JP3503092B2 - Crack repair method for cracked self-healing hydrated cured product - Google Patents

Description

BACKGROUND OF THE INVENTION [0001] [Technical Field of the Invention The present invention is a mortar, crack repairing cracks self-healing hydrated cured product was allowed with a self-repairing cracks hydration cured product such as concrete It is about the method. BACKGROUND OF THE INVENTION Mortar and concrete, which are hydrated and hardened products, are widely used as structural materials or surface finishing materials for various structures such as civil engineering structures and buildings. But,
Mortars and concretes that are frequently used in this way often have cracks due to their physical properties. [0003] The causes of the cracks include drying shrinkage,
Use of reactive aggregates, cracks in temperature, deformation of buildings due to external forces, corrosion of internal reinforcing steel, sink cracks due to insufficient iron control during construction, and the like can be mentioned. [0004] By the way, when cracks occur, problems such as water leakage, a decrease in the strength of the structure, the promotion of deterioration of the reinforcing steel and concrete due to the penetration of external substances, and a decrease in the appearance are caused. Currently, as a repair for cracks, resin injection and finishing materials are applied. However, it is best for the structure itself to have no cracks, of course.
Even if it occurs, it can be understood that if maintenance such as repair is unnecessary, the structure becomes a very preferable structure. An object of the present invention is to provide a hydrated hardened material such as mortar or concrete itself with a self-healing property against cracks, thereby making maintenance such as repair substantially unnecessary. Another object of the present invention is to repair cracks by making the self-healing hydrated cured product exhibit its self-healing properties more effectively. Means for Solving the Problems The present inventors have found that mortar and concrete manufactured using cement clinker as an aggregate are not hydrated inside even after a long age. Of cement clinker remains, and the degree of the remaining depends on the water-cement ratio (ie, the binder component of the amount of water used ) when mortar or concrete is manufactured.
(A ratio to the amount of cement) is smaller, the water cement ratio is larger, and is remarkable under the condition of the water cement ratio of 35% or less. I found it. Therefore, in the present invention, a hydrated hardened product such as mortar or concrete is made to contain unhydrated cement clinker in at least a part thereof, and is reacted with water penetrating from cracks to have a self-healing property. It is provided with. In the method for repairing a crack according to the present invention, water is actively permeated into cracks generated after hardening of a hydrated hardened material containing unhydrated cement clinker in at least a part of the aggregate. This causes the unhydrated cement clinker present in the cracked portion to react with water, reacts with the unhydrated cement clinker and water to form a cement gel, and is cracked by the cement gel. Part can be closed. In this case, by actively infiltrating water into the cracked portion, a sufficient amount of water is supplied to generate the cement gel, and a sufficient amount of the cement gel is generated in a short time, and the crack is generated. The part can be closed efficiently. In addition, regardless of the location of the crack, that is, for example, from the back side of the crack generation part or even from the side, supply and permeate water to repair the crack by reaching the water. Is also possible. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to FIGS. 1 (a) to 1 (d). These figures show the principle of crack repair when the present invention is applied to mortar. The mortar M is a material obtained by using a normal Portland cement clinker having a particle size of, for example, 5 mm or less as an aggregate, adding water and cement, and kneading the mixture to a necessary degree in the same manner as a well-known concrete mortar. is there. The unhydrated cement clinker 10 can remain in the form of aggregate even after the mortar or concrete is hardened. As a method, cement clinker itself is a baked ingot obtained in a so-called cement manufacturing process, and is crushed to a required aggregate size to give sufficient hardness.
It may be left in the form of aggregate. As a more reliable method, consideration is preferably given to the water-cement ratio (w / c). That is, by reducing the water-cement ratio, unhydrated cement clinker can be reliably left in the form of aggregate. The water-cement ratio is preferably as small as possible, but is preferably about 35% or less. By doing so, the cement clinker itself fully functions as an aggregate, and at the same time, by leaving a large amount of unhydrated cement clinker, it reacts with water penetrating from cracks generated after hardening and cement This is because a gel is formed and a sufficient crack is formed to provide self-healing properties. In addition, the water-cement ratio is more appropriate for increasing the strength of the mortar or concrete after hardening. Accordingly, the aggregate 10 made of the cement clinker has a distribution state as shown in FIG. Then, it is assumed that the mortar M is cured after a predetermined age period, and a crack portion 30 as shown in FIG. 1 (b) occurs after or during the curing. Thereafter, as shown in FIG. 1 (c), when moisture 40 penetrates into the cracked portion 30 from the surface, the unhydrated cement clinker (aggregate) 10 existing in the cracked portion 30 is mixed with the water 40. React and cement gel 5
0 to harden and close the cracked portion 30. In this way, the mortar M using the cement clinker as an aggregate can exhibit self-healing properties against cracks. Therefore, this mortar M is effective when applied as a finishing material for various structures, a structural material, or a material such as a secondary concrete product, similarly to the conventional general mortar. When present in the exposed places, it becomes a maintenance-free high-performance structural mortar. In the mortar M shown here, aggregate 1
Although an example in which only cement clinker is used is shown as 0, sand aggregate or the like may be mixed as needed and used together with aggregate 10 made of cement clinker. However, it is preferable not to use them together from the viewpoint of enhancing the self-healing property of cracks. When the hydrated cured product according to the present invention is applied to concrete, an appropriate amount of coarse aggregate may be added if necessary. The particle size) may be, for example, two types of large and small, 5 mm or less and 5 mm or more, and a small one may be used instead of the fine aggregate 10 and a large one may be used instead of the coarse aggregate. In this case, even in the concrete containing coarse aggregate, the crack self-healing property can be sufficiently improved. On the other hand, the crack repair of the hydrated hardened material according to the present invention causes the water 40 to actively penetrate into the cracked portion 30 after the crack is generated and before the water is flooded by rainwater or the like, thereby forming the cement gel 50. By supplying a necessary and sufficient amount of water for the above, the crack can be repaired as described above. According to this method, it is possible to generate a sufficient amount of cement gel in a short time and to effectively close the cracked portion. In addition, regardless of the location of the crack, the water can be repaired by supplying and penetrating water from the inside of the structure to reach the crack occurrence portion, for example. Here, for example, when there is a reinforcing bar as a reinforcing material that is frequently used inside the concrete,
The water 40 that permeates the cracked portion 30 comes into contact with the reinforcing bar, and there is a concern that the corrosion may progress. However, the water that has passed through the cracked portion 30 comes into contact with the unhydrated cement clinker 10 and exhibits alkalinity, thus exhibiting an effect of preventing corrosion of the reinforcing bar. As described above, according to the present invention, the hydrated hardened product such as mortar or concrete is provided with a self-healing property against cracks, thereby making maintenance such as repair substantially unnecessary. can do. Further, in the present invention, the crack can be repaired by actively infiltrating water into the cracked portion of the self-healing hydrated cured product of the crack.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a principle view of crack repair of a hydrated cured product according to an embodiment of the present invention. [Description of Signs] M Mortar 10 Aggregate (Cement Clinker) 20 Cement Paste 30 Cracked Part 40 Water 50 Cement Gel

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) E04G 23/02 C04B 2/00-32/02

Claims (1)

(57) [Claims 1] Cracks containing unhydrated cement clinker in at least a part thereof as an aggregate. A method for repairing a crack in a self-healing hydrated cured product, comprising reacting a Japanese cement clinker with water.