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Optimised technology for repair of vertical surface of concrete bridge elements

Organization, Technology and Management in Construction: an International Journal
Volume 15 (2023): Issue 1 (January 2023)
By:
Open Access
|Dec 2023

Figures & Tables

Fig. 1:

View of Klara jug bridge (left); column used for experimental work (right).
View of Klara jug bridge (left); column used for experimental work (right).

Fig. 2:

Surface preparation by hydrodemolition under high pressure to a depth of 1.5 cm, (left) and spraying of repair mortar (right).
Surface preparation by hydrodemolition under high pressure to a depth of 1.5 cm, (left) and spraying of repair mortar (right).

Fig. 3:

Finishing of repair mortar surface (left) and curing of repair mortar (right).
Finishing of repair mortar surface (left) and curing of repair mortar (right).

Fig. 4:

Appearance of concrete surface after surface preparation by hydrodemolition under high pressure (left) and test fields before pull off testing (right).
Appearance of concrete surface after surface preparation by hydrodemolition under high pressure (left) and test fields before pull off testing (right).

Fig. 5:

Roto nozzle for washing of concrete surface.
Roto nozzle for washing of concrete surface.

Fig. 6:

Testing of concrete before repair: (A) coring of concrete; (B) pull-off test.
Testing of concrete before repair: (A) coring of concrete; (B) pull-off test.

Fig. 7:

Mortar samples for compressive and bending strength testing (left) and testing of bending strength (right).
Mortar samples for compressive and bending strength testing (left) and testing of bending strength (right).

Fig. 8:

Influence of time period between the end of surface preparation and application of the repair mortar on pull-off tensile strength.
Influence of time period between the end of surface preparation and application of the repair mortar on pull-off tensile strength.

Fig. 9:

Comparison of the pull-off tensile strength test results for two cases: with and without surface preparation by washing with a roto nozzle.
Comparison of the pull-off tensile strength test results for two cases: with and without surface preparation by washing with a roto nozzle.

Results of the mechanical and durability tests on the repair mortar_

PropertyUnitIndividual test resultsAverage value
Compressive strengthN/mm271.770.775.271.370.274.372.2
Flexural strengthN/mm28.08.48.98.4
Static modulus of elasticitykN/mm228.45126.94129.33428.242
Capillary absorption coefficientkg/m2/h0.50.110.100.110.11
Chloride diffusion coefficient10–12 m2/s1.242.761.811.94

Mechanical properties of concrete from the bridge column_

PropertyUnitIndividual test resultsAverage value
Compressive strengthN/mm254.6 39.0
38.6
31.4
31.3
39.3
Pull-off tensile strengthN/mm22.202.042.24
2.681.90
2.452.05
2.272.44
2.032.35
Static modulus of elasticitykN/mm234.337 32.679
31.206
32.493

Results of the pull-off tensile strength tests for the case when the concrete surface is treated by hydrodemolition but without washing with a roto nozzle prior to application of the repair mortar_

TimeIndividual pull-off tensile strength results (N/mm2)Average pull-off tensile strength results (N/mm2)
0 min0.19 (100% A/B)0.16 (100% A/B)0.83 (80% A/B, 20% B)0.39
30 min0.34 (80% A/B, 20% B)1.11 (50% A/B, 50% B)0.53 (10% A, 90% A/B)0.66
60 min0.45 (10% A, 90% A/B)0.66 (80% A/B, 20% B)0.91 (50% B, 50% A/B)0.67
90 min1.17 (20% A, 80% A/B)1.39 (30% A, 70% A/B)0.83 (20% A, 80% A/B)1.13

Chloride concentration in concrete at different depths determined by the RCT method_

Test locationDepth (mm)Chloride content (% of concrete mass)
10–100.012
10–200.016
20–100.034
10–200.021
30–100.018
10–200.019
40–100.006
10–200.005

Shrinkage of repair mortar_

Age (day)13681728
Shrinkage (mm/m)0.0000.2380.3310.4450.6420.756

Results of the pull-off tensile strength tests for the case when concrete surface is prepared by hydrodemolition and washed with a roto nozzle prior to application of the repair mortar_

TimeIndividual pull-off tensile strength results (N/mm2)Average pull-off tensile strength result (N/mm2)
0 min1.10 (50% A, 50% A/B)1.32 (50% A, 50% A/B)0.001.21
10 min1.53 (20% A, 80% A/B)1.54 (50% A/B, 50% B)1.42 (100% A/B)1.50
20 min1.52 (100% A/B)0.000.001.52
30 min1.66 (50% A/B, 50% B)2.18 (10% A, 90% A/B)1.46 (20% A, 80% A/B)1.77
40 min1.60 (50% A/B, 50% B)1.97 (50% A, 50% A/B)0.001.79
50 min1.69 (50% A/B, 50% A)1.83 (10% A, 90% A/B)0.001.76
60 min1.48 (100% A/B)2.35 (50% A/B, 50% B)0.001.92
70 min1.83 (100% A/B)2.05 (50% A, 50% A/B)1.90 (20% A, 80% A/B)1.93
80 min2.32 (100% A/B)2.02 (60% A, 40% A/B)2.10 (50% A, 50% A/B)2.15
90 min2.21 (50% A, 50% A/B)2.59 (80% A, 20% A/B)2.50 (80% A, 20% A/B)2.43
100 min1.99 (10% A, 90% A/B)2.08 (60% A, 40% A/B)2.17 (80% A, 20% A/B)2.08
110 min1.75 (50% A/B, 50% B)1.69 (10% A, 90% A/B)1.81 (10% A, 90% A/B)1.75
120 min1.51 (20% A, 80% A/B)1.62 (50% A/B, 50% B)1.63 (20% A, 80% A/B)1.59
180 min1.46 (30% A, 70% A/B)1.70 (50% A/B, 50% B)1.11 (20% A, 80% A/B)1.42
240 min1.11 (20% A/B, 80% B)1.21 (20% A, 80% A/B)1.87 (50% A/B, 50% B)1.40
6 h1.07 (100% A/B)1.04 (100% A/B)0.85 (100% A/B)0.99
8 h1.02 (20% A, 80% A/B)0.95 (10% A, 90% A/B)0.71 (20% A, 80% A/B)0.89
24 h0.82 (10% A, 90% A/B)0.97 (20% A, 80% A/B)0.61 (20% A, 80% A/B)0.80
48 h0.75 (20% A, 80% A/B)0.55 (100% A/B)0.80 (50% A/B, 50% B)0.70
96 h0.49 (100% A/B)0.60 (50% A/B, 50% B)0.71 (50% A/B, 50% B)0.60
DOI: https://doi.org/10.2478/otmcj-2023-0018 | Journal eISSN: 1847-6228 | Journal ISSN: 1847-5450
Journal RSS Feed
Language: English
Page range: 233 - 242
Submitted on: Aug 31, 2023
Accepted on: Dec 8, 2023
Published on: Dec 29, 2023
Published by: University of Zagreb
In partnership with: Paradigm Publishing Services
Publication frequency: 1 issue per year
Keywords:
bridge,
concrete repair,
durability,
hydrodemolition,
pull-off tensile strength,
repair mortar
Related subjects:
Engineering,
Introductions and overviews,
Engineering, other

© 2023 Marijan Skazlić, Berislav Borovina, Ivan Gabrijel, published by University of Zagreb
This work is licensed under the Creative Commons Attribution 4.0 License.

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