Wetness expansion and density of asbestos cement pipes

Abstract

This paper presents measurements of the coefficient of wetness expansion and density of asbestos cement pipes. For the former, 24 specimens were used, each 300 mm long and 40 mm wide, and sawn from a 100 mm diameter ordinarily cured asbestos cement pressure pipe, and tested according to ISO R160. For density measurements, 54 specimens, each 30 mm square were sawn from nine asbestos cement pipes of different internal diameters. The specimen wet and dry densities were measured using a simple mercury displacement technique.The result showed a direct linear relationship between coefficient of wetness expansion and the percentage of water absorbed by the asbestos cement matrix. Ultimate expansion after 28 days of immersion was of the order of 800 x 10−6 m/m and 65-70% of total expansion took place during the first 24 hours.Dry density measurements varied from 1.77 to 2.01 g/cm3. Wet density measurements ranged from 2.06 to 2.25 g/cm3