Cement-based corrugated sheets reinforced with polypropylene fibres subjected to a high-performance curing method

Abstract

This work proposes and evaluates a curing method based on the accelerated carbonation (AC) for cement-based corrugated sheets reinforced with polypropylene (PP) fibres produced by the Hatschek process. These corrugated sheets were experimentally evaluated in order to identify how the AC affects the fibre-cement composites. The obtained performance was compared with air-cured corrugated sheets reinforced with PP fibres and air-cured corrugated sheets reinforced with polyvinyl alcohol (PVA) fibres. The AC conferred a high carbonation degree (86%) increasing bulk density (13%) and decreasing apparent porosity (22%) and water absorption (28%) by means of calcium carbonate formation. The modulus of elasticity (10.7 GPa) and limit of proportionality (8.3 MPa) doubled in comparison with air-cured corrugated sheets. The Darcian (k1) and non-Darcian (k2) permeability coefficients were retrieved from the Forchheimer’s equation. The clogging of the permeable pores caused by the AC resulted in a reduction of 49% and 95% in k1 and k2, respectively. The drying shrinkage halved (1 mm/m) by the influence of AC which clogged pores with carbonates in the range 0.06–1.50 µm. Water-tightness test and its evaluation through digital image analysis showed a reduced moistened area in the AC cured corrugated sheets (22% lower) and enabled the identification of the cracks, which have a great influence on water tightness and permeability. The AC mitigated defects and conferred lower permeability and higher physical–mechanical performance in comparison to the air-cured PP and PVA reinforced corrugated sheets.