钢渣水泥基地聚合物固化湿软黄土力学特性与微观机制  

Steel Slag and Cement Based Geopolymer Solidification of Wet and Soft Loess:Mechanical Properties and Micro Mechanisms

作　　者：陈锐 张星 朱月 CHEN Rui;ZHANG Xing;ZHU Yue(School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China)

机构地区：[1]长安大学公路学院,陕西西安710064

出　　处：《重庆交通大学学报（自然科学版）》2023年第6期55-61,共7页Journal of Chongqing Jiaotong University(Natural Science)

基　　金：国家自然科学基金项目(51708041);陕西省自然科学基金面上项目(2022JM-228);长安大学中央高校基本科研业务费专项资金项目(300102210213)。

摘　　要：采用低碳环保的地聚合物对湿软黄土进行固化处理,通过无侧限抗压和一维固结试验研究了地聚合物掺量和龄期对固化土强度和变形的影响,并结合微观特征分析(X射线衍射XRD、红外光谱分析FTIR和电镜扫描SEM)研究了其固化机理。试验结果表明:固化土的无侧限抗压强度q随龄期增加而增大,得出了q随龄期变化的预测公式;地聚合物掺量由5%增大到10%时,固化土的q随之增大,但掺量增加到20%时,其强度略微减小;当掺入比为10%和20%时,固化土压缩性显著降低,且呈现出明显的结构性特征。地聚合物的水化产物中主要包含水化硅铝酸钠与水化硅酸钙复合凝胶,水化产物随龄期明显增多。地聚合物的胶结与充填效应可视为一种化学结构性,是提高固化土力学性能的根本原因。结合宏微观试验结果,提出了地聚合物固化湿软黄土的机理模型。The geopolymer(GP),a low-carbon and environmentally friendly material,was adopted to solidify wet and soft loess.The effects of geopolymer content and age on the strength and deformation of solidified soil were studied through unconfined compression and one-dimensional consolidation tests,and the solidification mechanism was studied through microscopic characteristic analysis,including X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),and scanning electron microscopy(SEM).The experimental results show that the unconfined compressive strength q of solidified soil increases with age,and a prediction formula for the change of q with age is derived.The q of solidified soils increases with GP concentration from 5%to 10%,but the strength slightly decreases when the dosage increases to 20%.When the mixing ratio is 10%and 20%,the compressibility of the solidified soil is significantly reduced,and shows obvious structural characteristics.The hydration products of GP mainly include sodium aluminosilicate hydrate(NASH)and calcium silicate hydrate(CSH)composite gel,and the hydration product content evidently increases with age.The cementing and filling effects of GP can be considered as a chemical structuration,which is the fundamental reason for improving the mechanical properties of the solidified soil.Combined with the macro and micro test results,a mechanism model of geopolymer solidified wet and soft loess is put forward.

关 键 词：岩土工程 湿软黄土 地聚合物 无侧限抗压强度 微观特征 水化硅铝酸钙 固化机理 

分 类 号：TU411.3[建筑科学—岩土工程]