为获取力学性能良好的棉秆-聚苯乙烯(EPS)砌块,以棉秆长度和粒径为指标,将棉秆分为屑沫、碎屑以及纤维3种形态,研究不同棉秆形态对棉秆-EPS砌块物理力学性能的影响。结果表明:棉秆形态对砌块早期力学性能影响不显著;28 d龄期后的砌块,配合比一定时,当棉秆长度和粒径较小时(屑沫),砌块的抗压强度、抗劈裂强度及轴心抗压强度最大,分别为6.95,0.93,6.88 MPa;而棉秆粒径增大时(碎屑),其砌块的抗压强度、抗劈裂强度及轴心抗压强度均降低;当棉秆较长为纤维状态时,砌块的抗折强度和弹性模量均最大,分别为1.44 MPa和80.42 MPa,但棉秆纤维长度的增加会增大砌块的吸水率。说明棉秆的形态可有效改变棉秆-EPS砌块的物理力学性能,在应用时可根据工程的需要选择不同的棉秆形态。成果为植物纤维生态砌块的应用提供一定的理论依据。

In the aim of preparing cotton straw-expanded polystyrene (EPS) composite block with good mechanical properties, we probed into the influence of straw form on the physico-mechanical properties of the block. The form of straw was classified as particle, chip, and fiber according to length and particle size of straw. Result showed no significant effect on the early mechanical properties of block by straw form. However, when the mix proportion was fixed and the length and size was small (particles), the block of 28-day age or above had the largest compression strength, anti-splitting strength and axial compressive strength, reaching 6.95 MPa, 0.93 MPa and 6.88 MPa, respectively; when the particle size of straw increased (chips), the compression strength, anti-splitting strength and axial compressive strength of the block declined; when the length of straw increased (fiber), the flexural strength and elastic modulus of the block were the largest, amounting to 1.44 MPa and 80.42 MPa, respectively; but the elongation of straw fiber also instigated the water absorption of blocks. In conclusion, the form of straw has remarkable influence on the physico-mechanical properties of cotton straw-EPS block. We should select proper straw form according to specific engineering requirement.