玻璃粒径及掺量对可控性低强度材料性能影响

文章探究玻璃掺量及粒径对可控性低强度材料(controlled low strength materials, CLSM)的工作性能、力学性能及耐久性能的影响。根据流动度确定水胶比,开展经时流动度、泌水率、无侧限抗压强度(unconfined compressive strength, UCS)及冻融耐久性试验;采用X射线衍射(X-ray diffraction, XRD)和扫描电子显微镜(scanning electron microscope, SEM)分析CLSM的微观结构及强度机理。研究结果表明:玻璃掺量过多会导致保水性下降、增大离析泌水;所有配比28 d抗压强度均大于0.5 MPa,90 d最大增至5.2 MPa;玻璃掺量过多(玻璃与黏结剂质量比为2.0和2.5)且粒径为3~5 mm的CLSM耐久性较差。随养护时间增加,C-S-H特征峰值增加,并出现托贝莫来石晶体特征峰,CLSM强度提高。玻璃与黏结剂质量比为1.0的CLSM各性能可达到最理想效果;综合破碎工序,粒径3~5 mm、质量比1.0为最佳参数。

The effects of glass content and particle size on the working performance, mechanical properties and durability of controlled low strength materials (CLSM) were investigated. The water-to-binder ratio was determined according to the fluidity, and the time-depended fluidity loss, bleeding rate, unconfined compressive strength (UCS) and freeze-thaw durability tests were carried out. The microstructure and strength mechanism of CLSM were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results showed that excessive glass content would lead to decreased water retention and increased segregation bleeding. The 28 d compressive strength of all ratios was greater than 0.5 MPa, and the maximum compressive strength increased to 5.2 MPa at 90 d. The durability of CLSM with excessive glass content (glass-to-binder ratio of 2.0 and 2.5) and particle size of 3-5 mm was poor. With the increase of curing time, the peak value of C-S-H increased, and the characteristic peak of Tobermorite crystal appeared, and the strength of CLSM increased. The optimal CLSM performance can be achieved with a glass-to-binder ratio of 1.0. The particle size of 3-5 mm and the glass-to-binder ratio of 1.0 are the optimal parameters in terms of glass breaking process.