JPH09286644A - Cement admixture and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high density high strength concrete by adding an ammonium salt and/or a sodium salt, a potassium salt, calcium nitrate or calcium chloride and an iron compound in water. SOLUTION: To 100 pts.wt. water kept at 3-10 deg.C and removed in chlorine content, 1-3 pts.wt. ammonium salts and/or sodium salts and 1-4 pts.wt. potassium salts are added and are stirred for 12-18min. Next, 3-10 pts.wt. iron compound, 70-150 pts.wt. calcium nitrate or calcium chloride are added thereto, stirred for 25-35min and after that, are left standing for 10-15hr, cooled to 15-20 deg.C and 3-7 pts.wt. magnesium salt is added thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement admixture, and more particularly to a cement admixture capable of producing high-density and high-strength concrete and a method for producing the same.

[0002]

2. Description of the Prior Art For example, dams, seawall revetments, bridges, tunnels, general building facilities, sewer pipes,
The quality requirements for concrete and its secondary products used in various civil engineering structures, such as tetrapots and utility poles, are increasing year by year. Alternatively, various cement admixtures for improving physical and chemical performances such as chemical resistance and waterproofness are known.

For example, a cement whose main component is a composition consisting of a calcium aluminate compound having a molar ratio of Al ₂ O ₃ and CaO in a predetermined range and gypsum, and which aims to improve the strength development of Portland cement. Examples thereof include an admixture (JP-A-4-6133) and a cement admixture (JP-A-4-114945), which is composed of a cation exchange material and suppresses an alkali-aggregate reaction of concrete.

[0004]

However, even the conventionally known cement admixture has room for improvement in the performance of the concrete produced. That is,
None of the conventional cement admixtures enhances the bonding strength of the cement constituents itself, so there is a limit to the improvement of physical performance such as strength, durability, wear resistance, etc. Because of the coarseness, there is a limit to the improvement of chemical performance such as chemical resistance, waterproofness, and weather resistance.
The current situation is to compensate for the lack of performance, for example, by further coating the concrete surface.

In view of the present situation, the present invention takes part in the binding reaction of cement constituents during curing to produce high-density and high-strength concrete, and thus drastically improves wear resistance and chemical resistance. It is an object of the present invention to provide a cement admixture which can realize concrete having excellent physical and chemical performance, and a method for producing the same.

[0006]

Means for Solving the Problems To solve the above problems, the present invention is specified as follows.

First, the invention according to claim 1 of the present invention (hereinafter referred to as "first invention") is 1 to 3 parts by weight of at least either ammonium salt or sodium salt in 100 parts by weight of water. , 1 to 4 parts by weight of potassium salts, 3 to 10 parts by weight of iron compounds, 70 to 150 parts by weight of calcium nitrate or calcium chloride, and 3 to 7 parts by weight of magnesium salts. Regarding admixtures.

Further, the invention according to claim 2 (hereinafter referred to as "second
Invention ". ) Relates to the cement admixture according to the first invention, wherein the water is water from which chlorine has been removed in advance.

On the other hand, the invention according to claim 3 of the present invention (hereinafter referred to as "third invention") contains 100 parts by weight of water and 1 to 3 parts by weight of at least either ammonium salt or sodium salt. , 1 to 4 parts by weight of potassium salts are added at the same time, 3 to 10 parts by weight of an iron compound is added, and further 70 to 150 parts by weight of calcium nitrate or calcium chloride is added. It relates to a method for producing a cement admixture, which comprises adding 3 to 7 parts by weight of magnesium salts.

The invention according to claim 4 (hereinafter referred to as "the fourth"
Invention ". ) Relates to a method for producing a cement admixture characterized in that, in the above-mentioned third invention, sodium thiosulfate is first added to water to remove a chlorine content in the water.

Further, the invention according to claim 5 (hereinafter referred to as "fifth invention") is the water temperature of 3 to 10 until calcium nitrate or calcium chloride is added in the third or fourth invention. The present invention relates to a method for producing a cement admixture, which is characterized by keeping at 0 ° C.

As shown in these first to fifth inventions, the cement admixture according to the present invention contains various inorganic compounds, and has an ion-rich composition containing many alkali ions and metal ions. It is a thing. The present inventor has found that by mixing this composition with cement, concrete modified with a very dense and strong structure can be obtained.

Although this theory is not always clear, a large amount of ions present in the cement admixture according to the present invention increases the electron concentration and activates the ionization reaction of cement inorganic components such as calcium silicate and silica. As a result of such a catalytic action, the setting and hardening of the cement is promoted, and further, in that case, the hydroxyl groups and carboxylic acid groups which are mixed in the cement and interfere with the setting and hardening are added. The probability that an organic compound having a low ionization rate is involved in a rapid binding reaction between activated inorganic ions is reduced, and the synergistic effect of these increases the purity of the inorganic components and increases the binding strength. It is considered that concrete with crystallized structure is generated.

Due to the extremely dense ceramic crystal structure having a large bonding force between the constituent components, concrete having high density and high strength can be realized, and physical properties such as durability and abrasion resistance can be achieved. The mechanical performance is dramatically improved, and the chemical performance such as chemical resistance, water resistance and weather resistance is excellent.
In addition, it seems that it will be less likely to be attacked by neutralization that causes weakening of concrete strength.

As the water used in the cement admixture according to the present invention, as shown in the second or fourth invention, for example, sodium thiosulfate or the like is used in advance to remove the chlorine content (calcium) in the water. I will leave it. This is because it is possible to stabilize various ions in the aqueous solution. In that case, the addition amount of sodium thiosulfate is about 0.008 to 0.015 parts by weight with respect to 100 parts by weight of water, and after the addition, the mixture may be stirred for about 8 to 12 minutes. To do.

In the method for producing the cement admixture according to the present invention, first, 100 parts of this chlorine-free water is removed.
To 1 part by weight, 1 to 3 parts by weight of at least either ammonium salt or sodium salt and 1 to 4 parts by weight of potassium salt are added at the same time.

At this time, as the ammonium salts, for example, ammonium salts such as ammonium chloride can be used, and one or more of these can be used in combination.

The sodium salts include, for example,
Sodium chloride, sodium carbonate, sodium nitrate or the like can be used, and one or more of these can be used in combination.

Further, as potassium salts, for example,
Potassium carbonate, potassium chloride, potassium nitrate, potassium sulfate and the like can be used, and one or more of these can be used in combination.

At least one of the ammonium salt or sodium salt and the potassium salt are mixed in water, for example, by mixing them in advance. This is because the ionization of these components is promoted and the solution preparation is facilitated.

After the addition of these, stirring is carried out for about 12 to 18 minutes, and the water temperature is kept at 3 to 10 ° C. as shown in the fifth invention. At higher temperatures,
This is because the reproducibility of the obtained reaction product decreases.

Next, 3 to 10 parts by weight of the iron compound is added and stirred for about 12 to 18 minutes.

As the iron compound, for example, a +2 valent iron compound such as iron sulfate can be used, and one or more of these can be used in combination.

Also, when this iron compound is added to water, the water temperature is kept at 3 to 10 ° C. for the same reason as described above, as shown in the fifth aspect of the invention.

Next, 70 to 150 parts by weight of calcium nitrate or calcium chloride is added and stirred for about 25 to 35 minutes.

At this time, other calcium salts such as calcium phosphate or calcium silicate can be used instead of calcium nitrate or calcium chloride.

Then, the obtained aqueous solution is further added to 10 to 1
After standing for 5 hours, the water temperature is cooled to 15 to 20 ° C, preferably 17 to 18 ° C, and then 3 to 7 parts by weight of magnesium salts are added.

The magnesium salts include, for example,
Magnesium chloride, magnesium silicate, magnesium sulfate and the like can be used, and one or more of these can be used in combination.

The functions of the composition according to the present invention include, in addition to densification and stabilization of the cement structure, chemical resistance of cement and the like, improvement of water retention, reduction of expansion and contraction rate, and adhesive strength of mortar and the like. Improvement of the fluidity before hardening, etc., and other than cement admixture, for example, it shows excellent effects even when used in various applications such as coagulants for waste treatment such as residual soil and sludge. To be done.

In the above, when chloride is used as an additive component, it is preferable to avoid constructing the obtained concrete or the like in such a manner that it directly contacts a metal material such as iron. This is to prevent the metal material from being corroded or oxidized by the chlorine content contained in the concrete. For example, when potassium carbonate is used as the potassium salt, this composition can be used as an admixture for cement or mortar, but when potassium chloride is used, it can be used as a coagulant such as sludge. To

[0031]

Hereinafter, the present invention will be described in more detail by way of examples. Preparation of Admixture A To 123 kg of industrial water was added 12 g of sodium thiosulfate, and the mixture was stirred for 10 minutes to immobilize and remove the chlorine component in the water. Next, while maintaining the water temperature at about 7 ° C., 1.7 kg of ammonium chloride and 2.9 kg of potassium carbonate were simultaneously added, and the mixture was stirred for 15 minutes. After adding 0.6 kg, the mixture was further stirred for 15 minutes. Further, 130 kg of calcium chloride is added to this solution.
And stirred for 30 minutes, then left at room temperature for 12 hours,
When the water temperature is about 17-18 ° C, 6.1k
Admixture A was obtained by adding g of magnesium chloride. Concrete setting test The admixture A was diluted with 20 times (weight ratio) water, and mixed with 100 parts by weight of Portland cement (dry conversion) to 60 parts by weight of water (W / C60). Let it set. For comparison, Portland cement was mixed and set under the same W / C60 conditions as above using plain water only. Table 1 shows the measurement results of the setting start time and the setting time from each mixing point.

[0032]

[Table 1] When the admixture A according to the present invention was mixed, the setting started and ended early, and the time required for setting during that time was shortened to about half, and the binding reaction of the cement constituents was reduced. It can be confirmed that is being promoted. Concrete Penetration Test A penetration test was conducted on the above-mentioned two types of concrete at predetermined intervals. FIG. 1 shows the test results. It can be confirmed that when the admixture A according to the present invention is mixed, the curing proceeds in a short time, and the cement constituents are rapidly bonded. Concrete compressive strength test The admixture A was diluted with 20 times (weight ratio) water and mixed with Portland cement under the condition of W / C56 for curing. For comparison, Portland cement was mixed and cured under the same W / C56 conditions as above using the admixture X which was commercially available. Compressive strength tests were carried out on these two types of concrete after 7 days and 28 days. Table 2 shows the test results.

[0033]

[Table 2] When the admixture A according to the present invention is mixed, it can be confirmed that the compressive strength is significantly increased at any age. Mortar compressive strength test 10 times, 15 times, 20 times diluted solution of the above admixture A 1: 2
The mortar was mixed and cured under the condition of W / C65. For comparison, a 1: 2 mortar was mixed and cured using only ordinary water under the same W / C65 conditions as above. A compressive strength test was conducted on these four types of mortars. Table 3 shows the test results.

[0034]

[Table 3] When the admixture A according to the present invention is mixed, it can be confirmed that the compression strength is high and the mortar components are firmly bonded to each other at any dilution ratio. Mortar Bending Strength Test Similarly, the above-mentioned admixture A was diluted with 20 times (weight ratio) water, and this was mixed with ordinary mortar under the condition of W / C40 for curing. For comparison, ordinary mortar was mixed and cured using only ordinary water under the same W / C40 conditions as above. A flexural strength test was performed on these two types of mortar at predetermined intervals. Table 4 shows the test results.

[0035]

[Table 4] In this case as well, it can be confirmed that the flexural strength is significantly increased when the admixture A according to the present invention is mixed. Mortar Abrasion Resistance Test The admixture A was diluted with 20 times (weight ratio) water and mixed with 1: 3 mortar under the condition of W / C60 to cure. For comparison, a 1: 3 mortar was mixed and cured under the same W / C60 condition using only ordinary water. Abrasion resistance tests were performed on these two types of mortar. The test conditions are 16 days of age, using a Taber abrasion test machine,
5,000 rpm, load 500 gr, wear wheel GC-J1
It was set to 00. Table 5 shows the test results.

[0036]

It can be confirmed that when the admixture A according to the present invention is mixed, both the wear amount and the wear depth are small and the wear resistance is excellent. Mortar Sulfurous acid gas erosion test A 10-, 15-, and 20-fold diluted solution of the admixture A was mixed with ordinary mortar for curing. For comparison, the same ordinary mortar as above was cured using ordinary water only. A sulfurous acid gas erosion test was performed on these four types of mortars.
The test results are shown in Table 6.

[0037]

[Table 6] When the admixture A according to the present invention is mixed,
Even if the dilution ratio is off, the gas mass reduction rate is small.
It can be confirmed that it is difficult to be attacked by sexualization. Paste weather resistance test Paste containing the above admixture A under W / C50 conditions
Spray ordinary commercial paint with ordinary mortar
The weather resistance test using a sunshine weatherometer.
Done. The test results are shown in Table 7.

[0038]

[Table 7] When the admixture A according to the present invention is mixed, it can be confirmed that the weather resistance is excellent under both conditions of weather irradiation and salt spray. X-ray analysis, pore size distribution measurement test For comparison, a normal paste mixed with the admixture A and aged in water under the conditions of W / C37 was used, and only ordinary water was used for comparison under water under the conditions of W / C37. An X-ray analysis and a pore size distribution measurement test were performed on the cured ordinary paste. The test results are shown in Table 8.

[0039]

[Table 8] When the admixture A according to the present invention is mixed, the total press-fitting volume is small, the pore diameter ratio is large, the cured paste has a high density, and the paste components are firmly bonded to each other. I can confirm.

[0040]

As described above, when the cement admixture of the present invention is used, it is possible to obtain a concrete modified to have a very dense and strong room temperature ceramic crystallization structure.
High-density and high-strength concrete is realized, and physical and mechanical performance such as durability and wear resistance is dramatically improved, and chemical performance such as chemical resistance, water resistance and weather resistance is excellent.
In addition, it becomes difficult to be attacked by neutralization that causes weakening of concrete strength, and it becomes possible to drastically improve concrete performance, and it can be used for various purposes.

[Brief description of drawings]

FIG. 1 is a graph showing a hardening curve of concrete when the admixture of the present invention is mixed.

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

[Table 7]

[Table 8]

Claims (5)

[Claims] 1. In 100 parts by weight of water, 1 to 3 parts by weight of at least one of ammonium salts and sodium salts, 1 to 4 parts by weight of potassium salts, and 3 to 10 parts of iron compounds.
70 parts by weight of calcium nitrate or calcium chloride
A cement admixture comprising 50 parts by weight and 3 to 7 parts by weight of magnesium salts. 2. The cement admixture according to claim 1, wherein the water is water from which chlorine has been removed in advance. 3. 1 to 3 parts by weight of at least one of ammonium salts or sodium salts and 1 to 4 parts by weight of potassium salts are simultaneously added to 100 parts by weight of water, and then 3 to 10 parts by weight of iron are added. Compound is added and further 70
A method for producing a cement admixture, which comprises adding 150 to 150 parts by weight of calcium nitrate or calcium chloride, and then adding 3 to 7 parts by weight of magnesium salts. 4. The method for producing a cement admixture according to claim 3, wherein sodium thiosulfate is first added to water to remove chlorine in the water. 5. The method for producing a cement admixture according to claim 3, wherein the water temperature is kept at 3 to 10 ° C. until calcium nitrate or calcium chloride is added.