碱-偏高岭土改性水泥土抗压性能试验与分析

Experiment and Analysis of Compressive Properties of Alkali Metakaolin Modified Cement Soil

为了减少水泥使用,改善水泥土性能,采用偏高岭土等量替代部分水泥,并在碱(NaOH)激发作用下,通过无侧限抗压强度试验研究了偏高岭土和NaOH掺量对水泥土无侧限抗压强度及变形特征的影响。结果表明:适量的偏高岭土和NaOH均能有效提高水泥土抗压强度,当NaOH掺量为1.50%,偏高岭土掺量为3.0%时,水泥土抗压强度达到最大值,较素水泥土强度提高了54.21%;不同偏高岭土和NaOH掺量下,水泥土应力-应变曲线大致可分为压密阶段、线弹性阶段、塑性阶段和破坏阶段等4个阶段,且呈现脆性破坏特征;随着水泥土抗压强度的增大,变形模量总体上呈现增大趋势,水泥土变形模量E50与抗压强度的比值范围为68.53~109.03。

In order to reduce the use of cement and improve the performance of cement soil,metakaolin was used to replace part of cement in equal amounts,and under the excitation of alkali(NaOH),the effect of metakaolin and NaOH on the unconfined compressive strength and deformation characteristics of cement soil was studied by unconfined compressive strength test.The results show that appropriate amount of metakaolin and NaOH can effectively improve the compressive strength of cement soil,When the content of NaOH is 1.50%and metakaolin is 3.0%,the compressive strength of cement soil reaches the maximum value,which is 54.21%higher than that of plain cement soil;Under different content of metakaolin and NaOH,the stress-strain curve of cement soil can be roughly divided into four stages:compaction stage,linear elastic stage,plastic stage and failure stage,and it shows the characteristics of brittle failure.With the increase of compressive strength of cement soil,the deformation modulus of cement soil generally shows an increasing trend,and the ratio of deformation modulus E50 to compressive strength of cement soil ranges from 68.53 to 109.03.