A Study on Development of Fine Aggregate Incorporating Self-healing Performance for Repair Mortar

Abstract

Abstract

The cause of cracks in concrete building structure include: before hardening, plastic shrinkage, plastic settlement; and after hardening followed by cement dehydration heat, dry shrinkage, creep, alkali-aggregate reaction, freeze-thaw, corrosion of steel bar, structural weight. Other causes include defective design and construction. Buildings in Korea are undergoing aging process, which is starting to cause damage to human life and property. Concrete buildings decline in durability with the aging process. Penetration of harmful ions caused by various environmental factors lead to deterioration of building and decline in durability of structure is an inevitable process. Cracks in various structures and the occurrence of surface damage require technology to restore durability of structures. Therefore, it is necessary to develop materials that can integrate to cross-section of concrete and semi-permanent inorganic materials using standardized materials and construction technology. Since the 2000s, several countries have led the research and development of self-healing technology using many types of polymer and etc. This study has conducted an experimental research to test if the concrete cracks created by external shock or internal damage can be modified by endowing fine aggregates used for concrete-repairing mortar with self-healing power. The result of compressive strength of structure made by using general concrete mixture shows that cracked surface expands along the surface of aggregates. Therefore, the study endowed aggregates with self-healing capacity and performed a test on recovering cracks along the cracked surface for its appropriateness. According to the results, it is believed that as fine aggregates used for concrete-repairing mortar endowed with self-healing power react with water over time, it suppresses self-healing power during early mixing phase and self-healing power reacts to the cracked area to enable its restoration. Moreover, the result of comparing compressive and flexural strength shows that it may be possible to add fine aggregates used for concrete-repairing mortar endowed with self-healing power to ordinary mortar. In order to use basic data in this test to evaluate actual applicability, various endurance tests and analysis must be performed. The result can be used in various applications including repairing mortar.