بررسی مقاومت زنگ زدگی بلند مدت سازه های بتنی مسلح
Abstract
1- Introduction
2- Test methodology
3- Corrosion rate analysis
4- Corrosion potential measurements
5- Mass loss measurements
6- Models and statistical analysis
7- Conclusions
References
Abstract
Corrosion of steel in reinforced concrete is a serious concern for owners and asset managers of various concrete structures and infrastructure. Literature suggests there is limited research on long-term corrosion behaviour of various types of reinforced concretes under similar conditions of chloride and surrounding temperature environments. This paper presents results of a comprehensive experimental program designed to investigate the long term corrosion resistance of various types of reinforced concretes in the coupled effect of varying chloride and temperature conditions. Large size specimens (slabs) made of ordinary concrete (OC), lightweight concrete (LWC) and self-compacting concrete (SCC) were developed. The specimens were subjected to 365 days of corrosion under varying levels of chlorides and three temperature exposures respectively. The test results indicated that the corrosion rates of the rebars in LWC are the lowest compared to those of OC and SCC. Relations were developed for corrosion rates as a function of percentage chloride, temperature and time for different types of concretes. The current research can serve as a benchmark for adequate selection of type of concrete for construction in aggressive environments.
Introduction
Corrosion-induced deterioration of structures and infrastructure accounts for 2.5 trillion dollars per annum globally [1]. Significant efforts have been devoted to the development of new materials to enhance the service life of reinforced concrete structures and infrastructure against corrosion. Chloride attacks are the most detrimental to steel/rebar in any type of concrete, including ordinary, self-compacting or lightweight concrete [2–۴].
Recently, the use of lightweight concrete in construction has increased in the last 10 to 15 years [5–۱۰]. New techniques have been developed for construction with LWC, which are simple [11–۱۳], cost-effective and environmentally friendly [14,15]. Moreover, several studies on the structural performance of LWC have been undertaken over the last 20 years [16–۲۰]. However, research on the durability of LWC, and specifically on chlorideinduced corrosion of the rebars is scarce [4,21]. Furthermore, there are limited comparisons between chloride-induced corrosion of LWC and other types of reinforced concrete. Moreover, long-term chloride attacks, which may prove to be detrimental to the service life of various types of reinforced concrete in hot climatic conditions, have not been adequately investigated.