Reflective Cracking on Cement Treated Base (CTB) Pavements in Zambia: An Analytical Study

One of the predominant distress failure modes in cement treated base (CTB) pavements currently in Zambia is reflective cracking that typically reflect through the bituminous or hot-mix asphalt (HMA) surfacing layer. CTB materials are generally prone to shrinkage cracking, and this is considered to be one of the primary sources of reflective cracking mechanism in CTB pavements. The perpetual and premature occurrence of this distress is an undesirable financial burden on the Zambian taxpayers in terms of the costly road maintenance and rehabilitation activities that ought to be minimized. This paper is a theoretical and analytical discourse on the causes of this distress and recommendations for mitigation measures based on studies by different researchers worldwide. Remedial measures such as proper materials selection, optimizing mix designs, following proper construction, compaction, and curing practices, providing stress relief layers in the pavement structure, and delaying the final surface paving to facilitate adequate curing, and micro-cracking have been reviewed and assessed for their potential applications to CTB pavements in Zambia. The paper then concludes with a recommendation of mitigation measures that are feasibility considered applicable to the Zambia CTB needs for subsequent implementation by the Road Development Agency.