Protection of Concrete for Sewage Installations and an Accelerated Test on Protection Systems

Professor WU Chi-man, Lawrence (CityU)

Abstract
It is generally believed that concrete structures for sewage applications are subjected to biogenic sulfuric acid (BSA) attack, causing major concrete structure degradation. The problem is aggravated by environment improvements such as covering of sedimentation tanks that are traditionally open. In order to inhibit the attack caused by BSA, numerous protective methods had been attempted. Measures such as epoxy coating, acidic inhibitors, admixtures, etc. were explored. A program of evaluation of such protection candidates has been implemented. This involves initial laboratory accelerated test to screen out prospective candidates, followed by a two-year in-situ site test. In this presentation, the accelerated test will be described. The latest test results from the in-situ test on coated concrete samples at a sewage treatment plant in Hong Kong will also be provided.

About the Speaker
Ir Prof Lawrence WU obtained his BSc(Eng) and PhD from the University of Bristol, U.K. He also holds a Postgraduate Diploma in Management Studies from the University of West of England, Bristol, U.K. He is a Fellow of the Hong Kong Institution of Engineers (HKIE). He is also a Past Chairman of the Materials Division, and an ex-Council Member of the HKIE. He has been with the Department of Physics and Materials Science of City University of Hong Kong since 1987.

Prof WU has published over 150 papers at referred international journal and conferences relating to his research work in composite materials and structures, electronic packaging and electronic solder materials, solar cells, biosensors, fire resistant concrete and protective coatings for concrete.
Prof WU has been working in materials and structural failure analysis for over 20 years. He has produced over 350 consultancy reports with the majority in engineering failure investigations.