Sustainability of Flexible Pavement in terms of Micro Crack Healing Concept

Course Topics (Four Hours):

(First hour)

  • Flexible pavement distress (general): [Common asphalt pavement distress including rutting, potholes, cracking, bleeding will be discussed in both hot and cold weather regions].
  • Type of pavement cracking: [Various types of flexible pavement cracking including micro, macro and mega cracks, longitudinal and transverse cracks; block and alligator cracks will be verified].
  • Assessment of cracking: [Cause and remedy of various cracks will be assessed].

(Second hour)

  • Crack healing concept: [Theory of crack healing in binder and asphalt concrete will be explained].
  • Crack healing potential of asphalt concrete: [Factors affecting the crack healing potential of asphalt concrete including the impact of gradation, asphalt content and volumetric properties will be assessed].

(Third hour)

  • Influence of additives on the crack healing potential: [Influence of additives including polymers, stabilizing agents, and filler on the crack healing concept will be verified].
  • Implementation procedure of crack healing: [Procedure and mode of crack healing including external heating and induction heating and metallic filler will be explained].

(Fourth hour)

  • Testing to predict the effectiveness of crack healing: [Prediction of crack healing in the laboratory using various testing procedures will be explained].
  • Case studies on Crack healing: [Impact of crack healing on tensile, shear and compressive strength of asphalt concrete, Impact on resilient modulus and deformation, and the impact on extending the service life of the pavement will be verified].

(Questions and Discussion)


The fatigue life of Asphalt concrete pavement consists of two components, namely the resistance to fracture and crack, and the ability to heal the micro cracks. Both processes change with temperature and time. Such processes exhibit the sustainability potential of asphalt concrete pavement. The approach to study this potential requires mechanical tests like creep or relaxation, strength and repeated load tests. Repeated traffic loading causes deterioration to asphalt concrete pavement mixes in terms of micro cracking and decreases its stiffness. However, due to the crack healing phenomena effect, asphalt mixes can demonstrate strength recovery and prolongs the fatigue life of asphalt mixtures. Many studies have been conducted to characterize the asphalt healing and its mechanisms. The aim of this workshop is to thoroughly understand the cracking and healing mechanisms and to define appropriate laboratory tests, type of additives which can increase the healing potential and can be used for a reliable performance-related selection and characterization of the asphalt binders, and the suitable asphalt concrete mixture based on the traffic loading and the environment issues. It was felt that it is essential to evaluate whether it is possible to achieve accelerated healing in asphalt mixtures within laboratory conditions, which could represent the actual behavior in the field. It was concluded that the process of healing is a sustainable measure and can be used to balance the damage process, the amount and rate of healing of asphalt cement depend on several properties such as; its healing potential, stiffness, and surface free energy.




Prof. Saad Issa Sarsam was born in Baghdad (1955), got his BSc. In Civil Engineering (1977), Post graduate diploma in Transportation Engineering (1978); MSc in Transportation Engineering (1980). Worked as senior material Engineer for NCCL (1982-1988); Served as Director of NCCL- Mosul, Iraq (National center for construction laboratories; Ministry of Housing and construction) (1988-1993). Joined the academic staff at University of Mosul (1992-2005) and got the Assistant Professor degree at (2002); Joined the academic staff at University of Baghdad (2005 until now) and got the Professor degree at (2007). Served as Head of the Department of Civil Engineering, university of Baghdad (2016-2018). Published four books and 217 research papers in national and international scientific journals. Member of editorial board of nine international scientific journals, and reviewer of another five journals. Supervised 41 MSc Thesis's. Participated in 50 national and international scientific conferences. Worked for Ministry of Industry and Military manufacturing, Faw General Directory, (1989-1990). Worked as Consultant road Engineer for Municipality of Mosul on urban road resurfacing and construction (2001-2002). Worked for Training program at Iraqi Engineers Union for junior and senior engineers (2001-2004). Worked as Consultant Engineer for [Sumer Contracting Company (2004); AFM Group-Switzerland (2014); Ministry of Transport (2011-2017) and National center for construction laboratories and research (2011-2015)].

Areas of specialization and interest: (Modified asphalt concrete; Pavement evaluation and maintenance; Maintenance Management system, Quality assurance, Airport Engineering, Roller compacted concrete; Asphalt stabilized embankment models, Road user characteristics).