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Using asphalt pavements as a solar collector is a subject of current interest in the Netherlands. Some thermal analysis research has already been done. The effects of a system for cooling and heating asphalt pavements on the durability of the pavement structure are examined. With the finite element program FEMMASSE, thermal analyses have been done based on measuring data from a field test in the northern Netherlands, where polyethylene tubes were built in a main road to control the temperature of the pavement. Subsequently, a model for structural analysis was built by means of the finite element system CAPA 3D (computer-aided pavement analysis). The model was based on temperature distribution according to the thermal analysis. From these analyses it appears that high peak values in the stresses and strains arise around the tubes, which might affect the lifetime of the system negatively. Considering the research findings of the investigation it is concluded that the issue of energy extraction from asphalt pavements involves several complex engineering and financial issues that must be resolved before effective utilization is possible.

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Abstract. Non-dowelled short slabs are a cost-effective innovation of jointed plain concrete pavements. The development of this innovation has been concentrated in their structural performance. Still there is a lack of specific studies of the relation load transfer -crack width, being the crack width at joint the direct cause of the aggregate interlock. Considering that their provision of load transfer relies on aggregate interlock, the objective of the present article is to develop the relationship between the load transfer by aggregate interlock and its direct cause (the crack width) specifically for innovative nondowelled short concrete slabs pavements. For that, the analysis includes a validated nonlinear aggregate interlock model incorporated in a 3D Finite Element program, laboratory results, and field measurements performed as part of the present investigation. The results show that due to the small crack widths, the short slabs are able to provide adequate load transfer (not less than 70%) even without dowels bars. Indeed, in this case, the load transfer relies on aggregate interlock and the results of the Faultimeter (residual value more than 0) have confirmed this interlocking for crack widths at joints not more than 1.2 mm, which are typical values in short slabs when the joints are activated. For that, the Early Entry saw cutting method needs to be modified or applied as a complementary method to perform the joints. Although in short concrete slabs pavements the provision of load transfer is already guaranteed by the small crack widths at joints, the application of high-quality coarse aggregates provides even higher load transfer.

Due to environmental reasons and the shortage of natural resources, it is greatly valuable to recycle construction and demolition waste (CDW) as much as possible. One of effective ways to reuse more CDW is to produce a cemented road base material. The recycled CDW however is a mix of recycled masonry and concrete with a wide variation in composition. This implies that the mechanical properties of cement treated demolition waste are not only determined by cement content and degree of compaction, but also by the ratio of crushed masonry content to crushed concrete content. In order to optimize its mixture proportioning, this paper explores the response surface and contour plot of the combined effect of mixture variables on the mechanical properties including the unconfined compressive strength (UCS), the elastic modulus (E) and their ratio. It has been recognized that optimizing the mixture proportioning of cement treated demolition waste should not only consider its material properties, but also needs to take into account its structural behavior as a pavement layer. Analytical results indicate that increasing the degree of compaction is an economic technique to obtain the required strength, but it is not an efficient method to enhance the admissible elastic strain (the ratio of UCS to E) and to improve the flexural rigidity of the road base layer. Obtaining a desired low flexural rigidity certainly needs adjusting of the masonry content and the cement content.

Aggregate interlock is the dominant load transfer mechanism in non-dowelled Jointed Plain Concrete Pavements, as the innovative short concrete slabs. Although the Load Transfer Efficiency of this pavement innovation is based on that mechanism, the structural design methods do not relate the Load Transfer Efficiency by aggregate interlock with its direct cause, which is the Crack Width under the joints. The objective of the present article is to characterise in the laboratory the Load Transfer Efficiency−Crack Width relation for innovative short slabs Jointed Plain Concrete Pavements. Additionally, as an alternative to large-scale laboratory tests to study the Load Transfer Efficiency, a practical test on a reduced scale is proposed. The results confirmed that short slabs Jointed Plain Concrete Pavements with high-quality aggregates are able to provide adequate Load Transfer Efficiency (above 70%) without dowels bars. Based on the laboratory results, complemented with previous field data, a Load Transfer Efficiency−Crack Width curve is proposed and made available for structural design methods of short slabs Jointed Plain Concrete Pavements. Finally, the laboratory test on a reduced scale is useful to develop specific Load Transfer Efficiency−Crack Width relations using standard equipment available in traditional concrete laboratories.

Recent field observations on several newly constructed continuously reinforced concrete pavements (CRCPs) in Belgium indicate that the crack pattern is characterized by low mean crack spacing (approximately 1.0 m after 2 years in service) along with a high percentage of clusters of closely spaced cracks. Field surveys also indicate that it is difficult to reduce significantly the probability of a nonuniform crack pattern–-such as closely spaced cracks, meandering, and Y-cracks–-by slightly adjusting the amount of longitudinal steel. The nonuniform crack pattern is inevitable and common in conventional CRCP. Previous experience in the United States shows that active crack control for CRCP can eliminate the cluster cracks and that a more uniform crack pattern with straight cracks can be achieved. A new partial surface notch for active crack control was proposed and adopted first in the reconstruction project of Motorway E313 in Herentals, Belgium, in 2012. The introduction of the proposed active crack control method is described in detail. The effectiveness of improving the crack pattern is demonstrated in the field investigations.