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.