Experimental Study of Reinforced Concrete Ties under Load and Corrosion

Corrosion of reinforcing bars embedded in concrete is a worldwide problem that affects numerous reinforced concrete (RC) structures, which generates expansive products and decreases the cross section of the bars, compromising the safety of the structure. In Italy, the national highway network comprises a large number of reinforced concrete bridges whose service life exceeded 40 years. The cost of maintenance and replacement for these highway bridges due to corrosion damage is measured in billions of euros. In this study, the major aim is the experimental research on two sets of reinforced concrete elements subjected to load and corrosion, the following work is done: Problem statement, corrosion mechanisms of steel in concrete, the deterioration effects in reinforced concrete subjected to corrosion, and the influence of corrosion on structural performance are summarized firstly. Then, the previous experimental studies and effects of various parameters on bond strength, flexural strength, shear strength and column behavior of reinforced concrete specimens are discussed. After that, the design and results of experimental tests on reinforced concrete ties subjected to: cyclic loading, cyclic loading and simultaneous corrosion, static loading and corrosion, are described and discussed. An electrochemical corrosion process is used for the accelerated corrosion tests; the geometry of specimens and the loading procedure that reproduces the usual conditions for bridge elements under fatigue loading are presented. During the tests both transversal cracks evolution and longitudinal crack formation for corroded specimens are monitored. Test results confirm that the main effect of crack opening evolution is due to the interaction between corrosion and cyclic loading. Crack opening value is directly related to the bond between steel and concrete and so the previous results can be considered as findings about bond performance. The formation of longitudinal cracking caused by corrosion and its evolution, determined also from the loading condition were monitored. It can be assumed as an indicator of the corrosion level affecting rebars. Finally those observations underline the importance of a coupled mechanical and chemical test for a reliable evaluation of performance for structure under loading and corrosion. Keywords: reinforcement corrosion, cyclic loading, crack opening, structural damage

Grantor dc:publisher

Politecnico di Torino

Year dc:date

2012

Author dc:creator

• LU, LIHENG

• Settore ICAR/09 - Tecnica delle Costruzioni

Language dc:language

eng

Handle dc:identifier

http://hdl.handle.net/11583/2497132

OAI identifier oai:identifier

oai:iris.polito.it:11583/2497132