The 4th Asian Concrete Federation Symposium on Emerging Technologies for Structural Longevity (ACF2023- ETSL)

15 / 2022-02-28 22:53:28

Understanding of Water Transport Due to Environmental Actions by Weather Information and NIR Spectroscopy

Bulk Method,NIR Spectroscopy,Water Behavior,Weather Information

Almost all deteriorations of reinforced concrete structures are greatly affected by behavior of water drying and wetting either directly or indirectly. Therefore, it is very important to understand the relationship between environmental actions and water behavior in concrete.

It is known that the water behavior in concrete has the correlation of water content in concrete to some extent and thus it is required to evaluate it. However, environmental actions have multiple parameters such as temperature, humidity, wind speed, and so forth. Therefore, it is very difficult to evaluate its effect on water behavior in concrete.

In the previous research, Near InfraRed (NIR) spectroscopy is applied to estimate the water behavior in concrete. In the soil engineering field, the evaporation characteristics of the soil surface were estimated by applying Bulk method, which can estimate the amount of evaporation in a material using the evaporation factor of the target material and the weather information at the target location. These two methods are expected to understand the water behavior in concrete under the various environmental actions.

The purpose of this research is to validate the quantification of water behavior in concrete specimens using Bulk method and NIR spectroscopy. In the experiment, mass of water loss, distribution of temperature and humidity, and change of absorbance by NIR spectroscopy in test specimens were measured. Moreover, the water behavior in the test specimens were numerically estimated by applying the Bulk method using the weather information measured during the exposure test. It was found that there is a correspondence between the change in evaporation efficiency of test specimens calculated by Bulk method and the change in absorbance of the specimen measured by NIR spectroscopy. This result suggested that the water behavior in concrete under various environmental action can be evaluated quantitatively by applying these two methods.