Peng Gong

The alkali-silica reaction is a source of damage in concrete, which can cause serious expansion, cracking, and sometimes the failure of structures. In this paper, we use three ultrasonic methods, the attenuation spectrum method, the ultrasonic passband method, and the stretching factor method to detect the existence of alkali-silica reaction (ASR) damage and to track its progress in concrete. From our tests, we demonstrate the ultrasonic passband method and stretching factor method have… Show more

The alkali-silica reaction is a source of damage in concrete, which can cause serious expansion, cracking, and sometimes the failure of structures. In this paper, we use three ultrasonic methods, the attenuation spectrum method, the ultrasonic passband method, and the stretching factor method to detect the existence of alkali-silica reaction (ASR) damage and to track its progress in concrete. From our tests, we demonstrate the ultrasonic passband method and stretching factor method have performed well to achieve the above goals. Show less

In this paper, we demonstrate an ultrasonic passband method for the ASR damage detection in concrete. This method shows high frequency ultrasonic components diminish faster than low frequency components in concrete when ASR damage occurs, and therefore the ultrasonic passband shifts to the low frequency side due to ASR damage. The test results also show that the ultrasonic passband is logically related to specimen size. We also demonstrate a stretching factor method is able to track the… Show more

In this paper, we demonstrate an ultrasonic passband method for the ASR damage detection in concrete. This method shows high frequency ultrasonic components diminish faster than low frequency components in concrete when ASR damage occurs, and therefore the ultrasonic passband shifts to the low frequency side due to ASR damage. The test results also show that the ultrasonic passband is logically related to specimen size. We also demonstrate a stretching factor method is able to track the progress of ASR damage in concrete very well. Show less

The alkali-silica reaction (ASR) occurs between the reactive aggregates and the alkaline cement paste in concrete, eventually producing damage such as swelling and cracking. This research uses mechanical tests and ultrasonic tests to detect ASR onset in concrete specimens. Advanced signal processing techniques are used for the ultrasonic signal processing and ASR damage detection.

A submarine pipeline system is a major asset. Scour monitoring under submarine pipelines is a tough problem and lacks research. In this study, a three-index estimator based on active thermometry was developed for solving this problem and thereby a novel scour monitoring system was designed for nearshore and landfill sections. This novel scour monitoring system can tell whether a location along a pipe is surrounded by water or soil so that it can tell if the scour ocurred or not to the pipeline.

In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring.

This paper presents the concepts of valid sampling points (VSPs), invalid sampling points (ISPs) and useless sampling points (USPs), proposes SRSI Method to select VSPs, derives the error theory of ISPs and analyzes the experimental data by SRSI Method, Peak Method and the error theory of ISPs in the temperature and strain monitoring tests.

A novel fiber corrosion sensor based on distributed Brillouin optical time domain reflection (BOTDR) has been developed, which can monitor steel corrosion in concrete structures. The choosing method of valid sampling points on optical fiber was proposed, and furthermore, the evaluation formula was derived to make quantitative assessment of steel corrosion.