HE Bei¹, ZHANG Wuyu¹, TONG Guoqing¹, TANG Xin¹, LIU Chengkui^2,3

(1.School of Civil Engineering; Qinghai Provincial Key Laboratory of Energy-saving Building Materials and Engineering Safety,Qinghai University, Xining 810016, China; 2.Qinghai Building and Materials Research Co., Ltd., Xining 810008, China;3.Qinghai Provincial Key Laboratory of Plateau Green Building and Eco-community, Xining 810008, China)

Abstract：The effects of water glass modulus and water-binder ratio(the ratio of water to the mass of fly ash)on the macroscopic mechanical strength of fly ash geopolymer were investigated by unconfined compressive strength test.Scanning electron microscope and X-ray diffraction were used to explain the internal mechanism from a microscopic perspective.The results show that both the modulus of water glass and water-binder ratio have an important influence on the mechanical properties of fly ash geopolymer.When the water glass modulus is 0.8, 1.1, 1.3 and 1.5, respectively, the unconfined compressive strength of the fly ash geopolymer sample is increased first and then decrease.When the water glass modulus is 1.1, the mechanical strength is showed an optimal level.When the water-binder ratio is 0.28, 0.30, and 0.32, the mechanical strength of the sample is showed a decreasing trend.The fly ash glass body is dissolved in an alkaline environment, and the depolymerization-polycondensation reaction is occured between the substances.N-A-S-H gel substance is acted as the reaction product and played the role of filling the pores.When the number is 1.1 and the water-binder ratio is 0.28, the hydration reaction in the system is fully carried out, more gel substances are produced, and the structural integrity improvement effect is the most significant, and the macroscopic mechanical strength is the highest.

Keywords：fly ash geopolymer; water glass modulus; water-binder ratio

Received：2022-08-18，Revised：2022-09-28,Online：2023-01-13 08:40。

Funding Project：国家自然科学基金项目，编号：52168054；青海省高原绿色建筑与生态社区重点实验室开放基金项目，编号：KLKF-2021-007。

First Author：何蓓(1996—)，女，硕士研究生，研究方向为地基处理和碱激发胶凝材料。E-mail：1294480511@qq.com。

Corresponding Author：张吾渝(1969—)，女，教授，硕士，博士生导师，研究方向为岩土工程地基。E-mail：qdzwy@163.com。