Title: Durability of glass fibre cement composites subjected to influence of corrosive environment

Author(s): Z. B. Rudzińska

Publication: KILW

Volume: 51

Issue: 1

Appears on pages(s): 107-122

Keywords: glass fiber

DOI:

Date: 1/1/2005

Abstract:
The paper presents investigation results on durability of fine-grained cement composite mortar, modified by addition of glass fibres of hydrolytic glass of C-3 class. Natural sands of grain size 0-05 and 0-2 mm suitably were used. The influence of fibre content was determined on short-term (28 day) physical and mechanical properties of composites and confirmed their improvement with the increased fibre content (greater for mixes of lower sand content). Resistance of investigated mixes to long-term action of pore solution on matrices with alkalies originating from the binding agent only and environment was labelled after subjecting the samples to the action of water solutions (NaOH) sodium hydroxide: 3% for 650 days, 4% for 150 days and 4% NaCl for 650 days. Control samples were left during that time in a chamber of 95% φwzg (relative humidity). Aging effects were determined on the basis of measurements of mechanical properties (including crack resistance). The state of fibre surface and contact matrix-fibre zone after the contact of samples with NaOH and NaCl solutions (outer agents) and control specimens (internal agents - influence of pore solution only) have been assessed on the basis of fracture observations of the results by scanning electron microscope. It was foud that composites of composition approximating the standard mortar (s/c = 3, w/c = 0.43, alkalies contained in pore solution - independent of sand graining - as well as those infiltrating from sodium containing solutions at temperature of about 20oC, do not impair the 28-day effects of strength growth by addition of glass fibre. Lowering of sand content to s/c = 1) with grains 0-0.5 mm and w/c ratio to 0.24 lowers the resistance of composites (both without and with glass fibres) with respect to the action of alkalia.