The Possibility of Minimizing Rutting Distress in Asphalt Concrete Wearing Course

Abstract

The excessive permanent deformation (rutting) in asphalt-concrete pavements resulting from frequent repetitions of heavy axle loads is studied in this paper. Rutting gradually develops with additional load applications and appears as longitudinal depressions in the wheel path. There are many causes of the rutting of asphalt roads, such as poor asphalt mixing and poor continuous aggregate gradation. All factors affecting the mixture resistance to permanent deformation must be discussed, and all must be properly considered to reduce the rutting propensity of asphalt-aggregate mixtures. In this study, several mixtures were produced with the most common techniques in rutting resistance (using the most effective additives for each mixture), and their performance was compared with the (conventional) mixture currently used in Iraq. The tests focused on the asphalt-concrete mixture for wearing courses. Different mixtures types were tried, namely, dense hot asphalt mixture (HMA) with two different asphalt contents (4.7% and 5.3%), Open-Grade Friction Course (OGFC) mixture, Stone Mastic Asphalt (SMA) mixture, and Beton Bitumineux a Module Eleve (BBME). The modifiers included natural Sisal Fibers (SFs), Carbon Fibers (CFs), and mineral filler (hydrated lime, HL). Marshall test was carried out to find stability and flow values. Rutting was evaluated by the repeated load test for cylindrical specimens under two temperatures (40°C and 60°C) to obtain the permanent deformation parameters. The parameters were used as input to the VESYS 5W software to evaluate the rut depth during different times of design life under 7×10^6 Equivalent Single Axle Loads (ESALs). The results of the selected mixtures were compared with the mixture designed in the laboratory dense gradation mix Job-Mix Formula (JMF)) within the limits of the Iraqi specification (SCRB,2003). Manipulation of the aggregate gradation that is customary in the implementation of the local mixture showed that the best performance regarding rutting resistance was exhibited by JMF, which decreased the rut depth at 40°C and 60°C by 21.63mm and 44.304mm respectively, in comparison with the conventional mixture. Changing the aggregate gradation of the local mixture gives better performance in rutting resistance without additives or changing the percentage of asphalt, at the same cost.

Investigating the Impact of Domestic Sewage on Asphalt Concrete Pavement Strength

“…The impact of water-exposed pavements was evaluated by immersing Marshall specimens under controlled conditions. The Marshall methodology has been widely used in previous studies for measuring flow and loss of stability in pavements [47][48][49][50]. The specimens were immersed into fresh water and sewage for 14 days.…”

Mitigating Reflection Cracking in Asphalt Concrete Overlays with ECC and Geotextile

“…The key result of the OT is the number of load cycles to failure (Nf). Authors in [39] illustrated that failure is initiated when the peak load in a cycle decreases to 93% below the highest initial load [38,[40][41][42]. Another two parameters that can be from this test are the critical fracture energy (Gc) and the Crack Progression Rate (CPR).…”

Marshall Asphalt Mix and Superior Performance Asphalt Mix in Oman: A Comparative Study

“…The design of asphalt mixes for tropical climates with high temperatures, especially for roads that are projected to handle huge truck loads and higher design traffic volumes much greater than 1 million Equivalent Single Axle Loads (ESALs) is a challenging task. The primary concern when designing such an asphalt mix is making sure the mix is resistant to plastic deformation [1]. The current level of practice for pavement design is mostly based on empirical approaches in various nations of the Gulf Cooperative Council (GCC).…”