Haryati Yaacob

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.

Potentials of steel slag and copper mine tailings as construction materials

Abstract The present rate of utilisation of mine waste in a country like Malaysia is rather below expectation compared with some advanced countries. Many studies concentrate on a better way to increase the usage of industrial byproducts in order to ease disposal problems. Enormous quantities of steel slag and copper mine tailings are deposited in yards, polluting the environment. Researchers need to pay attention to the effective use of industrial byproducts in construction to address economic and environmental concerns. The potential uses of copper mine tailings and steel slag need to be explored and the negative impact of mine tailings should be reduced by exploring potential uses of these waste materials in the construction industry. Although copper tailings have negative effects on the environment owing to their acidic content, they also have some great economic value in terms of valuable metal contents. The engineering properties of steel slag and copper mine tailings were reviewed and their various areas of application are highlighted.

Characterisation and utilisation of steel slag for the construction of roads and highways

Abstract Steel slags are by-products from steel industries which can be used for the construction of roads and highways. Most of the physical and mechanical properties of steel slags are similar or better compared to conventional crushed stone aggregates. Most of the developed countries have successfully incorporating steel slags as an aggregate in hot mix asphalt, road base, sub-base and soil stabilisation in road works. This paper is a review of the physical, mechanical and chemical characteristics of steel slags and its utilisation in road pavement works. This paper highlights the flaws that need to be addressed, and further studies are required to develop an understanding of the potential of steel slag as a construction material. Hydrophobic property of steel slag provides a good adhesion with bitumen binder and helps to resist against the stripping and other defects of roads. Thus, it enhances a sustainable cost-effective green pavement in highway industry.

Noise Produced By Transverse Rumble Strips: A Case Study on Rural Roadways

Transverse roadway strips (TRS) are a common approach used by the local authorities in Malaysia for the purpose of road safety on rural roadway. However, there were complaints made by residents about the excessive noise pollution produced by TRS. The objective of this study was to evaluate the external noise produced by the application of TRS, to evaluate and to anticipate the annoyance response due to installation of TRS. The investigations were carried out through the changes of noise level indices, estimation of the annoyance response using the traffic noise index (TNI) and anticipation of resisident response anoyance. Measurements of the external noise level produced by the TRS were taken for two hours at two location with and without TRS. Results showed that TRS increased the equivalent noise level, LAeq1hour, L101hour and L901hour by as much as 14 dB(A), 16 dB(A) and 9 dB(A) respectively. TNI values also increased as much by as 42% and exceeded the suggested value for planning purposes of 74 dB (A) for 3% annoyance from the social surveys. This investigation shows that TRS noise has a very strong impact on the community and this was the reason behind the complaints made by people living in study area.

Effect of Charcoal Ash Coconut Shell from Waste Material at Different Size on the Physical Properties of Bitumen

Environmental pollution caused by abundant wastes from agricultural activities has increased in recent years because of increased productivity. Agricultural waste recycling has been employed to solve this problem. Coconut shell charcoal (CSC) ash is a by-product of coconut shell (CS) used as a bitumen modifier to enhance the properties of the binder. This study investigated the effect of fineness charcoal ash from CS on the rheological properties of bitumen. Penetration, softening point, and viscosity tests were performed to determine the properties of the binder. Laboratory simulation of aging called rolling thin film oven test was applied in this study. CSC at different sizes (< 75μm, 75–150μm, and 150–300μm) was added to replace bitumen 60/70 PEN at 0%, 10%, 15%, and 20% by weight of the binder, respectively. Result showed that the bitumen became more viscous and that the softening point of bitumen increased, whereas the rate of penetration decreased when CSC was incorporated. CSC at a proper amount improved the resistance of bitumen to temperature susceptibility. In addition, the modification of bitumen can relieve the effect of aging. Modified bitumen shows better result when incorporated with the finest particle (< 75μm) of CSC compared with other sizes.

Curing of Asphalt Emulsified Tack Coat Subjected to Malaysian Weather Conditions

Curing of asphalt emulsions ensures the proper strength development of the material with the evaporation of water. This paper focuses on determining the minimum curing time needed for Malaysian asphalt emulsions. Three factors, including curing conditions (indoor, outdoor, and curing at night), asphalt emulsion types (RS-1k, RS-2k, RS-2kL, RS-3k, Ralumac, and SRSB) and application rates (high, medium, and low), were investigated. The curing time was determined by weighing a specimen repeatedly at a certain time interval until a constant weight was achieved. Statistical analysis of analysis of variance (ANOVA) was also performed to study if there are differences between groups of variables. From the results, it was found that curing conditions incorporating weather characteristics (i.e., wind speed, temperature, relative humidity, and solar radiation) are the most significant factor affecting the curing time of a particular asphalt emulsion. Curing of asphalt emulsions for construction at night proved to be unworkable due to the absence of solar radiation with relatively low temperature and high relative humidity. On the other hand, a low application rate of asphalt emulsions generally cured faster regardless of the curing conditions and asphalt emulsion types.

Performance of warm-mix asphalt in the highway industry

Abstract Warm-mix asphalt (WMA) technologies could address the problem of deterioration of roads, reduce escalated energy costs and increase environmental awareness. This technology allows significant reduction in temperature for construction and paving of roads compared to conventional hot-mix asphalt (HMA) paving. In HMA production, the quarry mixing and paving temperatures are equivalent to bitumens viscosity of 170 and 280 cP, respectively, for a proper coating of aggregates and field paving. But in WMA, the viscosity of bitumen is reduced and increases the workability of the mixture. Sasobit and asphamin are the two major additives used with bitumen or in batching plant for the production of WMA. Besides, complex shear modulus (G*) is used to determine the rutting (G*/Sinδ) and fatigue factors (G*Sinδ) to control the deterioration of roads. A further study is needed to monitor the overall performance of WMA in the context of pavement temperature.

Effect of grinding period on physical properties of modified bitumen using palm oil fuel ash (POFA)

Malaysia is having rapid economic development in recent years, and this has placed high performance demand on its highway infrastructure. The increased in number of traffic has led to severe pavement deterioration. Due to this, better and stronger pavement materials are needed in order to cater the increasing number of axle loading. Palm oil fuel ash (POFA) which comes from the ash of burning mesocarp of the palm oil fruitlets has been used as a modifier to improve the properties of bitumen. POFA is a biomass that had pozzolanic properties (siliceous material). By using POFA in bitumen, it will promote sustainability and lesser landfill to dump this waste. The objective of this research is to evaluate the effect of grinding period of POFA and different percentage of POFA towards physical properties of modified bitumen. A few sets of samples of POFA modified bitumen at different grinding time and POFA content have been prepared and tested with penetration test and softening point test. The microstructural characteristics of POFA were also investigated by using Field Emission Scanning Electron Microscope (FESEM). From the result, it shows that grinding time and POFA content does not influence the physical performance of the bitumen.

Effects of Kaolin Clay on the Mechanical Properties of Asphaltic Concrete AC14

This study investigated the effect of kaolin clay on the mechanical properties of asphaltic concrete AC14 through Marshall Stability, resilient modulus, and dynamic creep tests. Four replacement levels of kaolin clay (2%, 4%, 6%, and 8% by weight of the binder) were considered. Kaolin clay functioned as an effective filler replacement material to increase the mechanical properties of asphalt mixtures. Asphaltic concrete with 2% to 4% kaolin clay replacement level exhibited excellent performance with good stability, resilient modulus, and creep stiffness.

Effects of Waste Plastic on the Physical and Rheological Properties of Bitumen

Plastic disposal is one of the major problems for developing countries like Malaysia, at the same time Malaysia needs a large network of roads for its smooth economic and social development. The limited source of bitumen needs a deep thinking to ensure fast road construction. Therefore, the use of plastic waste in road construction not only can help to protect environment but also able to help the road construction industry. The aims of this research are to study the effects of waste plastic on rheological properties of bitumen. Modified bitumen was prepared by using blending techniques. Bitumen was heated and plastic waste was slowly added. Rheological properties of bitumen were performance by penetration, softening point, viscosity and direct shear rheometer test. The results showed that when content of plastic waste increase, the penetration value, softening point and viscosity of bitumen also increase. Generally, plastic waste improves the performance of bitumen when it was added into bitumen. It can be said that the usage helps to improve the performance of the road pavement which also reduces the rutting effect.