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W o r l d C o n g r e s s o n
Materials Science & Engineering
Nano Research & Applications
ISSN: 2471-9838
August 23-25, 2018
Amsterdam, Netherlands
Materials Congress 2018
Page 36
T
his paper summarizes the corrosion resistance and bond strength of
coated and uncoated steel reinforcing bars in mortar or concrete. Coatings
investigated included pure enamel (PE) for corrosion protection, calcium silicate
modified enamel (ME) for bond enhancement, and double enamel (DE) with an
inner layer of PE and an outer layer of ME. For comparison, fusion-bonded epoxy
(EP) was also considered. For corrosion performance, mortar cylinders reinforced
with uncoated (UN) and PE-, ME-, DE-, and EP- coated steel bars were immersed
and tested in 3.5 wt% NaCl solution. The corrosion evolution was monitored
using electrochemical impedance spectroscopy (EIS). The increase in corrosion
resistance was as high as 100 times and 4 times when the steel bar was coated
with PE andME, respectively. Due to chemical bond between the enamel and steel,
the corrosion of damaged PE-coated bars was confined to damage areas with no
under-film corrosion as observed with EP coating. For bond behaviour, pull out
specimens were prepared with one steel bar placed along the center line of each
mortar cylinder. The effects of mortar curing time (28 days and 60 days) were
investigated. The PE-coated steel bars were also tested in large-scale reinforced
concrete (RC) columns under cyclic loads and in full-scale RC walls under blast
loads to understand how the bond improvement of enamel coating at material
level was translated to the performance of structural systems. The bond strength
can be increased by 2 times and 7 times when a steel bar is coatedwith PE andME,
respectively. The significant steel-concrete bond increase with ME resulted from
the increased surface roughness and the chemical bonding of embedded calcium
silicate particles in surrounding mortar. With enamel coating, the failure modes
of RC columns and walls can be changed from brittle to more ductile behaviour.
Biography
Genda Chen has received his PhD in Civil Engineering at State
University of New York at Buffalo. He is Professor and Robert W
Abbett Distinguished Chair in Civil Engineering, and Director of
the federal-funded, five-year INSPIRE University Transportation
Center at Missouri University of Science and Technology. He
is an Associate Director of the federal-funded, five-year Mid-
America Transportation Center headquartered at the University
of Nebraska, Lincoln. He has published more than 150 papers
in reputed journals in the field of interface mechanics and
deterioration, structural health monitoring, structural control,
and multi-hazard assessment and mitigation. He has been
serving as an Associate Editor of the
Journal of Civil Structural
Health Monitoring
, a section Editor of
Sensor
, and an Editorial
Board Member of 5 reputed journals.
gchen@mst.eduEnamel Coating for Steel Rebar in Concrete:
Corrosion Barrier and Bond Enhancer
Genda Chen
Missouri University of Science and Technology, USA
Genda Chen, Nano Res Appl 2018, Volume: 4
DOI: 10.21767/2471-9838-C4-016