Cement stabilization is one of the most common techniques for stabilizing recycled road base material, and offers a longer pavement life. With the cement effect, the increase in stiffness of the stabilized layer would provide better load transfer to the pavement foundation. The recycling method provides an environmental friendly option as the existing road base materials will not be removed. This paper presents a case study at a trial section along the North-South Expressway in Malaysia, where the Falling Weight Deflectometer (FWD) was adopted to determine the in situ stiffness of the cement stabilized road base material. The FWD would assess the compressive strength and the material stiffness of the cement stabilized layer. The improvement in the stiffness of the stabilized base layer was monitored, and samples were tested during the trial. FWD was found to be useful for the structural assessment of the cement stabilized base layer prior to the placement of asphalt layers. Results from the FWD were also used to verify the assumed design parameters for the pavement. Using the FWD, an empirical relationship between the deflection and the stiffness modulus of the pavement foundation is proposed in this paper.
Falling Weight Deflectometer (FWD) has been widely accepted as a non-destructive device for evaluating the condition of pavements in Malaysia. FWD has been used during pavement construction for assessing the performance of the pavement foundations along an expressway in West Malaysia. Chai and Faisal (2000) demonstrated that, when FWD tests are performed on the pavement foundation, information can be gathered from the FWD deflection basin. The FWD deflection measurements can be used directly to verify the design assumptions, such as the level of compaction and the recommended material stiffness. This approach may also serve to provide supplementary performance specification to sub-grade construction in highway projects.