Fundamental Research On Durability Environmental Zonation Standard (DEZS) Of Concrete Structures

Durability Environmental Zonation Standard (DEZS) of concrete structure isstudied from durability zonation and durability stipulations to put forward the basicmethodology of DEZS. It makes a mighty advance towards the quantitative durabilitydesign of concrete structures based on the theory of Structural Life-Cycle Cost (SLCC).The research contents are as follows:1. The durability conditions of the highway bridges, coastal quays and coastalunderground constructions are investigated inside Zhejiang province. Somerepresentative projects are detected in detail. The results indicate the remarkableregional difference in the durability degradation, which confirms the necessity of DEZSresearch. Some suggestions are proposed for the design and construction of the concretestructures in the southeast coastal area, offering reference for local stimulations ofZhejiang Province;2. First, the definition of DEZS is proposed. Second, the main content and thebasic principles are explained. Third, the scope of application and the significance ofDEZS are presented. Fourth, the criterion is established according to the severity ofenvironment effect on concrete structures. Fifth, the canonical representation ofmapping zonation correspondingly with durability regulations is confirmed. And Sixth,the basic methodology of DEZS is put forward, which is to dispose the environmentaleffects and the structural resistivity with focus on service life;3. The influencing factors of the environmental effects and the structural resistivityare discussed from three deterioration mechanisms: carbonation, chloride erosion andfreeze-thaw cycles. Thus the durability zonation indexes and the structural durabilityindexes in DEZS are identified initially;4. Following with the discussion of the limit states under the actions of carbonation,chloride erosion and freeze-thaw damage, the carbonation depth model, the chloridediffusion model and the freeze-thaw damage model are identified for DEZScorrespondingly, which are then applied in service life mode to form a probabilisticmethod of durability service-life prediction, according to the limit states respectivelyand the target reliability index;5. DEZS is established on two aspects. One is durability zonation determined bythe distribution of the minimum service life, which is predicted with normal inside conditions(given distribution of construction and material conditions) and varioussimplified outside conditions(various regional distribution of environmental conditions)by durability service life models on request of the reliability indexβ. The other isregional durability regulation presented in the form of combinative inside conditions,which are worked out through pilot calculation with normal outside conditionsrepresenting the zoned region, also by durability service life models on request of thereliability indexβ. At last, an example of DEZS is set in Zhejiang Province, whichcould be a reference to local standard for the southeast coastal area.This research was supported by the project of National Natural Science Fund"Fundamental Research on Durability Design and Assessment of Concrete Structures inChloride Erosive Environment" (50538070), 863 program of National Hi-TechResearch Development "Durability Test Method and Assessment Technology ofImportant Coastal bridges" (2006AA04Z422), the major project of Zhejiang Scientificand Technical Program "Research on the Key Technique of Safety and Durability ofImportant Coastal bridges in Zhejiang Province" (2003C23024), the West TrafficConstruction Project of National Traffic Ministry "Study on Durability Index System,Test Methodology and Assessment Standard of Concrete Bridges"(200631822302-06),the projects of Zhejiang Traffic Office "Survey and Assessment Research on Durabilityof Concrete Highway Bridge Structures in Zhejiang". Their support is gratefullyacknowledged.