本文選題：反射裂縫 + 三點(diǎn)彎曲加載試驗(yàn)　； 參考：《安徽理工大學(xué)》2017年碩士論文

【摘要】：反射裂縫是瀝青路面冬季破壞的主要誘因之一。在低溫收縮和荷載的共同作用下,下臥層出現(xiàn)開裂,裂縫處的應(yīng)力集中致使裂縫向上開展,裂縫處的應(yīng)力集中比沒有裂縫的部位大,易超過瀝青混合料面層的極限抗拉強(qiáng)度,引起面層的開裂。開展瀝青路面低溫反射裂縫低溫抗裂性能以及裂縫開展行為研究,可以為路面面層混合料設(shè)計(jì)提供理論依據(jù);研究反射裂縫的擴(kuò)展行為對(duì)預(yù)防瀝青混合料面層的早期破壞具有重大意義。總結(jié)了影響路面面層的反射裂縫開展的各個(gè)因素,發(fā)現(xiàn)在瀝青混合料中摻入纖維有助于改進(jìn)瀝青路面的抗裂性能,因此研究摻入不同纖維的瀝青混合料的低溫抗裂性能,并用預(yù)切口模擬瀝青路面面層底部預(yù)先存在的裂縫,研究存在于不同位置的反射裂縫在受荷載作用下的擴(kuò)展行為。設(shè)計(jì)了預(yù)切口小梁三點(diǎn)彎曲加載試驗(yàn),將溫度作為小梁試件低溫開裂性能的影響因素,將試驗(yàn)溫度定為-10℃、0℃、10℃;為研究纖維對(duì)于瀝青混合料小梁試件的開裂性能的改進(jìn)作用,將摻入聚酯纖維、玄武巖纖維和木質(zhì)素纖維的瀝青混合料與不摻入纖維的混合料進(jìn)行對(duì)比試驗(yàn);試驗(yàn)對(duì)路面反射裂縫進(jìn)行模擬,在試件底部預(yù)制切口深度為10mm的預(yù)切口,將預(yù)切口與中心的距離定為:Omm、20mm、40mm,對(duì)具有不同切口的試件進(jìn)行三點(diǎn)彎曲加載試驗(yàn)。結(jié)果表明,預(yù)切口小梁三點(diǎn)彎曲加載試驗(yàn)很好地模擬了瀝青混合料路面的低溫開裂特性和混合料試件的反射裂紋開展行為;試驗(yàn)溫度愈低,試件抗裂性能愈好;玄武巖纖維具有穩(wěn)定地改善瀝青混合料抗裂性能的作用;切口與荷載的水平偏移距離愈大,即反射裂縫偏移中心荷載的水平距離愈大,則試件抗裂性能愈強(qiáng)。采用ANSYS有限元軟件模擬了小梁在-10℃試驗(yàn)時(shí)裂縫的開展行為。通過試驗(yàn)結(jié)果分析、斷裂力學(xué)分析和有限元分析,得到了裂縫開展的起裂角的計(jì)算值、試驗(yàn)值和模擬值,用于描述裂縫開展行為。分析結(jié)果表明,小梁試件底部的反射裂縫開展行為具有一定的規(guī)律,針對(duì)不同位置的裂縫,給出了不同的起裂角范圍,衡量裂縫開展行為。當(dāng)裂縫偏移中心加載位置距離x=0mm時(shí),起裂角θ0范圍在0°至3.5°之間。當(dāng)x=20mm時(shí),起裂角范圍在6.9至17.5°之間較為合理。當(dāng)x=40mm時(shí),起裂角的開展范圍大概在20°至30°之間較為合理。
[Abstract]:Reflection crack is one of the main causes of asphalt pavement damage in winter. Under the joint action of low temperature shrinkage and load, the stress concentration in the lower horizontal layer cracks, the stress concentration in the cracks causes the cracks to develop upward, the stress concentration in the cracks is larger than that in the parts without cracks, and it is easy to exceed the ultimate tensile strength of the asphalt mixture surface. Cause the surface to crack. The research on low temperature crack resistance and crack development behavior of asphalt pavement can provide theoretical basis for pavement pavement mixture design. It is of great significance to study the propagation behavior of reflection crack to prevent the early failure of asphalt mixture surface. This paper summarizes the factors that affect the development of reflective cracks in pavement surface, and finds that adding fiber to asphalt mixture is helpful to improve the crack resistance of asphalt pavement, so the low temperature crack resistance of asphalt mixture with different fibers is studied. Pre-cut is used to simulate the pre-existing cracks at the bottom of the asphalt pavement surface, and the propagation behavior of the reflection cracks in different locations under the action of load is studied. The three-point bending test of pre-cut trabeculae was designed. The temperature was taken as the influence factor of the low-temperature cracking property of the trabecular specimens, and the test temperature was -10 鈩，

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