Enhancement of oriented cement-bonded boards' properties through CO₂ curing

This study investigates the effects of CO₂ curing on oriented cement-bonded boards. The boards comprised 35% and 45% (by mass) of strand-type particles of Eucalyptus spp. (8 × 2 × 0.1 cm) and 65% and 55% (by mass) of early high-strength Portland cement. To fabricate the boards, three layers of strands were arranged perpendicular to the previous layer, aiming for a target density of 1250 kg/m³, and the dimensions of the boards were 40 × 40 × 1 cm. The oriented cement-bonded boards underwent three different curing conditions: control, CO₂ curing for 6 h, and 12 h, followed by curing in a saturated environment until the 28th day. The results indicated that CO₂ curing increased the CaCO₃ content in the boards, particularly when the curing period was longer (12 h). The physical and mechanical performance of the CO₂-cured boards surpassed that of the control boards, with the modulus of rupture (MOR) increasing by 80% (6 h) and 84% (12 h) compared to the control. Scanning electron microscope investigations revealed that CO₂ curing produced a denser matrix, leading to an improved bond between the strands and the matrix, resulting in enhanced technical performance. Based on these findings, this study suggests that CO₂ curing can enhance the physical and mechanical properties of oriented cement-bonded boards, and a longer curing time (12 h) yielded superior performance.