Title:
Moisture Sensitivity of Cellulose Fiber Reinforced Cement
Author(s):
P. Soroushian and S. Marikunte
Publication:
Symposium Paper
Volume:
126
Issue:
Appears on pages(s):
821-836
Keywords:
cellulose fibers; cements; composite materials; deflection; flexure; flexural strength and toughness; fracture properties; kraft pulp; Materials Research
DOI:
10.14359/2398
Date:
8/1/1991
Abstract:
Cellulose fiber reinforced cement can provide the highest performance-to-cost ratio among fibrous cement composites considered for the replacement of asbestos cement. Such composites can find applications in the production of thin flat and corrugated cement sheets, nonpressure pipes, and many other thin-sheet cement products. There are, however, concerns regarding the moisture-resistance of cellulose fiber-cement composites. Considerable differences in flexural strength and fracture toughness values are observed when the specimens are tested at different moisture contents. This paper presents the results of a comprehensive experimental study concerned with the effects of moisture content on flexural performance characteristics of cellulose fiber reinforced cement. The cement composites considered in this investigation incorporated 0 percent, 1 percent, and 2 percent mass fractions of kraft pulp. The moisture conditions investigated included oven-dried, air-dried, and saturated. Comprehensive sets of replicated flexural test data were generated and analyzed statistically. Analysis of variance techniques were employed to derive reliable conclusions regarding the moisture-sensitivity of the flexural strength and toughness characteristics of cellulose fiber reinforced cement composites. The results generated in this study indicate signficant effects of moisture content on flexural performance of cellulose fiber reinforced cement. There is a tendency for flexural strength to decrease and flexural toughness to increase with increasing moisture content of the composite material. Microstructural studies indicate that high moisture contents tend to damage the fiber-to-matrix bond strength, leading to changes in failure mechanism that can describe the trends observed in moisture effects on flexural performance of cellulose-cement composites.