几种工业固体废弃物固结土壤中NaCl的机理  

Consolidation mechanism of NaCl in soil by various industrial solid wastes

作　　者：王兢[1] 倪文[1] 

机构地区：[1]北京科技大学土木与环境工程学院,北京100083

出　　处：《北京科技大学学报》2011年第12期1558-1564,共7页Journal of University of Science and Technology Beijing

基　　金："十一五"国家科技支撑计划资助项目(2006BAC21B03)

摘　　要：随着NaCl加入量的增大,利用矿渣、粉煤灰、脱硫石膏、石灰和硫酸铝作为土壤固化剂的固结土试块的抗压强度先增加后减小.当NaCl的质量分数为2%左右时,固结土试块的抗压强度在不同的养护龄期都是最大的;而Na+和Cl-的固结率在养护时间为3～7 d增长速度很快,在养护时间为7～28 d增长速率减缓,但还是保持增长的趋势,在养护28 d以后基本趋于稳定,基本都保持在60%～80%.通过29Si和27Al的核磁共振谱测试,发现在C—S—H网络状结构中大量存在四配位和六配位的铝,而Al对Si位的取代是Na+被固化的关键;同时发现NaCl能够促使Al从四配位向六配位转化,使硅氧体系的聚合度增加.With slag,fly ash,desulfurized gypsum,lime and aluminium sulphate as soil stabilizers,the compressive strength of consolidated soil first increased and then decreased with the amount of added NaCl increasing.The compressive strength of consolidated soil in every curing age reached its maximum value when the content of added NaCl was 2%.The consolidation rates of Na＋ and Cl-increased very fast when the curing age prolonged from 3d to 7d,then slowed down from 7d to 28d,and finally kept stable in the range of 60% to 80% after 28d.The results of nuclear magnetic resonance（NMR） of 29Si and 27Al showed that there were amounts of 4-coordinated and 6-coordinated Al in the C—S—H net.The NMR analysis also indicated that in the C—S—H net some of Si4＋ was substituted by Al3＋.The substitution provided a condition for Na＋ solidification.NaCl can promote the transformation of Al coordination from 4-coordinated one to 6-coordinated one,and improve the polymerization degree of the cementitious system.

关 键 词：土壤 固化剂 氯化钠 抗压强度 核磁共振 

分 类 号：TU411.6[建筑科学—岩土工程]