Research On Application Of Boron Ash In Road Engineering

China has world's fifth largest boron ore reserves which is distributed mainly over the northeast and southwest Liaoning,Jilin,Qinghai and Tibet four provinces.Boron ash commonly known as boron mud is waste material from producing borax.3 to 4 tons of boron ash will go along with the producing every ton of borax.Compared with the astonishing accumulating speed,its recycling speeding is unsurpassable. Accumulation of Boron ash not only takes up a lot of the land,but also has great destructive effect to environment,as boron ash has strong alkaline, it wastes a lot of land resources and pollutes environment.The following thesis will carry out a series of performance researches on boron ash based on the knowledge toward the value of it.These researches will provide scientific and feasible technological achievement for road application which are important for utilization of boron ash.This paper is one important part of the National Western Region Traffic Construction Projects "Research on application of boron ash in road engineering2008".The main content of the paper is as follow:1. Microcosmic analyses on physico-chemical properties of boron ashCombined with the alkalescence and feeble activities of boron ash, X-Ray Diffraction(XRD) technique, laser diffraction size analyzer, GKFâ…¢silicate rapid measuring analyzer and DSC analyzer are used to investigate the component,the particle size,the chemical composition and the heating stability of boron ash respectively.Based on these properties of boron ash,an activator which has low price and has already been used widely in highway engineering is put forward,that is lime which will be used in performance test.2. Research on performance test of lime-boron ash and cement-lime-boron ash binding materials based on semi-rigid pavement base theory(1)Research on the performance for road application of lime-boron binding material Through the 7d,28d unconfined compressive strength of five different lime contents,the best mixed proportion that lime:boron ash=12:88 is put forward going along with the economy. A series of tests including unconfined compression test,split strength,flexural strength, freezing resistance text,dry-wet cycling test,water stability test,drying shrinkage test,the modulus of compression test,the modulus of. rupture test should be done.The study indicates the performance of two materials is similar except shrinkage property but its freezing resistance seriously can not meet the demand.(2)Freezing resistance text of cement improved lime-treated boron ash binding materialTest shows cement can not improve the freezing resistance behaviour of lime-treated boron ash binding material.(3)Research on the reaction mechanism of lime-treated boron ash and the lime-cement stabilized boron ashInfrared spectrum analysis shows that the reactions mechanism of above-mentioned two materials are practically the same except the degree of hydration test.3. Research on the reaction mechanism and the performance of sand(stone chip)improved lime-cement stabilized boron ash(1)Research on the performance of lime-cement-boron ash stabilized sand(stone chip)Freezing resistance is the key point which is used to identify the type of mixtures. Performance test of above-mentioned two materials includes night contents:unconfined compression test,split strength,flexural strength, freezing resistance text,dry-wet cycling test,water stability test,drying shrinkage test,the modulus of compression test,the modulus of. rupture test.Through constructive study.Through these tests two better mixed proportions are found.They are5:8:44:43(cement:lime:boron ash:sand) and 5:8:26:61 (cement:lime:boron ash:stone chips)mixtures.Based on the comparison test between these mixtures,the performance of mixture added stones chips is better than sand.(2)Research on the reaction mechanism of lime-cement-boron ash stabilized sand(stone chip)The reaction mechanism of lime-cement stabilized boron ash and physico-chemical properties of the granular soil form the reaction mechanism of mixtures together.The granular soils'properties include three contents.They are gradation,point,rough and the chemical propertiesof blasted stones.All in all,research on utilization of boron ash has practical and strategic significance for developing north-east old industrial and our country.