Experimental Study On The Boron Ash Used In Road Sub-base

Boron ash, commonly known as boron mud, is a kind of industry waste. The industry use Boron-Magnesium ore to produce Borax, and prodces the Boron ash. Producing 1 ton borax will produce 3 to 4 tons of boron ash, Accumulation of Boron ash not only take up a lot of the land, but also have great destructive effect to environment as Boron ash has strong alkaline. The application of Boron ash in various fields has achieved some success, But not in the Road project. Therefore it is very important to draw on research results of application of Boron ash in other fields, and also important to reseach the application of Boron ash materials in the Road project with local conditions. In this paper, through experimental study of the pavement performance of Boron ash binder, we can see Lime-Boron ash can apply to the road base. This article is divided into five chapters.Chapter 1 is the introduction of the paper, introduced the research status of Boron ash and Modified soil, combined with the research experience of application of Modified soil in Road project and Boron ash in other industrial fields. Comprehensive studying of the application of Boron ash in Road Sub-base is necessary.Chapter 2 frist introduces the mechanism of Lime-Soil and Soil Stabilizer Modified soil, and then predicted the mechanism of Boron ash modified soil, Soil Stabilizer and Boron ash modified Soil and Lime modified Boron ash. The intensity of Boron ash-Soil comes mainly from the following aspects: (1) The Born ash is very small, large specific surface area and good dispensive, Boron ash can fill up the pore of soil, the compressive strength of soil have increased. (2) The Soil Stabilizer contains a lot of active substance, these substance can take chemical reaction with active substance in Boron ash or soil, so that the strength of soil has increased further more. The strength developing mechanism of Lime-Boron ash is that, the lime put into Boron ash produces a series of physical and chemical reactions, mainly include: ion exchange, crystallization, volcanic ash reaction and carbonation. MgO in the boron ash mainly in the form of MgCO₃, activation of MgO is the key of these reactions.Chapter 3 Learning from research experiences of Modified soil, and studying the influence of Boron ash to compressive strength of soil, we can get that Boron ash can enhance compressive strength of Black Clay, but it can not improve the water stability of soil. And then researched about adding Soil Stabilizer into Boron ash, and carries out the best ratio of BS Soil Stabilize, Boron ash and soil. The Soil Stabilizer can enhance compressive strength of Boron ash modified soil, but it can not improve the water stability. Learning from research experiences of Boron ash, and studying the influence of admixture to Boron ash, we can get that though laboratory test, the Soil Stabilizer can enhance compressive strength of Boron ash, but it can not improve the water stability. Lime can substantially increase the compressive strength of Boron ash,it can improve the water stability of Boron ash as well.Chapter 4 mostly studied the pavement performance of Boron ash used in the Road Sub-base though laboratory test. It contains the mechanical properties and stability of Boron ash binder. The mechanical properties mainly contain the compressive strength, tensile strength and modulus of compression. the strength and rigidity of Soil Stabilizer modified soil and Lime Modified Boron ash increase with time. And studied the shrinkage performance of Soil Stabilizer modified soil and Lime Modified Boron, With the growth of age, the largest shrinkage strain, the average shrinkage coefficient and the largest water loss of Lime-Boron ash and Boron ash-Soil are all decreased. Boron ash-Soil get the largest shrinkage coefficient when when its moisture is 9%, and the Lime-Boron ash is 11%. the largest shrinkage strain and the largest water loss of Boron ash modified soil are less than those of Lime-Boron ash. The stability of Lime-Boron ash include: water stability, Freeze-resistance and dry-wet stability. Freeze-resistance and dry-wet stability. The strength loss of Lime-Boron ash is little though effect of the freeze-thaw cycles. After 10 freeze-thaw cycles its strength loss is 9%, the antifreeze grade is greater than 10. Water has a great impact on the the compressive strength of Lime-Boron ash material,when put it in water for 24 hours its compressive strength has reduced 46.87%. Its compressive strength meets the needs of low-grade Road Subbase.With the increase of immersion time, the compressive strength no longer lost. When water has volatile, the compressive strength has great recovery. Although, the compressive strength of Lime-Boron ash has a great loss in water. Take the Lime-Boron ash as Highway Sub-base to design the pavement structure. The Lime-Boron ash replaces Lime-Soil as Highway Sub-base, it can save 78600 yuan per kilometre, And that can save land resources and large-scale use of Boron ash to reduce the Boron ash damage to the environment.Chapter 5 is conclusion part. It gives a summary of the work done in this essay and provides suggestions to the possible work which would be needed afterwards.