Performance of cementitious high-pressure mixtures with wheat and corn straw fiber and straw ashes

This study aimed to introduce a novel technique for producing straw fiber cement-based composites from wheat and corn straws. The research analyses the engineering characteristics, including compressive and flexural strengths, water absorption capacity, dry density, porosity, and thermal properties of the wheat and corn straw fiber cementitious composite (WCSFCC) mixtures. The hydration performance and compactness of WCSFCC mixes were described using XRD, SEM, and EDS analyses. The results show that the dosage of NaOH solution is the optimal approach for enhancing the surface of straw fibers and facilitating their effective integration with the cement matrix. The straw powder incineration method leads the straw ash particles to have a specific surface area 9.6 times higher than straw powder. The findings indicated that WCSFCC mixes with untreated straw powder had an optimal compressive strength ranging from 2.85 MPa to 3.79 MPa and corresponding thermal conductivity between 0.147 and 0.162 W/(m·K). Adopting the straw ash increased the compressive strength considerably. The analysis of WCSFCC mechanical properties and thermal conductivity with physical properties reveals a strong correlation between the mechanical properties and dry density, as well as thermal conductivity and dry density. However, the increasing porosity and water absorption capacity have compromised the mechanical properties and thermal conductivity of WCSFCC. The findings of this research may enhance the overall use of wheat and corn straw fibers. The manufacturing process of WCSFCC is simple, conducive to widespread use, and ecologically friendly. • Use wheat and corn straw fibers to produce lightweight heat-insulating brick. • Promot a solution for the rational use of agricultural waste sustainably. • Investigate the hydration performance of the straw fiber composite from XRD and SEM. • Present a new approach to green building development. • The chemical structure of straw ash can interfere with cement hydration, reducing hardening time.