JPH08135190A - Concrete jointing method - Google Patents

Abstract

PURPOSE: To form the rough face with unevenness on the surface of preceding concrete so as to be integrated with new concrete to be jointed thereon. CONSTITUTION: After placing preceding concrete 10, the surface of this preceding concrete 10 is covered with a thin layer formed of underwater unseparative mortar 11, and crushed stone 12 with grain diameter larger than the thickness of the mortar 11 layer is scattered in the thin layer of mortar 11 and subjected to curing by filling water. The construction joint face with a large number of protrusions and recessions formed by the protrusions of the crushed stone 12 is thereby formed on the surface of the preceding concrete 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete splicing method, and in particular, when a new concrete is spliced over a preceding concrete that has finished plowing work, these new and old concretes are integrated. A concrete splicing method for achieving the above.

[0002]

2. Description of the Related Art When constructing a concrete structure,
It is preferable to pour concrete all over the structure at once, but depending on the size and shape of the structure or the construction conditions for installing the formwork, it may not be possible to pour concrete at once. is there. However, in such cases, the method of constructing a concrete structure by appropriately dividing the places where concrete should be placed and integrating the concrete placed at each place by successively joining them is adopted. Has been done.

In such a construction method, in order to obtain a reliable and stable structure, it is necessary to firmly join the concretes to be spliced together at the splicing point. As a construction method, conventionally, for example, with respect to a horizontal joint surface, before or after hardening of concrete, the surface of the preceding concrete is treated, and after laying a thin layer of mortar on the surface of the further processed concrete, The method of placing new concrete is adopted.

That is, in the surface treatment applied to the preceding concrete, the leitance layer or the thin paste layer formed on the surface of the concrete is removed to expose the coarse aggregate in the concrete to form irregularities on the surface of the concrete. As a treatment method before hardening of concrete, for example, a so-called green cut method of spraying pressurized water to the surface of concrete to remove a thin layer, etc., as a treatment method after hardening of concrete. For example, a method using a wire brush and a method of spraying wet sand are known.

[0005]

However, the above-mentioned conventional methods for treating the surface of the preceding concrete to roughen it are labor-intensive operations, especially when the area of the jointing portion is large, It is difficult to perform these operations efficiently when surface-treating the joint surface where the reinforcing joint reinforcing bar projects. In addition, when performing surface treatment before hardening of concrete by the green cut method etc., work within a short time after the predetermined time has passed after placing concrete, depending on the timing at which the setting and hardening of concrete proceed. Since it has to be performed, it may not be possible to finish the work within a time suitable for the roughening work, and therefore unevenness is caused in the work and the surface of the concrete is roughened uniformly with a predetermined quality. There is a fear of not being able to do it. Furthermore, according to the above-mentioned conventional method, it is difficult to use it as a surface treatment method when splicing underwater concrete.

Therefore, the present invention has been made by paying attention to such a conventional problem, and a rough surface having irregularities is formed on the surface of the preceding concrete by a simple work, whereby the preceding concrete and the upper surface thereof are formed. A concrete splicing method that can easily integrate with new concrete to be spliced and can easily form a rough surface on the splicing surface even when the concrete to be spliced is underwater concrete. It is intended to be provided.

[0007]

The present invention has been made in order to achieve the above-mentioned object, and its gist is when a new concrete is spliced over the preceding concrete after the driving work. , A method of concrete splicing for integrating these old and new concrete, wherein after driving the preceding concrete, the surface of the preceding concrete is covered with a thin layer of water-separable mortar, By crushing crushed stones having a particle size larger than the thickness of this mortar layer into the mortar layer and performing water-filling curing, a joint surface is formed on the surface of the preceding concrete in which irregularities due to protrusion of crushed stones are formed, and Characterized by integrating the old and new concrete by sandwiching the joint surface and driving new concrete above it Lies in the way the joint da Nkurito.

Here, in the above description, the water-inseparable mortar refers to a mortar to which separation resistance in water is imparted by adding an in-water inseparable admixture. Further, as the water-separable admixture, for example, a cellulose-based or acrylic-based one which is currently commercially available can be used, and by adding this to mortar or concrete, it gives viscosity to mortar or concrete. Not only exerts resistance to separation in water, but also improves plasticity and self-leveling,
In addition, it is possible to suppress the occurrence of breathing and latance and delay the setting time.

Another aspect of the present invention is that when a new concrete is spliced over the preceding concrete for which the pouring operation has been completed, the concrete is poured to integrate these old and new concretes. A splicing method, after driving the preceding concrete, spread the underwater non-separable concrete with a thickness smaller than the maximum particle size of the coarse aggregate in the underwater non-separable concrete, and surface of the preceding concrete By covering and covering with water and curing it with water, a connecting surface is formed on the surface of the preceding concrete with unevenness due to the protrusion of coarse aggregate, and a new concrete is driven above the connecting surface by sandwiching the connecting surface. Thus, there is a concrete splicing method characterized by integrating old and new concrete.

In the above description, the underwater non-separable concrete refers to concrete to which separation resistance in water is imparted by adding a water non-separable admixture.

[0011]

According to the concrete splicing method of the present invention, the surface of the preceding concrete is covered with a thin layer of non-separable mortar, and the mortar layer is covered with crushed stone having a particle size larger than the layer thickness. Work to scatter or cover the surface of the preceding concrete and spread the water-inseparable concrete to a thickness smaller than the maximum grain size of the coarse aggregate in the concrete, and just flood-cure these surfaces Thus, even when the concrete to be spliced is underwater concrete, it is possible to easily form a roughened splicing surface on the surface of the preceding concrete.

That is, crushed stones and coarse aggregates are mainly processed by laying fluidized water-inseparable mortar or concrete on the surface of the preceding concrete, or by additionally spreading crushed stones. Is projected from the surface of a thin layer of mortar or concrete, which can easily form a large number of irregularities on the surface of the preceding concrete, so even if the area of the splice joint is large, or if reinforcement bars are projected. Even when the surface treatment of the connecting surface is performed, the connecting surface can be easily roughened.

In addition, since the mortar which is not separable in water or the concrete which is not separable in water is less likely to cause breathing, it is possible to suppress the formation of a leitance layer on the surface thereof.

Further, in order to prevent the surface of the non-separable mortar in water or the concrete of the non-separable water from being dried, water filling curing is carried out. However, since these mortar and concrete are hard to be washed with water, the surface mortar layer is Concavity and convexity are formed by the protrusion of crushed stone etc. while ensuring sufficient strength.

Furthermore, the work of laying and averaging the non-separable underwater mortar or concrete on the surface of the preceding concrete can be carried out from the soft state of the preceding concrete immediately after the placing of the preceding concrete. After laying mortar etc. of the concrete, curing of the preceding concrete can be performed immediately immediately after placing it, and due to the effect of retarding the setting of the mortar or concrete that is not submerged in water, a new concrete is added above the preceding concrete. When driving in, the integration of these old and new concrete can be exhibited more effectively.

[0016]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 shows a first embodiment of the concrete splicing method of the present invention. That is, the concrete splicing method according to the first embodiment of the present invention is the concrete 1
When we are going to splice new concrete above 0,
Before pouring the new concrete, a rough surface is formed on the upper surface of the preceding concrete 10, and the preceding concrete 10 and the new concrete are jointed by using this as a joint portion, thereby integrating these old and new concretes. It was adopted in order to achieve.

According to the first embodiment, immediately after the preceding concrete 10 is poured, the surface of the preceding concrete 10 is covered and the underwater-separable mortar 11, for example, the thickness of 20 is applied.
The particle diameter is larger than the thickness of the layer of the mortar 11 that is spread evenly, for example, 40 m.
The crushed stone 12 having a particle diameter of about m is evenly scattered over the entire surface of the spread mortar 11.

Here, the underwater non-separable mortar 11 is
For example, as a cellulose-based inseparable admixture in water, a cellulose ether having a cellulose skeleton and a part or all of H of an OH group is substituted with an alkyl group or the like,
Since breathing is less likely to occur, it is possible to easily suppress the formation of a laitance layer on the surface of the material, but it is necessary to perform water filling curing because the surface is easily dried. Further, since the mortar 11 which is inseparable in water is hard to be washed by water, it solidifies and solidifies to secure sufficient strength, and the crushed stone 1 having a particle size larger than the layer thickness thereof.
2 is projected to form a large number of irregularities, thereby forming a roughened connecting surface.

After completion of the water filling curing, if a new concrete is placed above the preceding concrete 10 by sandwiching the roughened joint surface, a large number of irregularities due to the crushed stones 12 function as a shear key. As a result, the preceding concrete 10 and the new concrete can be easily integrated, and due to the setting delay effect of the water-separable mortar 11, the integration of these old and new concretes can be more firmly achieved. .

FIG. 2 shows a second embodiment of the concrete splicing method of the present invention. That is,
According to this second embodiment, immediately after the preceding concrete 10 is driven in, the surface of the preceding concrete 10 is covered with the water-inseparable concrete 13 to remove the coarse aggregate 1 in the concrete 13.
No. 4 maximum particle size, that is, a thickness smaller than, for example, about 40 mm, for example, a thin thickness of about 20 mm is laid and leveled.

Underwater non-separable concrete 13
Is, for example, as an acrylic water inseparable admixture,
Since it contains a polymer or copolymer mainly composed of acrylamide, and breathing is less likely to occur, it is possible to easily suppress the formation of a laitance layer on the surface of this, while the surface is easy to dry, so that water-curing curing is possible. There is a need to do. Further, since the water-inseparable concrete 13 is hard to be washed by water, it solidifies and solidifies to secure sufficient strength, while allowing the coarse aggregate 14 having a particle diameter larger than the layer thickness to project. To form a large number of irregularities, thereby forming a roughened connecting surface.

After completion of the water filling curing, if a new concrete is placed above the preceding concrete 10 by sandwiching the roughened joint surface, the rough bones can be obtained as in the case of the first embodiment. The large number of concavities and convexities due to the material 14 function as a shear key, which facilitates the integration of the preceding concrete 10 and the new concrete, and due to the setting delay effect of the underwater non-separable concrete 13, these old and new. The concrete will be integrated more strongly.

Since the work in each of the above-mentioned embodiments can be easily performed even in the construction site of the underwater concrete structure, even if the concrete to be spliced is underwater concrete to be poured into water, the preceding concrete It is possible to easily form a rough surface due to a large number of concavities and convexities on the joining surface of 10 to easily integrate the preceding concrete 10 and new concrete.

[0024]

As described in detail above, according to the concrete splicing method of the present invention, the surface of the preceding concrete is covered with a thin layer of mortar which is inseparable from water, and the mortar layer is coated with this mortar layer. Crushed stone with a particle size larger than the layer thickness of, or covering the surface of the preceding concrete and laying a non-separable concrete with a thickness smaller than the maximum particle size of the coarse aggregate in the concrete, and It is possible to easily form a rough surface having unevenness on the surface of the preceding concrete by a simple work of simply flooding and curing these surfaces. Then, by joining new concrete above the preceding concrete with the rough surface as the joining surface, it is possible to easily integrate these old and new concretes, and the concrete to be joined is underwater concrete. Even in this case, a rough surface can be easily formed on the connecting surface.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a first embodiment of the concrete splicing method of the present invention.

FIG. 2 is an explanatory view showing a first embodiment of the concrete splicing method of the present invention.

[Explanation of symbols]

 10 Preceding concrete 11 Underwater non-separable mortar 12 Crushed stone 13 Underwater non-separable concrete 14 Coarse aggregate

Claims (2)

[Claims] 1. A concrete splicing method for integrating new and old concrete when splicing new concrete above the preceeding concrete for which the casting operation has been completed. After the concrete is poured, the surface of the preceding concrete is covered with a thin layer of mortar that is inseparable in water, and crushed stones having a particle size larger than the thickness of this mortar layer are scattered in the mortar layer to carry out water filling curing. To form a joint surface on the surface of the preceding concrete with unevenness due to the protrusion of crushed stones, sandwich the joint surface and drive new concrete above it to integrate the old and new concrete A concrete splicing method characterized by the above. 2. A concrete splicing method for integrating new and old concretes when splicing new concrete above the preceeding concrete for which the driving operation has been completed. After driving the concrete, spread the underwater non-separable concrete with a thickness smaller than the maximum grain size of the coarse aggregate in the underwater non-separable concrete to cover the surface of the preceding concrete and perform water filling curing. To form a joint surface on the surface of the preceding concrete that has irregularities due to the protrusion of coarse aggregate, and insert new concrete above this joint surface by sandwiching the joint surface to integrate the old and new concrete. A method of splicing concrete, characterized by