Publications
A comparative assessment of the physical and microstructural properties of waste garnet generated from automated and manual blasting process
Jan 15, 2021Journal Case Studies in Construction Materials
Publisher Elsevier
DOI https://doi.org/10.1016/j.cscm.2020.e00474
Cold mix asphalt (CMA) is an eco-friendly sustainable asphalt mixture, mostly for asphalt surface treatments (ASTs). However, material compatibility and poor adhesion leading to high voids, moisture damage susceptibility, and weak early strength remain challenging. Efforts to solve this limitation is beamed towards binder improvement and modification with modifiers, adhesion promoters, or polymers. Other forms of AST mixture improvement entail supplementary cementitious reinforcing or pozzolanic agents in the form of by-products. In this study, the physio-mechanical and microstructural desirability of spent garnet for use as fine aggregate in CMAwas explored. Spent garnet is a by-product of abrasive blasting, often produced in large quantities and disposed of in landfills. Often, spent garnet waste gets contaminated with toxic elements either during usage or in landfills. This study aimed to investigate the properties of Automatically (AG) and Manually generated (MG) spent garnet grades. The physio-mechanical, morphologic, and chemical parameters of spent garnet were assessed to achieve this aim. The result compared with relevant specifications on cold mixtures plus Jabatan Kerja Raya (JKR) requirement. Moreover, crystallinity and composition were studied using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and X-ray Fluorescence (XRF). The presence of toxic heavy metals that often contaminate spent garnet deposits in landfills was evaluated too. Results suggested that both AG and MG’s high sand equivalent and least water absorption of 98 %, 89 %, and 0.14 %, 0.2
A review on the usage of waste engine oil with aged asphalt as a rejuvenating agent
Jan 15, 2021Journal Materials Today Proceedings
Publisher Elsevier
DOI 10.1016/j.matpr.2020.12.330
The use of reclaimed asphalt pavement (RAP) has been becoming one of the best solutions to preserve natural resources in the construction sector. However, the stiffness property of aged asphalt resulted from the RAP is considered as the main obstacle in the field application. Nevertheless, waste engine oil (WEO), as one of the most common rejuvenating agent, has been used for renovating the characteristics of aged asphalt. This paper presents a review of the previous research works conducted on the rejuvenating of aged asphalt using WEO, including its benefits, drawbacks and its adverse side effect. It was observed that the inclusion of WEO as a rejuvenating agent gives positives and negatives influences on the attributes of aged asphalt. Therefore, an integration of WEO with other modifiers might be beneficial for renovating the performance of aged asphalt at both low and high temperatures. The results of this review can be used to predict future challenges in the renovation of aged asphalt using WEO.
The tailored traits of reclaimed asphalt pavement incorporating maltene: performance analyses
Oct 15, 2020Journal International Journal of Pavement Engineering
DOI 10.1080/10298436.2020.1824294
Environmental issues and fluctuations in the price of asphalt binders have increased the demand in usage of reclaimed asphalt pavement (RAP) material for asphalt mixtures. The RAP binder, nevertheless, is often highly aged and has several drawbacks, for instance, low cracking resistance, low workability, and low fatigue in the resulting mixtures. These issues can be resolved by using rejuvenators. As such, this research work assessed the engineering properties of reclaimed hot-mix asphalt (HMA) mixture rejuvenated by maltene-derived asphalt. The tests examined Marshall properties, moisture damage, resilient modulus (M R), dynamic creep, Cantabro loss, and rutting resistance, including the stripping and coating tests. The results showed that maltene had been effective in mitigating the aging effect of RAP asphalt, while the rejuvenated mixture exhibited considerable enhancement, especially when compared to the virgin and RAP mixtures without maltene. A simple cost analysis revealed that maltene was cost-effective as it compensated for the adverse effects of RAP, hence can be used to raise the content of RAP in asphalt mixture.
Evaluating the Chemical and Rheological Attributes of Aged Asphalt: Synergistic Effects of Maltene and Waste Engine Oil Rejuvenators
Aug 15, 2020Journal Arabian Journal for Science and Engineering
DOI 10.1007/s13369-020-04842-7
The service life of road pavement reduces as it ages and loses its properties due to the exposure to varying traffic loads and climatic conditions. This study explores the potential rejuvenation of the aged asphalt properties to enable it to be reused in pavement by adding hybrid rejuvenator (WEO-MLT). The WEO-MLT is composed of waste engine oil and maltene (MLT). Four types of binders, namely virgin asphalt, aged asphalt, 40% aged asphalt and rejuvenated asphalt, were prepared and evaluated via rheological and chemical tests [e.g. storage stability, asphaltene-to-MLT ratio, dynamic shear rheometer, bending beam rheometer, Fourier transform infrared (FTIR), thermogravimetric analysis and stripping resistance tests]. The results revealed that the WEO-MLT markedly enhanced the properties of aged asphalt at low and high temperatures. In contrast, the outcomes of FTIR suggested that the ageing properties of asphalt were not improved significantly by WEO-MLT due to the presence of a carboxyl group in its composition. TGA indicated that the initial decomposition for rejuvenated asphalt was approximately close to virgin asphalt. The stripping resistance test divulged the comparable performance of the rejuvenated asphalt to that of virgin asphalt. Therefore, WEO-MLT can be potentially used in the rejuvenation of the aged asphalt, paving the way to sustainable and eco-friendly asphalt production.
The influence of nano-carbon from coconut shell ash as modifier on the properties of bitumen
Aug 15, 2020Journal Road Materials and Pavement Design
DOI 10.1080/14680629.2020.1809502
Nanomaterials are small-sized materials between 1 and 100 nm which produce a greater surface area than common size materials. Coconut shell is one of the potential agricultural wastes to be used as nanomaterial due to its high strength and hardness. However, poor adhesion bonding was the problem of using this agricultural waste material as a modifier in the bitumen matrix. Therefore, in this study nanocarbon from coconut shell ash (NCA) was produced as bitumen modifier. NCA was produced and characterised using various techniques prior to be utilised at 0.0%, 1.5%, 3.0%, 4.5%, 6.0% and 7.5% by weight of bitumen PEN 60/70. The rheological test, using a dynamic shear rheometer (DSR), was performed on the unaged, rolling thin film oven and pressure ageing vessel samples. Subsequently, X-ray diffraction and atomic force microscopy were performed on the unaged samples. The DSR results revealed that NCA improved the rutting and fatigue cracking parameter of the bitumen. Also, the observations from microstructure properties showed that NCA delayed the ageing of the bitumen, produced a homogenous structure and increased the cohesion and adhesion properties of the bitumen. As a result, a strong bonding between the NCA and bitumen was formed and the properties of bitumen were altered.
Rejuvenation of Hot Mix Asphalt Incorporating High RAP Content: Issues to Consider
Jun 16, 2020Journal IOP Conference Series: Earth and Environmental Science
DOI 10.1088/1755-1315/498/1/012009
The asphalt used to construct or rehabilitation roads often contains reclaimed asphalt pavement (RAP) in order to diminish not only the use of raw materials but also waste. However, when high level of RAP in hot mix asphalt (HMA) is used, the rejuvenating agents must be employed. A number of aspects must be taken into account to increase pavement service life as much as possible. Thus, the main issues related to the rejuvenation of asphalt mixtures with high levels of RAP are addressed in this paper. In particular, the focal points of this paper will focus on the use of reclaimed asphalt mixtures with maximum efficiency, special attention is paid to how the binder is structured and chemically composes, nature and dose selection of rejuvenator, as well as the diffusion, blending efficiency, homogeneity, time and temperature mixing. A review of the extant and related literature shows that RAP utilization holds promise for the sustainable pavements, provided that some issues were taken into consideration during the designing and application process.
Review on the potentials of natural rubber in bitumen modification
Jun 11, 2020Journal IOP Conference Series: Earth and Environmental Science
DOI 10.1088/1755-1315/476/1/012067
In recent times both natural and synthetic rubber were blended with bitumen with the hope of producing a more durable hot mix asphalt. Although the application of natural rubber (NR) in bitumen modification have started long time ago prior to crumb rubber; only few literatures that completely characterised its performance are found today. This review aims to remind researchers and paving agencies on the benefits of NR rubberised asphalt. The study draw attention to NR production process and its unique properties, how NR was used to solve four major asphalt pavement failures namely rutting, fatigue, thermal cracking, and moisture susceptibility. It also presents barriers limiting the application of NR in bitumen modification with possible solution. Lastly, the concept of applying NR in warm mix asphalt was introduced.
A review on rejuvenating materials used with reclaimed hot mix asphalt
Feb 17, 2020Journal Canadian Journal of Civil Engineering
Publisher Canadian Science Publishing
DOI 10.1139/cjce-2019-0635
In recent years, flexible pavement construction technology has relied heavily on the use of reclaimed asphalt pavement (RAP). However, the brittle nature of RAP, which stems from the use of an aged asphalt, has introduced numerous complexities into the process, with important implications to pavement service life. The properties of the aged asphalt can be rejuvenated to improve the performance and the behavior of RAP mixtures. This paper presents a review of past works that have used rejuvenating materials with RAP, including their benefits and drawbacks, as well as the optimal approach to increase RAP content in asphaltic mixtures. The method of rejuvenating aged asphalt and the mechanism of rejuvenation are also reviewed. The findings of this review can be used to predict the current and future challenges in the regeneration of RAP mixtures using rejuvenating materials.
Restoration of Aged Bitumen Properties Using Maltenes
Jan 3, 2020Journal IOP Conf. Series: Materials Science and Engineering
DOI 10.1088/1757-899X/713/1/012014
Reclaimed asphalt pavement (RAP), a material frequently used in asphalt mixtures, is associated with several environmental and economic advantages. Many existing road construction technologies are capitalising on the availability of recycled materials. This study has looked on the usage of maltene as a rejuvenator in aged bitumen. Bitumen with Pen 60-70 was chosen as the control binder. Maltene was added into the aged bitumen at various concentrations (5%, 10%, and 15%) by weight of total binder. The characteristics of rejuvenated bitumen were examined with penetration, softening point, penetration index (PI), viscosity, and storage stability. As the maltene concentration increased, aged bitumen characteristics improved, while the level of stiffness reduced. Mixing temperature and time were significantly linked to the efficiency of blending between aged-virgin binders. Lower mixing temperatures undermined the diffusion of the virgin bitumen into the aged binder, thereby impairing blending efficiency. The results indicate that 15% of maltene can rejuvenate the properties of aged bitumen.