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  本文選題：瀝青混合料　切入點(diǎn)：離散單元法　出處：《大連理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：瀝青混合料(HMA)是一種由瀝青粘結(jié)料、骨料顆粒以及填料等組成的多相復(fù)合材料,其中粗骨料的質(zhì)量和體積約占總量的90%,瀝青混合料的性能很大程度上取決于粗骨料的性質(zhì)。研究表明,在所有影響混合料性能的因素中,形狀特征被認(rèn)為是僅次于骨料級配的第二大影響因素。目前,關(guān)于骨料形狀對瀝青混合料性能影響的研究大都是通過室內(nèi)試驗(yàn)完成的,得到的結(jié)果穩(wěn)定性和再現(xiàn)性較差,造成了一定的人力物力浪費(fèi)。近年來,離散單元法在瀝青路面研究中應(yīng)用廣泛。這種方法不但可以模擬骨料級配,還能夠研究骨料形狀特征對HMA性能的影響。本文首先研究了采用球形顆粒粘結(jié)成塊來構(gòu)建任意形狀粗骨料顆粒的方法。與以往研究不同的是,這里先隨機(jī)生成多面體殼,而后應(yīng)用非線性約束優(yōu)化的理論,將用于填充多面體殼的球形顆粒數(shù)目降到最少,從而得到多面體顆粒。文中給出了相應(yīng)的算法,并計(jì)算得到了多面體顆粒的相關(guān)形狀參數(shù)。為了研究顆粒形狀參數(shù)與HMA宏觀力學(xué)性能之間的關(guān)系,文中基于離散單元法建立了HMA圓柱形模型,在PFC3D軟件環(huán)境下進(jìn)行三軸試驗(yàn)?zāi)M,建立了瀝青混合料抗剪強(qiáng)度隨粗骨料顆粒的長細(xì)比和扁平比的分布云圖,并給出了它們之間的函數(shù)表達(dá)式。根據(jù)計(jì)算結(jié)果,提出了一個新的針片狀認(rèn)定指標(biāo)Q,同時也分析了級配設(shè)計(jì)時粗骨料顆粒形狀控制的基本原則。數(shù)值計(jì)算結(jié)果與實(shí)驗(yàn)結(jié)果的對比證明了結(jié)果的合理性。
[Abstract]:Asphalt mixture (HMA) is a kind of multiphase composite composed of bituminous binder, aggregate particle and filler. The quality and volume of coarse aggregate account for about 90% of the total amount, and the performance of asphalt mixture depends largely on the properties of coarse aggregate. Shape characteristics are considered to be the second most important influencing factor after aggregate gradation. At present, most of the researches on the effect of aggregate shape on asphalt mixture performance are completed through laboratory tests, and the results obtained are less stable and reproducible. In recent years, discrete element method has been widely used in asphalt pavement research. This method can not only simulate aggregate gradation, It is also possible to study the effect of shape characteristics of aggregate on the properties of HMA. In this paper, we first study the method of forming arbitrary coarse aggregate particles by bonding spherical particles into blocks. Different from previous studies, polyhedron shells are generated at random here. Then, by using the theory of nonlinear constrained optimization, the number of spherical particles filled with polyhedron shell is reduced to the minimum, and the polyhedron particles are obtained. In order to study the relationship between the shape parameters of polyhedron particles and the macroscopic mechanical properties of HMA, the HMA cylindrical model is established based on the discrete element method. The distribution of shear strength of asphalt mixture with the slenderness ratio and flat ratio of coarse aggregate particles was established by triaxial test simulation under the PFC3D software environment, and the functional expressions between them were given. In this paper, a new needle shape determination index Q is proposed, and the basic principle of coarse aggregate shape control in gradation design is also analyzed. The comparison of numerical results with experimental results proves the rationality of the results.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：U414

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本文編號：1598582