JPS6140965A - Concrete construction system - 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] Purpose of the Invention j <Industrial Application Field> The present invention provides a concrete structure in the field of civil engineering and construction that has high strength, has a smooth concrete surface, and has good adhesion to topcoat remortar. This paper proposes a system for forming

<Prior art> When forming concrete structures using plywood for formwork itself, cement hardening problems occur, and
Due to the effects of concrete coloring components in the material, color unevenness occurs on the finished surface of the concrete, making it unsightly.Recently, so-called reinforced frame plywood, which is reinforced by coating the plywood surface with acrylic or urethane resin paint, has become widely used. It became, but
Since the paint film thickness of this product is thin, curing inhibiting components and coloring components migrate to the mortar side through the paint layer and affect it, and cracks occur during repeated use of this product.
The above trends tended to become more severe.

The present inventor identified the shortcomings of the conventional reinforced plywood for frames, and as a result of intensive research, developed a new reinforced plywood for frames.
No. 85, Utility Application No. 58-195804, etc.

<Problems to be Solved by the Invention> The present inventor has conducted a comparative study of the necessary physical properties as a formwork for reinforced frame plywood on which various films can be overlaid, and found that biaxially oriented polypropylene film has the best physical properties. In the case of this biaxially oriented polypropylene film, if the slump of the mortar was about 18 or more, a smooth finished surface could be obtained without using a vibrator, but the slump was If the above-mentioned hard kneading was used, a bean-like or honeycomb-like surface that was not smooth was generated.

In the first place, the reason why this biaxially stretched polypropylene film overlay type frame forms a smooth and beautiful finished surface is that the contact angle of this film with water is second only to Teflon, and water or water-based mixtures have a slippery property. This is because the film's W4 abrasion and impact resistance are extremely high, so there is no scratching on the painted surface, which occurs when conventional vibrators are used with painted reinforced frames. Although a smooth concrete surface was obtained, as shown in Table 1 at the end of this specification, there were concerns about variations in the strength of the formed concrete. This variation is similar to that of conventional vibrators.
As it became clear through repeated experiments that this was inevitable during use, the present inventor developed a combination of a recently developed high-frequency vibrator, a reinforced frame by painting, and a biaxially oriented polypropylene film overlay type frame. As a result of a comparison with the case of using a conventional vibrator, it was found that the combination of a high frequency vibrator and a 12-axis stretched polypropylene film overlay type frame exhibited surprising effects.

Structure of the Invention j <Means for Solving the Problems> The mold frame used in the concrete construction system of the present invention is overlaid with a biaxially oriented polypropylene film as a surface material, as shown in the claims. , the overlay may be on only one side or both sides of the base plywood.

An unstretched polypropylene film meets the purpose of the present invention compared to a reinforced frame made by painting, but it is not as strong as a stretched film in terms of strength. It is more preferable that the reinforced frame used in the present invention has its end and end portions coated with waterproof coating.

The high frequency vibrator referred to in the present invention is a converter (
It is a type that uses a high-frequency power source with a safe voltage of 48 cm, which has been converted to a frequency four times the frequency of a conventional vibrator using a frequency converter), to rotate the motor built into the vibrating cylinder at ultra-high speed. The connected pendulums generate powerful vibrations.

Function: When this high-frequency pie-break is inserted into the ready-mixed concrete poured into the mold frame, a strong centrifugal force is generated around the pendulum, giving the mortar a violent circular motion. When a reinforced frame made of paint is used, the violent collision and friction of the mortar mixture causes scratches on the painted surface, which eventually leads to the paint film falling off. On the other hand, biaxially stretched polypropylene films have excellent abrasion and impact resistance, so even if they encounter the intense circular motion generated by a high-frequency vibrator, there will be no damage to the surface. does not occur.

<Example 1> In the RCC structure 1, the reinforced type frame according to the present invention was used for the part facing the outside as the mold frame, and the acrylic resin paint-coated type frame was used for the part facing the inside. A concrete wall was constructed by pouring fresh concrete into the wall, and a high-frequency vibrator was used to pierce the wall in conjunction with the pouring of fresh concrete. After the walls on the first floor were formed, they were disassembled and repurposed for the second and third floors, but the painted reinforced frames developed numerous scratches on the surface on the third attempt, and were replaced on the fifth. Eventually, the paint film fell off and the base plywood was exposed.

On the other hand, in the case of the biaxially oriented polypropylene film overlay type film of the present invention, a few scratches were observed on the film even after 10 uses, but there was no peeling or falling off. The surface using the frame had some honeycomb holes and yellow color unevenness, but the surface using the frame of the present invention had no holes and the hue was uniform.

The ready-mixed concrete used in this example had a slump of 15
, the nominal strength was 255, and the maximum dimension of the coarse aggregate was 20 mm.

Example 2 Using four pieces each of 900 x 1800 mlI-sized painted frames and four frames of the present invention type, two molds each capable of producing concrete plates with a thickness of 150 mm were created using separators. Ready-mixed concrete was poured into this, and the process of curing, demolding, and re-pouring of fresh concrete was repeated 10 times.One side of the same mold frame was tamped with a conventional Eve vibrator, and the other side was tamped with a high-frequency vibrator. When the strength of the cured product was examined each time, it was as shown in Table 1.

Table 1 Bending strength of concrete molding *Number of samples: 2 pieces from each molding, total 20 *Test paddy size: 150
X150X530mm*Test method: JIS-A
According to 1106.

*r range" is the average value of the difference between the maximum value and the minimum value.
As described above, it was found that when a reinforced frame overlaid with a polypropylene film was used and a high frequency vibrator was used, the average strength was maximum and the variation in strength was minimum.

Claims (1)

[Claims] When pouring ready-mixed concrete into the formwork to form a concrete structure, use (reinforced frame plywood overlaid with biaxially oriented polypropylene film as surface material) and use a high-frequency vibrator during and/or after pouring the ready-mixed concrete. A concrete construction system that forms a concrete structure with a smooth and beautiful finished surface and excellent strength, characterized by forming a concrete structure by compacting it.