The use of date palm fiber (DPF) as natural fiber in concrete and mortar continues to gain acceptability due to its low-cost and availability. However, the main disadvantage of DPF in cement-based composites is that it reduces compressive strength and increases the porosity of the composite. Hence, for DPF to be efficiently used in concrete, its negative effects must be counteracted. Therefore, in this study, silica fume was employed as supplementary cementitious material to alleviate the negative effects of DPF on the strength and porosity of concrete. The DPF was added in different dosages of 0%, 1%, 2%, and 3% by weight of binder materials. Silica fume was used as a cement replacement material at dosages of 0% to 15% (intervals of 5%) by volume of cement. The unit weights, mechanical strengths, water absorption, and microstructural morphology were all evaluated. The concrete’s fresh and hardened densities were reduced with the increment in DPF and silica fume. The compressive strength declined at all ages with the increment in DPF addition, while the flexural and splitting tensile strengths improved with addition of up to 2% DPF. Furthermore, the concrete’s water absorption escalated with an increase in DPF content. Silica fume significantly enhanced the mechanical strength of the concrete. The dissipation in compressive strength with the addition of up to 2% DPF was mitigated by replacing up to 10% cement with silica fume, where it densified the microstructure and refined the interfacial transition zone between the fibers and cement matrix, hence significantly decreasing the porosity and enhancing durability.

This paper introduces shallow geothermal systems as a potential solution for improving the thermo-mechanical performance of asphalt under extreme climate events. With the recent changes experienced in the climate, earlier infrastructure failure can be expected, predominantly for temperature-sensitive flexible pavements. With that in mind, the efficiency of geothermal systems in terms of heating and cooling was comprehensively argued in many studies. However, very limited studies discussed the structural performance of geothermal pavements. This study conducted a comparative experimental study to assess the change in the compressive and flexural strengths of asphalt under extreme heating and cooling conditions and to evaluate the change in asphalt structural performance due to integrating different types of geothermal pipes into the asphalt structure. This comparative analysis employed thirty-three asphalt specimens with and without copper and polyvinyl chloride (PVC) geothermal pipes. The results of this study show that the geothermal pipes negatively affected the compressive strength of the asphalt at a normal average temperature. However, their effect was relatively minimal on the asphalt (AC) compressive strength under extreme heating and cooling conditions. In contrast, under three thermal conditions—normal, heating, and cooling temperatures—the flexure strength of the AC was significantly improved by 14.3%, 85%, and 70%, respectively, due to the copper pipe integration into the AC. The study concluded that copper pipes were superior to PVC ones in terms of enhancing the AC structural performance.