In fabric-cement composites, the limited impregnation of cementitious matrix products due to thick and twisted yarns leads to premature failure due to poor bonding strength. In addition, cellulosic textile reinforcements have many challenges about durability, appearance of voids at mortar-fiber interface, and rise of microcracks. Textile performances were evaluated in different conditions: coated with micro-silica powder, pretreated, and without any treatment. This study also assessed how textile weave structure and yarn geometry configuration affect the interactions of two different jute textiles (Close Weave Jute Fabric – CJF and Open Weave Jute Fabric - OJT) when used as reinforcement in mortar matrix. Textile characterization and composite analysis (by four-point bending tests, SEM/EDS, and physical tests) were conducted to assess the different textile reinforcements, the mechanical behavior of produced composites, and visual and chemical compounds analysis of the interfacial transition zone between textile and mortar matrix after silica coating. Micro silica powder coating was deemed necessary to address limited impregnation and to avoid telescope pull-off. Weave structure determined the difference between jute fabrics to reinforce mortar matrix, being only OJF (larger interstices in the weave structure) with micro silica coating allowed a better matrix interaction and stood out from the other textiles and achieved the best specific energy of all samples, (4.28 ± 0.91) kJ.m-2. Calcium and silicon inside the yarn interstices and textile-matrix interface indicate the formation of strong bonds by calcium-silicate-hydrate products. The silica coating treatment enhanced formation of strong bonds, which demonstrated future promise for natural fiber application.
This study investigates accelerated carbonation as a low-energy alternative to autoclave curing in the production of fiber cement composites reinforced with lignocellulosic fibers. The effects of both curing routes on physical–mechanical performance, durability, and microstructural evolution were systematically evaluated before and after 25 wetting–drying cycles. Carbonation-cured composites achieved mechanical performance comparable to autoclaved materials, while exhibiting higher bulk density (≈1.37–1.38 g/cm3) and a reduction of approximately 15% in total void volume. Water absorption values were up to 17% lower than those of autoclaved counterparts. After accelerated aging, both systems showed stable mechanical properties, with increases in modulus of elasticity of approximately 21% (autoclaved) and 26% (carbonated), indicating ongoing hydration and densification processes. Thermogravimetric analysis revealed carbonation degrees of approximately 16–17%, corresponding to CO2 uptake values of up to 35.8 kg/m3 of fiber cement. X-ray diffraction confirmed the consumption of portlandite and the formation of calcium carbonate phases, contributing to pore refinement and matrix densification. Microstructural observations indicated improved fiber–matrix interaction in carbonated composites due to the precipitation of carbonation products at the interface, whereas autoclaved materials exhibited signs of fiber degradation associated with hydrothermal curing. These effects were reflected in higher deformation capacity and specific energy retention in carbonated systems. Overall, accelerated carbonation represents a promising alternative to autoclave curing, delivering comparable mechanical performance while enhancing fiber durability, refining pore structure, and enabling CO2 sequestration within the cementitious matrix.
Textile-reinforced concrete (TRC) is an alternative class of mechanical reinforcement for cement composites. The biaxial braided reinforcement structure in composite materials with diverse cross-sectional shapes offers high adaptability, torsional stability, and resistance to damage. In general, 3D textile reinforcements improve the mechanical properties of composites compared to 2D reinforcements. This study aimed to verify reinforcement behavior by comparing multidimensional braided textiles, 2D (one- and two-layer) reinforcements, and 3D reinforcement in composite cementitious boards. Experimental tests were performed to evaluate the effect of textile structures on cementitious composites using four-point bending tests, porosity measurements, and crack patterns. All textiles showed sufficient space between yarns, allowing the matrix (a commercial formulation) to infiltrate and influence the composite mechanical properties. All composites presented ductility behavior. The two layers of 2D textile composites displayed thicker cracks, influenced by shear forces. Three-dimensional textiles exhibited superior values in four-point bending tests for modulus of rupture (7.4 ± 0.5 MPa) and specific energy (5.7 ± 0.3 kJ/m2). No delamination or debonding failure was observed in the boards after the bending tests. The 3D textile structure offers a larger contact area with the cementitious matrix and creates a continuous network, enabling more uniform force distribution in all directions.
Due to the increasing interest in bamboo as a construction material, addressing its geometric variation along the culm and the gradient fiber distribution across the wall thickness is essential to develop standardized products for large-scale use. One option is the flattening–densification process, in which the curved material is pressed into prismatic panels that can be stacked and glued in multiple layers. This study assessed the effect of orientation and side arrangement on the physical and mechanical properties of two-layer densified panels, varying both the alignment of fibers (parallel or perpendicular) and the contact face with the adhesive (inner or outer layers with pith ring and skin). After 576 h of water immersion, panels glued in parallel with inner layers facing each other had the lowest water absorption (36.22%), whereas parallel panels glued with outer layers showed higher water absorption and thickness swelling (45.86 and 35.74%, respectively). Flexural strength was greater in parallel-aligned panels, with the highest value observed in the inner–inner configuration (200.3 MPa). The modulus of elasticity of parallel panels (average 20.9 GPa) was up to eight times higher than that of perpendicular panels (average 2.6 GPa). In shear tests, failure occurred along the glue line for parallel panels (up to 7.16 MPa) and by tension perpendicular to fibers in perpendicular panels (up to 5.28 MPa). Scanning electron microscope analysis revealed that adhesive penetration into the bamboo interphase occurred only in parallel panels glued with inner layers, while in other configurations the adhesive remained mostly on the surface (adhesive interphase or bamboo–adhesive interphase). These findings highlight how orientation and layer arrangement govern adhesive penetration and, consequently, the performance of engineered bamboo panels.