1. 1) Kishitani, E.: Series of durability of concrete structure, Salt-Damage (I), pp 10-13, 1986 (in Japanese)
2. 2) 'Investigation of chlorides in highway bridge', Department of planning, Japan Roads Association, pp. 1-3, Feb 1984
3. 3) Nationwide survey on airborne chloride I, Public Works Research Institute, PWRI Technical Memorandum No. 2203, Mar 1985 (in Japanese)
4. 4) Nationwide survey on airborne chloride II, Public Works Research Institute, PWRI Technical Memorandum No. 2257, Nov 1985 (in Japanese)
5. 5) Nationwide survey on airborne chloride III, Public Works Research Institute, PWRI Technical Memorandum No. 2687, Nov 1988 (in Japanese)