Moisture sensitivity and dimensional stability of carbonated fibre–cement composites

Abstract

The aim of this work was to improve the long-term performance of fabricated eco-cement composites and demonstrate the value-added use of carbon dioxide (CO2) in manufacturing sustainable products with better dimensional stability and moisture resistivity. Experiments were on pressed and non-pressed composites, fabricated with and without carbon dioxide curing. Dimensional stability comparisons were made between composites of date palm fibre and cement subjected to different moisture conditions, including air-dried, oven-dried and saturated conditions. Their flexural performances were then evaluated and compared with control specimens. The results revealed that the application of pressing and carbon dioxide curing as accelerating processing techniques have significant influences on the resultant products. The oven-dried composites exhibited poor flexural toughness behaviour compared with the air-dried or saturated specimens. Fibre growth in the transverse direction due to moisture conditions was observed to be efficient in strengthening the transition bonding areas with the matrix. In comparison with board length, the changes in board thickness and mass due to moisture effects were remarkable. This behaviour suggests that the final volume stability response of the composite is dominated by the orthotropic property due to the various constituents. Microstructural observations confirmed that carbon dioxide curing densified the matrix, leading to better dimensional stability of the composites, even after 25 wetting–drying cycles.