耐碱玻璃纤维ECC复合材料受压应力–应变关系

为研究耐碱玻璃纤维工程用水泥基复合材料（耐碱玻璃纤维ECC）的抗压性能及应力-应变关系,对33组高性能水泥基材料试件进行了轴压性能试验,分析了纤维掺量、纤维长度及水灰比对耐碱玻璃纤维ECC的受压性能及应力-应变关系的影响,提出了耐碱玻璃纤维ECC受压应力-应变关系计算模型。结果表明,掺入耐碱玻璃纤维可以明显改善水泥基材料在单轴受压状态下的抗裂、受力和变形性能;耐碱玻璃纤维ECC试件抗压强度和变形能力的提升程度与纤维掺量、纤维长度及水灰比有关;随着纤维掺量和长度增加,耐碱玻璃纤维ECC试件的抗压强度和变形能力大致呈递增趋势,但掺量过多会因“团聚”现象明显导致试件抗压强度降低;水灰比主要影响试件的抗压强度,水灰比越大,抗压强度越小;当纤维质量掺量为6.5%、纤维长度为18mm及水灰比为0.32时,碱玻璃纤维ECC的综合力学性能相对较优,其抗压强度和变形能力分别可提升25.6%和88%;提出的应力-应变关系模型的计算值与试验值吻合较好,可用于描述耐碱玻璃纤维ECC的受压破坏全过程。

Stress-strain Relationship of Alkali-resistant Glass Fiber ECC Composites under Compression

To study the compressive properties and the stress-strain relationship of alkali-resistant glass fiber engineered cementitious composites (ECC), 33 groups of high performance cement-based material specimens were tested under axial load. The effects of fiber content, fiber length and water-cement ratio on the compressive properties and stress-strain relationship of alkali-resistant glass fiber ECC were emphatically analyzed, the calculation model for stress-strain relationship of alkali-resistant glass fiber ECC was proposed. The results show that the crack resistance, mechanical property and deformation capacity of cement-based materials can be significantly improved by adding alkali-resistant glass fiber under uniaxial compression. The improvement of compressive strength and deformation capacity of the alkali-resistant glass fiber ECC is related to the fiber content, fiber length and water-cement ratio. The compressive strength and deformation capacity of alkali-resistant glass fiber ECC specimens roughly tend to increase with the increase of fiber content and length, but the compressive strength of specimens decrease due to the obvious "agglomeration" phenomenon when the fiber content is too much. The compressive strength of specimens is mainly affected by the water-cement ratio, and it exhibit smaller with larger of the water-cement ratio. When the fiber mass content is 6.5%, the fiber length is 18mm and the water-cement ratio is 0.32, the comprehensive mechanical properties of alkali-resistant glass fiber ECC are relatively better, and the compressive strength and deformation capacity can be increased by 25.6% and 88%, respectively. The calculation results of the proposed stress-strain relationship model are in good agreement with the experimental values, which can be used to describe the whole process of compression failure of alkali-resistant glass fiber ECC.