In this paper, pavement sections of the highway connecting Jeddah to Jazan were selected and analyzed to investigate the relationship between International Roughness Index (IRI) and pavement damage including cracking, rutting, and raveling. The Ministry of Transport (MOT) of Saudi Arabia has been collecting pavement condition data using the Road Surface Tester (RST) vehicle. The MOT measures roughness (ROU), rutting (RUT), cracking (CRA), and raveling (RAV). Roughness measurements are calculated in terms of the International Roughness Index (IRI). In the present three relationships, including CRA versus IRI, RUT versus IRI, and RAV versus IRI have been developed. The models relating to three types of distresses under study, and model relating IRI to ride quality have been studied in the present work. The results of the analysis indicate that a significant relationship exists between IRI and cracking, and IRI and raveling at 95% confidence level. The results also show that the rutting did not show a significant relationship to IRI values. It can be concluded from the results that cracking and raveling may possibly be described as ride quality distresses, whereas the rutting distress may be described as non-ride quality distress. The results indicate that while statistically significant relationships exist between IRI and both cracking and rutting, these relationships are not strong enough for IRI to be used as a surrogate measure for pavement condition

This study aims to evaluate and characterize the properties of modified asphalt cements exposed to high temperature. The Acrylate Styrene Acrylonhrtilrei (ASA) polymer and nano aluminum oxide (Al2O3) nanoparticles were added to the base asphalt cement with concentrations of 3, 5 and 7% of the weight of asphalt. The storage stability, viscosity, frequency sweep and MSRC test were considered for evaluation. The results demonstrate that the addition of ASA polymer and Al2O3 nanoparticles content have a great influence on the rheological properties of the asphalt cement at high temperatures. Additionally, it is clear that the storage stability of modified asphalt cements with ASA polymer and Al2O3 nanoparticles has good compatibility among the asphalt cement and the modifiers. Moreover, the complex modulus (G*) improves as the concentration of both modifiers increases. The improvement was 63.70% for 5% ASA polymer, and 71.12% for 5% Al2O3 at 75°C. Moreover, the modified asphalt cements demonstrates great resistance to high temperatures rutting, as the enhancement was up to 80 and 59% for 5% concentration of ASA and Al2O3. The modification of asphalt cements provides increasing the creep recovery up to 69.23 and 62.53%. It was found that the usage of ASA polymer and Al2O3 nanoparticles is able to mitigate asphalt cement problems at high temperatures, and 5% is considered as the optimum content of both modifiers

Governments face numerous challenges in sustaining road network conditions. This is attributed to road authorities’ shortages of financial and physical infrastructure. As a result, low-cost automated solutions are being pursued to solve these problems and provide people with appropriate road conditions. Several attempts have been made to improve these technologies and incorporate them into a Pavement Management System (PMS) but limited attempts are made for developing countries. This study aimed to design a low-cost pavement management system for flexible pavement maintenance. A detailed literature review has been carried out, followed by a qualitative assessment of the various indicators considered for PMS. The priority ranks of the PMS indicators were made using an Analytical Network Process (ANP) and each rank was validated by a sensitivity assessment test using the Super Decision-Making tool. This paper also provides the conceptual framework for the low-cost PMS, followed by a fishbone diagram of the indicators and sub-indicators. It is concluded that an emergency maintenance plan with an ANP weight of (0.41) is one of the most significant plans for a low-cost PMS, followed by a routine with an ANP weight of (0.39) and periodic maintenance plans with a (0.20) ANP weight. Moreover, the functional indicators with an ANP weight of (0.32) are the most significant indicators for a low-cost PMS, followed by structural (0.26), safety (0.24), and serviceability(0.18) indicators. This model will assist the road planners in making better decisions on pavement maintenance management plans. The model will suggest the pavement sections on a higher priority to be added in the maintenance plans, especially where the maintenance budget is limited.

Reliability of semi-circular bending (SCB) specimen for measuring the fracture behaviour of pavement materials under static and cyclic loadings has been examined. This study is divided into three phases. In the first phase a comparison between different equations suggested by several specifications and by researchers has been made. Three different SCB specimen types used for predicting mixed mode fracture behaviour of pavement materials have been evaluated in the second phase. In the third phase the applicability of using SCB specimen in predicting fatigue crack growth rate in pavement materials under mode I has been examined. 3-D finite element analysis (FEA) has been adopted. Although there is conformity of the specimen dimensions there is no unique equation to measure the fracture parameters. The prediction of the fracture behaviour of pavement materials obtained by the present FEA is acceptable. The value of K_IC predicted from each specimen type has been examined for its reliability by using the concept of maximum size of non-damaged defect (d_max). Mode I fracture toughness predicted by SCB-1 (standard specimen) is the only consistent value, while SCB-2 and SCB-3 (specimens with shifted crack) failed in this reliability test. To check the reliability of SCB specimen for measuring the fatigue behaviour of pavement materials, the relation between the stress intensity factor range (ΔK) and the crack mouth opening displacement (CMOD) through the whole life of the specimen has been examined. A good relation is found between the CMOD and the ΔK through the whole life of SCB specimen.

The use of recycled Reclaimed Asphalt Pavement (RAP) material into flexible pavement contributes to sustainable development with environmental and economic benefits. In the present work, Semi-Circular Bending (SCB) specimen has been adopted to study the flexural strength and mode-I fracture toughness of flexible pavement with and without RAP. Two different resources of RAP, namely KS and KF, with two different percentages (20% and 40%) have been examined. Smooth and cracked specimens have been cast to measure the flexural strength and mode-I fracture of flexible pavement containing RAP, respectively. Smooth and cracked specimens for flexible pavement without RAP, as control beams, have been cast for the sake of comparisons. The experimental results showed that, the flexural strength and mode-I fracture toughness of flexible pavement containing 40% RAP are higher than those of flexible pavement without RAP, for the two types of RAP. Comparison between the of work of fracture calculated based on AASHTO TP 105-13 and AASHTO TP 124-16 showed that, the calculation based on AASHTO TP 105-13 is more accurate than that based on AASHTO TP 124-16. Furthermore, the suggested quad-linear relation to work of fracture predictions is easier and more reasonable for presenting the experimental results especially for the descending part of P-LLD curve than that suggested as exponential curve by AASHTO TP 124-16. For all groups, the type of failure is intergranular-mode fracture.