钢纤维煤矸石混凝土冻融后本构关系试验研究

Experimental study on constitutive relationship after freeze-thaw of steel fiber gangue concrete

为探讨钢纤维煤矸石混凝土的抗冻性能和冻融后的力学性能,及推广应用钢纤维煤矸石混凝土这一绿色建筑材料,通过快速冻融试验和单轴受压试验,研究了冻融环境下不同钢纤维掺量的煤矸石混凝土的质量、动弹性模量以及应力-应变曲线随冻融循环次数和钢纤维掺量的变化规律,并提出了钢纤维煤矸石混凝土冻融后单轴受压本构关系。发现相比普通煤矸石混凝土,钢纤维煤矸石混凝土的抗冻性能有一定程度的改善,主要表现为其冻融后的峰值应变和极限应变增加、耗能能力增加,但强度并无显著提升。研究结果表明,钢纤维煤矸石混凝土不宜直接用于严寒地区,但对寒冷地区和夏热冬冷地区而言,其力学性能和耐久性能都已满足工程要求。最后基于已有的混凝土损伤力学理论,考虑钢纤维在煤矸石混凝土单轴受压过程中的作用,以及冻融损伤对钢纤维煤矸石混凝土力学性能的影响,提出了具有较高精度的钢纤维煤矸石混凝土单轴受压本构关系,这为煤矸石混凝土抗冻性能的进一步研究提供了参考,也对其推广应用过程中的实际工程的结构计算有一定参考价值。

In order to investigate the frost resistance and mechanical properties after freeze-thaw of the steel fiber gangue concrete and popularize the application of this kind of environmentally friendly building material,the variation laws of quality,dynamic elastic modulus and stress-strain curve of steel fiber gangue concrete along with the number of freeze-thaw cycles and the steel fiber content in freeze-thaw environment were studied,through fast freeze-thaw test and uniaxial compression test,and the uniaxial compression constitutive relationship of steel fiber gangue concrete after freeze-thaw was presented.The study showed that the frost resistance of steel fiber gangue concrete was improved to a certain extent compared with the ordinary gangue concrete,which was mainly manifested in the increase of peak strain,peak strain and energy dissipation capacity after freeze-thaw,but the strength did not increase significantly.Steel fiber gangue concrete should not be used directly in severely cold areas,but for cold areas and hot summer and cold winter areas,the mechanical properties and durability of the concrete had met the requirements of the engineering.Based on the existing theory of concrete damage mechanics,considering the effect of steel fiber in the uniaxial compression process of gangue concrete and the effect of freeze-thaw damage on the mechanical properties of steel fiber gangue concrete,uniaxial compression constitutive relation with high precision of steel fiber gangue concrete was proposed,which provided a reference for further study on the frost resistance of gangue concrete and also some reference value for the structural calculation of practical engineering in the process of its popularization and application.