JPS58115046A - Manufacture of endurable portland cement - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing Portland cement with improved durability. That is, the present invention relates to a method for producing Portland cement with improved durability by adding Ceracola to Bortland cement clinker having a mineral composition in a specific range, pulverizing it, and classifying the cement so that the particle composition falls within a specific range. It is something.

In the following explanation, 3CaO-8iO1 is C, S,
2Ca()Sing is C, S, and 3CaO'Al1m0
a is C, A, 4C & 0 'AM20s' FJ (
% is abbreviated as C4AF.

The main effects that impair the durability of mortar and concrete include mechanical deterioration such as drying shrinkage and freezing and thawing, as well as rainwater and
Chemical deterioration occurs due to erosion of seawater, chemicals, etc. In order to increase the resistance to any of these effects, it is necessary to appropriately select the materials used, the composition, the dimensions of the cracks, the construction method, the curing conditions, etc. Above all, the suitability of the materials used is extremely important. For this reason, extensive research has been conducted on the durability of Portland cement, but nothing of satisfactory quality has yet emerged. However, the following points have been pointed out as ways to increase the durability of Portland cement: (1) Reduce the plain specific surface area of cement.

(2) As for the mineral composition in the clinker, C, St-rich and Cs8 relatively small) and CsA't are reduced.

(3) As a chemical component in clinker, alkaline content (
K, O + Na, O) and free lime content (f, Cab
'.

Make it a little less.

However, even if Portland cement is produced that takes into account the above-mentioned points, there are problems in using it as a durable Portland cement, and a versatile Durable 4 Rutland cement cannot be obtained. In other words, Portland cement, which has a high C2S content, a small specific surface area, and a coarse powder, has low strength during short-term aging and increases in strength under long-term moist curing. If construction is carried out, sufficient curing measures will be required for a considerable number of days,
Therefore, there are drawbacks such as an increase in curing costs, or a risk that the cured product may not be able to secure the desired durability because its strength remains low even for a long time due to insufficient curing. Therefore, this alI Rutland cement is practically used as a durable cement.In order to increase the durability of cement, the invention was carried out using conventional techniques to coarsen cement particles.
Apart from the idea of technique, we achieved this by aligning the particle size of cement particles within a specific range that had been overlooked in the past, and further developed a highly durable Portland cement due to the mineral composition of Tarinka. And its composition is
Mineral composition in clinker is C, 840-80% by weight C
aA Ceracola is added to Bortland Cement Tarinka, which is less than 4% by weight, and pulverized.1 At that time, the particle composition of the cement is such that the particle composition of the cement is 30μ residue and 10% by weight or less, and the plain specific surface area is 3000 to 4000''/. It is characterized by classifying it with a special classifier and preparing cement T-.

The present invention will be explained in detail below along with examples.

Boltland cement clinker is generally C Karasu S.

C*S+CaA and C4AF are the main constituent minerals, and depending on the type and proportion of these constituent minerals, the water utilization reaction rate when in contact with water and the type of hydrate produced by the hydration reaction,
Since the size, shape, and coarse structure of the hardened hydrated cement differ, the types and proportions of these compositional minerals should be adjusted accordingly.
Il! Portland cements with different benefits are manufactured, such as ordinary cement, early strength cement, and toxic heat cement. When pulverized into cement with an appropriate particle composition according to the present invention, the clinker has a high CsS content (relatively less CsS), and the hydration heat generation and drying shrinkage of the cement are small. However, if the weight is less than 40%, the above resistance will decrease, and if the weight is more than 80%, normal construction and curing will not provide sufficient strength and durability. Therefore, a range of 40 to 80% by weight is appropriate. When the CIA content in clinker increases, it has a positive effect to some extent on improving the initial strength of cement, but it also increases hydration heat generation and drying shrinkage and reduces chemical resistance.
The following are appropriate. .

Further, the higher the 04AF content in the clinker, the smaller the drying shrinkage and the higher the resistance to chemical products, but it does not contribute much to the development of strength, so it is desirable to have a content of 5 to 15% by weight. Since durability increases when the alkali content (%0+Na, 0) and free lime content (f, caO) in the clinker are also small, it is preferable that each of them is 1% by weight or less.

Based on the above, in the present invention, the composition of the clinker mineral is adjusted to C, 840 to 80% by weight, and CsA to less than 4% by weight. Even if the particle size of the cement powder is adjusted to the range Kl# of the present invention, sufficient durability cannot be obtained if the composition of the clinker mineral is outside the above range. For example, as shown in the example below, K
Cm 8 weight scales are 25.0, 15.7, 85.0 (sample Na 7° 8.16), and C and A weight scales are 9
．． In all cases, the compressive strength against the Mg804 aqueous solution tMgC''* aqueous solution was less than half that of the present invention.

Next, any ceramic that is commonly used in the cement used in the present invention may be used. The amount of Setuu to be added may be within the usual range, and is 1.5 to 3 in terms of SO8 in cement.
．． A weight ratio of 0 is preferred.

In addition, other coagulant-controlled diarrhea (e.g. boric acid,
Carbonates, phosphates, silicofluorides, organic acid salts, etc.) may be used.

Durability 4 Rutland cement of the present invention uses the Talin force of the above mineral composition, and has a cement particle composition of 30 μm.
Residue: 10 weight bags or less, and Blaine specific surface area: 3000~
It is characterized by having a fixed rate of 4000sf/. If the Blaine specific surface area exceeds 4,000 cdlt, the amount of fine powder will be too large and durability will decrease, and if the Blaine specific surface area is less than 30,001 F, normal construction and curing will not develop sufficient strength and will not exhibit the characteristics of the present application.

Generally, the fineness of conventional cement has a Blaine specific surface area of 30.
Many of them are around 00 al/, and the sieve residue is based on 88 μm...9. In addition to the plane ratio surface 1: product, the difference in particle composition is also found to be an important factor in influencing the durability of cement. The present invention has determined the optimum particle composition for roundness that improves durability by determining the Blaine specific surface area, and has discovered significant force characteristics in particle regions that have been overlooked in the past. Based on the above findings, the present invention makes the 30μ residual in the Blaine specific surface area less than 10% by weight. If the 30μ residue exceeds 1O weight tcs, sufficient strength and durability cannot be obtained under normal construction and curing conditions.

The relationship between the Blaine specific surface area, which is a means of expressing the particle composition shown in the present invention, and the 30μ residue generally tends to be smaller for #1, which has a larger Blaine specific surface area. Here, a crusher (Karl mill) and a classifier Cc-C type separator, which have been conventionally used in cement factories as a crushing system, are used.

In the case of a combination of starch punt type top plate, cyclone type separator, etc.), the particle composition of the cement is in the range shown in Figure 1. However, those having the particle group @ in the above-mentioned captive region do not exhibit sufficient durability. For example, in the embodiment, Nll 1 and Mal belonging to the above prison area
The compressive strength of sample No. 2 when cured in water and in a chemical solution is lower than that of the present invention (see Table 3), and the drying shrinkage rate is conversely greater than that of the present invention, indicating inferior durability (see Table 4). There are large differences in freezing test results even with the same mineral composition due to differences in particle composition (see Table 5).By combining a specific range of mineral composition and particle composition, durability has been improved4. Rutland cement is obtained from various types of water such as calcium silicate hydrate, calcium hydroxide, calcium aluminate-sulfate hydrate (monosulfate hydrate), and calcium aluminate trisulfate hydrate (ettringite). It can be thought of as rounding, in which the hydrated material is produced with the appropriate shape, size, quantity ratio, and stray electricity to exhibit durability, and as a result, the composite fibers of the hydrated hardened material are formed that are suitable for durability. Ru.

As the classifier, for example, a superflow classifier disclosed in Japanese Patent Application Laid-Open No. 56-15876 may be used.

Next, examples of the present invention will be shown.

Example 1 4+WtI Roro 1-ReV1-1□fi + AJφ gate 1
Table 1 shows the mineral composition and chemical composition of Docement Tarinka, and the particle composition of the manufactured nine Portland cement, SO8 and the seven four-layer ratio used.
Table (Note) Mineral composition is based on Bogu's formula.

Using the samples shown in Tables 1 and 2, JIS R5201
(Physical Test Method for Cement) A mortar specimen was prepared and cured in humid air for 24 hours in a thermostatic chamber at 20℃, then cured in water at 20℃ for 6 days, and further submerged in the same thermostatic chamber. Magnesium sulfate 2.5 weight in an aqueous solution and chloride! After being immersed in a 2.5 weight gnesium solution for one year, the compressive strength was measured and the results are shown in Table 3.The chemical resistance of the product of the present invention is extremely good and stable over a long period of time. In the comparison product, disintegration and deterioration of the hard body can be seen.

Example 2 Using the samples in Tables 1 to 11!2, JIB R5201
Mortar specimen t based on (physical test method for cement)
-A type, Cement Association standard test method CAJ8 H-1
1-1971 (Length change due to hardening and drying of mortar fl
The drying shrinkage was measured under conditions of relative humidity (50%) in accordance with J.J. Specific Test Methods.

Example 3 Using the samples in Tables 1 and 2 and river sand (coarse particle ratio 1.95), sand/cement = 2.0, water/cement = 0.5
, IOX10X4 with an air content of 0.5 to 1.5 volume
A 0 m mortar specimen was formed and heated in a constant temperature room at 20℃ for 2 hours.
After curing in humid air for 4 hours and then curing in water at 20°C for 2 weeks, the durability index (F) at 50 cycles was determined according to A8TM666-75 (method for testing the resistance of concrete to rapid freezing and thawing). Ta. The durability index F here is the ratio between the dynamic elastic modulus when the number of freeze-thaw cycles is 50 and the dynamic elastic modulus before the start of the freeze-thaw test.

The test results were as shown in Table 5.

As shown in the Examples in Table 5 and above, the Portland cement produced by the method of the present invention and having a specific range of clinker mineral composition and cement particle set of 5X, t forms a dense hardened body, and It is a general-purpose durable Portland cement that has significantly superior durability compared to cement with a cement particle Mi composition and a clinker mineral composition obtained by the classification method of 1.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between the Blaine specific surface area and the 30μ residue, and Figure 2 is a graph showing the composition range of caA, C, and S. In the figure, B shows the conventional particle composition, and B shows the particle composition of the present invention. Patent applicant Onoda Cement Co., Ltd. Representative Patent Attorney Mitsuishi Shibe C and 1 other person) Figure 1 V'L->Specific surface area (Cm2/9)

Claims (1)

[Claims] Mineral composition in clinker is 2CaO-8iO140~8
0 weight - 13 CaO - A 31014 weight % or less Portland cement talin is crushed by adding Ceracola, and classified so that the fineness is less than 30μ residue 10 weight or less and the plain specific surface area is aooo ~ 4000aVtK. A method for producing Portland cement with improved durability, characterized by preparing cement by