JPH0254067A - Mass concrete 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] [Industrial application field] This invention is a pine slab for dams and large buildings.

This relates to a construction method for mass concrete, which is cast in large quantities in one place, such as on thick walls.

[Prior Art and Problems to be Solved by the Invention] Conventionally, when constructing this type of mass concrete, it was extremely long and thick (if a large amount of concrete was poured to form a large, long lump, So-called mascon cracks had occurred, and they were struggling to find a solution.

Here, we will explain about the cracks in the mask.

Due to the heat of hydration of concrete, mass concrete thermally expands during solidification. However, these mass concrete
In about 7 days, the temperature drops to about the outside temperature and heat shrinks. When mascon is placed on bedrock or in existing concrete, the boundary portions are firmly attached and do not shrink, but the weakly constrained portions contract and cracks occur. This is the so-called mascon crack.

This invention was devised in view of the above-mentioned circumstances, and its purpose is to provide a method for constructing mass concrete in which cracks in mass concrete do not occur.

[Means for solving problems]

According to the method of the present invention, first, a large number of rubber tubes are arranged in parallel in the width direction of the mass concrete, and the rubber tubes extend along the entire length in the thickness direction of the mass concrete at a plurality of locations in the longitudinal direction within a formwork for mass concrete. Place the formwork group.

Next, each rubber tube in this rubber tube form group is filled with air or water, and the gap between each rubber tube is closed, so that the mass concrete form is divided into multiple pieces using each rubber tube form group. After dividing, concrete is poured into the formwork.

After the concrete solidifies, the air or water inside each rubber tube form group is removed and removed, and new concrete is placed in the space provided.

Even when a large amount of concrete is placed at a time, it is divided into multiple pieces by each rubber tube form group.
This is to prevent so-called mascon cracks from occurring by preventing it from becoming one long lump.

〔Example〕

The mass concrete construction method of the present invention will be explained below with reference to illustrated examples.

First, as shown in Fig. 1, in the formwork 1 for mass concrete during reinforcement work for thick and long mass concrete, reinforcement is placed at multiple locations in the longitudinal direction of the mass concrete, extending over the entire length of the mass concrete in the thickness direction. A rubber tube form group 3 is arranged in which a large number of rubber tubes 2 are arranged in parallel in the width direction of the mass concrete.

At this time, each rubber tube 2 is supported by being held between two supporting reinforcing bars 4°4 extending in the width direction of the formwork 1 so that each rubber tube 2 is lined up as shown in FIG. Here, reference numeral 5 denotes a spacing reinforcing bar that is provided so that the spacing between the two supporting reinforcing bars 4.4 does not widen due to swelling when each rubber tube 2 is filled with air or water, which will be described later.

Next, each rubber tube 2 in this rubber tube form group 3 is filled with air or water, and the gap between each rubber tube 2 is closed as shown in FIG. After each rubber tube form group 3 is divided into a plurality of pieces, concrete 6 is poured into the formwork 1 divided into a plurality of pieces at once as shown in FIG. At this time, the concrete 6 is placed across the entire length of the rubber tube form group 3 at equal heights on both sides.

After the concrete 6 poured into the divided formwork 1 solidifies, some air or water is removed from each rubber tube 2 and each rubber tube formwork group 3 is removed. New concrete 7 is placed in the space after the formwork group 3 has been removed.

Note that when the air or water in each rubber tube 2 is to be slightly removed, this is done approximately 3 hours after the concrete 6 has been placed until the concrete 6 stops collapsing.

In addition, the new concrete 7 should be placed at approximately 7 pm after the concrete 6 is placed when the concrete 6 becomes as low as the outside temperature (when the thermally expanding concrete 6 contracts).
Do it in days. The concrete 7 used here is preferably one that expands slightly.

In this way, the mass concrete construction work is completed. Since the concrete 6, which is cast in large quantities at one time, is divided into a plurality of parts by each rubber tube form group 3, the whole is not a single large lump, so that so-called mass concrete cracks do not occur during solidification.

As shown in FIG. 6, the rubber tube 2 used here is formed so that its outer shape becomes a wavy uneven shape when the inside is filled with air or water.

This is to form irregularities on the pouring surface of the concrete 6 so that the concrete 6 and the new concrete 7 to be poured into the space after the rubber tube formwork group 3 is removed will be reliably bonded to each other. Or for sealing reinforcing bars for mass concrete.

(Effects of the Invention) The method for constructing mass concrete of the present invention is such that the mass concrete is placed at multiple locations in the longitudinal direction within the formwork for mass concrete during reinforcement work for mass concrete that is cast thick and long. A rubber tube form group is arranged in which a large number of rubber tubes extending over the entire length in the thickness direction are arranged in parallel in the width direction of the mass concrete.

Next, each rubber tube in this rubber tube form group is filled with air or water, the gap between each rubber tube is closed, and the mass concrete form is filled with a plurality of rubber tube form groups. After dividing the mold into multiple pieces, concrete is poured into the formwork.

Then, after solidifying the concrete poured into this divided formwork,
The method is characterized in that the air or water in each rubber tube is removed, each rubber tube form group is removed, and new concrete is poured into the space after each rubber tube form group has been removed.

According to this method, even if concrete is poured into the mass concrete formwork all at once, the mass concrete formwork is divided into multiple pieces by each group of rubber tube formworks, so the whole concrete is cast in one go. It does not form a single large lump, and so-called mass condensation cracks do not occur during solidification.

Further, the rubber tube is formed so that its outer shape becomes a wavy uneven shape when the inside is filled with air or water. Therefore, unevenness is formed on the concrete pouring surface,
It is possible to reliably connect the concrete that is placed in large quantities initially with the concrete that is newly placed in the space after the rubber tube formwork group has been removed. Alternatively, it can also seal reinforcing bars for mass concrete.

[Brief explanation of the drawing]

Figure 1 is a schematic perspective view showing a group of rubber tube forms installed in a mass concrete formwork, Figures 2 and 3 are enlarged plan views of section A in Figure 1, and Figure 4 is a mass concrete formwork. Figure 5 is a perspective view showing the state of concrete being poured into the formwork, Figure 5 is a perspective view showing the state in which new concrete has been poured into the space after each rubber tube form group has been removed, and Figure 6 is a perspective view showing the state of concrete being poured into the space after each rubber tube form group has been removed. FIG. l...Mass concrete formwork, 2...Rubber tube, 3...Rubber tube formwork group, 4...Support reinforcing bars, 5...Spacing reinforcement, 6.7...Concrete . 11th! i! I Part 2- Figure Figure Figure

Claims (2)

[Claims] (1) During reinforcing work for mass concrete that is cast thick and long, rubber tubes extending the entire length in the thickness direction of the mass concrete are placed in the formwork for the mass concrete at multiple locations in the longitudinal direction of the mass concrete. A rubber tube form group consisting of a large number of rubber tube forms arranged side by side in the width direction is arranged, and each rubber tube in this rubber tube form group is filled with air or water to close the gap between each rubber tube to form the mass. After dividing the inside of the concrete formwork into a plurality of pieces using each of the rubber tube formwork groups, concrete is poured into the formwork divided into the plurality of pieces, and concrete is poured into the divided formwork. After solidification, the air or water in each rubber tube is removed, each rubber tube formwork group is removed, and new concrete is poured into the space after each rubber tube formwork group has been removed. Construction method. (2) The mass concrete construction method according to claim 1, wherein the outer shape becomes a wavy uneven shape when the rubber tube is filled with air or water.