JPH0463183B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a method for chiseling a cement-based cured product, more specifically, a method for casting a cement-based cured product in contact with a solid surface, and after the cured product has solidified, Concerning the chisel method.

Conventionally, steel materials, etc. are buried in concrete or mortar, and in order to expose the surface of the steel materials after solidification, it is necessary to chisel using a rock drill, hammer, etc. This chiseling work required a great deal of labor, resulting in high costs and low work efficiency. In addition, this work always involves noise, vibration, etc., and is not favorable from the standpoint of environmental protection or occupational safety and health.

This invention was made in view of the above circumstances, and its purpose is to easily strip concrete, mortar, etc. from solid surfaces such as steel materials without using a rock drill, thereby impairing environmental protection and occupational safety and health. The purpose of this invention is to propose a chisel method that can reduce the construction cost and construction period.

The gist of this invention is to place a cement-based cured product in contact with a solid surface, and after the cement-based cured product hardens, when peeling off the cured product in contact with the solid surface,
A hardening retarder layer consisting of a mixture of a cement hardening retarder and a viscous elution modifier, which adheres to the solid surface and gradually dissolves the cement hardening retarder, is placed on the solid surface at the position where the hardened material is to be peeled off. A method for chiseling a cement-based hardened material, characterized in that an uncured hardening retardation layer is formed between the solid surface and the cement-based hardened material.
In FIG. 1, a hardening retarder layer 2 containing a cement hardening retarder and an elution regulator as main components is applied in advance to one surface of a solid 1 made of steel from which a cement-based cured product is to be removed. In FIG. 2, this solid 1 is erected and a cement-based hardened material 3 is poured. The cured product in the vicinity of the surface of the solid 1 to which the cure retardant layer 2 is applied is affected by the cure retarder and hardens more slowly than in other parts, and becomes a cure retardant layer 4. FIG. 3 shows the state in which the cured product 3 is peeled off after it has solidified. Even though the cured product 3 is solidified, the hardening retardation layer 4 near the hardening retarder layer 2 is not solidified, so a rock drill or similar tool is used to remove the hardened material 3. It can be easily suspended by internal excavation without using a Therefore, according to this method, the hardened material can be easily lifted from the solid surface of a steel material or the like buried within the cement-based hardened material, while reducing construction time and cost. Furthermore, it does not generate noise or vibration, ensuring environmental protection and occupational safety and health.

In this method, the hardening retarder is gradually eluted into the cement-based cured product from the hardening retarder layer, which is made up of a hardening retarder and an elution modifier provided on the solid surface. Even after curing, an uncured hardening retardation layer is formed near the surface. In addition, since the curing retarder is retained in the elution modifier and applied or pasted onto the solid surface, it is easier to peel off or elute than when the curing retarder is directly applied. There is no loss of functionality.

As the cement hardening retarder used in this invention, ionic or nonionic surfactants having a hardening effect such as lignin sulfonate, oxycarboxylic acid derivative, polyol complex, alkylbenzene sulfonate, etc. are used. . An elution modifier is a substance that is in a viscous state and can be applied to a solid surface and adhered to it.When a curing retarder is dissolved or dispersed and applied as a curing retarder layer to a solid surface, The hardening retarder has the property of being eluted or transferred little by little into the layer of the cement-based cured product. Examples of substances that have this effect include aqueous solutions or hydrophilic polymers such as carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), polyacrylic acid, polymethacrylic acid, polyvinyl acetate, and polyoxyethylene. Materials, natural thickening agents such as starch, or greases are suitable. The water-soluble polymer and natural glue are dissolved in water to form a viscous solution, and the curing retarder is dissolved in this. Greases can be used directly with a curing retardant or mixed and dispersed with a solution thereof. The curing retarder can be used by being mixed with the elution modifier, or the curing retarder may be directly applied to the solid surface, and the elution modifier may be applied thereon to form a curing retarder layer.

Hereinafter, an example of the composition of a hardening retardant layer that delays the hardening of a cement-based cured product and facilitates chiseling of the cured product using this chiseling method will be described.

Targeted solid: Steel Lignin sulfonate retardant *: PVA: Water = (18:3:79) (48:8:46) Lignin sulfonate retardant: Starch glue: Water (42: 14:42) Lignosulfonate-based retardant: Grease = kneaded product * Pozolith 8 manufactured by Nisso Master Builders was used as the ligninsulfonate-based retardant.

[Brief explanation of drawings]

The drawings show an example of construction using this chiseling method in the order of steps. Figure 1 is a side view of the steel material to which a hardening retardation layer has been applied in advance, and Figure 2 is a side view of the steel material with the hardening cement layer applied. FIG. 3 is a longitudinal sectional view of the cured product being cut. 1... Solid, 2... Curing retardant layer, 3... Cement-based cured product, 4... Curing retarding layer.

Claims (1)

[Claims] 1. Place cement-based hardening material in contact with a solid surface, and after the cement-based hardened material hardens, when removing the hardened material from the solid surface, apply a cement hardening retarder to the solid surface in advance at the location where the hardened material is to be removed. A hardening retarder layer consisting of a mixture with a viscous elution modifier, which adheres to the solid surface and gradually elutes the cement hardening retarder, is provided between the solid surface and the cement-based cured product, and an unhardened hardening retardant layer is provided between the solid surface and the cementitious hardened material. A method for chiseling a cement-based hardened material, characterized by forming a layer.