneading mechanism and subjected to secondary kneading to obtain an adjusted kneaded product, and then the second intermediate kneaded product is subjected to secondary kneading, The second-kneaded adjusted kneaded products are each sequentially subjected to molding. In such a case, the conveying means must adopt a suitably curved conveying path; however, as the conveying means in the present invention, not only a straight belt conveyor but also a bucket conveyor may be used as appropriate. What can be used is a rigid type, and if a bucket conveyor is used, there is no need for a straight line as in a belt conveyor, and the bucket conveyor itself can feed the mixture from the discharge port at the lower stage of the kneading mechanism to the charging port located at the upper stage. By appropriately bending the rails, a curved conveyance path as described above can be formed, and for example, material discharged from the lower stage of the same kneading mechanism can be transported around the kneading mechanism. It is possible to introduce and charge the material to the charging port in the upper stage by means of a conveying path provided surrounding the side. It is preferable to appropriately change the kneading speed during the primary kneading and the secondary kneading, especially when coarse aggregate such as gravel is added during the secondary kneading when the prepacked method is not used. The load for the second kneading is higher than that for the first kneading, but in order to properly satisfy this relationship, a transmission is disposed between the motor and the kneading mechanism,
Establish preferred speed and load conditions in each case. The charging to the kneading mechanism is changed to raw materials such as cement and sand and the above-mentioned intermediate kneaded material,
Furthermore, it is clear that the present invention can be appropriately carried out with a single kneading mechanism by switching the discharge port of the kneading mechanism to the above-mentioned conveying means and forming mechanism, and the kneading mechanism is used for primary kneading. Since a prepared kneaded product cannot be obtained during the molding process, the present invention can be carried out using relatively small equipment, although the molding operation may not be completely continuous. Concrete forming according to the invention may be carried out by any method. That is, the basic characteristics of the present invention, as mentioned above, are based on the many new discoveries made by the present inventors.Compared to the conventional method, the amount of water blended is relatively small, and the kneaded product has excellent relative fluidity. The purpose of this method is to obtain initial strength within a short period of time without compromising long-term strength. The purpose of the present invention can be achieved no matter what method or equipment is used. In other words, the adjusted mixture mixed at 2 hours can be fed into formworks that are successively brought in and formed, and in some cases, it is possible to create concrete with excellent strength even when used for on-site construction. Obtainable. However, as mentioned above, the reason for achieving initial strength in a short time is to use relatively compact equipment to manufacture mass-produced concrete products using a continuous process method, which results in a significant reduction in equipment and operating costs. It goes without saying that the purpose of the present invention is to obtain the desired results, and from this point of view, it is preferable that the present invention is implemented in conjunction with a compact and mass-produced system regarding its molding mechanism. Needless to say. That is, from this point of view, a forming mechanism suitable for implementing the present invention as described above is separately shown in FIG. 7 and subsequent figures. That is, a roller conveyor 60 is set on a conveyor table 61, and a reinforcement area A is formed on one end side of the conveyor table 61, a charging area B is formed in the middle part continuously from the reinforcement area A, and a charging area B is formed on the other end side of the conveyor table 61. An injection curing area C is formed in the area. As shown in FIGS. 9 and 10, the formwork member 70 consists of a formwork part 71 and a bed part 72 which also has a bottom plate 75, and the bed part 72 is formed slightly wider than the formwork part 71. This is as shown in Fig. 7, and in the reinforcement area A, the overhead crane 8
The formwork body 70 placed on the roller conveyor 60 is equipped with reinforcing bars and the like, and the formwork body 70 is driven by a drive chain 69 using sprockets or by hydraulic pressure. It is pushed toward the other side of the roller conveyor 60 by a pusher such as a cylinder. In the charging area B, coarse aggregate is sequentially charged into the form body 70 pushed forward from a hopper 80 as shown in FIG. 8 via a belt conveyor 81 driven by a motor 66. It is clear from the illustrated relationship that coarse aggregate is sequentially supplied to the hopper 80 from a storage hopper 82 via conveyors 83 and 84. From such charging area B to injection curing area C
A cleaning wire brush 63 in the form of a roll and a release agent coating roll 64 are provided between the charging area B and the rotating members 63 and 64, respectively, which are driven by a motor 65 at a required speed. More injection curing area C
While the formwork member 70 is being transferred to
The bottom surface of the bottom plate 75 in the bed portion 72 is cleaned and a release agent is applied. That is, in this embodiment of the present invention, the above-described formwork body 70 is laminated and polymerized to cover and seal the top surface of the formwork body 71, and the bottom plate 75 is used as the surface forming surface of the resulting concrete product. For this purpose, the wire brush 63 as described above is used to clean the condensation of mortar or the like that has adhered to the surface of the bottom plate 75 in the preceding process, and the coating roll 64 is used to apply a release agent. The fact that three push-up jacks 90 are arranged around the injection curing area C is the seventh point.
As is clear from FIG. 8, a stopper 91 is disposed on the outside of these push-up jacks 90, and when each jack 90 rises, the mold filled with coarse aggregate is removed as described above. As shown in FIG. 8, the laminated formwork is raised by the height at which the frame body 70 enters, and in this state, the locking portion 9 of the stopper 91 is
2 is advanced and locked to the bed part 72, and then the jack 90 is lowered below the conveyance line of the roller conveyor 60 as shown in FIG. 70 is sent in and stacked on the preceding mold part 70. The specific structural relationship regarding the formwork body 70 as described above is as shown separately in FIGS. 9 and 10, and the formwork body 71 is formed of a member having a C-shaped cross section. However, the bed portion 72 is provided with an I-beam 73 surrounding a pet plate 72a, and a bottom plate 75 as described above is attached to the bottom of the I-beam 73. These members 72a, 73, and 75 form a hollow structure, and a perforation 77 is provided on the circumferential side of the bed portion 72.
In the above-described stacked state, the connecting rod 93 having the flange portion 92 in the middle of the upper bed portion 72
The bottom plate 75 of the bottom plate 75 and the bed plate 72a of the lower bed part 72
and each formwork body 7 as shown in Fig. 9.
It is configured to be tightened individually for each zero. In addition, such connection tightening is performed by tightening the nut 9 against the connecting rod 93.
4 is as shown in the figure, but if necessary, an intervening body 96 or the like may be interposed between the bottom plate 75 and the bed plate 72a. Sheet members 78 and 79 are arranged in double layers on the upper and lower surfaces of the C-shaped member of the formwork part 71, respectively, and the space 7 between these seal members 78 and 79 is
By connecting a depressurizing mechanism (not shown) to the mold part 6 using the connecting hole 74, the inside of the mold part 71 can be depressurized. By covering the space 76 and reducing the pressure, the pressure inside the formwork 71 is reduced through the inner seal member 78 that generally acts as a mortar seal, and the airtight seal member 79 prevents outside air from entering. However, even if outside air were to enter through this airtight sealing member 79 portion, the outside air would be immediately exhausted within the space 76 under the most depressurized condition and would not enter the formwork portion 71. . Note that I in the bet portion 72
The shaped steel 73 is appropriately provided with openings 77, and steam is introduced into the hollow bed portion 72 to heat and cure the ready-mixed concrete charged and filled into the formwork portion 71. In the fifth and sixth steps, the injection mechanism 3 injects the adjusted kneaded material as described above into the formwork portion 71 prepacked with coarse aggregate as described above. This is the same as the case shown in the figure. However, in the case of the present invention in which the formwork parts 70 are connected to each other using the connecting rods 23 as described above, the formwork parts 70 are connected and fixed one after another to each formwork part body sent in sequentially as described above. After the curing process has been completed, the mold parts can be released and removed from the upper part in sequence, and each formwork member 7 can be removed during the heating and curing process as described above.
0 can be cured under completely restrained conditions, and by performing restrained curing in this way, it is possible to exceed the conventional limit on heat curing, such as a heating rate of 15°C/hr. Even if curing is carried out by rapid heating and temperature rise, there will be no adverse effect on the concrete structure, and from this point of view as well, it is possible to achieve desirable early strength in a short period of time. Specific embodiments according to the present invention will be described below. Example 1 In the case of paste The water-cement ratio (W/C) was varied with or without adding an alkyl sulfonic acid dispersant (trade name: Mighty, manufactured by Kao Soap Co., Ltd.) as appropriate for Portland cement. After the primary kneading, the kneading time according to the present invention was set at a constant 60 minutes, and then the secondary kneading was performed to obtain an adjusted kneaded product.The mixing relationship and the kneaded properties after the secondary kneading Compressive strength after 7 days and strength after 28 days (long-term strength) of concrete molded using such adjusted kneaded material (paste)
The results of each measurement are shown in Table 1 below. Table 1 also shows the strength after 2 hours of steam heating and curing at 80°C immediately after molding at the end of the table.

[Table] Considering the results in Table 1, those with symbols 7 to 10 have 3% Mighty added, which means that the amount of dispersant added is relatively large. It is clear from the measurement results of compressive strength that when a large amount of is added, the strength of the resulting concrete tends to be inferior to other cases. In addition, as a comparative example, for the products in Table 1, the water-cement ratio was changed in the same way as in the case of this table, and the conventional method was carried out in a single step with or without adding a dispersant. For various adjusted pastes and pastes with a water-cement ratio of W/C = 42% outside the scope of the present invention, the mixing relationship, kneaded properties, and compressive strengths of concrete at 7 days and 28 days using the pastes were determined. The results are shown in Table 2 below.

【table】

[Table] That is, when comparing the results of Tables 1 and 2 as described above, the products of the present invention shown in Table 1 are generally superior in relative fluidity in kneaded properties, and Strength in concrete, especially 28 day strength 100-200Kg/cm ²
It is clear that excellent values have been obtained. Example 2 In the case of alumina cement paste W/
Regarding the alumina cement paste prepared and mixed with 32% C, one was simply kneaded according to the conventional method, and the other was kneaded for a second time after taking a kneading time of 30 minutes to 180 minutes according to the present invention. The kneaded properties are as shown in Table 3 below.
While those obtained by the conventional method are almost unmeasurable, those obtained by the present invention show the measured values as shown in Table 3, and both exhibit excellent relative fluidity. In addition, the strength of concrete products made from this paste is also superior to that of the present invention (symbols 2 to 6) than the conventional method (symbol 1).

[Table] Example 3 Specific mixing relationship and after primary kneading for mortar adjusted with a constant W/C of 32% using Portland cement and silica sand with a diameter of 0.15 mm or less
The kneaded properties of the prepared mixed product obtained by secondary kneading after a 60-minute mixing time are shown in Table 4 below, and the 7-day strength and 28 The results of measuring the post-strength strength are also shown in the compressive strength column of Table 4. Also, materials 13, 14 and 15
Cases 1 to 12 are cases of the conventional kneading method without pre-kneading, and show that the present inventions 1 to 12 are effective in improving short-term and long-term compressive strength. In addition, in Mio, these concretes were heated at 80℃ for 2 hours.
With regard to the strength upon demolding when steam-cured for a period of time, it cannot be expected that the strength will be developed within 2 hours for products that are not based on the present invention.

【table】

[Table] Example 4 Using river sand along with the same Portland cement and silica sand as shown in Example 3, W/C was 36
%, 40%, and 43%, and the kneaded properties of the adjusted kneaded product obtained by second kneading with a mixing time of 30 minutes after the first kneading are shown in Table 5 below. The results of measuring the strength after 7 days and 28 days of the concrete obtained by molding such a prepared mixture are as shown in the column 5.
As shown in the compressive strength column on the right side of the table. The strength of the concrete after being steam-cured for 2 hours at a temperature of 80°C is as shown in Table 5. That's pretty low.

【table】

[Table] Example 5 Some examples of mortar formulations prepared using Portland cement, river sand, and a dispersant (Mighty) are shown in Table 6 below, and these mortars 1 to 7 were prepared according to the present invention. Secondary kneading with a mixing time of 60 to 120 minutes (Mortar 1
The properties at the time of kneading of the conventional methods (mortars 6 and 7) that do not require such kneading time and secondary kneading are as shown in Table 6, and the kneading time of the present invention is as shown in Table 6. All of the products obtained by secondary kneading are excellent in relative fluidity. Table 6 also shows the 28-day strength of concrete made by prepackaging such mortar with No. 4 crushed stone and injecting it.
It was confirmed that it had an excellent strength of about 60 to 180 kg/cm ² . In addition, in the case of the present invention, the amount of breathing is 0, and that of the conventional method (mortar 6,
7), and therefore the strength of the pre-pad concrete injected with this mortar is improved and shows a higher value than in cases 6 and 7. This is considered to be because the adhesion between the poured mortar and crushed stone was improved due to less breathing.

【table】

[Table] Example 6 A mortar prepared using portland cement, river sand, and a dispersant was prepacked with No. 4 crushed stone and poured under reduced pressure. Specific mixing examples for some of the concrete are shown in Table 7 below. and
The kneading time (subsequent secondary kneading) and heat curing temperature for the molded product are as follows. 1; Kneading for 120 minutes, 80°C 2; Kneading for 60 minutes, 80°C 3; Same as above 4; Kneading for 70 minutes, 80°C 5; Kneading for 60 minutes, 80°C 6; No kneading, 80°C 7; Kneading No storage, 60°C That is, Documents 1 to 5 are according to the present invention,
6 and 7 are comparative examples, and the initial strength of the products cured in this way (for materials 1 to 5, 1 hour, 1.5
After 28 days of heat curing and standard curing in high humidity air, warm water - air and water The respective intensities are as shown in Table 7. Regarding these strengths, measurement point 1 is the measurement value at one end of the concrete product, measurement point 2 is at the center, measurement point 3 is at the other end, and AV is the average value. In the case of the concrete shown in Documents 6 and 7, the compressive strength after 28 days of heat curing was approximately 2% lower than that of the standard cured concrete, whereas the concrete of Documents 1 to 5 according to the present invention In the case of concrete, it is also clear that there is no difference in the long-term strength of heat-cured and standard-cured concrete.

【table】

[Table] In other words, according to the results in Table 7, it is clear that the products according to the present invention have a strength (generally 100 kg/cm ² or more) that can be demolded in about 1.5 hours in all cases. (In the case of Document 4, it was not measured at 1.5 hours, but the fact that it obtained more than 200 kg/cm ² in 2 hours indicates that the strength for demolding was reached sufficiently in 1.5 hours.) (It is clear by referring to the measurement results in Item 5, etc.), and with conventional products that do not perform kneading time or secondary kneading, demolding strength cannot be obtained until more than 3 hours have elapsed (in Document 7, demolding strength is not obtained after 4 hours). (If you don't have it, you can't demold it.) Also, it is clear that the products of the present invention show far higher results than the comparative examples in terms of 28-day strength. Example 7 Using the equipment shown in Figures 5 and 6 of the attached drawings, mortar was prepared according to the formulation shown in Table 8 below, and the mixing time was as shown in the kneading method column. The mortar shown in the kneaded performance column was injected into a mold filled with 1394 kg/ ^m3 of crushed stone, and the 28-day strength and mortar with the same composition were obtained. The 28-day strength of the comparative examples obtained by injection molding immediately after kneading is as shown in the strength column of Table 8. That is, it was confirmed that all of the products produced by the method of the present invention had higher long-term strength than those of the comparative examples.

[Table] Example 8 Portland cement and river sand (less than 5 mm) were mixed for the first time using a dispersant, then kneaded for 30 or 60 minutes, and then river gravel of less than 20 mm was added for second kneading. Ready-mixed concrete was prepared using the same formulation as in the case of the present invention using ready-mixed concrete, in which these materials were simply kneaded at once. That is, the formulation relationships in this case are as shown in Table 9 below.

[Table] However, the W/ of each fresh concrete as above
The results of measuring C, dispersant %, slump value, temperature conditions, as well as the finished state and strength after 7 days and 28 days of concrete formed using this ready-mixed concrete are as shown in Table 10 below.

【table】

[Table] In Table 10, "primary finishing" means that finishing can be performed with a metal trowel, and "finishing possible" means the final surface finish. That is, according to the method of the present invention, even if the fresh concrete has the same water-cement ratio (W/C), the finished state is extremely good, there is no breathing, and it can be finished within a short time, and moreover, it has a 7-day strength. Around 100Kg/ ^cm2 , 150 in 28 day strength
It was confirmed that it exhibited an excellent value of Kg/cm ² or more. In addition, the compressive strength immediately after steam curing at 80°C for 3 hours in this case is as shown at the end of Table 10, and the concrete of samples 2 and 3 of the present invention has excellent initial strength as well. It was known that Example 9 Using the same raw materials as in Example 8 using the apparatus shown in Fig. 9, the kneading time was 40 minutes.
It was operated by injecting the adjusted kneaded material. The operation is carried out with an average feeding interval of 15 minutes for new formwork parts 70 that are sequentially fed into the laminated formwork parts,
The heat curing time for the laminated formwork body group was set to 2 hours, so generally 8 to 9 formwork bodies 70 were stacked as a laminated formwork body. Naturally, the time interval at which the cured product is taken out from above the laminated formwork group is every 15 minutes, and four concrete products are obtained every hour. The standard temperature for heating and curing by sending steam into the bed was 80°C. Concrete products obtained through such a production process
The result of measuring the strength after 28 days is 600-635
Kg/cm ² and was confirmed to have favorable long-term strength. According to the present invention as explained above, long-term strength can be sufficiently increased by utilizing the new fact confirmed regarding quantitative changes in relative fluidity when water is added to powder of a hydraulic material such as cement. It maintains high strength and enables early demolding within a short time of around 2 hours or less, and enables smooth injection molding under pre-packed conditions such as coarse aggregate, resulting in high strength and high quality. It is possible to obtain concrete products appropriately, and furthermore, it provides compact production equipment and is movable without requiring vast sites and equipment, especially stable production equipment such as water flotation equipment. This invention has many excellent effects such as making mass production possible, and is a highly effective invention industrially.

[Brief explanation of the drawing]

The drawings show the embodiments and technical contents of the present invention, and Fig. 1 is a chart showing the relationship between the passage of time and flow characteristics after water injection and kneading of cement paste, and Fig. 2 shows the relationship between the flow characteristics and the passage of time after water injection and kneading of cement paste. A chart showing the 4-week strength of concrete formed by secondary mixing with various mixing times,
Figure 3 is a chart showing the state of hydration heat generation over time for various cements, Figure 4 is a chart showing the hydration heat generation state of cements with dispersant added, and Figure 5 is a chart showing the state of hydration heat generation over time for various cements. FIG. 6 is a side view showing an example of the device according to the invention, FIG. 6 is a plan view thereof, FIG. 7 is a plan view showing an example of the forming mechanism, FIG. 8 is a side view thereof, and FIG. Partial sectional view showing connection and tightening and sealing relationships between formwork parts, No. 10
The figure is a similar partial sectional view showing its released state. However, in these drawings, 1 is a primary kneader,
2 is a secondary kneading machine, 3 is an injection mechanism, 4 is a fluidity tester, 11 is a fine aggregate measuring machine, 12 is a cement measuring machine, 13 is a flow meter, 20 is a conveyor that measures the mixing time, and 60 is a roller 70 is a formwork body, 71 is a formwork part, 72 is a bed part, 75 is a bottom plate, A is a reinforcement area, B is a charging area, and C is an injection curing area.

Claims (1)

[Scope of Claims] 1. An intermediate kneaded product obtained by adding water to cement or other hydraulic substance powder and first kneading the mixture to form tobermolite crystals as the hydraulic substance powder particles swell,
In addition, the kneading time is long enough to prevent the crystals from becoming entangled, and then the second kneading is carried out, and in this second kneading, the amount of water is adjusted so that the amount of breathing is substantially zero. 1. A method for producing concrete, characterized in that the prepared mixture is molded and hardened. 2. Intermediate kneading that has undergone primary kneading using a kneading mechanism and a conveying means connected at one end to the kneading mechanism to convey the kneaded material and to charge the kneaded material back into the kneading mechanism from the other end. The concrete according to claim 1, wherein the concrete is left on the conveying means for a required mixing time and then sequentially charged into the kneading mechanism again to obtain a second mixed mixed product. Manufacturing method. 3 Using a plurality of kneading mechanisms and a conveying means for conveying the kneaded material between these kneading mechanisms, water is added to cement or other hydraulic substance powder, and the first kneading mechanism
After the next kneading, the mixture is transferred to a conveying mechanism, and the required kneading time is taken on the conveying mechanism. 2. The method for producing concrete according to claim 1, wherein a prepared kneaded product is molded and hardened. 4. A patent claim that takes the kneading time of an intermediate kneaded material that has been mixed with water for the first time for 20 minutes or more until just before the state of generation of hydration reaction heat in the intermediate kneaded material increases in the steepest curve. The manufacturing method of concrete as described in item 1 of the scope of the above. 5 When taking the mixing time after the first kneading, keep the kneaded material at 35°C or higher within the upper limit temperature range that does not substantially generate crystals harmful to the development of concrete strength such as dicalcium alpha hydrate or aphelite. Claim 1 of heating within
The method of manufacturing concrete described in Section. 6. Water is added to cement or other hydraulic substance powder, fine aggregate such as sand, and powdered or fibrous auxiliary materials such as fly ash, water slag, other slag powder, and gypsum powder, and the mixture is mixed for the first time. A method for producing concrete according to claim 1. 7. Dispersant (or water reducing agent) during secondary kneading,
The method for producing concrete according to claim 1, wherein one or more penetrants are added. 8 Regarding one or more types of dispersant (or water reducing agent) and penetrant to be added, less than half of the amount thereof is added during the first kneading, and the remaining majority amount is added during the second kneading. A method for producing concrete according to claim 7, wherein a mixed product is obtained by preparing a mixed product. 9 During the first kneading, add most of the amount of water that should give the kneaded material fluidity higher than the capillary range and bring the amount of breathing to substantially zero, and during the second kneading. The method for producing concrete according to claim 1, wherein the remaining water is added to prepare a mixed mixture. 10 Using a plurality of kneading mechanisms and a conveyance means for conveying the kneaded material between these kneading mechanisms, only cement or other hydraulic substance powder including alumina cement, or sand or powdery auxiliary material is added to the hydraulic substance powder. Transferring the intermediate kneaded material obtained by adding water to the blended material and performing primary kneading in a first kneading mechanism to a conveyance mechanism, and generating tobermolite crystals along with swelling of the hydraulic substance powder particles on the conveyance mechanism; Moreover, the mixing time is long enough to prevent the crystals from intertwining, and then the second mixture is mixed with either or both of coarse aggregate containing fire-resistant coarse aggregate such as gravel or fine aggregate such as sand. The mixture is charged into a kneading mechanism, and a second kneading is performed under water amount mixing conditions adjusted so that the amount of breathing of the kneaded product obtained in this second kneading mechanism is substantially zero, and after this second kneading, A method for producing concrete characterized by molding and hardening a prepared mixture. 11 Using a plurality of kneading mechanisms and a conveying means for conveying the kneaded material between these kneading mechanisms, water is added to powder of cement or other hydraulic substance containing alumina cement, and primary kneading is performed in the first kneading mechanism. Transfer the intermediate kneaded material to a conveying mechanism, ensure relative fluidity on the conveying mechanism, generate tobermolite crystals as the hydraulic substance powder particles swell, and knead to such an extent that the crystals do not become entangled. After a period of time, the mixture is charged into the second kneading mechanism, and subjected to a second kneading process under water amount mixing conditions adjusted so that the amount of breathing of the kneaded product obtained in the second kneading mechanism is substantially zero. A method for producing concrete, characterized in that the adjusted kneaded product after the second kneading is introduced into a prepacked injection molding area containing fire-resistant coarse aggregate, and is molded and hardened. 12 Claim 10 or 1, in which a retarder is added in the secondary kneading together with a water reducing agent to adjust the hydration reaction in response to the progress conditions of the working process.
A method for producing concrete according to any one of paragraph 1. 13 During the second kneading, measure the relative fluidity of the kneaded product, and adjust the amount of water added, dispersant (or water reducing agent), and penetrant (or accelerator) to obtain the specified relative fluidity. A method for producing concrete according to claim 11. 14 During the secondary kneading, the maximum temperature of the kneaded material is heated within a limit that does not substantially generate crystals harmful to the strength development of concrete, such as dicalcium alpha hydrate or aphrite, and under such temperature conditions. The production of concrete according to any one of claims 10 or 11, wherein the mixing time is adjusted to coincide with the time just before the heat of hydration rises in the steepest curve. Law. 15. The method for producing concrete according to claim 11, wherein the secondary kneaded mixture is injected into a prepacked molding area of coarse aggregate under closed conditions and under reduced pressure. 16 A kneading mechanism having a cement or other hydraulic material powder charging system and a water addition system, one end of which is connected to the discharge part of the kneading mechanism, and the intermediate kneaded material that has been primarily kneaded by this kneading mechanism is mixed with the above-mentioned A conveying means is provided that generates tobermolite crystals as the hydraulic material powder particles swell, and that allows the kneading time to be long enough to prevent the crystals from becoming entangled, and the other end of the conveying means is connected to the charging mechanism of the kneading mechanism. 1. An apparatus for manufacturing concrete, characterized in that the discharge section of the kneading mechanism is provided with an introduction means for sending the adjusted kneaded material after the second kneading to the forming mechanism. 17 A first kneading mechanism equipped with a cement or other hydraulic substance powder charging system and a water addition system, and a second kneading mechanism with one end connected to the discharge part of the first kneading mechanism and the other end provided separately. A conveying means is provided which generates tobermolite crystals as the hydraulic substance powder particles swell and which takes a kneading time long enough to prevent the crystals from becoming entangled, and the second kneading mechanism A concrete manufacturing apparatus is provided with an introduction means for introducing the adjusted mixture into a forming mechanism. 18. According to claim 17, the first kneading mechanism is provided with a fine aggregate charging system, and the fine aggregate charging system is further provided with a fine aggregate measuring mechanism according to an underwater measuring method. concrete manufacturing equipment. 19. The concrete manufacturing apparatus according to claim 16 or 17, wherein the second kneading mechanism is provided with a coarse aggregate charging system. 20. The concrete manufacturing apparatus according to claim 16 or 17, wherein the second kneading mechanism is provided with a relative fluidity measuring mechanism. 21. The concrete manufacturing apparatus according to claim 16 or 17, wherein a strainer is provided in a conduit connecting the second kneading mechanism and the forming section. 22. The method according to claim 16 or 21, wherein the entire process from the first kneading mechanism to the molding section via the second kneading mechanism is formed under a substantially closed system. Concrete manufacturing equipment. 23 A first kneading mechanism equipped with a cement or other hydraulic substance powder charging system and a water addition system, and a second kneading mechanism with one end connected to the discharge part of the first kneading mechanism and the other end provided separately. A conveying means, the second kneading mechanism, and a mold, which generate tobermolite crystals as the hydraulic substance powder particles swell, and which have a kneading time that is long enough to prevent the crystals from becoming entangled. The forming mechanism has a forming mechanism in which frames are arranged in a layered manner, the second kneading mechanism is provided with an introduction means for introducing the adjusted kneaded product into the forming mechanism, and the forming mechanism has frames arranged in a layered manner as described above. Concrete manufacturing equipment equipped with a means of transporting formed formwork as is. 24. The concrete manufacturing apparatus according to claim 23, wherein a space for passing a heating medium such as steam is formed between each formwork arranged in a stacked manner.