Research On Gradation Of Lower Inflammable Matter Diatomite Modified Asphalt Mixture In Tunnel

With the develop of national economy and traffic capacity increase quickly, the phenomenon of vehicle large scale,traffic canalize and overburden was increasingly severity. The asphalt pavement was faced with ordeal. Expect for the skidding resistance performance, the anti-track performance at high temperature, the anti-water-damage performance, the crack resistance at low temperature and the ageing resistance performance, the asphalt pavement in tunnel would have fire resistance performance. When we used the asphalt pavement in tunnel, we should adopt the one of lower inflammable matter in asphalt mixture. The aggregate graduation and asphalt quality were two important aspects to ensure the road performance of asphalt concrete mixture。Diatomite modified asphalt was a late-model modified asphalt which had been sprung up in recent years. The anti-track performance at high temperature, the anti-water-damage performance, the crack resistance at low temperature and the ageing resistance performance were improved. With high benefit, the pavement can be extended around the country. As it can be seen from the practical engineering in YunNan and JiLin province, the road service performance can be improved by the diatomite added into。Diatomite modified asphalt was different from either the common petroleum asphalt or the polymer modified asphalt. Because of its characteristics of porosity, large specific surface area, small density, high sorption, high chemical stability, sound insulation, heat insulation, high melting point, the modification of diatomite on basic asphalt had its own particularity. The construction of diatomite asphalt pavement is simple; do not need special machines, and whose technologies from mixing to paving and rolling were the same as the common asphalt pavement. It was easy to control operation and had comprehensive application. The price of diatomite modified asphalt mixture was lower, which had huge economic benefit and could be used in high type road, rebuilding construction and etc. The development of diatomite modified asphalt could utilize the abundant diatomite resources and was meaningful to the economic development. The preparation technology of diatomite modified asphalt was researched in this paper. The conjunct effect of the high-speed cut and the mix made the diatomite interfused in the basic asphalt effectively, and obtained the best effect of modification. Basic asphalt and Changbai diatomite modified asphalt were researched on. The central composite design was used to make sure of diatomite's best use level into the asphalt. The paper briefly analyzed the diatomite mechanism of modification from several aspects, the diatomite structure, the consistency and dispensability with asphalt.A good gradation composition should have minimum mineral aggregate void volume when heat resistance be allowed, enough structure surface for asphalt to cover the aggregate to ensure the imporosity, better condition of interaction between asphalt and aggregate, and maximality strength of structure the asphalt had, these would make the asphalt mixture have better use quality. For SMA, the high assay coarse aggregate scale and high-grade coarse aggregate quality were leading cause for resisting rut ability in high temperature;the better cementation of matrices was key factor for improving low temperature property of mixture;the minor void volume and better cementation of matrices were fundamental conditions of good viability and water stability; the premium coarse aggregate and discontinuous grading had important consequences for improving skid resistance performance of asphalt pavement. The mixture of coarse aggregate of high assay, diatomite modified asphalt of preferable caking property and minor void volume were researched in this paper. The assay used volumetric parameter design index and grading limit of SMA, on condition of depressing asphalt volume, taking out cellulose, this was the meaning of lower inflammable matter, and using diatomite modified asphalt. It used the method of changing content of coarse aggregate in each particle size and testing volumetric parameter, and researched the appropriate scope of coarse aggregate in each particle size on percent passing. This article used the design formula of fine aggregate for grade location, which was ascertained by interference theory and filling theory in discontinuous grading. Then, we found the grading limit, and test it in the end. The check result manifest that, the grading limit resulting is appropriate, diatomite modified asphalt was good at the anti-track performance at high temperature, the anti-water-damage performance, the crack resistance at low temperature and the ageing resistance performance. The gradation from paper had definite reference value.