Prediction of service life due to the exposure of chlorides of reinforced concrete bridges near coastal areas in Vietnam = Dự báo tuổi thọ sử dụng của cầu bê tông cốt thép ven biển Việt Nam do xâm nhập clo (tóm tắt + toàn văn)

[...]... especially concrete bridges 1.10.2 Service life of reinforced concrete bridges at the coastal areas in Vietnam The service life of the reinforced concrete bridges which their spans cannot be substituted will be considered as equaling to the minimum service life of structural members (foundation, abutment, pier, and superstructure) 1.10 T = min ( Ti ) 19 ( 3.68) + Substructures lying in the coastal areas There... life of reinforced concrete bridges by invading chlorine "LifeConBridge" at the coastal areas in Vietnam was successfully constructed, in which the end of life is defined as the time at which cover concrete layer is completely cracked or the time at which the steel section loss due to corrosion endangers strength limit states 2 The service life of reinforced concrete bridges according to “LifeConBridge”... characteristics at the coastal areas in Vietnam and Climate change 3.6.1.1 Climate characteristics in Vietnam 3.6.1.2 Climate change in Vietnam in the future Prediction of climate change and sea water rising in Vietnam published by the Ministry of Natutal Resources and Enviroment is the base to evaluate the influence of these causes and to establish a plan to cope with them 3.6.1.3 General evaluation of the influence... + In the present condition in Vietnam, it is acceptable to use the formulation of determination of chloride diffusion coefficients in concrete according to the outputs of fast permeability tests ASTM C1202 as performed in Chapter 2 The output of the coefficients can be used as input of the prediction pattern + Service life pattern of the present study can help designers to have a reasonable designing... formulated to predict the service life of reinforced concrete bridges at the coastal areas in Vietnam due to chloride penetration based on MATLAB programming The service life includes two continuous stages: corrosion initiation stage and corrosion propagation stage The model was applied for some examples and the outputs show that: the corrosion initiation stage (t1) at humidity H=100% is consistent with the. .. pattern of the service life of reinforced concrete structures” – Scientific Magazine of Transport and Communications, issue 25/2009; 5/ Dinh, D.V “Analyzing of reinforced concrete structures with taking effect of stiffness reduction caused by cracking” - Scientific Magazine of Transport and Communications, issue 34/2011; 6/ Dinh, D.V “A prediction of the corrosion initiation stage for reinforcement in concrete. .. time (in years) which is dangerous to bearing capacity limit states is determined as: t2 = 26.8 1.8 ρth d icorr ( 3.67 ) Programming diagram for determinination of the service life of concrete bridges “LifeConBridge” 16 Figure 3.11: Programming algorithm for determining of the service life due to chloride penetration corrosion 1.9 Outputs and comments 1.9.1 Validation of outputs obtained based on the. .. output of Life3 65”; the corrosion propagation stage is consistent with the test result of Liu Therefore, the proposed model is believable 5 The effect of some parameters to the service life of reinforced concrete bridges in Vietnamese environment was considered for the proposed model (the thickness of cover concrete layer, ratio of water/cement, silica fume, chloride concentration threshold of reinforcement... cylinder and the wall thickness is assumed to be the thinnest concrete cover layer thickness 2) Stresses and strains in concrete appear due to the volume dilation of corrosive products Concrete cover is considered as a linearly elastic material 3) There are porous areas around concrete- reinforcement interface, corrosive products will diffuse into the gaps 4) During the development of cracking, a part of corrosive... inhibitor Ca(NO2)2 + Un-stained steel used 4 To use methods to increase the accumulating time of chloride concentration on surface Cs such as: + Membrane + Painting 5 To use a combination of the above methods The methods to increase the corrosion propagation time: Painting of reinforcement by using epoxy, coating or galvanizing CONCLUSIONS AND RECOMMENDATIONS 1/ Conclusion 1 Experiment study of fast chloride . concrete bridges impacted by chloride penetration near coastal areas in Vietnam, the author selects the thesis title Prediction of service life due to the exposure of chlorides of reinforced concrete. of the service life needs to be determined. In this thesis, the author is going to determine the service life for two cases: 1. The end of the service life is considered as the time the concrete cover. concrete bridges near coastal areas in Vietnam . 2. Purposes of the thesis The thesis aims at researching of the penetration and reinforcement corrosion of chloride in reinforced concrete bridges