JPS58199927A - Edge releasing method of steel member in cement-based hardened object - Google Patents

Abstract

PURPOSE:To simplify the releasing work of a cement-based hardened object as well as make it inexpensive by a method in which a steel member, e.g., steel bar, etc., whose surface is coated with an antifriction material, is positioned in a cement-based hardened object, the hardening of the object around the steel member is retarded, and the steel member is released from the cement-based hardened object. CONSTITUTION:One end of a shearing resistant iron bar 2 buried in the unit continuous wall A of a concrete continuous wall is projected toward the adjacent unit continuous wall A', and an antifriction agent 1 is coated on the periphery of the projected part of the iron bar 2. In the same way, when burying a shearing resistant iron bar 2' in a continuous wall A', the iron bar 2' is projected toward the continuous wall A and an antifriction agent 1 is coated on the projected part of the iron bar 2'. Under the condition, concrete 3 is placed and hardened, whereupon the hardening of the concrete in the peripheral area of the shearing iron bars 2 and 2' coated with antifriction agent 1 is retarded. In this way, releasing work for the steel member and the cement-based hardened object can be simply attained at low cost only by coating the antifriction agent on the bars without the need to use sheath.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cutting edges of steel materials in a cement-based cured product.

BACKGROUND ART Conventionally, a method of cutting edges using a sheath has been adopted as a method for edge cutting steel materials in cement-based hardened materials such as concrete. For example, in a concrete continuous wall where expansion joints are made, as shown in Fig. Alternatively, in the earth anchor construction method shown in FIG. The free length is secured.

In this construction method, a sheath is required for the tension members and the reinforcing bars for the sheathing, which makes construction laborious and increases costs.

The purpose of this invention is to cut the edge of a steel material in a cement-based cured material using a friction reducing agent instead of a sauce, and to cut the edge of a cement-based cured material and steel material in a simple operation and with low friction. shall be.

Next, the invention will be explained in detail based on the embodiment shown in FIG.

The lubricant 1 used in the method for cutting the edge of true wood in a cement-based cured material according to the present invention is mainly composed of a setting retarder and an elution modifier.

As a setting retarder, among 1jAE agents, water reducing agents, AE water reducing agents, etc., those having a curing retarding effect are used.

For example, oxy/carboxylic acid derivatives, polyol complexes
These include alkylbenzene sulfonate, likunin sulfonate, oxycarboxylate, alkino-allylsulfonic acid polymer, and the like. In addition, as a bath release regulator, it is in a highly viscous state and can be adhered to a solid surface. Conch I
It has the property of eluting or migrating into the J-layer without force), such as carbonyl 7-methylcellulose (CCMO), polyvinyl alcohol (PVA), polyacrylic acid, polymethacrylic acid, etc. There are natural glues such as polymer and starch glues, and greases.

Next, construction of a concrete IJ+G continuous wall (FIG. 6) and construction of an earth anchor (FIG. 4) using the above-mentioned anti-friction agent 1 will be explained.

First, to explain the case of constructing a concrete IJ-1-4 continuous wall, one end of the shear reinforcing bar 2 buried within the unit continuous wall A of the concrete continuous wall is attached to the outer periphery of the part that protrudes from the adjacent A. 4 Apply agent 1. Also, unit continuous wall A”
If the shearing reinforcing bars 2" buried in the wall protrude toward the continuous wall A, apply anti-friction agent 1 to the coworker. In this state,
Even if the concrete 6 is hardened after pouring l-troyi, the hardening of the surrounding areas of the shear reinforcing bars 2 and 2' coated with the g thickening agent 1 is delayed.

Therefore, even if the unit series VC%tjL-A" is deflected and shrinks due to heat, the adjacent single continuous wall of the shear reinforcing bar 2.2"
The inwardly projecting portion slides to ensure connection between adjacent unit continuous walls A, A''.

Further, the unit series [9A-A'' will not be damaged.

Next, I will explain when constructing an earth anchor.
A tensile material 5 such as a numbered steel rod is inserted into the bore hole 4 which has been drilled in the ground. The anti-friction agent 1 is applied to the outer periphery of the tensile material 5 only for a certain length from near the ground surface <71). Therefore, even if a lubricant 1 is applied to the deepest part of the tensile material 5, and a cement-based hardener 6 such as concrete IJ-t is filled into the bore link hole 4 and hardened, the tensile material Peripheral force S of 5 hardens only at the deepest part, and the area around the part to which anti-friction agent 1 is applied is slightly hardened.

After this, if tension is applied to the tensile material 5, the part coated with the anti-friction agent 1 will slide, making it possible to apply tension to the ground.

The curing speed of the curing agent 6 can be adjusted by changing the combination of the curing retardant and the elution modifier in the antifriction agent 1. After applying tension to the tensile material 5, the curing agent 6 hardens and the soil and the tensile material 5 can be integrated.

The method for cutting the edge of steel in a cement-based cured product according to the present invention has the above-described structure, and thus can obtain the following effects.

■ By simply applying an anti-friction agent without using any sauce, it is possible to cut the edges of two steel materials and cement-based hardened materials, making it possible to perform construction with simple work and low friction.

■ By adjusting the composition of the curing retarder and elution retarder in the lubricant, it is possible to harden the cement-based hardened product at the desired time, making it an effective substitute for sauce in a variety of construction applications, and subsequent peripheral hardening. can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of a conventional concrete continuous wall with expansion joints in construction, Fig. 2 is a longitudinal cross-sectional view of a conventional earth anchor in construction, and Fig. 3 is an edge cut that applies this invention. FIG. 4 is a vertical cross-sectional view of a concrete continuous wall constructed using the method, and FIG. 4 is a vertical cross-sectional view of an earth anchor constructed using the 1-force edge cutting method of the present invention. 1. Anti-friction agent 2. 2'... Rebar for shearing 6.. Concrete 4.. Poling hole 5.. Tension material 6..
Hardening agent A-A'... Unit continuous wall 1st Figure 21 Figure 2 Figure 4

Claims (1)

[Claims] (1) When cutting edges of steel materials such as steel rods in cement-based hardened materials, apply an anti-friction agent to the surface of the steel material in advance and place it in the cement-based hardened material so that it remains around the steel material even after the cement-based hardened material has hardened. A method for cutting edges of steel in a cement-based cured material, the method comprising cutting the edges of the steel and cement-based cured material by delaying the hardening of the steel.