Temperature Correction of Deflections and Backcalculated Elasticity Moduli Determined from Falling Weight Deflectometer Measurements on Asphalt Pavements

The evaluation of the bearing capacity of asphalt pavements is usually performed by analysing the deflections measured by a Falling Weight Deflectometer (FWD). The deflection changes with the pavement temperature. In evaluation is necessary to consider the thermal gradient of pavement and perform the temperature correction. The article contains an analysis of effects of the pavement temperature on FWD results on the long-term monitored sections. The temperature correction was performed on measured deflections or back-calculated elasticity moduli. The moduli recalculated to the temperature of 20 °C according to both procedures were similar. Comparison of moduli determined by recalculation to moduli backcalculated from the deflection bowls measured at the temperature of 20 °C, has proven smaller differences for the moduli determined from the deflection bowl corrected to the temperature of 20 °C.

Perencanaan Tebal Lapis Tambah dengan Alat Benkelman Beam dan Falling Weight Deflectometer

Pada kurun periode tertentu, perkerasan jalan akan rusak sehingga perkerasan ini perlu dilapisi ulang. Saat ini, terdapat kerusakan perkerasan jalan yang membutuhkan pekerjaan lapis tambah pada jalan tersebut sehingga perkerasannya perlu dilakukan pemeliharaan. Penelitian ini dilakukan dengan mencari nilai tebal lapis tambah perkerasan (overlay) dengan menggunakan alat Falling Weight Deflectometer (FWD) dan Benkelman Beam (BB). Perencanaan tebal lapis tambah berdasarkan Perencanaan Tebal Lapis Tambah Perkerasan Lentur dengan Metoda Lendutan (Pd T-05-2005-B). Segmen dari penelitian ini adalah di Jalan Banda Aceh-Medan, data yang diambil adalah dari titik yang sama antara Falling Weight Deflectometer (FWD) dan Benkelman Beam (BB). Untuk merencanakan tebal nya, kajian ini membutuhan lendutan hasil pengujian dari Falling Weight Deflectometer (FWD) dan Benkelman Beam (BB), kemudian hasilnya dikoreksi. Setelah mendapatkan hasil lendutan terkoreksi, proses selanjutnya adalah menghitung faktor keseragaman (FK), lendutan wakil (Dsbl ov), lendutan rencana (Dstl ov), tebal overlay (Ho), faktor ketebalan lapis tambah (Fo), dan ketebalan lapis tambah terkoreksi (HT). Hasil dari penelitian ini adalah tebal lapis tambah perkerasan dari Falling Weight Deflectometer (FWD) dan Benkelman Beam (BB), ketebalan yang didapat adalah 5,235 cm untuk Falling Weight Deflectometer (FWD) dan 3,722 cm untuk Benkelman Beam (BB). Selisih yang dihasilkan dari Falling Weight Deflectometer (FWD) dan Benkelman Beam (BB) adalah 1,513 cm atau sebesar 28,90% dalam bentuk persentase.

Relating Field Energy Attenuation in Portland Cement Concrete Pavements to Fracture Mechanics

Asset management of infrastructure is fundamental for maintenance planning and preservation of common property. A robust testing program is needed to assess the present-day status and for proper actions in time to minimize the ongoing depreciation of value. As a matter of fact, Portland Cement Concrete pavements show very little deterioration even after many years in service. Thus, it may be difficult to accurately predict the present asset value, other than using linear relations to the presumed design life. The primary reason for failure is cracking in concrete pavements, so assessing the dissipated energy from the load-deformation relation from a given load could be utilized for the purpose. The dissipated energy, i.e. the work data can be assessed by a falling weight deflectometer test, mimicking the passing of a truck or aircraft wheel load. In the present study, dynamic field data are evaluated, and the input data needed for the fracture mechanics model are used to predict the pavement life regarding cracking. To predict fracture energy and assess rolling resistance as well in concrete pavements, we need to consider the energy balance of the pavement system. To assess dissipated energy, falling weight deflectometer time histories are used to evaluate the pavement contribution to rolling resistance. Such analyses include all layers in the structure including the subgrade, so in the present case a way of sorting the dissipation at various depths is investigated. Field data were collected from a site, at mid-life of the predicted design life. The failure was confirmed several years later, and the remaining life was compared with the assumption that the dissipated energy near the edge was enough to initiate the cracks within the actual time to failure. Conversely, the dissipation at the mid-slab position was below the limit. The data from the field test were also used as an input for a finite element model to see if it was viable to further improve the prediction. The method seems to be promising, but more data are needed as the present set only represents the mid-life status.