Original
Paper(Vol.58 No.8 pp.678-683)
Study on Advancement in Reliability of Visual Test
Based on Photographic Questionnaire for Concrete Structures
Katsuya MITA and Masanori TSUJI
Abstract:Inspection of
reinforced concrete is important to ensure durability, and visual test is widely
applied to the inspection. In this study, reliability on the result of the
visual test for cold joint and sand streak was investigated, and it was
clarified that error among the results of visual test comparing with photographs
on questionnaires obtained by more than 100 students is fairly small. Then
method to predict durability of reinforced concrete based on visual test results
is proposed.The following (1),(2) and (3) are main conclusions.
(1) The
error in visual test by the proposed method among inspectors is significantly
small enough to inspect cold joint and sand streak, even when the inspectors are
students who have no experiences.
(2) Relation between the visual test result
for cold joint and the diffusion coefficient of chloride ion in hardened
concrete is very close, so that the durability of reinforced concrete structure
against chloride attack can be predicted based on visual test results. For a
example, the method specified in Japan Society of Civil Engineers standard
specification can be applied to the prediction.
(3) Relation between the loss
of mass under freezing and thawing test and the result of visual test for cold
joint and sand streak is close, so that the visual test can be an effective
method to predict durability against freezing and thawing and also to judge the
requirement for repair.
Key Words:Concrete, Visual test, Cold joint , Sand streak,
Chloride diffusion, Freezing and thawing