LONG TERM DURABILITY OF CONCRETE MADE WITH DIFFERENT WATER REDUCING CHEMICAL ADMIXTURES UNDER MARINE ENVIRONMENT

A detailed investigation on concrete specimens made with different waterreducing chemical admixtures was carried out. Chemical admixtures include air-entraining admixture (vinsol), water-reducing admixture (lignosulfonate group) and high-range waterreducing and air-entraining admixture (naphthalene, melamine, polycarboxyl and aminosulfonate group). Cylindrical plain and reinforced concrete specimens were tested after 10 year of exposure in the tidal environment. The test items include compressive strength, Young's modulus, carbonation depths, chloride ingress, pore size distribution of concrete, and electrochemical and physical evaluations of corrosion of steel bars in concrete. Moreover steel-concrete interfaces were examined by Scanning Electron Microscope (SEM). Naphthalene group of high-range water-reducing and air-entraining chemical admixture shows the best performance with respect to the strength development and chloride ingress in concrete. Formation of a good steel-matrix interface prevents the initiation of corrosion even for chloride concentration more than 2% of cement mass.

• INTRODUCTION

• EXPERIMENTAL METHODS: MATERIALS, MIXTURE PROPORTIONS AND ITEMS OF INVESTIGATION

• EXPERIMENTAL RESULTS AND DISCUSSION

• CONCLUSIONS

• REFERENCES