JPH03215334A - Aggregate for discovering crack of concrete - Google Patents

Abstract

PURPOSE:To clear crack parts of concrete after hardening and to repair cracks by adding capsules having a sealed dyestuff solution or a sealed liquid to be reacted with concrete, etc., to readily-mixed concrete. CONSTITUTION:This aggregate for discovering cracks of concrete is formed by sealing a dyestuff solution or a chemical solution A such as 1% solution of phenolphthalein in ethyl alcohol to be reacted with concrete components in a thin film B such as thin film of water glass and a brittle material C such as shell of hardened material of cement. The aggregate is added to readily mixed concrete and destroyed together with concrete at destroyed parts of concrete after hardening. The chemical solution A is released, crack parts are cleared and cracks are repaired.

Description

[Detailed Description of the Invention] 3-1 Field of Application and Technical Needs In the field of civil engineering and construction, when carrying out tests to investigate the strength of reinforced concrete structures or concrete structures or to elucidate the failure mechanism, concrete The cracks that appear on the surface must be closely observed. The cracks observed during testing may range from several microns to several hundred microns, and it is extremely difficult to detect microscopic cracks. Special paints have been developed and put into practical use as a coating method for observing strain on steel members. However, since concrete is extremely brittle and cracks with minute strain, it is impossible to detect cracks within the elastic range of the paint itself. Therefore, there are limits to the application of the coating method etc. to destructive testing of concrete members.

The present invention was developed to facilitate the observation of cracks in concrete. 3-2 Overview of the invention The method filed herein involves sealing a pigment liquid or a liquid that reacts with air, water, or components of concrete in a capsule made of a brittle material such as water glass, and then placing the liquid in concrete. In this method, the outside of the concrete is protected by a shell of hardened cement to prevent damage, and then mixed into the concrete aggregate to create test members and efficiently observe cracks during testing.

It is possible to seal a drug solution inside a microscopic shell and take advantage of the fact that when the shell breaks or dissolves under certain conditions, the drug solution inside reacts. This is a technology that has already been established in fields such as Therefore, microcapsule technology at the chemical reaction level cannot fall within the scope of the claims of this application. This is about an extremely original method of use in which capsules are made larger, wrapped in a strong shell, given a certain particle size distribution, and used as aggregate for concrete in the civil engineering and construction field.

3-3 Details of the invention Drawing [1] shows a cross-sectional view of the aggregate for crack detection.

A is the chemical content, and if a color reaction is used, "phenolphthalein 1% ethyl alcohol solution", which is used to determine the degree of carbonation of concrete, is suitable.

B is a thin curtain for stably preserving drug solution A. In addition, B uses a brittle material similar to concrete in order to break as the concrete cracks and cause A to flow out. Water glass etc. are suitable. Up to the configurations of A and B, methods that have already been put into practical use can be applied as methods for manufacturing microcapsules.C is a shell of a hardened cement body; After composing B, the surface of B is wetted with water, and the B is poured into fine cement powder to be granulated and recovered.

The overall dimension L of the aggregate for crack detection is 0. 15-5-, the size a of A is around 0.5L, and the thickness b of B is several microns to several tens of microns. The thickness of C is approximately 0.25L
shall be.

The outer shape is irregularly shaped sand grains and has enough strength to be used as part of fine aggregate. It also has a particle size distribution that satisfies the standards for artificial aggregates in JIS A 5002. The hardened cement shell integrates with its surroundings without affecting the properties of concrete after hardening. The water glass capsule falls to its knees and is destroyed along with the concrete. When cracks occur in concrete during testing, the crack-detecting aggregate along the cracks breaks down, and the chemical solution spreads into the cracks due to capillary action, making it easier to observe the ends of the parts and cut surfaces.

3-4 Point A to keep in mind when implementing the product is that it must not deteriorate over a long period of time. A may be either a dye solution or a reactive solution such as the aforementioned phenolphthalein ethyl alcohol solution, but
The solvent must be selected to be compatible with concrete.

It is important to control the temperature of the concrete so that chemical solution A does not change or expand and destroy the capsules. There are no particular problems with ordinary concrete.

A must be selected so that even if a part of the aggregate for crack detection is destroyed by the coarse aggregate or mixer during the production of fresh concrete and the chemical solution A leaks out and mixes in, the concrete will not change in quality.

3-5 Application and Application Method A does not only emit a dye, but also allows the chemical to be changed depending on the purpose of the test and the reaction after the capsule is broken to be actively utilized. For example, if a colored instant adhesive such as cyanoacrylate adhesive is filled in, it is possible to provide a self-repair function by penetrating into cracks after destruction and curing. Brittle materials such as concrete are broken into small pieces after cracking, and often do not retain their original shape. The ability to preserve the shape of a test piece after a certain level of failure has progressed and the test operation is stopped greatly contributes to the elucidation of the failure mechanism.

B can be anything that has an elastic modulus and strength close to that of concrete, and does not necessarily have to be water glass. C does not necessarily have to be a hardened cement product, as long as it does not affect the properties of the mortar or aggregate after hardening and has a strength close to that of the surrounding concrete.

Furthermore, B and C do not necessarily need to be different substances.

It is advantageous to integrate them with the same substance as long as it protects the chemical solution A and has the performance as an artificial fine aggregate for concrete.

The above description has focused on experimental specimens, but if there is no need to consider economic efficiency, the inspection drawing 1 (I) of an actual structure is a cross-sectional view of the aggregate for crack detection.

L: Dimensions of aggregate for crack detection (0.15~5cm) A
; Phenolphthalein 1% ethyl alcohol solution
Diameter a of A is approximately 0.5L B; Thickness b of water glass thin film B is several microns to several tens of microns C; Thickness C of hardened cement shell C is approximately 0.25L
With this, we will apply for an invention patent as an aggregate for crack detection.

that's all

Claims (1)

[Claims] (1) It is mixed into fresh concrete and destroyed together with the concrete at the fracture site of the concrete after hardening, and contains pigment liquid or concrete components and water.
Or artificial aggregates that emit a chemical solution that reacts with components in the air, clarifying cracks and fractured areas, and self-repairing cracks.