Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleYayıncıda açık erişim2025Assessing the reliability of the lightweight deflectometer test for compaction control in highway subbase layers through SPSS analysis
Seferoğlu, Mehmet Tevfik; Seferoğlu, Ayşegül Güneş; Akpınar, Muhammet Vefa; Iribagiza, Divine
The condition of the highway base/subbase layers is critical for the durability and performance of the road pavement. Compaction control plays an important role in determining the ability of these layers to support traffic loads, their strength and stability. Various methods are used to evaluate the compaction rate of subbase layers; such as nuclear density gauge (NDG) and sand cone. These methods also have their own limitations and difficulties. While the NDG test is used to determine the compaction percentages, the lightweight deflectometer (LWD) test is used as a relatively more practical, portable and non-destructive method to measure the surface stiffness modulus (Emod). In this study, the possibility of using the surface stiffness modulus obtained by the LWD test in the subbase layer instead of each other is investigated by establishing a correlation between the compaction percentages determined by the NDG test. To investigate how well the LWD results are in line with established methods, only correlation and regression analysis of SPSS software are focused on. Correlation analysis helped us assess the strength and direction of the relationships between LWD modulus values and compaction percentages, while regression analysis provided insights into the predictive capability of LWD in estimating compaction outcomes. These methods helped evaluate the reliability and accuracy of LWD as a compaction control tool, providing a deeper understanding of the role of LWD in highway subbase layer assessment.
- MakaleAçık Erişim2021Performance of AC overlays using geogrids on PCC contraction joints
Çelik, Muhammet; Seferoğlu, Mehmet Tevfik; Akpınar, Muhammet Vefa
It is widely known that vertical displacements and strains occur on the joints and these cause defects on the asphalt concrete (AC) overlays on existing Portland cement concrete (PCC) pavements. Various approaches were introduced to minimize these defects. In this study, the effect of joint support formed using the geogrid material with grout mortar on the vertical displacement of PCC and the strain at the bottom of the AC layer. Produced layers were exposed to 1,186,000 Equivalent Single Axle Load (ESAL) in an APT (Accelerated Pavement Test) facility and the results were monitored. According to the obtained results, the use of AC overlay reduces vertical displacement in the PCC by 75%. When geogrid reinforced AC overlay was used, an additional reduction in displacement by 41.2% was achieved. Geogrid reinforcement reduced strain values formed at the bottom of the AC layer from 29.5% to 92.5%. The use of geogrid at joints instead of increasing the thickness of the AC layer from 50 to 80 mm resulted a more significant reduction in both strain and displacement. Besides, the usage of a geogrid interlayer instead of increasing the thickness of the AC layer also provided a significant cost reduction of 57.9% in overall cost.