The determination of pavement layer stiffness is an essential step in evaluating the performance of existing road pavements and in conducting pavement design and analysis using mechanistic approaches. Over the years, several methodologies involving static, dynamic, and adaptive processes have been developed and proposed for obtaining in-situ pavement layer moduli from Falling Weight Deflectomet...

This study evaluates the back calculation of stiffness of a pavement section on Interstate 40 (I-40)in New Mexico through numerical analysis. Falling Weight Deflectometer (FWD) test has been conducted on a section on I-40. Layer stiffness of the pavement has been backcalculated by a backcalculation software, ELMOD, using the FWD test data. Commercial finite element software, ABAQUS, has been us...

Occurrence of top down and bottom up fatigue cracking in asphaltic pavements is common. Conventional pavement analysis methods ignore the existence of cracks in asphaltic layers. However, it seems that the responses of cracked pavement would not be the same as a pavement without crack. This paper describes effects of crack type, position and length, and vehicles tire inflation pressure and axle...

This study reports the first complete mapping of the gill epithelium in a tilapia species. Different gill epithelial cell types of the Nile tilapia, Oreochromis niloticus L. have been identified and located using different antisera against mammalian proteins and various histochemical techniques: Periodic Acid Schiff (PAS), Alcian Blue pH 1.0, 2.5, 3.5, Giemsa and Grimelius. The results show tha...

The bituminous pavement rehabilitation alternatives are mainly overlaying, recycling and reconstruction. In the recycling process the material from deteriorated pavement, known as reclaimed asphalt pavement (RAP), is partially or fully reused in fresh construction. Some of the advantages associated with pavement recycling are (i) less user delay (ii) conservation of energy (iii) preservation of...

Many rural roadways in Iowa have centerline and/or edgeline pavement markings. The current Manual on Uniform Traffic Control Devices (MUTCD), however, requires centerline and/or edgeline pavement markings only along streets and roadways with traffic volumes much greater than 400 vehicles per day (the volume-based definition of a low-volume roadway in the MUTCD). This project was initiated to ga...

Each of pavements’ life cycle phases such as material extraction, transportation, construction, operation, rehabilitation, and end-of-life emits greenhouse gases. Such emissions can be influenced by climate change via changes in the rates of pavement deterioration and thus intensity and frequency of maintenance and rehabilitation. However, climate change has not been given full considerations i...

The coupling effect between tire and pavement is an intensively researched subject to analyse the dynamic interaction of the vehicle-pavement system. By considering the 11.00 R20 tire and expressway asphalt pavement, ABAQUS software was employed in this study to establish an improved model for simulating the coupling effect, in which the tire rubber was taken as a neoHookean material and the pa...

A new study showing a functional and physical interaction between the ROP effector RIC1 and the microtubule severing enzyme katanin brings together auxin signaling and microtubule ordering in Arabidopsis pavement cells.