JPS6041628B2 - Method for producing quick-hardening mixed cement - Google Patents

Description

[Detailed description of the invention] The present invention is 11CaO・7A1.

03.CaX, (where X represents halogen), 3CaO
This invention relates to a method for producing a quick-hardening mixed cement in which fly ash, slag, silica-alumina powder such as pozzolan, etc. are mixed with a fast-hardening cement whose main component is a SiO2 solid solution.

It has long been known to produce mixed cement by mixing silica-alumina powders such as fly ash, slag, pozzolan, etc. with ordinary Bortland cement. The long-term strength is high, but the strength before that tends to be low.

These trends are greatly influenced by the properties of the mixture. Also 11Ca0.7A1203・CaX2,3Ca0,S
A fast-setting cement made by mixing anhydrous gypsum and other sulfates, carbonates, boric acids, or borates with clinker containing iO2 solid solution, etc., develops high strength within a few hours after pouring water, and maintains excellent strength even after that. Stably discover.

In this fast-hardening cement, the early strength development is 11Ca
It is already known that 0.7A12O3 depends on the hydration of CaX2, and that the strength development after 1 day mainly depends on the hydration reaction of 3CaO-SiO2 solid solution (Japanese Patent Publication No. 1973).
(See Japanese Patent Publication No. 52-44335). 11CaO, 7A1203, CaX2, 3CaO
- When using an admixture for a fast-setting cement containing SiO2 as the main component and anhydrous gypsum added, a specially adapted admixture must be prepared in order to maintain the excellent properties of this cement.

Based on these technical backgrounds, the present invention attempts to produce a quick-setting mixed cement having excellent properties of quick-setting that deviates from the concept of conventional mixed cement by mixing the above-mentioned fast-setting cement and silica-alumina powder. Conducted various research.

Among a series of experimental examples, the experimental results using fly ash as the silica-alumina powder will be described in detail, and the technical contents of the present application will be explained below.

Table 1 shows the chemical and mineral compositions of the quick-setting cement and fly ash used in the experiment.

The powder level of fly ash is 4200d1q in plain value.
There is. [Experiment 1] This fast-setting cement was mixed with fly ash in the proportions shown in Table 2, mixed at a water ratio of 65%, and an organic acid was added so that the initial setting time of the mortar was approximately 3 ml. The relationship between the mortar strength and the fly ash mixing ratio in the case of adjustment was determined.

The results are shown in FIG. Mortar strength test is JIS
I went to R52Ol for 1 ru shellfish. From Figure 1, as the amount of fly ash mixed with quick-hardening cement increases,
The strength of Rutal decreases, and when 4% of fly ash is mixed with fast-setting cement (11Ca0, 7A120
3.CaF2 content is approximately 1% by weight) Mortar strength is approximately 35k91d in 3 hours and approximately 75k91d in 11 days.

[Experiment■]

In a quick-setting mixed cement (Table 2 B) in which 6 parts of fast-setting cement and 4 parts of fly ash are mixed, a part of the fly ash in the quick-setting mixed cement is calculated as 5, 10115 and 2 in terms of Caq. As in Experiment 1, the setting time of the mortar was set at about 3.
Mortar strength and C of slaked lime in a mixture of fly ash and slaked lime when adjusted to Cy13-
The relationship between aq and the amount of calculation was determined.

The results are shown in FIG. Figure 2 shows that when some of the fly ash in the quick-setting mixed cement is replaced with slaked lime, the early strength development (about 3 hours) is slightly better;
It has been observed that the amount of organic acid used for setting control increases as the amount of slaked lime replacement increases, and that the strength development of the mortar after one day does not show any effect or even worsens.

[Experiment■]

Next, in the same quick-setting mixed cement (Table 2 B) used in Experiment ①, a part of the fly ash in the fast-setting mixed cement was adjusted to 1, 5, 1 to 20 and 25% by weight in terms of SO3. As in Experiment 1, the setting time of the mortar was increased by approximately 3.
The relationship between the strength of the mortar and the calculated amount of SO3 of anhydrous gypsum in a mixture of fly ash and anhydrous gypsum was determined when the strength of the mortar was adjusted so as to make it more dusty.

The results are shown in FIG. In this case, the replacement amount of anhydrous gypsum is preferably 1 to 15% by weight as SO3 with respect to fly ash. If it is less than 1% by weight, it will have little effect on improving the strength of the mortar, and if it exceeds 15% by weight, the stable growth of the hardened product will be poor. Summer.

From FIG. 3, it can be seen that when a part of the fly ash in the fast-setting mixed cement is replaced with gypsum, the early and subsequent strength development of the mortar is improved.

[Experiment■]

Next, part of the fly ash in the same quick-setting mixed cement (Table 2 B) used in Experiment ① was replaced with anhydrous gypsum to give a concentration of 15% by weight in terms of SO3, and at the same time, part of the fly ash was In CaO calculation, 1, 10, 20,
Replaced with slaked lime to make it 30 and 4% by volume,
As in Experiment 1, the relationship between the strength of the mortar and the CaO content of fly ash, anhydrous gypsum, and slaked lime in the mixture was determined when the setting time of the mortar was adjusted to about 3 particles.

The results are shown in FIG. From FIG. 4, it can be seen that when part of the fly ash in the quick-setting mixed cement is replaced with gypsum and slaked lime, the strength of the mortar is further improved and a mixed cement with good stability can be obtained.

In this case, the replacement amount of slaked lime is C
The aO content is preferably 1 to (a)% by weight, and if it exceeds 2% by weight, the strength development of the mortar after one day tends to deteriorate and the workability tends to decrease. As is clear from these experimental results, when mixing silica-alumina powder with quick-setting cement to make a quick-setting mixed cement, sufficient strength cannot be achieved if silica-alumina powder is mixed alone with the quick-setting cement. do not. Strength development is improved by replacing a portion of the silica-alumina powder with anhydrous gypsum.
However, in this case, differences occur in early strength development depending on the properties of the silica-alumina material. For example, when natural pozzolan, fly ash, and slag are used, the strength development is good with slag, but poor with natural pozzolan. Replacing a portion of the silica-alumina powder with anhydrous gypsum slightly improves early strength, and also significantly improves strength development after 1 day. Furthermore, when a part of the silica-alumina powder is replaced with anhydrous gypsum and slaked lime, the difference in early strength development due to the properties of the silica-alumina powder disappears compared to when anhydrous gypsum is replaced, and the strength with the above characteristics is eliminated. An expression appears. Therefore, in producing a fast-setting mixed cement characterized by early strength development, it is important to replace a portion of the silica-alumina powder with anhydrous gypsum and slaked lime or quicklime.

In this way, a wide range of silica-alumina powders can be used without strictly checking the properties of the silica-alumina powders. A suitable amount of anhydrous gypsum to replace a portion of the silica-aluminous powder is 11C in a fast-setting mixed cement.
The larger the amount of a0・7AI203・CaX2, and the smaller the amount of arica alumina powder mixed, the larger the amount, and on the contrary, the more 11Ca0
-The smaller the amount of 7AI203/CaX2 and the larger the amount of silica alumina powder, the smaller the amount.

Further, the appropriate amount of slaked lime or quicklime to replace a portion of the silica-alumina powder depends on the amount of silica-alumina powder mixed, and the larger the amount of silica-alumina powder mixed, the greater the amount. A part of the silica-alumina powder is replaced with 1 to 15% by weight of anhydrous gypsum calculated as SO3 and 1 to 2% quicklime or slaked lime calculated as CaO in a quick-setting mixed cement.
Ca0●7A1203●Cax2 component is 5-25% by weight
Mix it with fast-setting cement to make a fast-setting mixed cement.

In addition, 11Ca0・7A120 in the quick-hardening mixed cement
3. If the amount of the Cax2 component is less than 5% by weight, early strength development will be poor, and if it exceeds 25% by weight, the strength development on an hourly basis will be good, but the strength will not increase in the first to seventh days of wood age. It is small, and the strength does not change after the 7th day of age, making it impossible to expect a stable increase in strength.

The fineness of fast-hardening cement is 3000 to 70 in plain value.
00CF1fIy1 silica alumina powder is 2000~
8,000 dIy, and anhydrous gypsum, slaked lime, and quicklime of 5,000 to 10,000 dIy are appropriate, and the quick-hardening mixed cement made by mixing these has a feather μ residue of 1 to 1.
The 15μ residual amount is 10 to 6%, and if the powder is finer than this, the amount of water mixed will increase, and the effect of the present invention will be significantly impaired.

The present invention is based on these findings, and 11Ca
When producing a quick-setting mixed cement by mixing silica-alumina powder with a quick-setting cement whose main component is 0.7A1203.CaX2, 3Ca0-SiO2 and anhydrous gypsum added to it, a part of the silica-alumina powder is added. SO3
1 to 15% by weight of anhydrous gypsum and 1 to 15% of Caq
11Ca0.7A1 in quick-setting mixed cement replaced with 2% quicklime or slaked lime.

03. This is a method for producing a quick-hardening mixed cement, which is characterized in that the two components of Cax are mixed in an amount of 5 to 25% by weight.

In the present invention, as a fast-hardening cement, anhydrous gypsum is added to a clinker containing 11Ca0.7A1203.CaX2 at 10 to 6...F amount % and 3Ca0.SiO2 at 5% by weight or more, and the weight ratio of Al2O3 in the clinker to SO3 in the anhydrous gypsum is used. (Al2O3/SO3) is 0.7
Add it so that it becomes ~1.8 and use the pulverized one.

In addition, fly ash, silica alumina powder,
Blast furnace water slag, high-lime-containing coal ash slag in which lime is burned and the ash is fixed using lime, and crushed pozzolans are used.

Furthermore, it is preferable to use anhydrous gypsum as the gypsum used to replace a portion of the silica-alumina powder, but about half of the gypsum used may be replaced with hemihydrate gypsum or dihydrate gypsum.

Further, the quick-hardening cement may contain a small amount of sulfate such as sodium sulfate or potassium sulfate, or limestone. Even if the content of calcium haloaluminate is reduced due to the presence of silica-alumina, the quick-hardening mixed cement produced according to the present invention exhibits good early strength development when mixed with water, unlike conventional mixed cement. Also, the mortar has good workability and stability.

Therefore, the present invention can be widely used as a fast-hardening civil engineering and construction material by changing the blending ratio of the mixed materials and changing the hydration characteristics of cement. Example 11 29.5% by weight of Ca0.7A1203.CaF2
, to a powder made by adding 21% by weight of anhydrous gypsum to clinker containing 45% by weight of 3Ca0.SiO2 and pulverizing the mixture.
1 each of limestone fine powder and sodium sulfate fine powder
Fly ash, blast furnace water slag, and porazone having the chemical components shown in Table 3 were ground to a plain value of 3,600 to 6,500 cILIy, and mixed with the quick-hardening cement prepared by adding % by weight in the proportions shown in Table 4. Mortar setting time and mortar strength tests were conducted on the mixture kneaded at a ratio of 65%, and the results shown in Table 4 were obtained.

In this test, the setting time of the mortar was adjusted by adding an organic acid so that the initial setting time was about 3 times. In addition,
As a comparative example, the results when only silica-alumina powder was mixed are also shown.

From these results, it is recognized that the fast-setting mixed cement produced according to the present invention has excellent properties regardless of whether fly-fired slag, blast-furnace slag, or pozzolan is used.

[Brief explanation of drawings]

The drawings illustrate the results obtained from Experiments 1 to 2, and FIG. 1 is a drawing showing the relationship between the mixing ratio of quick-setting cement and fly ash and the compressive strength of mortar.

Claims (1)

[Claims] 1 10 to 60% by weight of 11CaO・7Al_2O_3・CaX_2 (X represents halogen), 3CaO・
Anhydrous gypsum is added to the clinker containing 5% by weight or more of SiO_2, and Al_2O_3 in the clinker and SO in the anhydrous gypsum are added.
The weight ratio of _3 (Al_2O_3/SO_3) is 0.7~
A part of silica-aluminum powder selected from fly ash, blast furnace water slag, coal ash slag, or pozzolan is added to quick-hardening cement made by crushing to a particle size of 1.8.
1-15% by weight of anhydrous gypsum in terms of O_3 and 1-20% by weight in terms of CaO of quicklime or slaked lime are substituted for 11CaO and 7Al_2 in quick-setting mixed cement.
A method for producing a quick-hardening mixed cement, which comprises mixing the O_3 and CaX_2 components in an amount of 5 to 25% by weight.