JPS6231462Y2 - - Google Patents

Description

[Detailed explanation of the invention] The purpose of this invention is to prevent collapse of the inner wall of the pile due to contact with construction jigs that utilize the center hole of the pile, such as auger screws used in the pile hollow construction method, or due to earth pressure during construction. This relates to concrete piles. Conventionally, when burying a concrete pile using the center hole of a concrete pile by inserting an auger screw or the like and excavating mud, the auger screw or other jig and its blade may come into contact with the wall of the center hole of the pile. There were problems such as damaging the wall surface and weakening the wall, and increasing earth pressure entering the central hole, causing the inner wall to collapse.

However, this invention provides a layer of resin concrete on the inner wall of ordinary concrete, thereby significantly strengthening the inner wall of the central hole of the pile and solving the problems of the conventional method.

That is, this idea involves feeding a predetermined amount of ordinary ready-mixed concrete (for example, a mixture of 1 part cement, 2 parts sand, and 3 parts gravel and mixing it with an appropriate amount of water) into a form for centrifugal forming. Rotate to form concrete layer 1, then feed an appropriate amount of resin concrete made by mixing styrene resin at a ratio (weight) of 15% (by weight) to the cement of the above-mentioned ordinary ready-mixed concrete to the inside of concrete layer 1, and centrifugally form it. Layer resin concrete layer 2 with outer diameter 500mm and wall thickness 80mm.
A concrete pile of mm was obtained. The resin concrete layer has the purpose of reinforcing the inner wall and is designed to reduce the pile thickness.
It was recognized that the objective could be achieved with less than 1/3. Practically speaking, resin concrete with a thickness of 6 mm to 30 mm is suitable for concrete piles with a wall thickness of 80 mm.
The desired purpose can be achieved by setting the thickness to about 1/10 to 1/2 of the pile wall thickness.

That is, if the thickness of the resin layer is too large, the increase in the strength improvement effect will be saturated and it will be uneconomical, while if it is too thin, the strength improvement will be insufficient.

Furthermore, if the amount of resin used in the resin concrete of this invention is less than 5% (by weight, the same applies hereinafter) of the amount of cement, no effect of the resin will be observed (for example, protection of the inner wall of the pile by the blade of an auger screw). ), no improvement in performance is observed even if the amount exceeds 25%, so the resin amount is preferably between 5% and 25%, and about 15% is best.

As the resin for the resin concrete, in addition to the styrene resin, acrylic acid ester resins were also found to have similar effects.

The concrete pile of this invention strengthens the inner wall and significantly improves water resistance, so methods such as removing mud through the central hole of the pile or rotating an autoscrew inside when installing underwater to remove mud. It has sufficient strength even when used in piles, and is effective in preventing collapse of the inside of the pile.

In addition, in this invention, a resin concrete layer is placed directly on the inner surface of the ordinary concrete layer to obtain the effect of improving strength, and the ordinary concrete layer and the resin concrete layer, which are mostly made of the same concrete, are The contact has the effect of ensuring that the bond is established without the need for other means. Therefore, the basic material of the concrete pile of the present invention is concrete, and the application of conventional concrete piles is not limited, and effects such as improved strength can be obtained.

[Brief explanation of the drawing]

The figure is a sectional view of an embodiment of this invention. 1... Ordinary concrete layer, 2... Resin concrete layer.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A concrete pile in which a resin concrete layer with a resin content of 5% to 25% (by weight) of cement is provided inside the ordinary concrete layer. 2. The concrete pile according to claim 1, wherein the resin concrete is a mixture of styrene resin (including copolymerization) or acrylic acid resin (including copolymerization) and ordinary concrete.