JP2664414B2 - Quick-setting cement - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a quick-setting cement containing a special clinker whose particle size distribution is adjusted.

"Prior art and its problems" In recent years, many civil engineering structures and building structures require repairs, especially underground structures, etc. Water stoppage materials are used as repair materials. In such a waterproof material as a repair material, it is necessary that the setting and hardening be a very short time of about several tens of seconds to several minutes, and that sufficient strength be developed over a long period of time.

By the way, as a conventional waterproof material, there are a material using various additives mixed in Portland cement, and a material using quick-setting cement. In the former waterproofing material, calcium chloride, sodium silicate (water glass), etc. are used as additives, but the amount of additives must be increased in order to use these as quick-setting materials. . However, in a waterproof material using a large amount of calcium chloride as an additive,
There is a problem that there is a possibility that the reinforcing bar or the like is corroded, and that the shrinkage becomes large and cracks are easily generated. On the other hand, in the case of using water glass, many alkaline components in the water glass may be eluted, which may cause contamination, and there is a problem that the waterproof effect by adding water glass can hardly be expected. As described above, in the water stopping material using an additive, the amount of the additive must be increased in order to give quick-setting properties, and thus various adverse effects are caused.

The quick-setting cement-based water-stopping material using the latter quick-setting cement has an ultra-fast setting as a base clinker (11
_{CaO · 7Al 2 O 3 · CaF} 2), (CaO · Al 2 O 3), (3CaO · 3Al 2 O
₃ · CaSO ₄₎ various promoter calcium aluminate mineral cement consisting mainly of such, are those prepared by the addition of such fluidizing agents. The base clinker used has a Blaine value of 3000 to 6000 (cm ² / g) in fineness, but this type of fineness has a quick-setting property even though the main mineral has fast-setting properties. Insufficient, therefore, in the water-blocking material using the above-mentioned base clinker, various quick-setting additives are added to give a quick-setting property. However, in such a water-stopping material to which various quick-setting additives are added, mixing is complicated and sufficient attention is required, and the cost of the quick-setting additives is increased because the quick-setting additives are expensive. Also,
In order to obtain the necessary quick-setting properties, a large amount of fast-curing clinker is required, but it is advantageous to reduce the amount as much as possible from the viewpoint of cost. Furthermore, the water-blocking material using these ultra-fast curing clinkers has a large temperature dependence, so there is a problem that at low temperatures, instantaneous setting properties are lost and workability is impaired. However, there has not yet been provided one having sufficiently small temperature dependence.

The present invention has been made in view of the above circumstances, and it is intended that a special clinker having a particle size adjusted to have an ultra-fast-hardening clinker with a further quick-setting property and having a very small temperature dependency. It is an object of the present invention to provide a quick-setting cement.

"SUMMARY OF THE INVENTION" instantaneous setting cement of this invention, the clinker contained in the _{cement, 11CaO · 7Al 2 O 3 ·} CaF 2 5-60 wt%, a 3CaO · SiO ₂ 30 to 80 Clinker for ultra-rapid hardening cement having a weight percentage of 5200 (cm ² / g) is crushed and a special clinker whose particle size is adjusted so that the particle size of 5 μm or less is 60 to 100% by weight. The above problem was solved by setting the blending amount to 10 to 80% by weight.

 Hereinafter, the instantaneous setting cement of the present invention will be described in detail.

Ultrarapid hardening cement clinker used in the instant setting cement of the present invention, in very _{early, 11CaO · 7Al 2 O 3 ·} CaF 2
In the presence of Ca (OH) ₂ and CaSO ₄ , 3CaO.Al ₂ O ₃ .3CaSO ₄ .32H ₂
O expressing strength by generating a (ettringite), it is hereafter are those having the property of expressing the intensity of the generation of C-S-H due to hydration of 3CaO · SiO _2.

Since the specific surface area of this clinker for ultra-fast-setting cement is increased by reducing the particle diameter, the hydration reaction becomes extremely large. Further, a _{11CaO · 7Al 2 O 3 · CaF} 2 very large hydration reactivity as mineral composition, to an alkali component effective to promote the hydration compared to the large portion of the particle size fines portion of the cement The hydration reaction rate becomes very fast due to the presence of such a large amount. As described above, reducing the particle diameter not only increases the specific surface area but also has the effect of promoting hydration in terms of both mineral composition and trace components. In addition, 3CaO · SiO _2, which exhibits not only the initial strength but also the strength after that, has a small particle size, so that the hydration activity is increased, so that a stable strength is exhibited from the beginning.

In the properties of ordinary cement clinker, the specific surface area increases as the particle size decreases, and the hydration activity becomes extremely high. When the specific surface area of the cement clinker is too large, it is difficult to use the cement because initial handling cannot be performed. Particularly in the case of quick-setting cement, the maximum specific surface area is 6000 (cm ² /
g) (Brain value). However, as an example of the use of a material with an increased fineness, there is a use as an injectable material, but this is a use of a hydraulic substance having a very low activity, and the hydration activity improvement by increasing the terminal degree is fully utilized. Not something.

By the way, the above-mentioned clinker for super-rapid hardening cement has a quick-setting property even though the clinker is simple, but is still insufficient for use as a water-stopping material. . Further, since the handling time is very short and the temperature dependency is large, none of them satisfy both the sufficient handling time and the extremely initial strength at normal temperature (20 ° C.) and low temperature (5 ° C.).

However, the present inventors have found that a special clinker obtained by subjecting this clinker for ultra-fast-setting cement to particle size adjustment has sufficient instantaneous setting properties by itself, and that the temperature dependence of hydration properties is extremely small. . That is, in the clinker for ultra-fast-hardening cement, the amount of the
With a special clinker adjusted to be 100% by weight,
It was confirmed that the instantaneous setting was sufficient and the temperature dependency was small, and the effect was sufficiently observed. In this case, it was also confirmed that when the amount of the particles having a particle diameter of 5 μm or less was set to 70 to 100% by weight, the above-described effects of the instantaneous setting and the temperature dependency were further enhanced.

By applying this special clinker with adjusted particle size to the water-stopping material, it is possible to obtain a water-stopping material having instantaneous setting without adding an accelerating additive. Thus, it is possible to reduce the amount of the ultra-fast hardening clinker used as a base. Therefore, calcium-aluminate hydrate, which is said to be slightly unstable in the long term, can be reduced, and it can be replaced with a material that stabilizes long-term strength (flag powder, fly ash, etc.). Improvements and cost reductions are possible. In addition, since the temperature dependence of the special clinker is small, it is possible to impart a property with low temperature dependence to the water-stopping material. Therefore, the water-stopping material has a temperature of several tens of seconds to one minute at room temperature. And the high strength at the very beginning, and the handling time is in a usable range even at a low temperature. Therefore, the water stopping material using the above-mentioned special clinker has a drastic improvement in the instantaneous setting property as compared with the conventional product, and the strength is almost the same at room temperature even at low temperature. It can be used without considering the difference in properties depending on the temperature, and is very useful. The amount of the clinker for ultra-fast-setting cement adjusted to an amount of 5 μm or less is from 10 to 80% by weight without losing its instantaneous setting property and the handling time is within the usable range. A content of 60% by weight is more advantageous in terms of instantaneous setting property and handling time, and is therefore preferable.

"Examples" Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples unless it exceeds the gist.

(Example 1) Clinker for ultra-fast setting cement was used with a Blaine value of 5200.
(Cm ² / g) and classified using a classifier to obtain clinker having a particle size of 3 μm or less. Inspection results of the chemical and mineral compositions of the clinker before classification (hereinafter referred to as No. 1) and the clinker after classification (hereinafter referred to as No. 2)
Table 1 and Table 2 show the measurement results of the particle size distribution in Table 1.
Shown in the figure. According to FIG. 1, No. 1 has an intermediate particle size of about 12 μm, while No. 2 has a maximum particle size of about 5 μm and an intermediate particle size of 2 μm.
m, resulting in very fine particles. In terms of chemical composition, No. 2 has more 11CaO ・ 7Al ₂ O ₃・ CaF _{2 which} has more alumina component and faster hydration than No.1, and No. ₂ has hydration due to increase in surface area. It was found that not only the activity was improved but also the activity was high in composition.

Table 3 shows the clinker amounts shown in Table 1 which were determined to be 5 μm or less. In addition, a type II anhydrous gypsum is blended with these clinkers so that the molar ratio of SO ₃ and Al ₂ O ₃ (SO ₃ / Al ₂ O) becomes 1.2, and cement (from No. 1 to C-1, No. 2) More C
-2), and the hydration heat generation rate and cumulative hydration heat generation at a curing temperature of 20 ° C. and 5 ° C. were measured, and the results are shown in FIGS. 2 and 3.

According to FIG. 2, the hydration heat generation rate of the cement containing a large amount of fine clinker is high, which is considered to be due to the synergistic effect of the influence of the clinker particle size and composition. Also,
Looking at the difference due to the curing temperature, the decrease in the hydration heat generation rate due to the transition from 20 ° C in the very early stage of cement using No. 2 to 5 ° C is small, and No. 2 with a lot of fine powder is in the very early stage. It was confirmed that the temperature dependency was small. According to FIG. 3, the cumulative hydration calorific value up to 6 hours is similar to the hydration calorific value at the very early stage, and the segment using No. 2 having a large amount of fine powder at 20 ° C. and 5 ° C. It was confirmed that the difference was small and the temperature dependency was small. And, as the material age progresses, in the case of using No. 2 having a large amount of fine powder, the accumulated hydration calorific value tends to be higher at 5 ° C than at 20 ° C.

As described above, the more the fine powder is, the faster the hydration rate becomes, and the cement becomes hardly temperature-dependent.

The above cement was blended as shown in Table 4 to prepare a quick-setting binder. Measurements of the hydration heat generation rate and the cumulative hydration heat generation are shown in FIGS. 4 and 5.

According to FIG. 4, the heat generation rate of hydration at the very early stage is higher at 20 ° C. because of the larger amount of cement in the case where the No. 1 clinker having a large particle size is mixed, but it becomes higher at 5 ° C. The difference almost disappears. The same tendency is exhibited in the instantaneous binding material, as in the case of using No. 2 which has a large amount of fine powder in the plain cement, the temperature dependence is smaller. According to FIG. 5, at 20 ° C., those using cement having a small particle size are higher in 6 hours, but are higher in 24 hours when the particle size is larger. The cement using No. 2 seems to settle hydration by about 6 hours, but the large particle size using No. 1 generates hydration heat thereafter. Further, when cement made of No. 2 clinker is used, the calorific value of hydration in the very early stage becomes almost the same without using a setting accelerator called calcined alum, although the amount of addition is small.

As described above, by using the cement composed of No. 2 clinker containing a large amount of fine powder, the amount of added cement can be reduced, and the cement can be used as a quick-setting binder without using a setting accelerator. It becomes a binder with a very small temperature-dependent instantaneous setting.

Table 5 shows the measurement results of the handling time and the compressive strength of the instantaneous binding material. Here, the measurement of the handling time was performed by attaching a conical cone (350 g) having a diameter of 1 inch and a height of 2 inches in place of the beaker needle and measuring the time until the penetration reached 1.5 mm. The strength measurement was measured using water /
The test was performed according to JIS-R5201 for a material to which water was added so that the instantaneous binder was 25%.

Looking at the handling time, at 20 ° C, the time is almost the same for all binders, but at 5 ° C, the one with less fine powder clinker is slower, and as with the result of the heat of hydration measurement, It was confirmed that the coagulability at the very early stage was low in the temperature dependency of the fine powder portion. Next, when looking at the compressive strength, at 20 ° C., the composition became 100 (Kg / cm ² ) or more in 10 minutes in any of the formulations, indicating that the curing was sufficiently performed. Then, as the material age progresses, all the samples show a steady increase in strength. At 5 ° C., a binder using a clinker having a large particle size does not show sufficient strength development at an age of 10 minutes due to a low hydration rate in the initial stage, but a binder using a clinker having a large amount of fine powder is used. Shows sufficient strength expression. As described above, since the instantaneous setting binder using the clinker in the fine powder portion has a small temperature dependency, it exhibits a sufficient initial strength even at 20 ° C. and 5 ° C., and is sufficiently stable for a long period of time.

FIGS. 6 and 7 show the change in the pore size distribution of the instantaneous binding material depending on the material age. In the case of using the No. 1 clinker having a large particle size, as shown in FIG. 6, there are many pores having a large diameter of 1000 mm at a material age of 10 minutes.
In the case of using the clinker of No. 2 with a lot of fine powder, the number of pores with a diameter of about 1000 mm was very small as shown in Fig. 7, and the pores were hydrated due to hydration from the very beginning. You can see that it is filled. In addition, even if the material age is advanced, the one using No. 2 with a large amount of fine powder is filled more quickly and is more solid. in this way
The one using No.2 shows high strength from the beginning and the cured body becomes dense, the water permeability is extremely low and the durability is high, so the water stop material It becomes suitable.

(Example 2) The clinker for quick-setting cement was set to a brane value of 5200.
(Cm ² / g), and classified using a classifier.
Three types of clinker having the particle sizes shown in the table were prepared. Using these clinkers, type II anhydrous gypsum was added and S / A = 1.2
5 cement was made, and a quick-setting binder was produced using the cement. The composition is 40% cement, 39% fly ash, 1% high fluidity additive, 20% silica sand (S-3 from No. 3, S-4 from No. 4, S-5 from No. 5) At 20 ℃, 5
The handling time at 10 ° C. and the strength at an age of 10 minutes were measured, and the results are shown in Table 7. In addition, Table 7 also shows the measurement results of a commercially available conventional product as a comparative example.

From the results shown in Table 7, if the amount of 5 μm or less in the clinker is reduced, the rapid hardening property is reduced, but if it is up to 60%, high strength can be obtained even at a low temperature. On the other hand, the comparative example (conventional product) showed good results in both the handling time and strength at 20 ° C, but it was confirmed that the handling time was long at low temperature (5 ° C) and the strength did not appear in 10 minutes. Was.

Using the cement composed of the clinkers of Samples Nos. 3 and 5, instantaneous binders having the formulations shown in Table 8 were prepared.
And the handling time at 20 ℃ and 5 ℃ and 10
FIG. 9 shows the measurement results of the partial strength. Table 8 and 9
From the results shown in the table, in the case of using No. 5 having a large amount of fine powder, the handling time is shortened when the added amount of cement is increased, and the handling becomes difficult, but the strength becomes high.
On the other hand, the one using No. 3 with a small amount of fine powder has a long handling time at low temperature when the amount of added cement is small, and the strength tends to be in a slightly lower position, but it is very advantageous in terms of cost. Become. Alumina cement (CaO0.Al ₂ O ₃ ) as an additive, when added, has a slightly longer handling time and a higher strength. You can say that you have. However, it is expensive and it is preferable to reduce the amount of use.

"Effects of the Invention" As described above, the quick-setting cement of the present invention
Because it has been subjected to particle size adjustment to the clinker for ultra-rapid hardening cement, while having sufficient instantaneous setting alone,
The temperature dependence of the hydration properties becomes very small.

Therefore, by applying this quick-setting cement to the water-stopping material, a water-stopping material having a quick-setting property can be obtained without adding an accelerating additive. In addition, the amount of ultra-fast hardening clinker used as a base can be reduced, so that calcium-aluminate hydrate, which is said to be slightly unstable in the long term, can be reduced, and the long-term strength is correspondingly stabilized. It can be replaced with a slag (slag powder, fly ash, etc.), which can improve quality and reduce cost.

In addition, by applying the quick-setting cement to the water-stopping material, the water-stopping material can be given a small temperature-dependent property. Therefore, the water-stopping material has a temperature of several tens of seconds to one minute at room temperature. It has a handling time and high strength at the very beginning, and the handling time is within the usable range even at low temperatures.Therefore, the instantaneous setting is dramatically improved compared to conventional products, and the strength is low at low temperatures. Is almost the same as normal temperature, and can be used without considering the difference in properties depending on the temperature at normal temperature and low temperature, which is very useful.

[Brief description of the drawings]

1 to 7 are diagrams relating to the quick-setting cement of the present invention. FIG. 1 is a graph showing the particle size distribution of a trial clinker, and FIG. 2 is a graph showing the hydration heat generation rate of the trial cement. Graph, FIG. 3 is a graph showing the cumulative heat of hydration of the trial cement, FIG. 4 is a graph showing the rate of heat of hydration of the quick-setting binder, and FIG. 6 and 7 are graphs showing the pore size distribution of the quick-setting binder.

Claims (1)

(57) [Claims] 1. A Madokayui cement containing clinker, said _{clinker, 11CaO · 7Al 2 O 3 ·} CaF 2 5-60 wt%, ultrarapid hardening cement having a 3CaO · SiO ₂ 30 to 80 wt% The clinker for use is made of a special clinker which has been crushed to a Blaine value of 5200 (cm ² / g), and the particle size of the crushed product has been adjusted so that the proportion of particles having a particle size of 5 μm or less is 60 to 100% by weight. Is from 10 to 80% by weight.