Salihudin Hassim

Determination of SMA Slab Properties Using a Newly Developed Roller Compactor (Turamesin)

Compaction of asphalt mixtures in the laboratory is critical to meaningful results. Over the years, several compactors were developed to closely simulate field compaction. However, none of the devices or equipment was found to effectively compact asphalt mixtures. Therefore, a new automatic roller compactor (Turamesin) was developed which is able to compact any asphalt mixtures to the required slab thickness and density. The machine was developed by researchers from the Universiti Putra Malaysia, under the Ministry of Science, Technology and Innovation. In this study, Stone Mastic Asphalt (SMA) mixture was selected. The study was carried out in order to establish criteria for slab compaction and explore the potential for the newly developed Turamesin for use in the SuperPave mix designs. A total of nine slabs were prepared with different combinations of compactive efforts. Data was collected and analyzed to determine the appropriate values of the compactive efforts that results in optimum performance of the asphalt mixture. It was observed that the compact slabs of asphalt mixture to a design air void of 4%, a compactive effort of applied pressure of 8.0 kgf/cm squared, and 75 passes of roller were required.

CHARACTERIZATION OF EFFECTIVE TIRE CONTACT AREA FOR VARIOUS TREAD PATTERNS

The effective tire-pavement contact area affects the relative damage of asphalt pavement and should be incorporated in both mechanistic and empirical response analyses of pavements. A new machine called ROTOCOM Wheel Tracker (RCWT) was designed and fabricated to capture the effective tire contact area apart from slab compacting, and conducting simulative laboratory wheel tracking tests. The main focus of this paper is laboratory measurement of effective tire contact areas for various tread patterns. Seven tire treads were selected for the footprint image analyses at five tire loads and four tire inflation pressures. An image processing MATLAB-based program was coded to calculate the contact areas of the 280 imprints obtained from both sides of the RCWT. Factorial analysis indicated significant effects of tire tread, tire load, and inflation pressure on the resulting contact area. Comparison between effective and traditional contact areas indicated that the current pavement design procedure with traditional circular contact area extremely overestimates the actual tire-pavement contact area up to 92%.

Effect of Steam Aging on Performance-Related Properties of Hot Asphalt Mixture

AbstractThis study presents a new laboratory technique for binder aging by using a steam cooker. This new technique is used to study the effect of steam and heat on asphalt during storage and aspha...