JPH072329B2 - Method for producing mortar or concrete - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is mainly used when kneading water, fine aggregate or mortar or concrete obtained by kneading fine aggregate and fine aggregate and coarse aggregate with powder of hydraulic substance such as cement and gypsum. The present invention relates to the production of the mortar or concrete by adjusting the water content on the surface of the fine aggregate which is a constituent material. That is, more specifically, the present inventors have found that the cement, powder of fine aggregate, etc., at the interface of the granules, there is a specific amount of surface adsorbed water bound to the surface, which is mortar or It was newly found that it has a great influence on physical properties such as breathing and strength of concrete. Further, the inventors of the present invention have made it possible to quantify and measure water in a specific water-containing state, such as surface-adsorbed water, which is bound to the surface of various fine aggregates, by the newly invented method. Further, in the present invention, by utilizing this, under the conditions according to the purpose, the water content of the fine aggregate is determined and adjusted to be optimal, and the characteristics peculiar to each fine aggregate are used to the maximum extent. In particular, in the case of the split kneading method in which the compounding water is dividedly added (twice) and kneaded, the optimum primary water amount is determined by the above method, and the primary water is mixed with the fine aggregate, cement, etc. An object of the present invention is to provide a method for producing mortar or concrete in which high quality and stable quality can be obtained by kneading and then adding materials such as secondary water according to the purpose and performing secondary kneading.

Fine aggregate (and one or more kinds of coarse aggregate, fiber material or other auxiliaries or additives) and compounded water are added to hydraulic material powder such as cement and mixed to form mortar or concrete. It has been widely practiced conventionally to adjust such a raw kneaded product, but the properties of the thus-prepared raw kneaded product such as separation breathing property or flow moldability may have some variations. As is well known. In particular, in the case of the kneading (divisional kneading) method using primary and secondary water developed by the present inventors, it is possible to divide the amount of water required for kneading and determine an appropriate primary water amount (or secondary water amount). It is necessary, and depending on how such changes are made, the characteristics greatly influence, and even if the blending water amount is the same, breathing and fluidity vary greatly. In addition, according to the results of the inventors' study of various sands, the sands with different primary water amounts (or secondary water amounts) that have favorable fluidization or separation breathing characteristics can be obtained. However, when it is carried out, the properties of these materials fluctuate considerably and it is difficult to obtain a stable kneaded product.
That is, regardless of the water content in this seed sand, the surface water ratio is based on the surface dry condition based on the surface properties of the sand (specifically, the kind) in adjusting the kneaded product as described above. It does not always show uniform behavior, and therefore, in the actual kneading adjustment, its characteristics must be changed depending on the sand used.

By the way, regarding such fine aggregate, JIS A1109 "specific gravity and water absorption test method of fine aggregate" is defined, that is, the top surface inner diameter 38mm placed on the table, the bottom surface inner diameter 89mm, height 74
The thickness of the sample is 4 mm or more and the thickness is 4 mm or more. A sample is struck and filled 25 times with a stick (weight 340 ± 15 g, diameter 25 ± 5 mm) in a metal flow cone, and when the flow cone is pulled up, the fine aggregate slumps for the first time. When the surface is dry and saturated (Saturated
surfa-ce-dry condition), and the fine aggregate-containing water in this state is such that the voids inside the fine aggregate are filled with water (saturated water) and the surface is in a dry state without water. In this state, moisture is not exchanged between the aggregate and the cement paste in the concrete. Therefore, in the preparation of the raw kneaded product as described above, the moisture content obtained by the above test is used as the ineffective water content of the fine aggregate itself, and the water content of such fine aggregate is mixed. The reference values are those that are not involved and are excluded when determining the formulation water. However, such JIS
According to the results of repeated examinations for measuring and adjusting various fine aggregates according to the regulations and adjusting the kneaded product using the fine aggregates, the surface dry saturated state according to the JIS regulations as described above (below It is unreasonable to consider that the effective water and the ineffective water (that is, whether or not the properties of the kneaded material are changed in adjusting the kneaded material) are considered to be at least the above-mentioned by the JIS surface dry state). It was concluded that the specific characteristics of the sand could not be elucidated.

Explaining the situation during this period, the inventors of the present invention have selected C sand (JIS surface dry state is 2.8%), E sand (JIS surface dry state is 1.3%), and crushed sand (JIS surface dry state is 2.3%) from Oigawa. Using various sands with different JIS surface dry conditions, these sands were each lowered by 730mmHg from atmospheric pressure so as not to leave air content on the surface of the sand grains using a vacuum mixer (below -730mm
(Hg) under reduced pressure and water was added and mixed under this reduced pressure condition to prepare samples with a predetermined water content, and these samples were placed in a container made of acrylic synthetic resin with a certain accuracy. After being filled in the same state and moved up and down 15 times on the flow test table and compacted, the weight was measured, and the water content and porosity (in the absolute dry state) were obtained, and the results of these measurements are summarized. The water content in JIS dry state for these fine aggregates is also shown in Fig. 1.

According to FIG. 1, the variation of the bulking (porosity) is shown due to the variation of the water content in each fine aggregate as described above even under the JIS surface dry condition described above, and more than that. It is clearer than the case. In addition to this, the effect of the particle size due to the change in water absorption rate for the fine aggregate screened separately or the result according to this was also confirmed by the centrifugal force test, and in any case, the JIS surface dry state (Q Even when the amount of water is measured as), a certain amount of water adheres to the sand surface, and it can be said that the above-described change in bulking occurs due to the change in the amount of adhered water. That is
The water content in the JIS surface dry state (Q) does not mean that the sand surface is in a dry state because it is simply impregnated into the tissue, but it has water (βlim) attached to the sand surface in a low limit state. It can be said that the water content and the water content contained in the tissue in a saturated state, that is, the internal saturation rate (Q ₀ )
The water absorption rate Q in the surface dry condition should be Q = Q ₀ + βlim. Therefore, if the moisture content in JIS surface dry condition Q is not analyzed and considered in this way, it corresponds to the actual condition for fine aggregate such as sand. It cannot be clarified.

However, regarding the above JIS surface dry state Q, it is needless to say that it can be obtained in accordance with JIS regulations, but in order to obtain the Q value in accordance with this JIS regulations, for example, after subjecting to water immersion treatment for 24 hours, water reduction is repeated. Therefore, it takes a certain amount of time to obtain the desired state. However, such a Q value can be appropriately determined by a treatment within a short period of time, and for example, the present inventors can add and mix an appropriate amount of water to decompressed sand under reduced pressure, and then Once the atmospheric pressure is restored and then the pressure is reduced again, the same amount of water is added to the dry sand and the mixture is mixed for an appropriate time at atmospheric pressure for a relatively short time (10 minutes). Q)
It has succeeded in obtaining a value corresponding to the value, and in the present invention, such a value can be adopted as the value Q'according to the Q value. That is, although this value Q'may take a value that is slightly different from the JIS surface dry state Q value, the Q value itself may also be in accordance with the JIS regulations, whether it is a water treatment or a drying treatment operation. There is room for error intervention in the determination of whether the filling operation is performed by the stick with respect to, or whether collapse has occurred, and it is sufficient if at least the Q or Q'value obtained by the same method is used. It can be said that the measures can be trusted.

In addition, a little explanation of the definition of terms in the present invention will be given. In the prior art including JIS, the sand is considered to be the same with respect to at least the determination of the compounding water, and accordingly, it is grasped as a uniform amount of water as described above. However, in the present invention, a raw kneaded material such as cement paste, mortar or ready-mixed concrete is used. Regarding that, the water on the surface of the fine aggregate such as sand attaches importance to the influence on other compounds, and attaches or adsorbs to the fine aggregate is emphasized and grasped as adsorbed water or attached water as described above. To do. However, also in the present invention, regarding the amount of water in the same state or meaning as in the JIS regulation described above, it is of course expressed as water absorption, water content or surface water as in the conventional case, such as the adsorption or attachment. The term has a meaning in consideration of whether it affects or changes the paste content.

By the way, regarding the JIS surface dry state Q as described above, even if it can be analytically understood as Q ₀ and β lim as described above, only one value is obtained as a result of this test or measurement. The Q ₀ value and β
Naturally, it is not possible to obtain any of the lim values. Moreover, the inventors of the present invention described the above regarding the fine aggregate as described above.
Apart from Q ₀ and βlim, there is something that should be called the maximum surface adsorbed water ratio βmax as a concept different from the βlim, and that the existence of the same amount of added water is obtained when a kneaded product is obtained using sand adjusted as βlim. As a result, it has been confirmed from the results of various field studies that the properties of the kneaded material change considerably depending on the amount of sand added, that is, such βmax is the maximum that can be stably adsorbed on the sand grain surface. With each water, each sand grain can not bind the water beyond this limit, that is, if the water is less than βmax, it is bound to the sand grain peripheral surface until it reaches βmax, and the water exceeding βmax is released from the sand grain surface into the kneaded product. It can be said that βmax is the amount of water (rate) at which water is not transferred between the cement paste and the sand grains when adjusted as an actual kneaded product. The above-mentioned Q ₀ (JIS surface dry condition Q minus βlim) is exactly the amount of water contained in the sand structure.

Therefore, the inventors of the present invention have made repeated studies on obtaining data that can clarify these relationships, but under the conditions required for speed and mass productivity as in today's JIS A1109
Therefore, even if it is possible to measure βmax and βlim accurately if it is left alone, there is no industrial value, and if it takes a long time, water vapor diffusion is inevitable during that time. Therefore, the accuracy of the measurement result cannot be obtained. Therefore, it is indispensable to obtain the measurement result within a reasonably short time by using the forcing force, and as such forcing force, wind force, impact force, etc. are considered, and thermal energy etc. are considered. Can be adopted. However, in the case of using wind force or impact force, even if the amount of sample to be measured is relatively small as a typical sample, the equipment becomes large and the operating energy becomes large and it is necessary to work hard to prevent the dissipation of water. . In the case of heat energy, of course, it is costly and economically disadvantageous. Therefore, the present inventors use a centrifugal force as a method without these disadvantages, particularly as a method capable of accurately obtaining a measurement result under preferable control conditions even for a large number of samples, and efficiently using a compact facility. We devised a method for separating and measuring water such as sand. That is, the details of the water separation test apparatus for fine aggregates designed and used by the present inventors to realize the measurement method for such purpose are shown in FIG.
Between the first cylinder with a height of 10 cm and the second cylinder 10 having a height of 5 mm and having the acrylic plate 11 attached to one end of 0, the wire mesh 12 and the filter paper 13 and the thickness of the metal wire 12 having a diameter of 0.15 mm are provided. 200g of sample fine aggregate is placed in the 1st cylinder with 1.6mm punched iron plate 14
The one that is filled with the second cylinder 10 and that is filled with the absorbent cotton 16 is made to face each other as shown in FIG. 3 and the vinyl tape 15 is adhered to the peripheral surface of the facing joint portion so as to be integrated and sealed. As shown in FIG. 4, a rotary plate 22 in a case 20 provided with a lid 21 accommodates a half or more of the rotary plate 22 in a receiver 24 tiltably provided with a shaft 25.
By rotating 22 a predetermined centrifugal force is applied, the separated and discharged water from the first cylinder is absorbed by the absorbent cotton 16 of the second cylinder, and is rotated for the test. The water absorbed by the absorbent cotton 16 is prevented from flowing backward when the rotation of the plate 22 is stopped.

Incidentally, as described above, sealing the pipe body 10, 10 with a vinyl tape 15 is a key point in determining the critical surface adsorbed water rate βlim and the surface dry saturated state as described above in the present invention. When a centrifugal force is applied by simply using a container with a lid and a test material charged, the air inside the container is released to the outside under the centrifugal force operating condition, and the inside of the container is generally depressurized and The conversion flow of air between the inside and outside of the container is repeated, and moisture is also diffused and discharged by such a conversion flow of air between the inside and outside of the container. Will be increased. Appropriately prevent the dispersal of water due to such flow conversion of air to exert centrifugal force,
It is necessary to obtain the measurement result, and therefore it can be said that the formation of the sealed state is important.

However, with the device as described above, as an example, Eigawa E
JIS A11 for sand (FM = 3.23, porosity ε = 33.8%)
The Q value measured by 09 is 1.39%, but the amount of attached water was set to -730 mmHg from atmospheric pressure for the absolutely dried state once dried at 110 ° C for 24 hours (hereinafter simply referred to as -730mmHg In the vacuum mixer, we prepared the ones with various water contents changed in the range of 1Q to 10Q and attached them, and the centrifugal force of 453g (g weighted acceleration) over 120 minutes. Such centrifugal force conditions and processing time can be changed as appropriate, but in the case of specific measurement, the same is applied to all samples), and the results of water separation treatment are summarized to summarize the results on the horizontal axis (processing time). Is the fifth on a logarithmic scale
As shown in the figure.

That is, according to the results shown in FIG. 5, those having a water content of at least 4Q or less have an orderly decrease in water content in proportion to the centrifugal action time, and those having a water content of 1Q show almost no decrease in water content.
On the other hand, in the case of 6Q or more, it rapidly declines within the first 5 minutes, but thereafter it decreases slowly, and after at least 5 minutes, there is almost no difference from the water content lowering state in 4Q or less. The behavior of decreasing the water content is shown. In other words, there is an inflection point at a water content of about 5% in the horizontal logarithmic graph of 6Q or more, and it was easy to separate until such an inflection point was observed, but it was difficult to separate after that. Therefore, the state of such an inflection point is judged to be a state in which water is maximally restrained on the aggregate surface, and it is recognized as the maximum surface adsorbed water rate βmax. It should be noted that such a phenomenon is almost the same in any other sand, although the specific numerical values are different.
Apart from the one in Fig. 5, FM = 3.01 and porosity ε = 33.0.
% Sagami River sand has a Q value according to JIS A1109 of 3.12% and the fifth
Although it is considerably higher than in the case of the figure, it is as shown in FIG. 6 that the results of exactly the same test measurement are summarized in the same manner. That is, in the case of this Sagami River sand, the water content in the logarithmic graph along the horizontal axis as shown in FIG. 5 decreases substantially linearly up to 3Q, while at 4Q and above, there is a clear change at the position where the centrifugal force action time is 5 minutes. Bends are recognized and show an intermediate inflection pattern in 3Q, and in this case, it is recognized that the above-mentioned βmax exists around 3Q.

In addition, the results of the same centrifugal force separation test performed on each of the above-mentioned fine aggregates and other representative five kinds of fine aggregates whose initial water contents are adjusted to be around 1Q respectively are also shown. As shown in Fig. 7, even if some fluctuations were observed, the water content contained around 1Q was 1.4-
It was confirmed that all the fine aggregates remained almost unchanged regardless of the length of the separation treatment, even if they differed considerably by 3.7% .These results indicate that the test results according to JIS A1109 are hydrous. It can be said that the rate is stable. However, the fact that the amount of water that affects breathing, fluidity, etc. in an actual kneaded product is such a Q value or more is that even if it is 4Q or less or 5Q or less in FIGS. It is clear from the fact that the water content does not decrease, and it is considered from the results of FIGS. 5 and 6 that the breathing and the fluidity (workability) are affected by exceeding the maximum surface adsorbed water rate βmax.

In addition, in the test measurement as described above, the addition of attached water under the reduced pressure condition as described above is a key point in measuring in a short time, and it is necessary to add water to the fine aggregate. At this time, if the pressure is reduced to -730 mmHg, the air adhering to the surface of the fine aggregate can be effectively removed, and when water is added and mixed in this state, the added water causes the fine aggregate to become a tissue. The water is effectively permeated inside and the attached water becomes stable and constant. On the other hand, in the case of simply mixing with water in the atmosphere, the attached water is likely to be unevenly distributed on the surface of the fine aggregate, and therefore the measurement results fluctuate due to instability. For example, the Oigawa E sand that has been completely dried is hydrolyzed in a vacuum mixer under the above-mentioned reduced pressure condition, and the water that has been mixed and hydrated in the atmosphere is subjected to the centrifugal separation treatment. Even if the treatment time is the same, the measurement result changes, and the water-mixed product in the air has a low water content and a considerable variation. The one that adopted the reduced pressure condition was almost stable and had almost no fluctuation even in the result of the repeated test.
The same result was confirmed in any case such as the Sagami River sand, slag sand, or standard sand. Therefore, it is accurate that water is mixed under reduced pressure to have a predetermined Q value. It is indispensable for obtaining measurement results, and at least the history of encounter with water in fine aggregate must be constant.

Further, the results of examining various fine aggregates for centrifugal separation as described above will be explained.
For each type of fine aggregates, we prepared representative ones with water content equivalent to 3Q, and these fine aggregates were subjected to the same gravitational acceleration of 453g as in the case of the E sand produced by Oigawa in Fig. 5 above. The results of the centrifugal separation treatment are also shown in the lower part of Table 1 in relation to the elapsed treatment time.

In addition, it is a logarithmic scale up to 90 minutes like this, but Fig. 9 shows a graph with a large horizontal axis interval to clarify the change between 90 minutes and 120 minutes. The value taken at the position of 0 min on the horizontal axis is the value corresponding to 3Q in each fine aggregate, and this will reduce the water content in each treatment time, but Sagami River sand ( Except for X ... X) and sand from North America (▲ …… ▲), the decrease in water content due to the treatment action is in a roughly parallel relationship, and in all cases, 120 minutes treatment is about twice the JIS surface dry condition Q. The water content is considered to be almost unaffected by the influence of the coarse grain ratio FM and the porosity ε shown in Table 1.

However, it is clear from FIG. 10 that the results as described above are arranged by using the Q factor, and it is clear that a linear correlation with the Q value is recognized.
The first is 30 minutes, 60 minutes and 120 minutes.
It becomes like Fig. 1 (a) to (c). That is, the linear relationship gradient between the water content (SW) after the action of centrifugal force and the Q value of the fine aggregate is 30 minutes.
2.5 and 60 minutes are 2.3 and 120 minutes are 2.0, which are almost orderly, and become smaller as the processing time becomes longer, but almost all of the measurement points are orderly on the chart SW = 2.5Q, 2.3Q and 2.0 It is located on the straight line of Q. However, considering the Sagami River sand and the North American sand that deviate from the straight line of Q = 2.5 or 2.3 or 2.0 in the above chart, the reason why the value deviated from the reference line is It is recognized that this is due to the internal water saturation rate (Q ₀ ) in the aggregate, that is, the relationship deviating from the reference line is approximately the same even when centrifugal force separation treatment is performed for at least 30 minutes or more. As shown in Fig. (A), the Sagami River sand has a Q ₀ about 0.55% higher than the reference line, and the value of Q ₀ is about 0.5% higher in North American sand as well. Therefore, in order to shorten the time required for the test measurement and to obtain a preferable βmax (or Q ₀ ) value, it is generally about 5 minutes in the case of the treatment under the centrifugal force condition as described above. It takes about 30 minutes for North American sand and Sagamigawa sand, and the difference from the reference line is almost the same even after 120 minutes of treatment, so it is practical to set it for about 5 to 30 minutes.

By the way, considering the relationship between βmax and βlim mentioned above, it is clear that water attached to the surface of the sand grains is presumed to have the same attachment force or surface tension. The amount of hydrated water can be understood as the thickness of the water film adhering to the sand surface, and it is physically difficult to make the adhering water amount (thickness) below the minimum, and the βlim is recognized. Water can be easily attached until the thickness of the water film reaches a certain value, but it is difficult to attach water beyond the certain thickness, and even if it is attached, it can be easily separated and separated. From that point, the above βmax exists. In addition, it can be considered that the specific values of the thickness (quantity) of βlim and the thickness of βmax are those obtained by taking a thickness which is several times larger than βlim. That is, when this magnification is A, the JIS
The surface dry condition Q is Q = βlim + Q ₀ , Aβlim = A (Q−Q ₀ ) ... I, and sand containing water of 5Q or more was treated by the centrifugal force utilization as described above. The measured value β, which is the water content at the point where the inflection of the water content lowering state, which is sometimes dehydrated proportionally with time over a specific and relatively short time, appears
z can be expressed as the following formula II.

βz = Aβlim + Q ₀ …… II By substituting the above equation I into this equation II and rearranging it, Q ₀ is obtained. Therefore, Q ₀ can be calculated from this formula III. Further, when Q ₀ is obtained in this way, βlim and βmax (βmax = βz−Q ₀ ) are obtained from equations I or II.

By the way, theoretically, it is possible to obtain Q ₀ (etc.) by the above formula III, but specifically, the result differs depending on what value A in the formula III takes. It is clear that That is, it is necessary to take the value of A within an appropriate value or an appropriate range in relation to the actual sand, and it goes without saying that artificially manufactured glass beads, iron or other metal particles (whichever is preferable) Is a spherical shape, has no systematic inner hole, and has little unevenness, etc.
It is possible to measure βlim and βmax with a sample with Q ₀ = 0, but in the case of such an artificial sample, the material is different from sand, so βlim and βmax with such a sample are measured.
Is not valid in the case of sand. Therefore, the inventors of the present invention conducted extensive research to elucidate their relationship with respect to sand. However, as artificial sand, one with a specific amount of Q ₀ = 0 (one with no pores systematically) was specially manufactured or selected. This is also practically difficult (the material still has proper pores or something similar), and it is not possible to obtain a sample of such sand with Q ₀ = 0.

The actual operational in accordance connexion present invention shall apply those employing sand near Q ₀ = 0 as convenience Q ₀ = 0, since such sand is absolutely not Q ₀ = 0 Even if the measurement result deviates to some extent, it is possible to set it within the allowable error range because there is some deviation due to the natural production of sand. That is, the water content βz after the action of centrifugal force as described above is obtained for a plurality of samples obtained for convenience,
This βz value is the JIS surface dry state Q of each sample
Of the βz / Q values obtained by dividing by, the one with the largest value (relatively the smallest Q) was used as the reference sample in which the internal water saturation rate Q ₀ was regarded as zero. βz / Q
Is smaller than that, the difference from the measurement result by the reference sample is set as the internal water saturation rate Q ₀ and the above β
ask for lim. Further, generally, the amount of water within the range of about 2 to 7 times the value of βlim can be used as βmax.

However, it is clear that cement paste intervenes between the fine aggregate particles in a kneaded product using a hydraulic substance powder such as cement mixed with sand as described above. Water and other substances that have been adsorbed) will be mixed. Therefore, as the primary water used for concrete kneading, it is possible to analyze and consider such a paste side and a sand particle side. When the amount of water on the paste side is Wp, the primary water W ₁ / C Can be expressed as the following IV formula.

W ₁ / C = Wp / C + β ₀ S / C …… IV However, β ₀ in this IV formula is the water content on the sand side, and as a kneaded product that does not change the properties of the kneaded product depending on the amount of sand added. The stable amount of water on the sand side can be understood as βmax + Q ₀ . Regarding the stable amount of water on the paste side, details have been clarified in Japanese Patent Laid-Open No. 58-56815, which has already been proposed by the present inventors. For primary water, a hydraulic substance powder was used. On the other hand, in the case of cement, the amount is adjusted so as to form a slurry region close to a fananiquer or capillary state.
15 to 38%, especially for ordinary Portland cement, the maximum torque value for kneading was found to be around 24% of the cement amount. Such a water amount was used as a specific Wp / C value. Recommended.

In addition, regarding the compounded water of the present invention obtained as described above, it is natural that it is adopted as the value obtained by subtracting the water content when applying this to the sand that is actually used and has a certain amount of water. .

A concrete embodiment of the present invention will be described below.

Example 1 The physical properties of various sands specifically adopted by the present inventors are as follows.
As shown in the table, the experimental coefficient A is from Oigawa F
Sand, mountain sand P and mountain sand K are standard samples (Q ₀ = 0)
As shown in the lower half, the βlim value obtained by the experiment and the variation values of the Q ₀ value and the βlim value when A ′ is 2.50, 2.76 and 2.86 are shown. Incidentally, the hydraulic substance powders mixed to obtain mortar as described below for these sands are all ordinary Portland cements,
The mixing ratio, that is, the sand cement ratio (S / C), depends on the volume ratio,
Generally, it was carried out based on the case of S / C = 2.

The above-mentioned various sands were appropriately selected, and the value of A'in Table 2 was variously changed according to the above-mentioned divided mixing method using the primary and secondary waters proposed by the present inventors. FIG. 12 shows a summary of the results of measuring the breathing amounts according to JIS A1123 after adjustment of various mortars. In this case, the W / C as cement paste was set to 24%, and the amount of primary water added to this amount of water was arranged by A '.
In the table, Oigawa H sand, Sagamigawa B sand, Sagami crushed sand, and mountain sand P are used, and the reference sand for these samples is mountain sand P (A ′ = 2.76). , A'when the standard sand is other than that
It can be said that the above-mentioned measurement results for the respective sands are almost the same as the position of A on the horizontal axis with respect to each numerical value fluctuates accordingly. However, according to the results shown in FIG. 12, it was confirmed that the amount of breathing in all sands was around 4 and the amount of breathing was the lowest before and after that.
Even if the position on the horizontal axis fluctuates (however, the amount is small in any case), βli
It can be said that by setting the magnification A to m to about 2 to 7, it is possible to obtain a mortar having stable characteristics with the minimum occurrence of breathing.

However, the surface water-saturated state is regarded as ineffective water for the one shown in FIG. 12 according to the conventional method, and the primary water amount is appropriately determined.
The results of obtaining the breathing amount according to the same JIS A1123 for the kneaded materials adjusted for the same four kinds of sand as those in Fig. 12 are as shown in Fig. 13, and the breathing amount is generally rather high, (Around 0.5% in the lowest state),
Moreover, the breathing minimum is 20% for Oigawa F sand, 30% for Sagami River B sand, 40% for Sagami crushed sand, and 35% for mountain sand P. What is the primary water amount for each sand? Whether or not it is in the lowest state is that the primary water amount in the lowest state can be obtained only after adjusting a large number of kneaded products for each sand and measuring the breathing amount.

Further, those shown in FIGS. 12 and 13 are obtained by measuring the breathing specified in JIS A1123, and the kneading according to Japanese Patent Application No. 57-44639 (Japanese Patent Laid-Open No. 58-162867) proposed by the present inventors separately. According to the method for measuring the amount of intrinsic breathing water in the product, the kneaded products prepared in the same manner as in Figs. 12 and 13 were arranged in the same manner. The results are shown in Fig. 14 in which the primary water amount was determined according to A above. And the conventional method is the 15th
It is clear that even in this case, in FIG. 14 according to the present invention, the breathing water is in the lowest state around A = 4 (A = 3 is the lowest only for sand P) in this case as well. As in the case of FIG. 12, it is clear that if the sand is selected within the range of A = 2 to 7, the kneaded material in the minimum state of breathing can be obtained by using any sand. It should be noted that in the case of this internal peculiar breathing water, the breathing is measured inside the kneaded product, and it is not the one that floats and separates on the surface as in the case of JIS A1123 (only that gives an accurate amount of separated water). Therefore, as shown in the figure, the breathing water ratio is rather high, and the breathing water ratio varies widely depending on the type of sand. Is the lowest as

However, the breathing amount is generally higher in the conventional method of FIG. 15 than that of FIG. 14 as in the case of FIG. 13, and the lowest point in Oigawa F sand. Is 25%, while Sagami River B sand is 40%
%, 30% for Sagami River crushed sand, 35% for mountain sand P, and the lowest point varies with each sand.
It is almost the same as in Fig. 13, and it is clear that it is difficult to find the primary water amount in the minimum breathing amount state common to any sand as fine aggregate.

Further, the 4-week strength after molding of each mortar having S / C = 2 obtained as described above was obtained for the one according to the present invention, and the results are as shown in FIG.
In any of the four types of sand mentioned above, A = 4 or so,
Generally, the primary water is determined according to A = 2 to 7 and the high compressive strength is obtained.
kg / cm ² or more, Oi F sand generally 20 kg / cm ² or more even, at least 10 kg / cm ² at Sagami River crushed sand, the mountain sand P 25 kg / cm ²
The above strength increase is shown, and it is clear that it is necessary to set A = 3 to 6 in order to obtain at least the maximum compression strength.

Example 2 Concrete was prepared using river sand (5 mm or less) produced in Yufutsu, Hokkaido, and fine sand and gravel obtained as crushed stone powder.
That is, the Q value of Yufutsu-sangawa sand is 1.94% and Q ₀ is 0.78%, whereas the fine sand has Q of 3.37% and Q ₀ of 1.8%.
248kg / m ³ and the latter was mixed at a ratio of 64kg / m ³ (synthetic Q value by this combination was 2.01%, Q ₀ was 0.83%) and
718 kg / m ³ and ordinary Portland cement were mixed at a ratio of 450 kg / m ³ {S / C is (1248 + 64) /450=2.92}, and the water-cement ratio is 30.9% based on the absolute dry standard using primary and secondary water. When kneading the dry concrete of, the primary water amount W ₁
/ C = Wp / C + β ₀ Wp / C was set to 17% by the formula of S / C, and the adhering water rate βlim (the above composite Q and Q ₀ to 2.01−0.83 = 1.18) was set as the reduced state of the fine aggregate surface. %), And therefore β ₀ = 1.18 × 2 = 2.36%, W ₁ /C=17+2.36×2.92≒23.9(%), and knead with this primary water. After that, the remaining secondary water was added and kneaded to prepare concrete.

That is, the surface dry specific gravity of the fresh concrete obtained as described above is 2.45 kg / l, and the filling rate of the molded body with this fresh concrete is as low as 30.9% in the water cement ratio (W / C) as described above. , Despite being dry concrete 95.4
%, Which is considerably high, and β
Filling rate of green concrete mixed with primary and secondary water by the conventional method without using the ratio (A) to lim
It was confirmed that the filling rate was significantly improved compared to 92.3%.

Further, the compressive strength after 28 days of the product molded from the green concrete prepared by the above-mentioned method of the present invention is
It is 409 kg / cm ² , which is considerably high, and the water permeability performance test result to measure the water drop (mm) after ² hours is 3 m.
m was the same as that of the comparative example according to the conventional method but 150 mm in the same water permeability test and the same W according to the present invention.
By / C, it was confirmed that even a kneaded product using the primary and secondary waters, a product having a marked difference in water permeability was obtained.

Example 3 Adopting various processes as a kneading method, ordinary Portland cement was used as cement (C), sand (S) was hill sand (FM = 2.7) from Nishioketa, Kagawa Prefecture, and Tokushima was used as coarse aggregate (G). Using crushed stones (FM = 6.64 and 7.96) from Naruto prefecture, and using a Vintsol manufactured by Yamamune Chemical Co., Ltd. as an admixture (Ad), kneading was carried out for the following eight types. W ₁ is primary water, W ₂ is 2
Next water means →, and indicates a kneading process.

However, the sand (S) had a water absorption rate of 2.05% and a surface dry specific gravity of 2.51 kg / l, and the Q value obtained by performing the dehydration test by the centrifugal force was 2.05 and Q ₀ value. Is 0.73 and βlim is 1.32, and in the above cases ₁ to 3, all of the above A values for W ₁ / C are set to 3. That is, βmax = A × βlim = 3 × 1.32 = 3.96 β ₀ = βmax + Q ₀ = 3.96 + 0.73 = 4.69, and for the absolute dry standard W ₁ / C, α = Wp / C = 24%, W ₁ / C = α + β ₀ × (S / C) = 24 + 4.69 × 3.32 = 39.6%, and W ₁ / C on the surface dry basis is as follows.

Table dry standard W ₁ / C = bone dry basis W ₁ /C-Q×S/C=39.6-2.05×
3.32 = 32.8% As described in the above kneading process, the total kneading time is 120 seconds in total, and the mixing ratio of the obtained kneading concrete per m ³ is as shown in Table 3 below.

In Table 3 above, the W / C value is based on the surface dry standard, but when this is shown as W / C in the absolute dry standard, it is 71.6
%belongs to.

However, the results of the test and measurement of the physical properties of the green concrete obtained by the above kneading methods are summarized in Table 4 below.

That is, it was confirmed that the one according to the present invention had a small breathing rate, a relatively high 4-week strength, and a small standard deviation and a small coefficient of variation, and that an excellent and stable concrete was obtained.

Example 4 While the kneading method of Example 3 was changed variously, A was changed.

The cement (C) used is ordinary Portland cement,
As sand (S), river sand from the Ashida River in Hiroshima Prefecture (coarse grain ratio = 2.96)
Is S ₁ and Kagawa Prefecture Kashu's sea sand (coarse grain ratio = 2.60) is S ₂ , coarse aggregate (G) is Hiroshima Prefecture Araya crushed stone (coarse grain ratio = 6.5
3) was used, and Pozzolis No. 8 was used as the admixture (Ad).

The composition per m ^{3 of the} kneaded concrete is as shown in Table 5 below, and the W / C is shown on the basis of surface dryness. When this is taken as the absolute dry basis, W / C = 65.4%.

The physical properties and mixing ratio of the sands S ₁ and S ₂ by the centrifugal force dehydration test are as shown in Table 6 below.

As a specific kneading method, according to the above-mentioned Example 3, the value of A is 0 to 7
Determined W ₁ / C. That is, the respective values by the method of the present invention in this case are as shown in Table 7 below, and for α = Wp / C, 24%
And

Further, the results of the test measurement of the characteristics of each green concrete obtained as described above are as summarized in the following Table 8.

That is, according to the present invention, it is clear that A having 3 to 7 is excellent in strength and has a small standard deviation and a small coefficient of variation.

Example 5 Q value was determined by the method specified in JIS dry condition,
Q'determined within a short time by decompression processing and centrifugal force processing
It was obtained as a value and the present invention was carried out.

The sand used is the fine-grained sand (FM = 1.73) produced by Hanno, which is the same as the coarse-grained sand (FM = 3.62) produced by Hanno in Saitama Prefecture.
It was compounded in the ratio of.

The treatment for obtaining the Q'value was carried out by the following method after preparing the above sand as absolutely dry sand and adding 12% water.

Each sand as described above was subjected to an averaging treatment (for example, a treatment with a centrifugal force of 453 g for 3 minutes), then taken out, and then subjected to the treatment for 30 minutes by utilizing the centrifugal force described above to obtain a βz value. That is, the βz value is 5.38 (this is βz '
And the βz value of the above is 4.92.
The value obtained by subtracting βz ″ from such βz ′ (5.38−4.92 = 0.46) is obtained as Q ₀ ′, and the Q ′ value according to the Q value is Obtained as.

However, even when such values of Q ′ and Q ₀ ′ are used and the magnification A with respect to βlim is selected in the range of 3 to 5, the same results as those shown in each of the above-described embodiments can be obtained. did it.

According to the present invention as described above, the actual condition of adhering or adsorbed water as a kneaded product with respect to fine aggregate such as sand, which is a substantially indispensable material in preparing this kneaded product of hydraulic material, is described. Elucidated and accurately determined the primary water amount when adjusting the kneaded material according to the split kneading method that can exhibit particularly reasonable and preferable characteristics, as the best state with little breathing and adequate fluidity In addition, it is possible to analytically elucidate and determine the rational amount of water on the paste side and the fine aggregate side, and constantly stable quality characteristics are not affected by the type and brand of fine aggregate and are complicated. It is an invention that can be obtained without repeating various test measurements and has a great industrial effect.

[Brief description of drawings]

The drawings show the technical contents of the present invention. FIG. 1 is a diagram showing the relationship between the surface dry saturated water state and the porosity according to JIS regulations for various fine aggregates, and FIG. 2 is the method of the present invention. Explanatory view showing a disassembled state of a closed container used in the water separation measuring method utilizing centrifugal force in section, in a sectional view and a plan view, FIG. 3 is a sectional view of the combined state, and FIG. Overall cross-sectional view, Fig. 5 is a chart summarizing the relationship between centrifugal force action time and water content when performing centrifugal separation moisture separation measurement on fine aggregates with different amounts of attached water, Fig. 6 is a chart of the results of the same measurement for fine aggregate different from that of Fig. 5, and Fig. 7 is for various fine aggregates adjusted to have an initial water content of about 1Q. Fig. 8 is a graph showing the results of the same centrifugal force separation test of Similar centrifugal separation result charts for those hydrolyzed under reduced conditions as hydrolysis,
Fig. 9 is a graph summarizing the results of centrifugal separation processing of various fine aggregates. The horizontal axis is a logarithmic scale up to 90 minutes, and the interval between 90 and 120 minutes is clear for clarity. Figure 10 shows the results of rearranging the initial water content of Figure 9 by the Q factor, and Figure 11 shows the results for treatment times of 30 minutes, 60 minutes, and 120 minutes. Fig. 12 shows the result of sorting out about
Fig. 13 is a chart summarizing the results of measuring the breathing amount according to the JIS method for those obtained by dividing and kneading mortar with different primary water amounts with various different ratios to, and Fig. 13 shows the conventional JIS surface dry state. Chart showing bleeding amount measurement results of mortar with the same water-cement ratio with the same sand as in Fig. 12 obtained by the primary water for the standard divided kneading, and Fig. 14 is the same as sand in Fig. 12. Fig. 15 shows a summary of the results of measuring the inherent breathing amount proposed by the present inventors for various mortars that have been divided and kneaded by determining the primary water content, and Fig. 15 shows the case where kneading is based on the conventional JIS table dry state. Chart of the above-mentioned intrinsic breathing amount measurement result of
Fig. 16 shows the 4-week strength of various mortars prepared as shown in Figs.
It is the chart which arranged by the magnification of the reduction state adhering water ratio in the surface dry satiety state regarding the next water amount. Therefore, in these drawings, 10 is a synthetic resin pipe, 11 is an acrylic plate, 12 is a wire mesh, 13 is paper, 14 is a perforated iron plate, 15 is adhesive tape, 16 is absorbent cotton, 20 is a case, 21 is a lid, and 22 is a rotation. A plate, 23 is a rotating shaft, 24 is a receiver, and 25 is a shaft.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masanori Tsuji 21 Matsuya-cho, Minami-ku, Osaka-shi, Osaka (72) Inventor Mitsutaka Hayakawa 3-6-47 Inamuragasaki, Kamakura-shi, Kanagawa

Claims (1)

[Claims] 1. A mortar obtained by adding and kneading fine aggregate and compounding water to a powder of hydraulic substance such as cement or gypsum, or one or more kinds of coarse aggregate, fiber material, auxiliary agent and the like. In kneading and manufacturing by adding water to the added concrete in a divided manner, the water content as a surface dry water-saturated state and the water-saturation rate in the opening internal voids of the fine aggregate are obtained with respect to the fine aggregate,
The critical surface adsorbed water rate of the fine aggregate surface is determined by subtracting the saturated water rate from the surface dry saturated water content, and the maximum surface adsorbed water rate in the range of 2 to 7 times the critical surface adsorbed water rate is obtained. Obtained, the primary water amount of the above-mentioned divided addition is determined from the maximum surface adsorbed water rate, and the primary water amount is added to and mixed with the fine aggregate, and at the same time a hydraulic substance powder is also added to carry out primary kneading, Next, a method for producing mortar or concrete by a split kneading method, which comprises secondary kneading by adding secondary water for obtaining required characteristics such as fluidity.