Rheological properties of warm mix asphalt binders and warm mix asphalt binders containing polyphosphoric acid
|نوع نگارش مقاله||
scopus – master journals – JCR
۴٫۲۷۶ در سال ۲۰۲۰
۲۶ در سال ۲۰۲۱
۰٫۹۰۱ در سال ۲۰۲۰
|شاخص Quartile (چارک)||
Q1 در سال ۲۰۲۰
خرید محصول توسط کلیه کارت های شتاب امکان پذیر است و بلافاصله پس از خرید، لینک دانلود محصول در اختیار شما قرار خواهد گرفت و هر گونه فروش در سایت های دیگر قابل پیگیری خواهد بود.
فهرست مطالب مقاله:
This paper presents the laboratory investigation of properties of warm mix asphalt (WMA) binders and WMA binders containing polyphosphoric acid (PPA).Two types of warm mix additives were used to produce the WMA binders. Superpave tests were carried out on original and short-term aged binders through the rotational viscometer, the dynamic shear rheometer (DSR), and the bending beam rheometer (BBR). The results indicated that the WMA binders with diﬀerent warm mix additives showed diﬀerent viscosity values, however, the addition of PPA remarkably increased the viscosity values of these two kinds of WMA binders used, in the present study, to a similar level. The WMA additive type and the PPA had signiﬁcant eﬀects on the complex modulus (G*), phase angle (d) and G = sin d regardless of the binders’ aging state (without aging or short-term aging). In addition, two WMA binders with diﬀerent additive types showed signiﬁcant diﬀerences on the creep stiﬀness and m-value, and the addition of PPA degraded the low temperature rheological properties of the WMA binders.
|بخشی از متن مقاله:|
New technologies have been developed due to the importance of environmental concerns in the manufacture of hot mix asphalt (HMA). Warm mix asphalt (WMA) is one of the new technologies with the objective of minimiz- ing CO2 emissions in the production and placement process of HMA by reducing the temperatures at which these are mixed and compacted [1–۳].
WMA Technologies that allow lower HMA production temperatures may demonstrate positive impacts on pave-
ment performance. Because the lowered mixing tempera- ture reduces oxidative hardening of asphalt binder, it should reduce susceptibility to cracking by improving pavement ﬂexibility and longevity .
Reducing production (mixing) and paving (compaction) temperatures by using WMA in place of HMA yields ben- eﬁcial environmental eﬀects :
Reduced emissions and odors from plants; Reduced smoke; and Improved working conditions at the paving site.
WMA can be produced with organic additives and chemical additives or through the foaming technologies (water-bearing additives or water-based processes) . By now, considerable research on WMA has been conducted in many countries [۵–۱۱]. The application of organic additives produces a decrease in asphalt viscosity when the mixing and placement temperatures are above the melting point of the wax, while the chemical additives reduce the surface tension of the asphalt binder without modifying- the rheological properties [12,13]. The foaming technolo- gies are based on the injection of small amounts of water along with the liquid asphalt binder during the mixing pro- cess which in-turn causes the asphalt binder to expand in volume and foam at a given temperature. The foaming pro- cess helps the liquid coat the aggregate at reduced temper- atures . In this study, WMA binders were produced with one type of chemical additive and one type of organic additive.
The considerably lower cost of polyphosphoric acid (PPA) compared with polymer modiﬁers has made PPA modiﬁcation a popular choice for pavement applications. The PPA allows to signiﬁcantly harden bitumen in an easily controllable way. PPA-modiﬁed asphalt binders could increase early resistance of the pavement to rutting by increasing initial stiﬀness and may extend the in- service life of the pavement by improving the low- temperature ﬂow properties. These improved properties may result in both reduced fatigue and low temperature cracking [۱۴–۱۶]. Edwards et al. observed that adding PPA especially to a non-waxy bitumen showed consider- able positive eﬀects on the rheological behavior at higher and medium temperatures and little eﬀect at low tempera- tures [17,18]. Some researchers even reported that addition of 1% PPA by weight of asphalt binder improves the high- temperature performance by approximately ۱۰ C and the low-temperature performance by approximately ۲ C [19,20]. Although the properties of WAM binders and PPA modiﬁed binders were separately investigated in many previous studies, not many studies looked into the proper- ties of WMA containing PPA.
Hence, the main objective of this study was to experi- mentally investigate the eﬀect of PPA on WMA binders with diﬀerent WMA additives. In this study, the WMA binders were produced with two diﬀerent warm asphalt additives. The viscosity properties for the binders in the original state, the high temperature rheological properties in the original state and after rolling thin ﬁlm oven (RTFO) short-term aging state, and the low temperature properties for the binders after RTFO procedures were evaluated. Fig. 1 shows a ﬂow chart of the experimental design used in this study.
لطفا پیش از ارسال نظر، خلاصه قوانین زیر را مطالعه کنید: فارسی بنویسید و از کیبورد فارسی استفاده کنید. بهتر است از فضای خالی (Space) بیشازحدِ معمول، شکلک یا ایموجی استفاده نکنید و از کشیدن حروف یا کلمات با صفحهکلید بپرهیزید. نظرات خود را براساس تجربه و استفادهی عملی و با دقت به نکات فنی ارسال کنید؛ بدون تعصب به محصول خاص، مزایا و معایب را بازگو کنید و بهتر است از ارسال نظرات چندکلمهای خودداری کنید.