Publication: Evaluation of damaged reinforced concrete beams repaired with epoxy injection and strengthening with carbon fibre reinforced polymer using acoustic emission technique
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Date
2020-09-01
Authors
Saliah, Soffian Noor Mat
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Abstract
Damage due to increasing loading in reinforced concrete (RC) structures is a crucial
phenomenon where it may cause structural failure and collapse. Rehabilitation of
damaged RC structure is important to restore structural integrity. The most promising
techniques are structural crack repair and strengthening. However, assessment on
damaged RC structure repaired with epoxy injection and strengthening with carbon
fibre reinforced polymer (CFRP) is extremely required. From the literature review, it
was found that the damaged RC beam repaired with epoxy injection and strengthened
with CFRP using acoustic emission (AE) signal parameters are still limited. This study
aimed to investigate, correlate, evaluate and develop flexural crack behavior (crack
mode) of RC beam repaired with epoxy injection and strengthened with CFRP
supplemented with AE signal parameters namely signal strength, average frequency
(AF), rise angle (RA) and intensity analysis (IA). Flexural static test was carried out
in the laboratory of heavy structure on RC beam size of 200 mm x 300 mm x 1500
mm. The RC beam was intentionally damaged prior to be repaired with epoxy injection
and strengthened with CFRP. The flexural static test was carried out until failure. All
analyses were derived from the AE signal collected at sensors labeled CH6 and CH7.
Both sensors were then compared, analysed and discussed. It is found that the AE
signal parameter are dependent on the type of repaired and strengthened RC beams.
At the same time, good relationships between load application, AE signal parameter,
crack modes and crack patterns were inferred on the RC beams. From the AF vs RA
value, clear trend between the relationship of the crack mode on identification of
tensile crack and shear crack were found. The IA well corresponds to the repaired and
strengthened technique for each crack mode by the plots of intensity zone at CH6 and
CH7. In addition, the understanding on visual inspection supplemented with AE
technique is useful in future monitoring and maintaining of damaged RC structure
repaired with epoxy injection and strengthened with CFRP.