JP2003105972A - Method for concrete jointing of successive pours - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for concrete jointing of successive pours suppressing the crack initiation of new concrete. SOLUTION: In this concrete jointing method, polymer cement is placed at the poured joint face of hardened concrete in the case of placing and jointing new concrete to the hardened concrete, and the new concrete is placed in contact with the polymer cement.

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 in which generation of cracks in a concrete splicing portion is suppressed, and a hardened concrete body having the splicing portion.

[0002]

2. Description of the Related Art Conventionally, when new concrete (new concrete) is spliced onto hardened concrete (old concrete), after the surface of the splicing surface of the old concrete has been surface treated, a thin layer of mortar is cast on this splicing surface. However, new concrete is placed on this. Specifically, a method using a wire brush, a sand plast method (wet sand spraying method), or a chipping method is used to remove the fragile layer caused by bleeding water or leitance, and after cleaning, moisten with water, Mortar of the same composition as the mortar content in the new concrete is placed on this joint surface to a thickness of about 1 to 2 mm.
New concrete is placed on this. However, in the conventional jointing method using such cement mortar, when many cracks occur in the new concrete due to distortion such as drying shrinkage of the new concrete caused by the difference in the placing time of the old concrete and the new concrete. There is. Also, when new concrete is directly placed without placing mortar on the joint surface, many cracks occur in the new concrete.

[0003]

DISCLOSURE OF THE INVENTION The present invention is to solve the problems of the conventional concrete jointing method, in which the generation of cracks in the concrete jointing portion is suppressed and the jointing portion thereof. An object of the present invention is to provide a concrete hardened body having:

[0004]

[Means for Solving the Problems] That is, according to the present invention, (1) when new concrete is spliced to hardened concrete, polymer cement is placed on the splicing surface of the hardened concrete, and There is provided a concrete splicing method, which is characterized in that new concrete is placed in contact with the concrete.

The concrete splicing method of the present invention is
(2) A method in which a concavity is provided on the joining surface of hardened concrete, polymer cement is placed in the depression, and new concrete is placed in contact with the polymer cement. (3) The joining surface of hardened concrete is surfaced. After the treatment, a method of placing polymer cement in a thickness of 3 to 10 cm and placing new concrete in contact with the polymer cement, (4)
Polymer cement is placed before or after the old concrete is cured, and after the polymer cement is cured, just before the new concrete is placed, another thin layer of polymer cement is placed, and before the polymer cement is cured, the new concrete is placed. Including the method of placing. The present invention also relates to (5) a hardened concrete body which has been jointed by any of the methods described in (1) to (4) above.

The concrete splicing method of the present invention is a method in which polymer cement is interposed between old concrete and new concrete, and the new concrete is dried by using polymer cement instead of conventional cement mortar. The strain due to shrinkage or the like is absorbed and relaxed, and the occurrence of cracks is effectively suppressed.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below based on embodiments. The concrete splicing method of the present invention, in the case of splicing a new concrete to the hardened concrete, pour polymer cement on the splicing surface of the hardened concrete, and pour new concrete in contact with this polymer cement. This is a characteristic concrete splicing method. In the description of the present invention, polymer cement, polymer cement mortar, and polymer cement concrete may be simply referred to as polymer cement.

As the polymer of the polymer cement used in the present invention, an aqueous polymer dispersion, a re-emulsified powder resin, a water-soluble polymer, a liquid polymer or the like can be used, and an ordinary commercial product can be used.
Specific examples of the polymer include natural rubber latex (NR),
Chloroprene rubber (CR), styrene butanediene rubber (SB
R), acrylonitrile butadiene rubber (NBR), methyl methacrylate butadiene rubber (MBR), and synthetic rubber latex such as butadiene rubber (BR), polyacrylic acid ester (PAE), polyvinyl acetate (PVAC), vinylidene chloride,
Thermoplastic resin emulsion such as vinyl chloride (PVD), polyvinyl propionate (PVP), ethylene vinyl acetate (EVA) and polypropylene (PP), thermosetting resin emulsion such as epoxy resin, asphalt, rubber asphalt, and paraffin Bituminous emulsion such as, mixed disversion such as mixed latex and mixed emulsion, re-emulsified powder resin such as ethylene vinyl acetate (EVA), vinyl acetate vinyl versatate (VAVeoVA), cellulose derivative, polyvinyl alcohol (PVA, poval) ),
Water-soluble polymers such as polyacrylic acid salt and furfuryl alcohol, liquid polymers such as unsaturated polyester and epoxy can be used.

The amount of the polymer used is preferably 1 to 200 parts by weight, more preferably 10 to 100 parts by weight, based on 100 parts by weight of cement.
70 parts by weight is more preferable in terms of strength. If it is less than 1 part by weight, a sufficient crack reducing effect cannot be obtained. On the other hand, if it exceeds 200 parts by weight, the crack reducing effect is improved, but the hardening of the polymer cement is delayed and the strength and durability tend to be lowered. Further, it is not preferable in terms of cost to increase the amount of the polymer used more than necessary.

As the cement component of the polymer cement used in the present invention, various cements such as Portland cement and alumina cement, and hydraulic cement such as mixed cement can be used.

In the present invention, any of polymer cement, polymer cement mortar, and polymer cement concrete can be used. Aggregates mixed with polymer cement mortar or polymer cement concrete include river sand, mountain sand, land sand, silica sand, crushed sand, sea sand,
Aggregates generally used for mortar and concrete such as crushed stone, river gravel, mountain gravel, sea gravel, and slag aggregate can be used. The amount of aggregate used is preferably 0 to 400 parts by weight relative to 100 parts by weight of cement in terms of workability and crack reduction effect. If this amount exceeds 400 parts by weight, the crack reducing effect and workability are deteriorated.

Further, the polymer cement, polymer cement mortar or polymer cement concrete of the present invention includes a commonly used dispersant such as a water-reducing agent, organic fiber, a shrinkage-reducing agent, and a quick-hardening agent and a retarding agent including a quick-setting agent. Setting time adjusting agent, dispersant, etc., gel time adjusting agent, swelling agent, rust inhibitor, antifreezing agent, coloring agent, heat of hydration inhibitor, thickener, water retention agent, shrinkage reducing agent, water reducing agent, waterproofing agent , Foaming agent, foaming agent, defoaming agent, alkali aggregate reaction inhibitor, filler, AE agent, A
E Water-reducing agents, fluidizers, admixtures such as water-separable admixtures, admixtures, etc. may be used alone or in combination of two or more.

In the present invention, polymer cement (ie.
The construction thickness of polymer cement, polymer cement mortar, polymer cement concrete) is preferably 1 to 10 cm, more preferably 3 to 10 cm. If the thickness is less than 1 cm, the crack reducing effect is not sufficient. On the other hand, if the thickness exceeds 10 cm, the cost will increase.

The polymer cement is preferably placed after the joint surface of the hardened concrete is surface-treated. This surface treatment is, specifically, a method using a wire brush, a sand plast method (wet sand spraying method), a chipping method, or the like to remove the fragile layer caused by bleeding water or leitance to remove the surface to be placed. to clean.

The polymer cement, as shown in FIG.
The polymer cement 12 may be provided on the flat placing surface 11 of the old concrete 10, and the new concrete 13 may be placed thereon. In addition, as shown in FIG. 2, the old concrete 10
It is preferable to provide a recess 14 in the driving surface 11 and to drive the polymer cement 12 in the recess 14 in order to effectively prevent the water leakage at the splicing portion. The depth of the recess 14 may be approximately the same as the thickness of the polymer cement 12. The method of the present invention can be applied not only to horizontal splicing, but also to vertical splicing.

The pouring time of the polymer cement may be after hardening of the old concrete or before hardening. Before or after hardening the old concrete, pour the polymer cement, just before pouring the new concrete, further pouring the polymer cement thinly and then pouring the new concrete before this polymer cement hardens, It is preferable because the adhesion between the polymer cement and the new concrete is improved, and water leakage at the joint can be prevented more reliably.

[0017]

According to the concrete splicing method of the present invention, polymer cement is interposed on the splicing surface between old concrete and new concrete instead of the conventional cement mortar, and the new concrete is dried by this polymer cement. Since the strain due to shrinkage or the like is absorbed and relaxed, the generation of cracks is suppressed. Further, since the splicing surface is sealed by the polymer cement, the effect of preventing water leakage at this portion is excellent. Further, the effect of preventing water leakage can be further enhanced by forming the recesses and driving the polymer cement.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a concrete splicing method according to the present invention.

FIG. 2 is a schematic diagram showing a concrete splicing method according to the present invention.

[Explanation of symbols]

10-old concrete, 11-placement surface, 12-polymer cement, 13-new concrete, 14-recess

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazuo Yangi             4-8-15 Nihonbashihonmachi, Tokyo Pacific Ocean             Material Co., Ltd. F term (reference) 2E172 AA05 AA07 DD00 DD04 DD08

Claims (5)

[Claims] 1. When splicing new concrete to hardened concrete, polymer cement, polymer cement mortar or polymer cement concrete (hereinafter referred to as polymer cement) is placed on the splicing surface of the hardened concrete, A concrete splicing method, which comprises placing new concrete in contact with the polymer cement. 2. The concrete splicing method according to claim 1, wherein a recess is provided in the splicing surface of the hardened concrete, polymer cement is cast in the recess, and new concrete is cast in contact with the polymer cement. . 3. A polymer cement is placed in a thickness of 3 to 10 cm after surface-treating the joint surface of the hardened concrete,
The concrete splicing method according to claim 1 or 2, wherein new concrete is placed in contact with the polymer cement. 4. A polymer cement is placed before or after the hardening of the old concrete, and after the hardening of the polymer cement, immediately before the placing of the new concrete, a thin layer of the polymer cement is set, and the polymer cement is hardened. The concrete splicing method according to any one of claims 1 to 3, wherein new concrete is placed before the step. 5. A hardened concrete body spliced by the method according to any one of claims 1 to 4.