JPH01256663A - Method of curing water-hardenable cement compound - Google Patents

Abstract

PURPOSE:To enhance the strength of the outer surface of a concrete compound so as to prevent occurrence of defects due to curing, by providing a layer containing water-absorptive resin in contact with the inner surface of a molding frame, and by leaving the layer on the outer surface of the cement compound upon parting of the molding frame for curing the cement compound. CONSTITUTION:When a concrete 2 is charged into a molding frame 1 so as to build a wall, there is provided a layer 3 containing water-absorptive resin in contact with the inner surface of the molding frame 1. After thus charged concrete 2 being cured, the molding frame 1 is parted while the layer 3 is left on the outer surface of the concrete 2. The concrete 2 is cured while its outer surface being covered with the layer 3, and after predetermined curing period elapses, the layer 3 is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a curing method for hydraulic cement compositions (hereinafter referred to as concretes) such as concrete and mortar.

[Problem that the invention seeks to solve]

The retention period of formwork and sheathing plates filled with concrete is specified in the Building Standards Act and JASS5, and proposals have been made to extend this retention period in order to improve the quality of concrete and light resistance. ing. However, conventionally, many efforts have been made to remove the formwork as early as possible and use it repeatedly to increase the operating rate of the formwork.

However, if the mold is demolished early, it is necessary to cure it by supplying water from the outside or by covering the exposed surface to prevent moisture evaporation. It was difficult to maintain proper curing conditions.

This invention has been made in view of the above-mentioned problems. The purpose of this is to suppress the evaporation of water from the surface of poured concrete without the need for labor-intensive work, to supply the water necessary for hydration, and to maintain surface strength even if the formwork is removed early. The purpose of the present invention is to propose a curing method for concrete that can produce a high-quality cured product that has a high hardness and can prevent the occurrence of defects due to curing.

[Means and Examples for Solving Problems] This concrete curing method is based on the method of curing concrete by providing a water-absorbing resin-containing layer in contact with the inner surface of the formwork when pouring concrete into the formwork. When demolding, the resin-containing layer is left attached to the surface of the cement composition and cured.

Examples will be described below with reference to the drawings.

In FIG. 1, when constructing a wall by pouring concrete 2 into a formwork 1, a water-absorbing resin-containing layer 3 (hereinafter referred to as a water-absorbing layer) is provided in contact with the inner surface of the formwork 1. As shown in FIG. 4, this water absorption layer 3 consists of two layers of polypropylene nonwoven fabric 4,
The water-absorbing resin granules 5 and a water-absorbing substance such as pulp are weakly bonded with a small amount of binder and inserted between the holes 4 and 4.

When the concrete 2 poured into the formwork 1 has hardened to the extent that it is not easily damaged, a water absorption layer 3 is formed as shown in Fig. 2.
is left attached to the surface of the concrete 2, and the formwork 1 is removed from the mold. The concrete 2 is cured with its surface covered with a water-absorbing layer 3, and when sufficient strength is developed after a predetermined curing period, the water-absorbing layer 3 is removed as shown in FIG. 3 and a wall is constructed.

Figure 5 is a detailed view of the form l and the concrete 2 poured inside it. It is fixed by driving into a wooden formwork 1. Further, an S-shaped locking tool 8 whose one end is locked is provided protruding from the water absorption layer 3 and embedded in the poured concrete 2 to lock the water absorption layer 3 to the concrete 2. After removing the formwork fasteners 9 and the end pieces 10, the formwork 1
is peeled off at the interface with the water absorption layer 3 and demolded. The water-absorbing layer 3 is in contact with the two concrete surfaces, is retained with a retainer 8, and is left for curing.

The water-absorbing resin used in this curing method is made of a water-soluble resin with a crosslinked structure, and rapidly absorbs a large amount of water and swells in water. Various types of resins can be used, but types that do not easily reduce water absorption performance even when adsorbing electrolyte ions such as calcium ions, such as those with hydroxyl groups as the water absorption functional group (Sumitomo Chemical Co., Ltd., Sumikagel R) -3
0, etc.) is preferable. Furthermore, it is desirable to cover the surface of the water absorbing layer with a fabric, porous membrane, etc. that has a filter function and has fine pores that are difficult for cement particles to pass through.

[For production]

This invention consists of the above configuration. With this curing method, the water absorption layer provided in contact with the inner surface of the formwork absorbs free water from the surface layer of the concrete placed within the formwork and swells. This absorbed water is difficult to evaporate and is retained within the water absorption layer for a long period of time. Therefore, even if the formwork is removed relatively early, by leaving the water absorption layer attached to the concrete surface, the water required for hydration of the cement is replenished, and suitable curing conditions can be established without the need for manpower. Can be maintained.

In addition, the water-absorbing layer prevents rapid temperature changes and drying of the concrete surface, and absorbs excess free water.
Contributes to the formation of high quality cured products without defects.

For example, when constructing a high-rise concrete building using this curing method, the formwork can be removed relatively early and used as formwork for the next floor one floor above, so the equivalent of the first floor can be
All you need to do is prepare the set. The water absorption layer can be attached to the concrete surface for a longer curing period than the formwork, and the removed water absorption layer will be reused for attachment to the inner surface of the formwork on the second floor above, so two sets must be prepared.

〔Effect of the invention〕

This invention is as described above, and according to this curing method,
■Work efficiency (Able to cast concrete and create high quality hardened material.

■It is possible to increase the operating rate of formwork and reduce equipment costs.

[Brief explanation of the drawing]

Figures 1.2.3 are longitudinal cross-sectional views showing an example of this concrete curing method in the order of steps; Figure 4 is a cross-sectional view of the water absorption layer;
FIG. 5 is a detailed sectional view of the formwork with concrete poured inside. 1...Formwork, 2...Concrete, 3
...Water-absorbing resin gold layer (water-absorbing layer), 4...
...Nonwoven fabric, 5...Water-absorbing resin granules, 6...
... Paper pressure, 7 ... Nail, 8 ... S-shaped locking tool, 9 ... Formwork tightening tool, 10 ... Thick material.

Claims (1)

[Claims] (1) When pouring a hydraulic cement composition into a formwork, a water-absorbing resin-containing layer is provided in contact with the inner surface of the formwork, and when the formwork is removed, the resin-containing layer is attached to the surface of the cement composition. A method for curing a hydraulic cement composition, characterized by leaving it in place for curing.