风积沙混凝土轴心受压力学性能研究

试验设计风积沙和粉煤灰内掺替代等质量的河砂及水泥,制备了10组风积沙-粉煤灰混凝土,进行60d风积沙-粉煤灰混凝土轴心抗压试验,开展风积沙-粉煤灰混凝土轴心受压破坏形貌、微观结构、应力-应变关系、轴心抗压强度、峰值应变、弹性模量、泊松比等内容的试验研究。结果表明：弹性阶段各掺量风积沙混凝土应力-应变曲线基本趋于一致,进入弹塑性阶段后,风积沙混凝土较基准混凝土应力增长较快,混凝土脆性增加。轴心抗压强度、弹性模量及泊松比随风积沙掺量增加呈现先增大后减小的变化趋势,随粉煤灰掺量增加在降低。最后,对过镇海经典模型上升段本构参数A进行二次演化,建立了本构参数与轴心抗压强度和风积沙掺量之间的演化模型,得出风积沙混凝土应力-应变上升段本构方程。

Study on Axial Compression Performance of Aeolian Sand Concrete

In this experiment, 10 groups of Aeolian sand-fly ash concrete were prepared by using aeolian sand and fly ash instead of river sand of the same quality, the axial compression test of 60d aeolian sand-fly ash concrete was carried out and the experimental study on the axial compression failure topography, microstructure, stress-strain relationship, axial compressive strength, peak strain, elastic modulus and Poisson"s ratio of aeolian sand-fly ash concrete was obtained. It was found that the stress-strain curves of the aeolian sand concrete in the elastic stage were basically the same. After entering the elastoplastic stage, compared with the reference concrete, the stress of the aeolian sand concrete increased rapidly and the brittleness of the concrete increased. The compressive strength, elastic modulus and Poisson"s ratio of the concrete first increased and then decreased with the increase of aeolian sand content., and decreased with the increase of fly ash content. Finally, the secondary evolution of constitutive parameter A in the upwelling section of the Guo Zhenhai classic model was carried out, and the evolution model between constitution parameter and axial compressive strength and aeolian sand content was established. The constitutive equation of the rising section of the stress-strain curve of aeolian sand concrete was obtained.