| Minerals that adversely affect the quality of concrete (hereinafter referred to as “harmful minerals”) are known to exist in multiple forms in nature, and the deterioration phenomena and mechanisms caused by the harmful minerals vary depending on the type of mineral. Among these, regarding laumontite, it has been indicated by ASTM that concrete deterioration occurs due to volume changes caused by repeated wetting and drying, and its use has been minimized. However, there is debate as to whether the primary deterioration phenomenon causing by laumontite, surface spalling, represents progressive deterioration into the internal concrete. If the deterioration is limited to the surface, it can be said that there are no structural issues, allowing for the use of the aggregate with the understanding of surface deterioration. In this presentation, we will report on the evaluation of the deterioration mechanism of concrete surfaces caused by laumontite observed through scanning electron microscope and its progression into the internal structure. Additionally, we would like to discuss the conditions for the use of rock aggregates containing laumontite. |
