JPH0324747Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Field of Industrial Application) This invention relates to high-strength concrete treads for use in assembled stairs, and is used in the field of manufacturing precast concrete treads for stairs. (Prior art) Conventionally known concrete stairs are cast on-site, but when cast on-site, concrete is poured after the formwork is set, and the formwork is removed after the concrete has hardened. This not only causes a delay in the construction period, but also has construction difficulties such as restrictions on the construction period as it interferes with other construction work. In recent years, prefabricated construction methods have become popular, and various building materials are provided as precast concrete products. However, when it comes to stair treads, if they are made to be equivalent to those cast on site, they will be large and heavy, making them inconvenient to handle, and the main parts If the thickness was made thin enough to withstand the required strength, there were disadvantages such as the edges tending to chip, which is not desirable in practice. In order to solve this problem, the applicant proposed a precast concrete tread made by molding and solidifying a material in which a predetermined amount of steel fiber was added to cement mortar.
No. 23936). (Problems to be solved) Steel fibers have a high specific gravity, so when vibration molding is used, the steel fibers move downward, making it difficult to evenly distribute the steel fibers in the product. There were problems in that the strength decreased and the surface condition deteriorated. Additionally, there was a risk that the steel fibers exposed on the surface would rust and the strength of the product would weaken over time. Furthermore, it has the disadvantage that it makes a lot of noise when going up and down. (Means for solving the problem) The stair tread of this invention consists of a predetermined amount of cement,
It is constructed by molding and solidifying a material made by adding an appropriate amount of water to sand and vinyl fiber, and providing an attachment part for the stringer. The amount of the vinylon fiber is about 1 to 2% (volume), and the thickness of the single fiber is 14 μm to 0.23 mm.
(1.8 to 500 deniers) and a length of about 4 mm to 24 mm. If it is larger than this, the kneading and dispersion tends to be uneven, and if it is smaller than this, the reinforcing effect will be reduced. A material piece (400
When the relationship between bending stress and deflection was measured using a 100 mm × 100 mm × 100 mm, the results shown in Figure 1 were obtained (No in Figure 1 corresponds to No in Table 1, Vf indicates vinyl fiber). From this result, it can be seen that it is practically appropriate for the amount of vinylon fiber mixed in to be 1% to 2% (volume ratio). The specific shape of the tread in this invention is as follows:
It is not limited to what is shown in the examples.

[Table] (Function of the invention) In this invention, vinylon fiber has the effect of significantly increasing the tensile strength and impact strength of the product. Furthermore, since vinylon fiber is lightweight (1/6 the specific gravity of steel fiber), it is easy to distribute it evenly in the material, and there is no risk of embrittlement due to rust. Furthermore, since vinylon fiber absorbs energy, it becomes a tread with high impact resistance. The material with the composition shown in Table 2 is used in the shape shown in Figure 4 (length 1200 mm, width 370 mm, height 160 mm, tread thickness 50 mm).
An impact test was conducted on the molded and solidified product to a size of 40 mm (rise-up thickness: 40 mm), and the results shown in Table 3 were obtained. When the relationship between bending stress and deflection was measured, the results shown in FIG. 2 were obtained. The formulation in Figure 2
No corresponds to No in Table 2.

【table】

【table】

[Table] (Example) Cement 697Kg/m ³ , Water 279Kg/m ³ , Fine aggregate (sand) 1046Kg/m ³ , Admixture 3.00Kg/m ³ , Diameter 0.2
20 mm long vinyl fiber fiber 13.0 kg/m ³ is uniformly kneaded and filled into a predetermined mold, and reinforcing bars 3 with pipes 2 welded at both ends are buried in the horizontal part of the tread 1. The footboard 1 is constructed by solidifying the above-mentioned material. When the tread plate 1 of this example was used by providing a threaded groove at the tip of the pipe 2 and screwed onto the stringer 5 with the bolt 4, it was found that there was no sense of anxiety and the noise was lower than that of one using steel fiber. , and no chipping of the corners was found. (Effects of the invention) That is, according to this invention, since the step board is made of precast concrete mixed with vinylon fiber, the main part can be made relatively thin, and there is no fear of chipping of the edge part. In addition, unlike treads containing steel fibers, there is no risk of rusting, there is less noise when going up and down stairs, and there is no risk of embrittlement over time as it is highly resistant to alkalis in concrete and weather resistant. Furthermore, since mass production can be carried out in factories, uniform products can be manufactured with high precision, and they can be easily assembled on site, so there are no restrictions on when each component can be delivered to the site, and there are no restrictions on the construction period. There are effects such as no.

[Brief explanation of the drawing]

1 and 2 are graphs showing the relationship between bending stress and deflection, FIG. 3 is a side view showing the state of use of this invention, and FIG. 4 is a partially cutaway perspective view of the same embodiment. 1...Treadboard, 2...Reinforcing bar, 3...Stringer.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A stair tread made by molding and solidifying a material obtained by adding an appropriate amount of water to a predetermined amount of cement, sand, and vinyl fiber, and providing an attachment portion to a stringer. 2 The amount of vinylon fiber is 1-2% (volume)
A stair tread according to claim 1 of the utility model registration claim.