Mohd Khairul Idham

Effect of Aging on Resilient Modulus of Hot Mix Asphalt Mixtures

Asphalt hardens as a result of an aging process. This study was undertaken to determine the effect of field aging simulated by laboratory aging method of different hot mix asphalt (HMA) mixture. Three types HMA mixtures were used for this study namely Asphaltic Concrete with 10 mm nominal maximum aggregate size (AC 10), Aspaltic Concrete 28 mm (AC 28) and Porous Asphalt 10 mm (PA 10). The resilient modulus test was carried out as an indicator of the performance at a 25 °C and 40 °C. Generally, all samples show similar trend which aged mixture produced slightly higher resilient modulus compared to unaged mixture while an increase in temperature from 25 °C to 40 °C might reduced the resilient modulus up to 88%. This study also found that the difference increment of resilient modulus after the aging process attributed by asphalt content, air void and gradation of respective mixtures.

Effect of Chemical Warm Asphalt Additive on the Rutting Characteristic of Aged Binder Containing Waste Engine Oil

This paper presents a laboratory study on the effect of chemical warm asphalt additive on the rutting characteristic of aged binder containing waste engine oil. The aged binder and waste engine oil were blended with 0%, 1%, 2% and 3% of chemical warm asphalt additive. The samples were tested for rutting characteristics (rutting resistance, G*/sin  and creep recovery) using Dynamic Shear Rheometer (DSR). G*/sin  was tested at temperature 64°C and creep recovery was tested at temperature 60°C under stress of 50 Pa. The results showed that the chemical warm asphalt additive slightly decreased the rutting resistance of the aged binder containing waste engine oil sample. Meanwhile, the elasticity of asphalt binder was improved with the addition of additive by the reduction of creep compliance. As a conclusion, results of the testing showed that chemical warm asphalt additive could be applied with aged binder and waste engine oil with the satisfactory performance.

Effect of different sizes of palm oil fuel ash (POFA) towards physical properties of modified bitumen

In the past decades, numerous numbers of studies have been carried out to find ways enhancing properties of bitumen. Other than using polymer, agricultural waste such as palm oil fuel ash (POFA) is one of the waste products that can be used to modify bitumen. In this study, the physical and rheological properties of POFA modified bitumen were examined based on different grinding hour and different percentage of POFA. The bitumen were mixed with different percentages of POFA (0, 5 and 7%) which passed through 0.075 mm sieve and grinded at different period (1 and 4 hour). The samples were then tested and compared to conventional bitumen. From TEM results, POFA grinded at 1 hour have sizes between 3-7 µm while POFA grinded for 4 hours have finer sizes between 500 nm to 3 µm. The results showed that fineness of POFA affect properties of bitumen significantly. Modified bitumen becomes harder than conventional bitumen thus decreasing in penetration value and increasing in softening point temperature. Modified bitumen gives best results when added with 7% POFA sizes of 500 nm to 3 µm compared to 3 to 7 µm.

Thin cold-mix stone mastic asphalt pavement overlay for roads and highways

Abstract This paper presents the latest development in the design of thin cold-mix stone mastic asphalt (SMA) pavement using modified bitumen emulsion that addresses the topmost global issues, environmental pollution and energy crisis. The hot-mix asphalt (HMA) pavement is generally known to have higher strength and is more durable compared to others, but have some disadvantages on environment, economy and safety-related issues. Cold-mix asphalt (CMA) pavements are widely used because of its simple technique and easy to construct. Currently, there are no established standards and specifications of mix design for CMA, especially for gap-graded pavement in Malaysia, and the laboratory test results are inconsistent. The use of 4·75mm nominal maximum aggregate size (NMAS) for the HMA has the highest potential for preventive and reactive maintenance of roads. Further study is needed to design and develop 4·75mm NMAS cold-mix SMA pavement in order to achieve and produce a cost-effective sustainable pavement.