New Optical Sensors for Determination of Corrosion in Reinforcement Concrete

Corrosion of reinforcement steel of concrete is one
of the main causes of deteriorations of structures.
Principally, it is an electrochemical process, which
can be divided by two mechanisms acidic and
chloride initiated corrosion. Optical sensoric
materials were prepared, which allow a
non-destructive monitoring of these processes. The
sensors are embedded into concrete structures and the
signal is transported through optical fibres.
pH indicator azo dyes have been synthesised for
monitoring of acidic attack. An aldehyde group has
been used as dye reactive functionality for the first
time. The dyes have been covalent bound to poly(vinyl
alcohol co ethylen) by acetal spacer bridge to assure
long term stability of the sensor. The colour change
of such prepared pH indicator materials occurs in the
pH interval of 11 to 13 and allows to predict the
acidic attack in an early stage. The response time of
these sensors is in the range of seconds. The optical
detection of chloride ions in alkaline media has been
investigated. Benzimidazolotrimethine dyes tend to
form J aggregates under influence of chloride ion
concentration in pH of 10 to 13. A suitable polymer
has been developed poly(vinyl alcohol co vinyl
butyral), in which the dye is dissolved as host guest
system. Such prepared sensor material allows a
precise determination of chloride concentration and
shows an excellent selectivity against other anions,
which are typical in the presence of concrete
structures. To the best of our knowledge it is the
first optical sensors for determination of chloride
in alkaline media.

Autorentext
1970, Knezha, Bulgaria, 1990 - 1995 MS in Chemical Engineering, 2000 - 2004 PhD in Organic Chemistry, 1996 - 2000 "Aroma" AD, Sofia, Bulgaria, Production Technologist 2004 - 2005 "Max ProDis" Ltd., Sofia, Bulgaria, Production Manager 2005 - 2007 "Biesterfeld PRO" Ltd,"LifeScience" Division, Sofia, Bulgaria Sales Manager, 2007- now "Biesterfeld PRO" Ltd, "LifeScience" Division, Sofia, Bulgaria, Commercial manager

Klappentext
Corrosion of reinforcement steel of concrete is one of the main causes of deteriorations of structures. Principally, it is an electrochemical process, which can be divided by two mechanisms - acidic and chloride initiated corrosion. Optical sensoric materials were prepared, which allow a non-destructive monitoring of these processes. The sensors are embedded into concrete structures and the signal is transported through optical fibres. pH-indicator azo dyes have been synthesised for monitoring of acidic attack. An aldehyde group has been used as dye-reactive functionality for the first time. The dyes have been covalent bound to poly(vinyl alcohol co ethylen) by acetal spacer bridge to assure long-term stability of the sensor. The colour change of such prepared pH-indicator materials occurs in the pH interval of 11 to 13 and allows to predict the acidic attack in an early stage. The response time of these sensors is in the range of seconds. The optical detection of chloride ions in alkaline media has been investigated. Benzimidazolotrimethine dyes tend to form J-aggregates under influence of chloride ion concentration in pH of 10 to 13. A suitable polymer has been developed - poly(vinyl alcohol co vinyl butyral), in which the dye is dissolved as host-guest system. Such prepared sensor material allows a precise determination of chloride concentration and shows an excellent selectivity against other anions, which are typical in the presence of concrete structures. To the best of our knowledge it is the first optical sensors for determination of chloride in alkaline media.