Experimental Investigation on the Dynamic Properties of RC Structures Affected by the Reinforcement Corrosion

Cracking of the cover concrete due to steel corrosion is considered as one of the major issues of durability of reinforced concrete (RC) structures. This paper tentatively studies the feasibility of DIC to reinforcement corrosion induced concrete fracture and cover cracking measurement. Advantages and limitations of DIC-based non-contact full-field measurement for corrosion induced concrete fracture and cover cracking are discussed. Drawbacks in this test need improvement are pointed out and test method for further study of whole process of simulating the real reinforced concrete cracking is put forward.

Download Full-text

Which Rust Deposition Model Should Be Used in Predicting Concrete Cover Cracking due to Reinforcement Corrosion?

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.468-471.1000 ◽

2012 ◽

Vol 468-471 ◽

pp. 1000-1004 ◽

Cited By ~ 1

Author(s):

Roger Zou ◽

Frank Collins

Keyword(s):

Predictive Model ◽

Concrete Cover ◽

Zone Model ◽

Reinforcement Corrosion ◽

Rust Layer ◽

Rc Structures ◽

Cover Cracking ◽

Porous Zone ◽

Walled Cylinder ◽

Concrete Interface

The critical amount of corroded steel that causes concrete cover cracking can be readily calculated based on thick-walled cylinder theory. However, the results may vary significantly depending on how the rust deposition is considered. There are several rust deposition hypothesis proposed in the literature for modelling concrete cover cracking of RC structures due to reinforcement corrosion. Among them, three are considered representative ones and have been widely cited in the literature. They are: (i) assumes a certain amount of rust product carried away from the rust layer and deposited within the open cracks proposed by Pantazopoulou and Papoulia; (ii) assumes all of the rust products build up around the bar and all of them are responsible for the expansive pressure proposed by Bazant; (iii) assumes certain amount of rust products deposited into a porous zone around the bar/concrete interface proposed by Liu and Weyers. In this paper, all three rust deposition hypotheses were examined for the critical amount of corrosion to induce cover cracking. When compared to the test data available from the literature, it showed that the porous zone model proposed by Liu and Weyers gives the best predictions. Thus it may be concluded that assuming a porous zone around the steel/concrete interface would be reasonable and may be adopted in developing concrete cover cracking predictive model.

Download Full-text

Experimental Investigation of the Transient Behavior of MR Fluids

ASME 2011 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, Volume 1 ◽

10.1115/smasis2011-5240 ◽

2011 ◽

Cited By ~ 6

Author(s):

Ju¨rgen Maas ◽

Dirk Gu¨th

Keyword(s):

Magnetic Field ◽

Experimental Investigation ◽

Response Time ◽

Dynamic Properties ◽

Transient Behavior ◽

Current Control ◽

Large Signal ◽

Carrier Fluid ◽

Mr Fluids ◽

The Magnetic Field

The transient behavior of MRF actuators is an important property for certain applications that is mainly affected by three delays, occurring from the dynamic properties of the coil current, the magnetic field and the torque generation by the MRF. In order to investigate the transient behavior of the generated torque with respect to the magnetic field, which is mainly affected by the motion of the MR particles in the carrier fluid, the mentioned response time of the electrical and magnetic domains must be in an appropriated ratio in comparison to the MRF response time to obtain reliable results by experiments. Therefore a special disc-type test actuator with outstanding dynamics is designed that minimizes the delays by the use of an ultrafast current control and a magnetic core made of soft ferrite material for preventing the effects of eddy currents. For the experimental investigation of the transient behavior of MR fluids, the small signal as well as the large signal behavior is analyzed for different test signals and load conditions of the actuator. Various results of the investigated transient behavior are shown finally for two different MR fluids featuring response times of about 1 ms for the fluid itself and switching times of about 4 ms for the MRF actuator.

Download Full-text