Oyun-Erdene DOLGORSUREN

Current situation and problems in design, construction and maintenance of concrete structures in Mongolia

Takumi SHIMOMURA

In recent years, the population of Mongolia has been increasing rapidly, and it is necessary to urge the development of infrastructure. There are various problems will be occurred, such as deterioration, maintenance, and renewal of concrete structures. Therefore, the purpose of this study was to investigate the issues that upper mentioned. In order to evaluate the situation in Mongolia more relatively, I implemented this study in the comparison case of Japan and Vietnam.
Firstly, I studied about infrastructure management, project implementers, and cement, concrete production and manufacturing systems. Regarding the cement production system in Mongolia, 100% of the cement is produced domestically. Besides, the concrete production system, there are about 200 factories that produce various types of concrete, and that the production of precast concrete has been increasing in recent years.
Secondly, I summarized data of the construction industry in Mongolia. As a result, issues related to construction design standards and maintenance systems were arisen. The construction design standards are majority inherited from Russian old standards and may not be suitable for the current situation in Mongolia. Therefore, I thought that it is necessary to proceed the investigation of the design standards, revise it through. In addition, regarding the maintenance of structures, the current situation is about regular reparations are not conducted frequently. Thus, the maintenance period of the construction company need to be lengthen while satisfying the construction quality standard.
Finally, I investigated the deterioration of concrete structures in Mongolia. As a result of a conventional literature, it was found that freezing damage was a problem along with an initial defect. Currently, the researched information about deterioration is not sufficient to continue this work, doing so its further investigation is required. One of the causes of the above-mentioned deterioration was that the quality of the materials used for concrete in Mongolia was not good. Therefore, concrete characteristics experiment was conducted. In the examination procedure, the composition was determined by the concrete mix design methods of Mongolia, Japan, and Vietnam, by using and Japanese concrete materials. And then, a slump test and a compressive strength test were conducted to examine the fresh properties and strength development. As a result of the slump test, proper fresh properties could not be obtained with Mongolian and Vietnamese cases. It was considered as the difference in the shape and particle size distribution of the aggregate. As a result of the compressive strength test, the cases of all three countries succeeded the target strength. All in all, it was indirectly proven that cement commonly used in Mongolia and Vietnam is not significantly different from Japanese cement.