Investigation of the Influence of Moisture Content on Fatigue Behaviour of HPC by Using DMA and XRCT

Abstract

High-performance concrete (HPC) is a topic of current research and construction projects, due to its outstanding compressive strength and durability. In particular, its behaviour under high-cycle fatigue loading is the focus of current investigations, to further pave the way to highly challenging long-lasting constructions; e.g., bridges or offshore buildings. In order to investigate the behaviour of HPC with different moisture contents in more detail, a mixture of silica sand and basalt aggregate with a maximum grain size of 8 mm was investigated with three different moisture contents. For this purpose, cyclic compressive fatigue tests at a loading frequency of 10 Hz and different maximum stress levels were performed. The main focus was the moisture influence on the number of cycles to failure and the development of concrete temperature and strain. In a further step, only the mortar matrix was investigated. For this purpose, the mixture was produced without basalt, and the moisture influence was investigated on smaller-sized test specimens using dynamic mechanical analysis (DMA) and X-ray computed tomography (XRCT). It was shown that the moisture content of HPC had a significant influence on the fatigue damage behaviour due to the number of cycles to failure decreasing significantly with increased moisture. In addition, there was also an influence on the temperature development, as well as on the strain development. It was shown that increasing moisture content was associated with an increase in strain development. XRCT scans, in the course of the damage phases, showed an increase in internal cracks, and made their size visible. With the help of DMA as a new research method in the field of concrete research, we were also able to measure damage development related to a decrease in sample stiffness. Both methods, XRCT and DMA, can be listed as nondestructive methods, and thus can complement the known destructive test methods, such as light microscopy.

The high cycle fatigue testing of High‐Performance Concretes using high frequency excitation

“…Figure 1 shows the DMA setup schematically. Besides, there are detailed descriptions of this setup and other DMA setups used in geophysics in [14][15][16]. As shown in Figure 1 setup, to measure the force, a pre-calibrated aluminum cylinder is used.…”

High‐speed fatigue testing of high‐performance concretes and parallel frequency sweep characterization

“…This research aims to explore the mechanical properties of UHPC being developed within the priority program SPP 2020 [1]. HPC and UHPC have superior properties while being lighter in weight compared to regular concrete.…”

“…Due to the reduced cross section of slender concrete structures, the ratio between permanent and variable loads decreases, making them more vulnerable to oscillations. Therefore, it is necessary to conduct fatigue verification during the design process [1].…”

Monitoring concept for the propagation of compressive fatigue in externally prestressed concrete beams using digital image correlation and fiber optic sensors

“…In the last decades, remarkable progress has been made in the characterization of the fatigue behavior of concrete materials. Systematic studies investigated the fatigue response with a focus on loading frequency and temperature, [8][9][10][11] moisture content, [12][13][14] type of loading, [15][16][17][18][19][20] as well as loading sequence and variable amplitude. [21][22][23][24][25] Most experimental findings are based on material tests, that is, using cylindrical specimens.…”