Study On Technique Of Durable Improvement Of Stabilized Soil

Soil firming agent is a new type of building material used to build roads, water cellar andcollecting field in the loess plateau area, which can stabilize the loess effectively at roomtemperature, but the engineering practice shows that its durability is the main bottleneck of itspopularization and application. Therefore developing the technique to improve the durabilityof solidified soil is the main aim of the studyIn this paper, five ways to try to improve the durability of solidified soil were putforward from view of chemistry and physics, which were soaking curing in Na2SiO3, NaOHand Na2SO4combined saline solution (323solution was determined by the orthogonalexperiment), soaking curing in saturated limewater, adding sand in the mixture, adding fiberin the mixture and coating waterproof agent on the solidified soil surface respectively.Strength test, wet-dry test, freeze-thaw test and microstructure test were conducted to researchthe effect of aforesaid five ways on the durability of solidified soil. Research conclusions areas follows.1）The unconfined compressive strength test results of test block cured under saltsolution show that the order of unconfined compressive strength from high to low was323solution maintenanceâ†'saturated limewater maintenanceâ†'water curingâ†'standard curing.The unconfined compressive strength test results of test block under physical improvementmode show that adding sand can significantly increase the compressive strength of solidifiedsoil. Doped fiber and coated waterproof agent against the strength of the solidified soil.2）The wet-dry test results of test block cured under salt solution show that the order ofstrength after wet-dry circulation from high to low was323solution maintenanceâ†'saturatedlimewater maintenanceâ†'water curingâ†'standard curing. The mass change of block curedin323solution in the process of wet-dry circulation is smaller than other maintenance mode.The wet-dry test results of test block under physical improve mode show that block addedsand has the highest strength after wet-dry circulation. The change of mass and volume ofblock added stand are more stable than untested block.3）The freeze-thaw test results of block cured under salt solution show that the loss ofstrength of block cured by323solution is the least, the loss of strength of block cured bysaturated limewater is the less. The change of mass and volume of blocks cured in323 solution and saturated limewater are less than block under standard curing. The freeze-thawtest results of block under physical improvement show that the block added sand has thehighest strength after freeze-thaw circulation. The change of mass and volume of block addedstand are less than the block under other physical mode or untreated block.4）Scanning electron microscope (SEM) test results showed that323solution curing andsaturated limewater curing can enable stabilized soil generate more dense gel, thus reducingthe porosity and macro pore of solidified soil; Sanding can change the internal structure ofstabilized soil, thus reducing the porosity and macro pore of solidified soil.Based on the above test results, we can conclude that323solution curing and saturatedlimewater solution curing can improve the strength and durability of the stabilized soil, andthe323solution is better than the saturated limewater; Adding sand into mixture also canimprove the strength and durability of stabilized soil.