偏高岭土-磷酸基地聚物的力学性能及微观结构分析
Mechanical Properties and Microstructure Analysis of Metakaolin-Phosphoric Acid Based Geopolymer
段立伟 1罗安邦 1陈英豪 2王德辉 3罗正东2
作者信息
- 1. 岳阳路桥集团有限公司,岳阳 414000
- 2. 湘潭大学土木工程学院,湘潭 411105
- 3. 福州大学土木工程学院,福州 350108
- 折叠
摘要
为明确不同浓度磷酸溶液激发偏高岭土的最佳液固比(L/S)值,本文设置了 4、5、6、7、8 mol·L-1五组磷酸溶液以及0.6、0.7、0.8、0.9四种L/S值来制备偏高岭土-磷酸基地聚物(MPAG).以MPAG的7和28 d抗压、抗折强度作为评价指标,探究上述预设变量对MPAG力学性能的影响,进一步研究每组浓度最佳L/S值试样经硫酸盐侵蚀后的抗压强度,并对MPAG物相组成和微观形貌进行表征及分析.结果表明:MPAG主要由无定形磷酸铝相组成;当磷酸溶液浓度为4～6 mol·L-1时,L/S值为0.6时,制得的试样抗压强度更大,溶液浓度增大至7或8 mol·L-1时,推荐L/S值为0.7;MPAG抗硫酸盐侵蚀能力佳,浸泡28 d后抗压强度保留率达84％～93％;任一L/S值下,使用6 mol·L-1磷酸溶液制备的试样均取得该L/S值的最大抗折强度;当L/S值为0.6时,28 d最大抗折强度为6.80 MPa.本文研究结果可为MPAG的制备及应用提供参考.
Abstract
In order to clarify the optimal liquid-solid ratio(L/S)values for the activation of metakaolin at different concentrations of phosphoric acid solution,five sets of phosphoric acid solution of 4,5,6,7 and 8 mol·L-1 were set up,and four L/S values of 0.6,0.7,0.8 and 0.9 were used for preparation of metakaolin-phosphoric acid based geopolymer(MPAG).The 7 and 28 d compressive and flexural strengths of MPAG were used as the evaluation indexes to investigate the effects of above preset variables on its mechanical properties.The compressive strength of samples corresponding to the optimal L/S value concentration of each group after sulfate erosion were further investigated.Finally,the phase composition and microscopic morphology of MPAG were characterized and analyzed.The results show that MPAG is mainly composed of an amorphous aluminum phosphate phase.Greater compressive strength can be obtained by using L/S value of 0.6 when the concentration of phosphoric acid solution is 4～6 mol·L-1,and when the concentration increase to 7～8 mol·L-1,the recommended of L/S value is 0.7.MPAG exhibits good sulfate resistance,with a compressive strength retention rate of 84％to 93％after 28 d immersion.The samples prepared with 6 mol·L-1 phosphoric acid under any L/S value achieved the maximum flexural strength for that L/S value.The 28 d maximum flexural strength is 6.80 MPa when L/S value is 0.6.The results of this study can provide references for the preparation and application of MPAG.
关键词
磷酸激发/偏高岭土/地聚物/力学性能/微观表征/硫酸盐侵蚀Key words
phosphoric acid activation/metakaolin/geopolymer/mechanical property/microscopic characterization/sulfate erosion引用本文复制引用
基金项目
湖南省自然科学基金项目(2023JJ50008)
湖南省研究生科研创新(QL20230154)
湖南省住建厅建设科技计划项目(KY202316)
出版年
2024
国家科技期刊平台
NSTL
万方数据