木质素磺酸钙改良粉土抗硫酸盐侵蚀性能研究

Sulfate Resistance Analysis of the Modified Silt by Calcium Lignosulfonate

粉土是路基工程中常见的土体填料,其结构性差,在硫酸盐侵蚀环境下易受到侵蚀.为改善粉土的抗硫酸盐侵蚀性能,采用木质素磺酸钙来加固土体,通过无侧限抗压强度与抗硫酸盐侵蚀试验,分析木质素磺酸钙掺量、养护龄期和硫酸盐环境下浸泡天数对改良粉土无侧限抗压强度的影响.结果表明:改良粉土的无侧限抗压强度随木质素磺酸钙掺量的增加先增大后减小,随养护龄期的增长逐渐提高.其他条件相同下,当掺量为5%养护龄期为28 d时,试样的无侧限抗压强度最大为394.6 kPa,是未处理粉土的5.46倍.同时,此时改良粉土的抗硫酸盐侵蚀性能最好,在硫酸盐环境下浸泡28 d后改良粉土的无侧限抗压强度是侵蚀后素粉土的4.9倍.SEM试验结果表明,掺入适量木质素磺酸钙可对土体内部孔隙进行填充,使土体强度、抗硫酸盐侵蚀性能增强.

Silt is a common soil filler in subgrade engineering,and its structure is poor,which is vulnerable to erosion in sulfate erosion environment.In order to improve the sulfate resistance of silt,calcium lignosulfonate was used to reinforce soil.Through unconfined compressive strength and sulfate resistance test,the effects of calcium lignosulfonate content,curing age and soaking days in sulfate environment on unconfined compressive strength of improved silt were analyzed.The results show that the unconfined compressive strength first increases and then decreases with the increase of calcium lignosulfonate content,and increases with the increase of curing age.Under the same other conditions,when the content is 5%and the curing age is 28d,the maximum unconfined compressive strength of the sample is 394.6kPa,which is 5.6times higher than that of the untreated silt.At the same time,the resistance to sulfate attack of the improved silt was the best at this time,and the unconfined compressive strength of the improved silt soaked in sulfate environment for 28dwas 4.9times that of the eroded plain silt.It could be seen from the SEM results that adding appropriate content of calcium lignosulfonate can fill the internal pores of the soil,which greatly improves the strength and sulfate resistance.