JPH09118556A - Concrete hardener body using superfine-pulverized fly ash - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concrete hardener body capable of imparting high-early- strength and high-later-strength effects by using a superfine-pulverized fly ash. SOLUTION: The fly ash superfine-pulverized into >=4000cm<2> /g Blaine specific surface area is added, preferably kneaded with <=7% alkaline reaction accelerator solution, heated at a high temp. below the b.p. of water and pressed. In the case that the concrete is placed and rolled on a roadbed or under floor ground, a heated asphalt concrete is placed and rolled on the concrete before starting hardening or directly after starting hardening.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete hardened product using ultrafine pulverized fly ash, which is suitable for pavement for road surface or floor surface, secondary concrete product, etc. .

[0002]

Conventionally, concrete using cement mixed with fly ash has been developed for the purpose of effectively utilizing fly ash which is industrial waste. Since mixed concrete develops initial strength slowly, it is not used for concrete and secondary concrete products that require early strength. In addition, because the outer shape of fly ash is spherical,
Often used to increase flowability, no consideration was given to micronization that disrupts the spherical profile.

Next, the conventional compacted concrete is required to exhibit extremely early strength after construction. Therefore, although super-compacted ordinary Portland cement having a low water cement ratio is constructed by compaction, the initial strength development is slow. The use of fly ash cement was problematic. 3 fly ash when used
It is 0% or less, the initial strength is low, and it is experimental.

The present invention solves the problem of strength development in the very early stage of concrete which uses a large amount of fly ash, and also provides concrete having high water-tightness and high chemical resistance, which has an increased late strength, a small drying shrinkage. To aim.
Especially, it is intended to be applied to compacted concrete and materials for secondary concrete products which require early strength.

[0005]

In order to solve the above problems, the first concrete hardened material of the present invention is the addition of fly ash which has been finely ground to a Blaine specific surface area of 4,000 cm ² / g or more. It has a feature.

Secondly, it is characterized in that it is kneaded with an alkaline reaction accelerator solution of 7% or less, heated and pressurized at a high temperature below the boiling point of water.

Thirdly, the present invention is characterized in that concrete is laid and compacted on the subgrade or floor surface, and heated asphalt concrete is laid and compacted on the concrete before hardening or immediately after the start of hardening progress.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, fly ash, which is usually used without fine pulverization, is ultra finely pulverized, and an alkaline solution is mixed without using water, and then heated and pressurized. It is characterized by being made, and is a method for accelerating the hydration reaction of fly ash, that is, ultrafine pulverization, use of an alkaline solution as a reaction accelerator, heating, pressurization (rolling pressure), etc. The method is applied comprehensively in an optimal manner.

The embodiment will be described in detail below. An ordinary fly ash is prepared by using a Blaine specific surface area of 4,000.
0 cm ² / g or more, for example 5,000 cm ² / g position until micronised fly ash 60 parts of micronised to the extent, including those, 40 parts cement and sand 180 parts, as alkaline reaction accelerator solution After kneading with 30 parts of 5% sodium sulfate solution and heating at 80 ° C for 30 minutes, diameter 5 cm and height 5
A column of cm was formed under pressure of 100 kgf / cm ² , and thereafter, it was cured at room temperature and in a humid atmosphere for 1 day and 3 days, respectively. As a result, the compressive strength of this sample was 219 kgf / cm for one day.
² , the material of 302 kgf / cm ² was obtained for 3 days.

On the other hand, in an experiment under the same conditions where 60 parts of ordinary unground fly ash, 40 parts of cement and 180 parts of sand were kneaded with 180 parts of water, the 1-day strength was 25 kgf / cm ² . Age 3 days strength is 51kgf / cm
² , the strength of 7 days old was 73 kgf / cm ² . Also, the strength of the mortar containing 20% of the classified fly ash that has almost the same particles as that of ultra-fine crushing is 142k for 3 days.
It is gf / cm ² , and when the amount of fly ash mixed is small, the strength of the classified fly ash also increases. From these facts, it is possible to clearly discriminate the difference between high strengthening and early strengthening when using ordinary spherical fly ash or unpulverized classified fine fly ash and when using the same amount of ultrafine pulverized fly ash. .

By the way, since the ordinary Portland cement using 100 parts of cement has a weight of about 150 kgf / cm ² , it is clear that the strength and the early strengthening property are particularly excellent as compared with this. Examples of the alkaline reaction promoter include sodium sulfate solution, NaOH, K
It is possible to use OH, K ₂ SO _4, etc.

Next, an experiment was carried out under the same conditions as above except that the amount of fly ash was increased and 80 parts of ultrafine pulverized fly ash, 20 parts of cement and others were found to have a strength of 126 days per day.
kgf / cm ² , age 3 days strength is 216 kgf / cm ^2.
Met. By the way, if normal uncrushed fly ash with the same composition is used, it will be 10 to 15 kgf / c in 1 day of age.
m ² and 30 kgf / cm ² on the same 3 days, and it is recognized that a sufficiently high strength can be realized compared to the above-mentioned one using 100 parts of ordinary Portland cement.

As is clear from the above embodiment, fly ash is effective only when the amount of the usual spherical classified fine particles that have been burned and discarded is limited.
Therefore, in the present invention, the condition is that the particles are pulverized into ultrafine particles, and the concentration of the alkaline reaction accelerator solution is also preferably 7% or less in order to obtain the initial effect.
Also finely pulverized and has a Blaine specific surface area of 4,000 cm ² / g
It is desirable that the particle size be above (particle size of about 6 μm or less), and the temperature at the time of heating should be the boiling point of water (about 1 μm) in order to obtain the reaction promoting effect.
00 ° C) or lower is preferable.

In addition, when the above-mentioned ultra-finely crushed concrete is used for pavement or the like and the concrete is laid on a roadbed or a floor substratum, etc. When laying and rolling the ordinary asphalt concrete that has been heated to around 200 ° C on the compacted concrete at the stage of laying and rolling, it will be rolled while being radiated to approximately 100 ° C or less during the laying, There is an advantage that the early strengthening and high strength of concrete are further promoted.

[0015]

EFFECTS OF THE INVENTION According to the hardened concrete of the present invention configured as described above, concrete construction for various works,
In the production of secondary concrete products, the very high strength of concrete can be exhibited at an extremely early stage, and a large amount of fly ash can be effectively used at low cost. Further, it is possible to obtain a concrete having a high strength in the latter stage of the concrete, a small drying shrinkage, a high watertightness and a high chemical resistance. Further, compared with the case where fine particles of fly ash are used, the curability in the early and late stages is excellent, and the labor and time for classification can be saved.

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Claims (3)

[Claims] 1. A Blaine specific surface area of 4,000 cm ² / g
A concrete hardened body using ultrafine pulverized fly ash to which the fly ash that has been ultrafine pulverized is added. 2. A concrete hardened product using the ultrafine pulverized fly ash according to claim 1, which is kneaded with an alkaline reaction accelerator solution of 7% or less, heated at a temperature not higher than the boiling point of water, and pressurized. 3. The ultrafine pulverization according to claim 1 or 2, wherein concrete is laid and rolled on a subgrade or floor surface, and heated asphalt concrete is laid and compacted on the concrete before hardening or immediately after hardening starts. Hardened concrete using fly ash.