Research On The Strength Growth Law Of Solidified Soil For Pavement Base

With the rapid economic and social development of our country,the construction of highway infrastructure in our country has entered a new period of development.At present,the basic and subbase fillers of highway construction in China are still dominated by lime,cement,slag,sand and the mixture of these materials.However,with the continuous improvement of highway environmental protection engineering requirements,the development of these resources will be strictly restricted.As a new type of base filler which can be combined with roadbed soil,soil curing agent has very important practical significance in both technical and economic aspects.Strength is the main technical index of solidified soil as a road base,so it is urgent to explore the strength growth law and strength formation mechanism of soil solidification reasonably and scientifically.In this thesis,a proper amount of cement,water-based polymer and the two were mixed with the same kind of clay to solidify,through the unconfined compression test and indirect tensile strength test under different amount of curing agent,the strength modification effect,influence factors and modification mechanism of solidified soil were obtained respectively.The research results can provide a new way and scientific basis for the treatment of solidified soil.The solidified soil with cement content of 6%,8%,10%,12% was prepared,and the unconfined compressive strength and indirect tensile strength of the solidified soil were tested at the curing temperature of 20? and 50?.The law of age changes.The research results show that cement can greatly increase the unconfined compressive strength and indirect tensile strength of the solidified soil,and the higher the cement content,the greater the strength of the solidified soil.Under the same curing age,the curing temperature of 50°C can promote the growth rate of the strength of cement-solidified soil and increase the strength of the cured soil compared to the curing temperature of 20°C.It was also found that the higher the amount of cement,the smaller the influence of temperature on the unconfined compressive strength and indirect tensile strength of cement-solidified soil.Prepared solidified soil with water-based polymer content of 0.5%,1%,2%,4%,and tested the unconfined compressive strength and indirect tensile strength of the solidified soil at curing temperatures of 20?and 50?The law of change with the maintenance age.The test results show that: water-based polymer will reduce the unconfined compressive strength and indirect tensile strength of the solidified soil in the early stage.However,it has a significant improvement effect on the strength of the solidified soil in the later stage,and the higher the content of water-based polymer,the more obvious the strength improvement effect.The 14 d compressive strength of 4%water-based polymer solidified soil is 50% higher than that of plain soil.Increasing temperature can increase the growth rate of unconfined compressive strength and indirect tensile strength of water-based polymer solidified soil,and increase the final compressive strength,but it will reduce the final indirect tensile strength of solidified soil.The study also found that the growth rate of compressive strength and indirect tensile strength of water-based polymer solidified soil gradually accelerated with the increase of water loss rate,while the strength of plain soil gradually slowed down with the increase of water loss rate.The effects of water-based polymer content and curing temperature on the unconfined compressive strength and indirect tensile strength of water-based polymer-cement composite solidified soil were investigated.The results show that lower water-based polymer content can improve the unconfined compressive strength and indirect tensile strength of composite solidified soil.However,if the content is too high,it will have an adverse effect on the strength growth of the composite polymer.More than 4% of the water-based polymer content will reduce the compressive strength of the composite solidified soil,and more than 1% of the water-based polymer content will reduce the indirect tensile strength of the composite solidified soil.Temperature can improve the compressive strength and indirect tensile strength of composite solidified soil,and accelerate its strength growth rate.At the same time,this thesis also explores the influence mechanism of cement and water-based polymer on the strength formation of solidified soil.The results show that cement mainly affects the strength of solidified soil through hydration reaction.The strength of water-based polymer solidified soil mainly comes from the water-losing cementation between water-based polymer and soil particles.