1. N. B. Eden andJ. E. Bailey,J. Mater. Sci. 19 (1984) 150.
2. R. Feret,Bull. Soc. Encour. Ind. Nat. Paris II (1897) 1604.
3. ASTM Annual Standards Part 14.C31 (ASTM, Philadelphia, 1977) p. 11.
4. A. Short andW. Kinniburgh, ?Lightweight Concrete? (Applied Science, London, 1978).
5. A. M. Neville, ?Properties of Concrete? (Pitman, London 1977) p. 424.