JPS62242051A - Concrete casting and connecting construction method - 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 (Field of Industrial Application) The present invention relates to a method for concrete jointing in the construction of wall-shaped reinforced concrete structures such as intake and drainage facilities, waterways, retaining walls, etc.

(Prior art) Conventionally, when constructing the various wall-shaped reinforced concrete structures shown in Figs. 3 and 4, the lower concrete IJ was first constructed.
- After pouring the (al), the upper concrete (b) is poured on top of it.For this purpose, the upper concrete (1
)) and the lower concrete (al), a concrete pour joint (cl) is created.

(Problems to be Solved by the Invention) After concrete is poured, it gradually hardens due to the hydration reaction of cement, but a large amount of heat is generated during this process. For this reason, concrete expands during the hardening process, and after the heat reaches its peak, it gradually cools down, but during this cooling process, the concrete contracts.

At the same time, a phenomenon of drying shrinkage occurs due to moisture dissipation in the concrete.

Therefore, when pouring the upper concrete (b), since the lower concrete (a) has already hardened, the shrinkage of the lower concrete (upper concrete (1)) is restrained by at, and the upper concrete (b) Pour seam (C
A crack h(a) will be generated upward from 1.

Since the shrinkage of the upper concrete IJ-bl is due to the characteristics of concrete, the cracks (4)
It is virtually impossible to prevent 1. Currently, a large number of crack-prevention reinforcing bars are placed to disperse cracks.

(Means for solving the problems) The present invention aims to solve these problems,
In the concrete pouring method, in which new concrete is poured over existing concrete that has already hardened, a thin layer of concrete that has a slower hardening speed than the new concrete is deposited on top of the existing concrete. It is characterized by pouring new concrete over the existing concrete, and its purpose is to provide a concrete pouring method that is easy to perform and can suppress cracks that occur in concrete that is poured over existing concrete.

(Function) As described above, in the present invention, a thin layer of concrete having a slower hardening speed than new concrete to be poured onto the concrete is deposited on the existing concrete that has already hardened, and then Therefore, when the new concrete concrete is hardened and is about to undergo shrinkage deformation as described above, the thin layer of concrete, which has a slow hardening speed, has not yet hardened. First, since the new concrete does not have enough rigidity to restrain shrinkage deformation, the new concrete can be freely deformed, and the occurrence of cracks in the new concrete is suppressed.

(Example) The present invention will be described below with reference to the illustrated embodiments.

In Figures 1 and 2, (1) is the existing lower concrete that has already hardened, on top of which a thin layer of concrete (2) with a slow hardening speed to which a hardening retardant has been added is poured, and then the same thin layer (2) is poured. A new upper concrete (3) without the addition of a hardening retarder is poured on the layer (2).

Since the illustrated embodiment is configured as described above, when the upper concrete IJ-t (3) hardens and is about to undergo shrinkage deformation, the concrete thin layer (2) has not yet hardened. , since the strength and rigidity sufficient to restrain the shrinkage deformation of the upper concrete (3) is not developed, the upper concrete (3) can be freely deformed, and cracks may occur in the upper concrete (31). is prevented.

Although the present invention has been described above with reference to embodiments, the present invention is of course not limited to such embodiments, and the seed design may be modified without departing from the spirit of the present invention. be.

(Effect of the invention) According to the invention, as described in ii. The strength and rigidity of the thin layer reduces the force that restrains the shrinkage deformation of the newly constructed concrete above it, and by absorbing the shrinkage deformation of the newly constructed concrete, it is possible to suppress the occurrence of cracks in the newly constructed concrete. .

As described above, according to the present invention, it is possible to suppress the occurrence of cracks in splicing concrete during concrete splicing with simple construction.

[Brief explanation of drawings]

Figure 611 is a front view showing the implementation status of one embodiment of the concrete pouring method according to the present invention, and Figure 2 is a view taken in the direction of the arrow in Figure 1.
Figures 1 and 3 are front views showing the implementation status of the conventional concrete pouring method, and Figure 4 is a view taken along the arrow IV-M in Figure 3. (1)... Lower concrete (2)... Thin layer of concrete with slow hardening speed (3)
・Upper concrete sub-agent Patent attorney 2 persons other than Kaihon Important Cultural Property

Claims (1)

[Claims] In the concrete pouring method, in which new concrete is poured over existing concrete that has already hardened, a thin layer of concrete that hardens at a slower rate than the new concrete is deposited on top of the existing concrete. A concrete pouring method characterized by pouring new concrete on top.