JPS5957939A - Cement admixing material - 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 cement admixtures for concrete using superplasticizers.

In the past, various methods have been developed for producing high strength concrete. Among them, the method of using a high-performance water reducer to make the water-cement ratio of concrete relatively small and adding it to a value higher than the Setsukou fJ Engineering S standard value can achieve high strength by simply performing steam curing at normal pressure. Because it is easily obtained, it is used in the manufacture of piles, balls, muffler wood, propulsion humidifiers, etc. In addition, nitrite was further added in order to completely improve the initial strength development of this technology! 11 (Japanese Unexamined Patent Publication No. 55-51743) and a method in which a fired mixture of aluminum sulfate and fluoride is added (4? Japanese Unexamined Patent Publication No. 56-67257) have been proposed.

However, these techniques still have the problem that the slump loss becomes significantly large due to the use of high performance water reducing agents. Furthermore, for the reasons described below, even though high strength was obtained, there was a drawback that cracks were likely to occur.

That is, when steam curing is not performed, the ettringite production reaction of Ceracola is slow and takes place gradually due to the small water-cement ratio. As a result, this reaction proceeds in parallel with the water utilization reaction of the calcium silicate phase, and unreacted Ceracola remains in the hardened product, which causes cracks to occur during outdoor curing. On the other hand, in the case of steam curing, the reaction of Ceracola is extremely fast and can proceed separately from the reaction of the silicate phase, so there is almost no fear of cracking. However, when combined with aluminum sulfate, metal thiosulfates, nitrates, nitrites, chromates, etc., the reaction of the silicate phase is promoted, so the two reactions are separated again. ]l- It becomes difficult to advance, cracks and the durability becomes inferior to V'C.

As a result of various studies to solve the above-mentioned drawbacks, the Ministry of the Invention found that it would be better to further distribute oxycarboxylic acid or its salt, and completed the present invention.

That is, the present invention provides Ceracola, a metal thiosulfate,
One or more selected from nitrates, nitrites, chromates, aluminum sulfate, and light bread (hereinafter simply referred to as aluminum sulfate, etc.), and oxycarboxylic acid or its salt (hereinafter simply referred to as oxycarboxylic acid, etc.) This is a cement admixture for concrete that uses a high-performance water reducing agent that contains all of the following:

The present invention will be fully explained in detail below.

First of all, the concrete using the tube performance water reducing agent in the present invention is a general term for paste, mortar, and concrete in which an appropriate amount of polyalkylaryl sulfonate-based or triazine interrupter high-strength compound-based dispersant is used. Rir. Commercially available high-performance water reducing agents are all trade names, including chemical soaps ``Mighty 1UO'' and ``Mighty 150'', genuine oils and fats ``Ball Fine 51ONJ, Departure Kokusaku Valve'' [Sun 70-PSJ, Hozoris Bussan ■ “NL-145
0J, [1JL-4000J, Showa Denko ■ "Melment" etc. These are active ingredients added 0.3 to 2% by weight 8 times to the cement content of concrete. Hemihydrate K, soluble anhydrite Sae,
It may be insoluble anhydrite, or, as shown in JP-A-50-123596, compounds of metals and non-metals belonging to Groups I to II of the Periodic Table of Elements, or compounds of the metals and 400 by adding one or more types of non-metallic compounds to natural products or chemical compounds whose main components are stone leaves or anhydrite that becomes anhydrite when fired.
It may also be a special hard stone/leaf obtained by firing at 1,000°C to 1,000°C.

As aluminum sulfate, one or more selected from aluminum sulfate, light bread, common thiosulfates such as sodium, potassium, and calcium, nitrates, nitrites, and chromates are used; , Japanese Patent Publication No. 56-372
As shown in Publication No. 57, there is no problem even if it is mixed with a fluoride such as OaF 2 or MgF 2 and fired to reduce the rapid setting property. As oxycarboxylic acids, malic acid, citric acid, etc. , tartaric acid and their sodium, potassium, zinc, lead, iron,
Although salts such as strontium, magnesium, calcium, lithium, and copper can be used, citric acid and its sodium and potassium salts are most preferred from the viewpoint of performance, economy, and nontoxicity.

Other organic acids such as gluconic acid and maleic acid exhibit setting retarding properties but cannot improve workability and are therefore unsuitable for the present invention.

Next, to explain the mixing ratio and effects of each component, the mixing ratio of each component depends on the concrete distribution conditions,
It is difficult to specify a uniform ratio because different lids are used depending on the required working time, design strength, curing method, etc. Therefore, the general usage ratios for concrete using high-performance water reducing agents are 2 to 12% by weight of Ceracola and 0.1 to 5% of aluminum sulfate, etc., in terms of anhydride. fti%, oxycarboxylic acid, etc. is 0.
06~0.5m These components can also be added separately at the time of concrete mixing without being mixed in advance.0 If Ceracola is less than 2]if%, the amount of ettringite produced is small, so it is not strong. The effect is small, and 12% by weight
If it exceeds this, unreacted gypsum tends to remain in the hardened product, making it difficult to achieve the desired high strength objective.

The degree of effect of aluminum sulfate etc. varies depending on the type, but if it is less than 0.1%, the effect of normalizing early strength, especially the delay in the hydration reaction of the silicate phase at low temperatures, is small; For 0-oxycarboxylic acids, which have poor workability when the concentration exceeds 0.06% by weight, there is no improvement in slump loss at less than 0.06 wt%, and it is difficult to separate and hydrate into the two reaction patterns described above. As a result, cracking and durability cannot be improved. Moreover, if more than 0.5 liters of violet is added, the strength will decrease.

Although oxycarboxylic acids and the like are well known as setting retarders for cement, it is not known that the ingredients according to the present invention described above prevent slump loss in concrete using high performance water reducing agents. not present. By using the oxycarboxylic acid, etc. according to the present invention in combination with Ceracola, the two water utilization reactions can be carried out separately, and the cracking durability is improved. At the same time, when ettringite is formed, it absorbs a large amount of water, which reduces the water content of concrete and increases its strength.

The cement admixture of the present invention, which is composed of the above six components, significantly improves the workability of high-strength concrete, and the use of an alkali metal carbonate further enhances this effect. As the alkali metal carbonate, sodium and potassium carbonates and bicarbonates are generally used, and the amount of the cap used is at most 1% by weight based on the cement content of the concrete IJ-t.

If the amount added is too large, queflorescence with poor strength development may occur.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 The concrete shown in Part 1 was mixed by changing the types of Ceracola, aluminum sulfate, oxycarboxylic acid, etc. and the addition cover according to the 9 woodcuts in Part 2, and the slump, strength, and strength were measured indoors at 5°C over time and outdoors. The appearance of cracks was observed after one year of curing. The results are shown in a total of 446 tables. Experimenter 1 is plain,
Experiments A2 and 6 are comparative examples, and the others are examples of the present invention.

The Ceracola was replaced with sand, and the other ingredients were simply added to the outside of the cement. In addition, the measurement of compressive strength is
A test piece of 0φ x 20crn was used, and the mold was cured for 6 days and then left in a room at 5°C. Specimens for observation of fin fins were also conducted using test pieces of the same size, and slump measurements were repeated at intervals of time.

Table 6 Comparative examples of Experiments A1 to A1 shown in Table 6 either fail to improve workability, exhibit poor strength, or show cracking.

Example 2 In the formulation of Experiment A8, a similar test was conducted by further adding an alkali metal reconstituted salt. The results are shown in Table 4. Note that no cracking was observed after one year.

Below is the blank space Example 6 The concrete of Experiment A11315 was molded into a 10φ x 20-hole formwork, then cured in a room at 25°C for 6 hours, then raised to 75°C at a rate of 20°C/hr and held for 4 hours. When the strength was measured for 24 hours when slowly cooled, it was 4801827.839Kff/
After that, when the specimen was left outdoors for a year and cracks were observed, numerous cracks appeared in the specimen of Experiment 71L6, but none were observed in the other specimens.

Patent applicant Denki Kagaku Kogyo Co., Ltd.

Claims (1)

[Claims] Ceracola and one selected from metal thiosulfates, nitrates, nitrites, chromates, aluminum sulfates and light bread.
A cement admixture for concrete using a high-performance water reducing agent containing oxycarboxylic acid or a salt thereof.