JPS58146621A - Top treatment of on-site concrete pile - Google Patents

Abstract

PURPOSE:To reduce the cost of chipping the top of pipe by a method in which a superretardant plasticizer composed mainly of a hydroxycarboxylate in an excessive amount beyond a specific ratio to the amount of cement is mixed in the concrete of the top of a pile to hinder the coagulation of the cement. CONSTITUTION:After concrete 1 for on-site pile is placed, a superretardant plasticizer composed mainly of a hydroxycarboxylate in an excessive amount more than 3% of cement amount is mixed in a banking concrete 1a while turning a propeller-shaped mixer 2. By this, the setting of the concrete 1a in the banking portion can be avoided until the time to treat the top of the pile, so that the treatment of the pile top can be attained only by jetting water to flush the necessary portion.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pile cap treatment method for cast-in-place concrete piles.

Cast-in-place concrete piles are placed in muddy water using tray pipes.

In this case, it is unavoidable that the strength of the concrete of the finished pile l [s is insufficient due to the inclusion of slime, etc. in hot water. I have to pray for heat.

The cost required for iFrri of ζO pile meditation can be said to be essentially wasteful.

9. The noise generated at 1lrj, the pollution +s
Amidst all the oi*tz, Hiro is #1, especially in construction work in urban areas.
It is ItI4.

In addition to these, there are also major disadvantages in terms of construction time.

Several measures have been considered in the past to ameliorate this problem.

To give an example of this, C1) After pouring the contour concrete, mix water or earth and sand to weaken the foldable concrete.

This method slightly reduces the strength of the concrete itself and makes it easier to grind, but it has almost no effect on most people.

In fact, there seems to be no shortage of reports that this method has nine benefits.

(2) After concrete is poured, use a bucket to scoop up and remove the concrete containing slime from the top.

The fatal problem with this method is muddy water, but concrete with a grade of 20 degrees Celsius cannot be cleaned up with just a single puke.

If we were to really try to implement it, there would be no choice but to take the risk of having people enter and do the work, which would create a serious safety issue.

(3) After concrete is poured, high-pressure air is blown into the concrete containing slime at the top to force separation and reduce later work.

Originally, in this method, even if air was pumped into the concrete, the air would not be spread evenly throughout the concrete, but would only exist as bubbles that would partially solidify.

Therefore, even if there is a slight increase, the effect is small.

The present invention has been made in view of the above-mentioned circumstances and to develop a new means that is easy to analyze. In general, ultra-retardant water reducers are added at a cement weight ratio in the range of α1 to α7.
[It is said that there is no sudden effect on the properties of animals.]

Currently, several theories have been proposed regarding the mechanism of the setting retardation property of ultra-retarded water reducers, but it is said that the retarder adsorbed on cement particles forms a kind of retention.
The theory that it suppresses the reaction between unhydrated cement and water seems to have the most support.

This theory is considered to be the most rational explanation for the test results, stating that the effect of the retarder extends the incubation period of cement at the initial stage of water use. If #11 of the agent is shaken to a great extent, the protective film covering the Ryumento particles will expand at4ho, and even if the protective film is destroyed and the hydration reaction is about to start, the surrounding Furthermore, if a retardant component is present in the water, it is possible that a retention agent may be formed in the new material, and the retardation effect may continue for a long time (or it may not harden semi-permanently). i) expected.

From this point of view, the present invention was developed by observing the setting retardation properties of mortar to which a 10-fold amount of an ultra-retarded water reducing agent was added than usual.

In other words, to study the setting retardation properties of ultra-retarded water reducers, we will use ultra-retarded water reducers to delay Oi11 pongee (originally cement) for several hours to 3 days with the aim of improving the IIO performance of contourito batting lines. However, among the several commercially available ultra-retardant water reducers, if one containing oxycarboxylate as its main component is added to the cement by weight or more, it will slow down the hardening of the cement for several weeks. Recent studies have shown that VC-g can be inhibited through ultra-retarded water reducing agents! The state caused by adding 1lII is
It's simply due to poor curing! i! It turned out that if the IF was low, the p was also in a state where mt would flow out just by applying tap water.

The present invention was made based on new findings regarding the effect of oxycarboxylate on cement setting retardation, and its gist is that concrete distribution of cast-in-place piles
By mixing an excessive amount of an ultra-retarded water reducer mainly composed of oxycarboxylic acid salts by 3 cm or more of the weight of K-cement, setting of this area is prevented, and the conventional method of pile l1ls (l1ls) is prevented. The key point is that it is intended to significantly reduce the

Details of this will be explained below based on the drawings.

Figure 1 shows the outline of the construction method of the present invention. After pouring concrete 1 for cast-in-place piles, as shown in the figure, an ultra-retarded water reducing agent containing oxycarboxylate as a main component is added directly to the overlay concrete 1. are combined by rotating the propeller-shaped mixer 2 at the same time.

In this case, the amount of the super retarder to be added is at least 3 times the weight of the cement in the concrete la in the excess layer, and the stirring time is 5 to 10 minutes.

Due to the treatment of piles, the concrete IJ-1m for the residence and the concrete pile remains unhardened until the surrounding excavation is completed and the piles are treated.

Therefore, when treating the pile head, it is possible to wash away the excess concrete with concrete water, and the treatment work can be partially completed with a device that conveniently uses an electric dumpster.

``Example'' As a mixing means, a hand
was stirred.

The amount of ultra-retarded water reducing agent added is set to 10 times the weight of cement in the concrete in the overfill area.

In this example, nine things that are clearly apparent are as follows.

(The area treated with 17 is so strong that it is necessary to partially use an electric shock absorber [-, and most of it is washed away by spraying water.)

(2) In this example, the sharpening efficiency of the untreated pile was $14 Vm'', which was nearly three times as high as 8 ruj1.

(3) A strength test was conducted by extracting a core from the concrete below the specified top after being treated with a super retardant and folding. There is no difference at all compared to the exchange rate. That is,
The super retardant used in l& has no adverse effect on the main body of the pile.

As described above, the construction method of the present invention eliminates the need for conventional breaker and compressor, and improves the total pile head treatment. In addition to significantly reducing the cost of pile cap treatment, the construction period required for pile cap treatment can be halved.

This greatly reduces noise and dust generation.

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional view of a cast-in-place concrete pile showing the gist of the construction method of the present invention. l...Hun/Lee) 1m...Excess concrete) 3...Kisa-0 Inventor Junro GodaJi @ Inventor Eiji Okubo 1) Shun Naka Inventor Saku 1) Akira Active- Person: Yoshihiko Kubo Applicant: Takenaka Construction Co., Ltd. Zudere 4 Procedural Amendment (voluntary) 1. Indication of the case Showa Era Patent 1 II O 8027g No. 1 Name of the invention Antigen treatment method for cast-in-place concrete piles 3. Amendments made Relationship with the patent applicant case (31$2) Takenaka Corporation 4, agent's scope of claims column in the specification. 6. Contents of the amendment The description of the scope of the patent claims has been revised as shown in the attached document.
1 [@Km By mixing an excessive amount of a water-reducing agent whose main component is a dicarboxylic acid salt in an excess amount of 3 Km or more of the amount of cement, this part will be prevented from coagulating, and a prayer for the accumulation of piles will be made. ``Pile head treatment method characterized by reducing the pile width to a large width.''

Claims (1)

[Claims] For cast-in-place concrete piles, setting of this area can be prevented by mixing an ultra-retarded water reducer mainly composed of oxycarboxylic acid salts in an excess amount of 3 seconds or more compared to the amount of cement in the concrete head of the pile. A pile head treatment method characterized by preventing the piles from forming and greatly reducing the fold 9 of the piles 1IIIs.