[01] Saad Issa Sarsam, Department of Civil Engineering, College of Engineering, University of Baghdad, Baghdad, Iraq. [02] Siham Almas Barakhas, Department of Civil Engineering, College of Engineering, University of Baghdad, Baghdad, Iraq.

The implication of asphaltic materials into the subgrade soil is referred as asphalt stabilization, it usually changes the whole geotechnical properties and behaviour of the soil under repeated loading applied by vehicles through the pavement system. The asphalt material supports the cohesive property and bind the soil particles through the thin film of asphalt, it also introduces some elastic property and introduce the resilience action against deformation under repeated wheel loading. Due to aging and continuous loading, micro cracks will initiate indicating the starting point of distress. This work investigates the possibility of micro crack healing when exposing the cutback asphalt stabilized layer to external heating. Stabilized soil specimens of 100 mm diameter and 200 mm height have been prepared in the laboratory at optimum asphalt content, and at one percent of asphalt above and below the optimum. Specimens were cured for one week at laboratory environment, then the specimens were subjected to repeated compressive stress at 20°C using the Pneumatic repeated load system (PRLS). The test was stopped after a predetermined number of load repetitions, the specimens were released from the testing chamber, and stored in an oven at 60°C for 120 minutes, and then the specimens were cooled to 20°C for 60 minutes, fixed at the testing chamber, and subjected to another cycle of repeated compressive stresses. It was concluded that The resilient modulus was increased by (50, 4, and 17)% due to healing process at asphalt content of (5, 6, and 7)% respectively, while the permanent deformation and initial deformations have decreased due to crack healing by (71, 7, and 56)% and (44, 37, and 42)%, respectively for asphalt content of (5, 6, and 7)%.

Crack Healing, Asphalt Stabilization, Cutback, Subgrade, Repeated Compressive Stress

[01] Garcia A., (2010), “Temperature influence on the healing rates of asphalt concrete”, 2nd International Symposium Service Life Design for Infrastructure, Delft, The Netherlands. [02] Garcia Hernandez, A, Schlangen, E & Ven, MFC van de (2011) “Asphalt mastic self-healing”, Proceeding of the 3rd international conference self-healing materials (pp. 299-300). Bath, UK. [03] Garcia, A., Schlangen, E., Ven, M.V.D., Bochove, G.V. (2012) “Optimization of composition and mixing process of a self-healing porous asphalt” Construction and Building Materials, 30, pp. 59-65. [04] Sarsam, S.I., (2015), "Crack Healing Potential of Asphalt Concert Pavement", International Journal of Scientific Research in Knowledge, 3 (1), pp. 001-012. [05] Qiu J (2012). “Self-Healing of Asphalt Mixtures: Towards a Better Understanding of the Mechanism”, PhD. Dissertation, Delft University of Technology (TU delft). [06] Sarsam S, Rahem F (2009). “Cracking and crack healing in Asphalt concrete pavement”. Graduation Project report, Department of Civil Engineering, University of Baghdad. [07] Barakhas S. A. (2015) “Verification of the structural capacity of asphalt stabilized embankment”, MSc. Thesis, College of Engineering, University of Baghdad, Iraq. [08] Sarsam S. I., Alsaidi A. A. and Alzobaie O. M. (2014) ‘Impact of Asphalt Stabilization on Deformation Behaviour of Reinforced Soil Embankment Model under Cyclic Loading”, Journal of Engineering Geology and Hydrogeology JEGH, 2(4):46-53. Sciknow publication Ltd. USA. [09] Prakash, S. and Sarsam, S., (1981), "Effect of Curing Time on Soil Cutback Mix for Faloga Soil" IRC, Indian Highways, Vol. 9, No. 10. [10] AASHTO, (2013). “Standard Specification for Transportation Materials and Methods of Sampling and Testing”, American Association of State Highway and Transportation Officials, 14th Edition, Part II, Washington, D.C. [11] Sarsam S. I. and AL-Zubaidi I. (2014) ‘Assessing Tensile and Shear Properties of Aged and Recycled Sustainable Pavement”, International Journal of Scientific Research in Knowledge, (IJSRK) 2(9), pp. 444-452, 2014. [12] Sarsam S. I., Al-Delfi K. H. (2014) “Initial Cracking Potential of Asphalt Concrete’, International Journal of Scientific Research in Knowledge, IJSRK, 2(12), pp. 538-548. [13] Yoder E. J. and Witczak M. W. (1975) “Principles of pavement design”, 2nd edition, John Wiley and sons Inc. [14] Sarsam S. I. and Husain A. (2015) “Impact of Nano Materials on the Durability of Asphalt Stabilized Soil”, American institute of science, Journal of Nano science and Nano engineering Vol. 1, No. 2, pp. 23-37.