Sensitivity of the Flow Number to Mix Factors of Hot-Mix Asphalt

Abstract

In the design of pavement infrastructure, the flow number is used to determine the suitability of a hot-mix asphalt mixture (HMA) to resist permanent deformation when used in flexible pavement. This study investigates the sensitivity of the flow numbers to the mix factors of eleven categories of HMAs used in flexible pavements. A total of 105 specimens were studied for these eleven categories of HMAs. For each category of asphalt mixture, the variations in flow number for different contractors, binder types, effective binder contents, air voids, voids in mineral aggregates, voids filled with asphalt, and asphalt contents were assessed statistically. The results show that the flow numbers for different types of HMA used in Colorado vary from 47 to 2272. The same mix may have statistically different flow numbers, regardless of the contractor. The flow number increases with increasing effective binder content, air voids, voids in mineral aggregates, voids filled with asphalt, and asphalt content in the study range of these parameters.

Effect of Several Lime Materials on Split Mastic Asphalt Properties

“…The Air Void content also helps predict the performance of the mix over its service life [17]. Air Void is also strongly correlated with Flow [18]. A minimum Void in mineral aggregate (VMA) is recommended to satisfy the required mixture durability.…”

Comparison of Testing Method Effects on Cracking Resistance of Asphalt Concrete Mixtures

“…The Hot Mix Asphalt (HMA) used in this research is composed of 60/70 binder with performance grade PG and siliceous aggregates with the nominal maximum aggregate size of 12.5 mm. This aggregate gradation is a common sieve size for manufacturing the HMA mixture for overlaying the roads in real pavement construction projects and laboratory investigation of asphalt mixtures [35,65]. The physical properties of the used aggregates are mentioned in Table 1 and their gradations are illustrated in Figure 5.…”

Comparative Study of Hot Asphalt Mixtures Properties Designed by Marshall and Superpave Methods. (Dept. C)

“…Sample (D): the mix volumetric properties of sample (D) were determined as in shown in table (11). Then a relation between asphalt content and air voids was drawn as shown in figure (16) to determine optimum asphalt content (corresponding to 4% air voids). The optimum asphalt content is found to be (4.713%).…”

“…As for the surface layer, it was found that the limits of the 4B gradation, which is used in in this study and usually used in the Marshall Mix design method, do not meet the control points and restricted zone of the Superpave method. Therefore, a modified gradation was used as shown in table (16) [3]. Then a new aggregate gradation was designed for sample (S New ) in accordance with the modified gradation limits as shown in figure (20).…”