Carbon Activated Timber

Building construction contributes a significant portion to the global consumption of energy and greenhouse gas (GHG) emissions, and decarbonization has become one of the main targets. This has turned much attention to renewable materials, particularly timber construction. Wood is a natural composite, and it causes challenges in its natural state due to its mechanical properties and functionality, which has constrained its use in construction. Laminating wood sections into glue-laminated (glulam) and cross-laminated timber (CLT) components overcomes limitations in dimensions and inconsistencies in its properties. We went beyond these technologies and explored the potential of combining timber of the radiata pine species with synthetic fibers, aiming for hybrid natural–synthetic composite beams. This research illustrated various reinforcement mechanisms and analyzed their structural properties. The results from the experiments showed that carbon fiber-reinforced timber composites have up to 49% additional increase in load-bearing capacity compared to unreinforced beams. An identical amount of strain required less stress, and the composite portrayed a metal-like ductility property, a characteristic referred to as pseudo-ductility. It reduces the material consumption in beams through a more efficient use of materials, particularly around compression areas before tensile rupture. The resulting composites are sustainable yet structurally capable, contributing to the reduction in CO₂ emissions in timber construction systems.

Figure 1. Sketch model

Figure 2. Different reinforcement mechanisms (Cases 2, 3, 4, 5, 6) compared to the benchmark/unreinforced case (Case 1)

Figure 3. (a) A milling machine grooving design patterns for fibers’ lamination; (b) Case 2 and Case 3 samples (bottom side up) after grooving, next to benchmark case 1.

Figure 4. (a) Some of the radiata pine sample pieces ready for testing. (b) Experiment setup showing reaction-bearing plates used at supports and between the loading anvil and the sample.

Figure 5. A slow deformation is seen at the compression (top) zone of the 40 × 80 beam sample.

Figure 6. A 40 × 80 sample piece from benchmark case 1 (left) compared to the most promising reinforced 40 × 80 sample Case 4 (right) after loading

Figure 7. A 40 × 40 sample piece from benchmark case 1 (left) compared to the most promising reinforced 40 × 40 sample Case 5 (right) after loading.

Figure 8. Some pieces from each design case after testing: (a) 40 × 80 mm cross-sectional samples, (b) 40 × 40 mm cross-sectional samples.

Figure 9. Load vs. extension graph of (a) Case 1, 40 × 80 sample pieces, vs. Case 4, 40 × 80 sample pieces; and (b) Case 1, 40 × 40 sample pieces, vs. Case 5, 40 × 40 sample pieces.

Figure 10. Flexure stress vs. flexure strain graph of case 4, 40 × 80 sample pieces, compared to case 5, 40 × 40 sample pieces.

Figure 11. Application of the reinforcement mechanism onto a carbon fiber-reinforced timber bench.

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