Study On The Influence Of Early-age Material Property On Durability For Concrete In Different Construction Condition

The durability problems of engineering structure have been increasingly outstanding throughout the world. Consequently, research on durability of concrete material and structure and the life-cycle performance bas become a hot topic. However, within the parameters of subject, the previous study focused on materials or existing structures and the influence of material and structure performance in construction stage on durability of harden concrete was neglected. Due to inseparable relationship between early-age properties and durability of concrete, it is promising to analyse the influence of early-age properties on durability from construction stage.Therefore, for the sake of research on the relationship between early-age properties in construction stage and durability in latter life, by experiment of four kinds of vibration and curing condition in construction, the effect rules of early-age properties on durability has been studied systematically in this article. The result of this article plays an important role in establishing the durability evaluating technique based on analysis of concrete early-age property. The mainly research contents are as follows:(1) Material properties during28d for concrete specimens of four kinds of vibration and curing conditions were experimented, including slump, hydration, air content, shrinkage, strength, elastic modulus, uniformity and density. The results indicated the influence of construction conditions on early-age properties. It was concluded that in order to make concrete early-age properties satisfy the standards, curing measures during7d must be noticed.(2) Durability indicators after28-day curing age for concrete specimens of four kinds of vibration and curing conditions were experimented, including air permeability, chloride ion content and corrosion current density of steel bar. The results indicated the influence of construction conditions on durability in life. Also, the durability evaluating technique based on analysis of concrete early-age property was studies. It was concluded that it is necessary to test permeability indicators during quality acceptance of concrete structure rather than testing the strength only. (3) Based on the backscattered electron imaging technique of Scanning electron microscopy (SEM) and mercury intrusion porosity (MIP) method, porosity for concrete specimens of four kinds of vibration and curing conditions was experimented. The results indicated the influence of construction conditions on concrete porosity. Also, the Micro-mechanism of the influence of construction condition on concrete properties was studied.