ارزیابی تاثیر پودر آجر در بهبود رفتار خستگی مخلوط‌ آسفالتی

روسازی راه ها به عنوان سطوحی که تحت بارگذاری مکرر و متعدد محورهای سنگین قرار می گیرند، باید دارای مقاومت کافی در برابر خرابی ها باشند. پدیده خستگی یکی از مهم ترین دلایل بروز ضعف در روسازی راه می باشد که بر اثر تکرار بارگذاری در آن رخ می دهد. تحقیقات آزمایشگاهی فراوانی به منظور افزایش عمر خستگی مخلوط های آسفالتی صورت گرفته که در آن ها سعی گردیده تا با استفاده از افزودنی های مطلوب، بتوان کیفیت مخلوط های بتن آسفالتی در برابر بار وسایل نقلیه افزایش داد. در سالیان اخیر استفاده از افزودنی ها از جمله پلیمر، پودر آهن، آهک هیدراته، ضایعات شیشه، خرده لاستیک و پودر آجر جهت بهبود خواص قیر و در نتیجه بهبود خواص مخلوط های آسفالتی مورد توجه قرار گرفته است. در این مقاله تاثیر استفاده از افزودنی پودر آجر ضایعاتی بر روی پارامترهای خستگی مخلوط آسفالتی مورد ارزیابی قرار گرفته است. نتایج حاصل از این پژوهش بیانگر تاثیر مثبت این افزودنی در بهبود عملکرد خستگی مخلوط های آسفالتی می باشد.

Evaluation of brick powder to improve the fatigue behavior of asphalt mixtures.

Acting as a surface which is supposed to tolerate several reloading of heavy axes, pavement shall hold enough resistance against failures. Fatigue phenomenon is one of the most important causes of weakness in road pavement, which is occurred due to reloading of it. Many laboratory researches are carried out with the purpose to enhance fatigue life of asphalt concrete mix, in which researchers have tried to improve quality of asphalt concrete mix against load carrying transportation vehicles. During recent years, additives like polymer, iron powder, hydrated lime, glass wastages, crumb rubber and brick powder are also considered for improving tar and, consequently, asphalt mix properties. Generally, hotmix asphalt (HMA) mixtures consist of three components: mineral aggregates, asphalt binder and air voids. It is well recognized that mineral fillers play an important role in the properties of mastics and hotmix asphalt (HMA) mixtures. Better understanding of the effects of fillers on the properties of mastics and HMA mixtures is crucial to good mix design and high performance of HMA mixtures. In this stydy, the effect of brick powder on fatigue parametrs have been investigatedFiller content for mix design should be determined based on the overall performance of HMA mixtures.It has been recognised with growing concern that agricultural and industrial wastes are increasingly produced in large volume. In order to reduce environmental hazards and conserve natural resources, the use of waste materials in highway pavements would be extremely effective in terms of recycling waste materials. The main purpose of this study was to investigate the effects of waste materials as filler on the performance of hot mix asphalt (HMA) mixtures.It is well recognized that mineral fillers play an important role in the properties of mastics and hotmix asphalt (HMA) mixtures. Better understanding of the effects of fillers on the properties of mastics and HMA mixtures is crucial to good mix design and high performance of HMA mixtures. Laboratory experiments were conducted to investigate the effect of different fillers on properties of mastics and HMA mixtures. The properties of HMA mixtures were investigated by Marshall, indirect tensile stiffness modulus and indirect tensile fatigue tests. The results indicated that WBP mixtures exhibited higher fatigue life and better performance than control mixtures. With the increase of filler content, some properties of HMA improved while others decreased. The effects of filler were exerted on HMA mixtures through the mastic. Fillers with rough particle texture (such as manufactured sand) tend to increase the stiffening effect of the mastics and mixtures. Considering the overall effects of filler on the properties of HMA mixtures, a filler content range would be required in order to ensure the performance of the mixtures. Waste materials can be mainly regarded as the following classifications: (a) industrial wastes such as cellulose waste, slag, bottom ash and fly ash; (b) municipal/household wastes such as incinerator residue, scrap rubber and waste glass; (c) mining wastes such as coalmine refuse and (d) construction and demolition Based on the results, in consequence of increased awareness of environmental issues and natural resources constraints, the studied waste materials can be advantageously utilised in road construction.