偏高岭土基地聚合物对水泥固化红黏土的改善机制  

Improvement Mechanism of Metakaolin-based Geopolymer on Cement Stabilized Red Clay

作　　者：王志良[1] 陈玉龙 申林方[1] 施辉盟 WANG Zhiliang;CHEN Yulong;SHEN Linfang;SHI Huimeng(Faculty of Civil and Architectural Engineering,Kunming University of Science and Technology,Kunming 650500,China)

机构地区：[1]昆明理工大学建筑工程学院,昆明650500

出　　处：《材料导报》2024年第8期137-143,共7页Materials Reports

基　　金：国家自然科学基金(42067043,42167022,11962008)。

摘　　要：为了研究偏高岭土对水泥固化红黏土的改善效果,开展了三种组合(纯水泥、水泥+偏高岭土以及水泥+偏高岭土+水玻璃)的红黏土固化试验。基于固化剂化学组分和固化土的干密度、pH值以及物相成分等,研究了新型复合碱激发体系作用下偏高岭土对水泥固化红黏土的作用机理。研究表明:当水泥、偏高岭土和水玻璃掺入比分别为12%、5%和3%时,红黏土固化效果最佳,相比于纯水泥固化土其强度提高了2.82倍。在n(SiO_(2))/n(Al_(2)O_(3))从2.53增加至4.05过程中,固化土强度发展较快,随后逐渐趋于稳定。由于水泥水化生成的Ca^(2+)能够平衡固化体系中的部分负电荷,在n(Na_(2)O)/n(Al_(2)O_(3))较小的情况下固化土强度得到了显著提升。最后通过固化土微观形貌及主要物相组成发现,新型复合碱激发体系的试样中含有无定形地聚物凝胶且主要物相特征峰峰值有所降低,说明产生了更多的地聚合凝胶产物。The stabilized tests of three combinations(pure cement,cement+metakaolin and cement+metakaolin+sodium silicate)were carried out to study the improvement effect of metakaolin on cement stabilized red clay.Based on the component content of the stabilization agent,the dry density,pH value and mineral composition of the stabilized soil,the stabilization mechanism of metakaolin on cement stabilized red clay was stu-died under the action of a new composite alkali excitation system.The results showed that when the contents of cement,MK and sodium silicate were 12%,5%and 3%,respectively,the stabilized effect of red clay was the best,and its strength was 2.82 times higher than that of pure cement stabilized soil.When n(SiO_(2))/n(Al_(2)O_(3))increased from 2.53 to 4.05,the unconfined compressive strength of stabilized soil developed rapidly,and then tended to stable gradually.As Ca^(2+)generated by cement hydration could balance part of the negative charge in the stabilizing system,the strength of the stabilized soil had been improved significantly when n(Na_(2)O)/n(Al_(2)O_(3))was small.Finally,through the micro-morphology and main phase composition of the stabilized soil,it is found that the sample of the new composite alkali activation system contains amorphous geopolymer gel and the characteristic peak value of the main minerals decreases,indicating that more geopolymerized gel products are produced.

关 键 词：红黏土 地聚合物 偏高岭土 无侧限抗压强度 土体加固 

分 类 号：TU472[建筑科学—结构工程]