JPS58115051A - Admixing agent for underwater concrete - 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 provides underwater concrete that is mixed with an admixture for underwater concrete and that does not separate even when poured freely in water, hardens, and develops desired strength. .

Traditionally, underwater concrete is poured using tremie pipes, concrete pumps, packets, etc., taking care to minimize the amount of unwashed concrete being washed away by the surrounding water. however,
In reality, concrete may be washed away by water and separated, and may not become a hardened concrete or its strength may be significantly reduced.

In recent years, underwater concrete has been developed that does not require the use of devices such as the tremie tubes mentioned above, and can be poured directly into water without shading, and can be deposited and hardened on the bottom of the water. The present invention also aims at producing such good underwater concrete, and as a result of extensive research, we have discovered an admixture that is effective for such underwater concrete.

That is, according to the invention, water-soluble cellulose ethers, water-soluble metal sulfate salts or metal chlorides.

It is an admixture for underwater concrete consisting of an antifoaming agent and an antifoaming agent.

Water-soluble cellulose ethers used in this invention include alkylcelluloses such as methylcellulose and ethylcellulose; hydroxyalkylcelluloses such as hydroxymethylcellulose, hydroxydiethylcellulose, hydroxybropic 7, and lulose; ethylhydroxyethylcallose; , non-ionic cellulose ethers such as methylhydroxypropyl cellulose; ionic cellulose ethers such as carboxymethyl hydroxyethyl cellulose. Particularly preferred are hydroxyalkylcelluloses, among which hydroxyethylcellulose is generally used. moreover,
Hydroxyethyl cellulose has the number of moles of ethylene oxide reacted per unit of cellulose molecule - b: %
It is preferable to have a value of 2.6 to 5, and due to the phase opening effect with gold BM, the setting and hardening speed as underwater concrete is high and the compaction rate is also good.

The water-soluble gold j11 sulfur mound used in the present invention includes:
General si N m sodium, lithium sulphate.

Potassium sulfate, etc., and metal chlorides such as sodium chloride, lithium chloride, and electrified potassium.

More than one noodle such as calcium tofu is used.

The effect of adding these gold-salts is to prevent the concrete from flowing out (separation) in water and to significantly increase the compressive strength, compared to the addition of only cellulose ether. It is preferable to mix 2 to 300 parts by weight, particularly 5 to 2001 parts by weight, of the gold kI4 salt with respect to 100 parts of cellulose ether. In other words, if the amount of gold m-salt is less than the above-mentioned mixing ratio,
As underwater concrete, it is not sufficiently effective in preventing outflow (separation) and in terms of pressure and strength, and in the case of a large number of ψ km, phenomena such as gelation occur, which increases workability and is economically unfavorable.

In addition, in the present invention, it is also possible to use 0.5 to 15 parts by weight of an antifoaming agent, preferably 10 parts by weight, per 100 parts by weight of droxyethyl cellulose, in order to obtain sufficient compressive strength especially as underwater □ concrete. It is very necessary to obtain it. The antifoaming agent is not particularly limited to known antifoaming agents.
For example, Nopco I””L 8N deformer 14
-) IP (more than Sannobuyu wNm), Eng., P. Deaoma 61 (Hipposha Yushi Kogyo-w), Anti-70s 1'
These include 1-Technology [manufactured by I-yaku ■], Nirasan Disform (Nippon Oil Company ■Tai), and Miracle Babunone-8 (-Katayama Chemical Industry Research Institute).

The manner in which the underwater concrete admixture of the present invention is added to and mixed with concrete is not limited to rI.・Generally, water is added to the cement ingredients to make a slurry.
One method in which the additive is mixed with the cement components in advance is preferably adopted.

As the cement component, Portland cement such as ordinary meltland cement and early strength Portland cement, mixed cement such as If furnace cement, silica cement, and fly ash cement may also be used as appropriate. In addition, fine and coarse aggregates such as sand and gravel are added as needed.
It can be mixed with cement additives such as additives or coagulation agents. Therefore, the concrete in the present invention refers to ordinary concrete (1%) or mortar (i!). To'
In addition, paste formulation is also included.

The underwater concrete additive of the present invention is applied to the cement component of concrete by 0.25 to 0.1 to the needle part.
By using 0.04 k1 part, preferably 0.5 to 0.7 k1 part, the effect as an underwater concrete is exhibited. Although the above-mentioned addition lid may be larger than 2.0 weight parts, it is not economical.

Thus, the underwater concrete produced according to the present invention is
Since the cement components and fine aggregate and coarse aggregate are mixed well, they do not separate even if they fall freely into the water and are poured to the bottom of the water, and harden to form concrete with strong holes.

There is also a φ effect that makes the surrounding water look ugly. Therefore, it is extremely useful for various underwater construction works such as quay wall improvement work and lankyakusode reinforcement work.

Examples will be shown below, but the present invention is not limited thereto.

Actual hI example 1 1! ! A concrete composition containing 4.151 grams of Portland cement, 785 grams of fine aggregate, 899 grams of coarse aggregate, and 203 grams of σ water is mixed with 936% hydroxyethyl cellulose, 4.7% sodium sulfate, and Nopco PDI (as an antifoaming agent). San Nopco Co., Ltd.) 1.7% admixture as the main component and NL4000 (policys product #) as an auxiliary agent.
were added to cement in a predetermined ratio as shown in Table 11.

Next, the properties of concrete that has not hardened yet and the compression of gorged concrete Ii+1! The temperature was measured. Next 11
The determination was based on the following test method.

1) Cement runoff rate: According to the test method for cement runoff rate of underwater concrete in "Underwater Concrete" co-authored by Gumizo Akatsuka and Rin Seki, Konoshima Publishing, graded P250-251.

2) Underwater strong motion*: submerged l 10 x 20c
Oil is applied to concrete that has not hardened yet into the formwork, and after forming in water without using a hammer, it is pulled open in the air, and the surface is smoothed when the formwork is lightened with a mallet.
132 How to make concrete strength test specimens and J Engineering SA 1108 Concrete test method.

The results of this example are shown in Table 1.

J161 in Table 1 and Table 2 corresponds to a comparative example in which no admixture is added, and the underwater compressive strength cannot be measured because material shadowing occurs during underwater molding.

Example 2 Ordinary Rutland cement 858N, 4111it
The cellulose shown in Table 2 was added to the mortar composition with a constant m' content of material 1623N and water 4209.

058%, 0.029% and 0.01% (2) of gold kI4 base and antifoam agent for 1+cement placement, respectively.
The steel frame strength in water and the underwater compression IiI & I vagina were determined for each mortar obtained.

(9) The measurement was performed using the following method.

1) Good suspension: Preliminarily place in a 1000-meter graduated cylinder.
Add 10'00 of water, then measure out 50' of hot mortar and drop it into the water. After 1 minute of falling,
Using a whole pipette, measure the graduated cylinder aI41J1.
Rank M (4o.

-), and IL! [Searching for the gate of S substances.

2) Underwater compression %pJ: Φ5X10c+++ submerged in water
Examples 1 and 1 were tested uniformly using the molds.

The order of cellulose used as a component of the admixture is shown below.

(lO) The results are shown in Table 2.

From the above results, the use of water-soluble cellulose ether with high viscosity increases the compressive strength, which is generally 10,000
OP or more, preferably 50,0OOOP or more in %1, and the water-soluble cellulose ether H used above
KO's MS is 2.8° + 1JJ *HIc S's M 8
It is 4i1.8, and HICO or compression strength is larger.
*The condensed oil layer is smaller in HICC! It's there.

(11) Table 2 (12)

Claims (1)

[Claims] 1) Water-soluble cellulose ether, water-soluble metal sulfur t1N
2) An admixture for underwater concrete mainly containing a pot or a metal chloride, and an antifoaming agent 2) An admixture for underwater concrete 3 according to claim 1, wherein the water-based cellulose ether is hydroxya or alkylcellulose. ) The hydroxyalkyl cellulose is hydroxyethyl cellulose, a mixture and additive for underwater concrete according to claim 2. 4) The number of moles of ethylene oxide in the hydroxyethyl cellulose is 26 to 5, according to claim 394. Admixture for underwater concrete and leet 5) Patent claim s which is gold with 4 sulfuric acid or sodium sulfate
b) The admixture for underwater concrete according to claim 1 6) The admixture for underwater concrete according to claim 1, wherein the gold mmide is sodium chloride or calcium chloride 7) Based on 100 mkt parts of water-soluble cellulose ether , an admixture for underwater concrete according to claim 1, comprising 2 to 30.0 parts of a metal sulfate or a total metal compound and 05 to 151 km of an antifoaming agent.