Title：Predicting Chloride Ingress and Additional Service Life for Reinforced Concrete Treated with Electrical Chloride Extraction

Speaker：Li Zheng

Time：November 13，2017 at 10:30a.m.

Venue：Anzhong A322

Presentation Abstract:Electrochemical chloride extraction (ECE) is an attractive, non-destructive method to extend the service life of reinforced concrete structures exposed to chloride environment.However, the application of the anodic field can cause deleterious changes to the concrete microstructure and, hence, its longer-term chloride resistance.In this report, a laboratory scale study is reported that describes the effects of ECE on the chloride resistance.Three cement combinations, i.e. 100%PC, 70%PC/30%FA and 50%PC/50%GGBS, were selected to produce concrete test specimens with w/c ratios ranging from 0.35 to 0.55.Chloride ingress properties before and after ECE were measured.No significant difference between untreated and ECE-treated concretes for PC and PC/FA mixes, however, resistance to further chloride ingress was reduced following ECE for the PC/GGBS mixes.As the chlorides distribution was different from that of non ECE treated samples, care is required for the residual service life prediction.A numerical model based on Fick’s second law of diffusion is proposed for the prediction of chloride penetration and further service life of ECE treated concrete structures.Simulations with the numerical model was carried out in several scenarios in comparison with those from most popular used ERFC Models, such as Bamforth model and Life-365.

Biography：Dr. Li Zheng is a senior specialist in Concrete Technology Unit (CTU) at the University of Dundee. He has over 35 years of experience in concrete technology research and completed many research projects supported by funding from EPSRC, DEFRA, and DTI et al and published a number of technical papers. His work is concerned with concrete durability, blended cements, foamed concrete, optimization and mathematical modelling of concrete performance. He obtained his MSc degree at Southeast University in 1984 and then worked in the Department of Civil Engineering at Zhejiang University till 1996, and then went to University of Dundee and obtained his PhD degree there in 2001.