Search Results (13)

This study investigates the development of high-performance asphalt binders modified with Trinidad Lake Asphalt (TLA) and styrene–butadiene–styrene (SBS) polymers to enhance pavement durability under extreme climate conditions. A comprehensive evaluation of physical, rheological, and mechanical properties was conducted using Superpave performance tests, Multiple Stress Creep Recovery (MSCR), and a Dynamic Shear Rheometer (DSR). The results indicate that integrating 20% TLA significantly increases stiffness and rutting resistance by 51.7% compared to unmodified PG 64-22 asphalt, while 10% SBS improves elasticity and enhances elastic recovery by 85.3%. However, at 15% SBS, excessive viscosity was observed, reaching 13,000 cP at 135 °C, posing workability challenges and sampling challenges in the lab environment. The MSCR test confirmed that binders modified with 20% TLA and 15% SBS exhibited over 88% recovery and reduced non-recoverable creep compliance (J_nr < 0.01 kPa⁻¹), demonstrating superior resistance to permanent deformation. Additionally, low-temperature rheological testing (BBR at −12 °C) revealed that SBS incorporation mitigates excessive stiffness caused by TLA, improving the binder’s flexibility. These findings underscore the potential of TLA-SBS modified binders in achieving long-lasting, traffic-resilient pavements for extreme climatic conditions. Field validation is recommended to assess long-term feasibility in real-world applications. Full article

This study investigates the combined impact of Trinidad Lake Asphalt (TLA) and styrene–isoprene–styrene (SIS) on the performance of PG 64-22 asphalt binder. The study specifically examines how the addition of TLA and SIS affects the stiffness, viscoelastic properties, and ability to resist deformation of the asphalt binder, using the Superpave test method. The findings demonstrate that the addition of SIS improves the ability to withstand deformation, with the best results seen in the mixture containing 20% TLA and 5% SIS. This blend achieves a harmonious combination of stiffness, pliability, and ease of use. Increasing the SIS content to 10% and combining it with a 20% TLA greatly enhances resistance to rutting, but it also decreases workability. In addition, a mixture consisting of 10% TLA and 10% SIS provides excellent resistance to fatigue and possesses viscoelastic properties that are well suited for reducing oxidative aging and cracking. Although SIS typically enhances the performance of binders, an excessive quantity can result in unwanted rigidity, requiring meticulous optimization. The results highlight the importance of customizing TLA–SIS combinations according to specific environmental conditions in order to optimize advantages. Subsequent studies should investigate the prolonged impacts and alternative combinations of additives to further improve the performance of binders. Full article

This study investigates the transformative effects of incorporating Trinidad Lake asphalt (TLA), crumb rubber modifier (CRM), and the warm mix additive leadcap (LC) into petroleum-based asphalt binder PG 64-22. Our results show that LC significantly reduces binder viscosity, leading to easier application and lower energy consumption, especially when combined with TLA and CRM. The addition of TLA and CRM enhances rutting resistance, with notable improvements in both pre- and post-aging conditions, particularly in formulations combining PG 64-22, 20% TLA, and 10% CRM. These formulations exhibit superior performance metrics, such as increased percentage recovery (% rec) and reduced non-recoverable creep compliance (J_nr), indicating improved flexibility and deformation resistance. Furthermore, LC balances increased rigidity and susceptibility to fatigue cracking from higher TLA and CRM levels, respectively. These modifications also promote environmental sustainability by reducing energy usage and emissions during production and paving. This study highlights LC’s critical role in advancing high-performance, eco-friendly warm mix asphalt binders, offering valuable insights for sustainable pavement engineering and setting a new benchmark for advanced asphalt technologies. Full article

This research investigates the synergistic impact of Trinidad Lake Asphalt (TLA) and Crumb Rubber Modifier (CRM) on the performance characteristics of PG 64-22 asphalt binder. Employing Superpave test analysis and Multiple Stress Creep Recovery (MSCR) testing, our study reveals that the incorporation of TLA significantly elevates the viscosity of the binder due to its high asphaltene content. This viscosity enhancement translates to increased stiffness and durability of the asphalt binder. Furthermore, CRM contributes to improved elasticity and deformation resistance, counterbalancing the stiffness induced by TLA. Our results indicate that the combined use of TLA and CRM not only boosts viscosity but also mitigates stiffness, thereby enhancing the binder’s resistance to rutting, especially post-aging. However, an elevated concentration of TLA increases the risk of fatigue cracking, a concern effectively alleviated through the integration of CRM. At a critical temperature of −12 °C, Bending Beam Rheometer (BBR) tests demonstrate that TLA augments stiffness while CRM enhances low-temperature flexibility. This study underscores the necessity of optimizing TLA and CRM ratios to achieve a balance between enhanced performance and practical feasibility. The findings highlight the potential of TLA and CRM to substantially improve asphalt binder performance, contributing to the longevity and resilience of pavement structures. Full article

This study delves into the transformative effects of Trinidad Lake Asphalt (TLA) on asphalt binders, revealing significant improvements in various performance metrics. Our findings indicate that TLA substantially increases binder viscosity and enhances rutting resistance, as evidenced by elevated G*/sin δ values in both original and RTFO-aged states. TLA-modified binders demonstrate superior rheological properties, including improved J_nr and percentage recovery, indicating enhanced resistance to permanent deformation and reduced fatigue cracking. However, an increase in TLA content correlates with higher G*·sin δ values, suggesting a trade-off with fatigue resistance and a higher susceptibility to cracking. Additionally, while TLA initially improves binder flexibility at low temperatures, excessive content can increase stiffness, adversely affecting stress relaxation properties. Notably, TLA enhances storage stability, ensuring minimal phase separation and excellent homogeneity. These insights underscore the need for the precise control of TLA content to optimize pavement durability. Future research should focus on fine-tuning TLA incorporation with additives like crumb rubber to maximize the structural integrity and longevity of asphalt pavements. Full article

Natural asphalts (NAs) can be an economical and environmental alternative in pavement construction. Most studies have investigated them as binder and asphalt mixture modifiers due to their high compatibility with conventional asphalts. In this article, some of the studies carried out on the use of NA in pavements are summarized and described in a chronological order. The main aspects described in the reviewed studies were the type of asphalt binder or modified mixture, the type and content of the modifier, the manufacturing processes of the asphalt or modified mixture, tests performed, and main results or conclusions. In general terms, NAs show better performance as binder and asphalt mixture modifiers in high-temperature climates. Additionally, they tend to improve water and ageing resistance. As main limitations, it is reported that NAs tend to negatively affect the workability and performance of asphalt mixtures in low-temperature climates. Finally, recommendations for future study topics are provided at the end of this paper. Full article

As more persons are adjusting to home working in light of the COVID-19 pandemic, there has been a significant increase in the use of technology. Trinidad and Tobago, like many other Small Island Developing States, began exploring strategies in the areas of recycling and reuse techniques to mitigate negative environmental impacts from the disposal of waste toners. The reuse of waste toners as a performance enhancer in bituminous materials has successfully been achieved in foreign jurisdictions; however, the lack of research on the utilization of the indigenous Trinidad Lake Asphalt (TLA) and Trinidad Petroleum Bitumen (TPB) has stymied the application of this strategy locally. The influence of four waste toners (A, B, C, and D) on the rheological properties of an unmodified TLA/TPB paving binder was measured using the dynamic shear rheology (DSR) testing technique. The addition of waste toners noted improvements in the rheological parameters of stiffness, elasticity, and viscosity, exhibiting superior temperature susceptibility. Of great interest was the observation at 90 °C, where the modified paving binders containing 5% Toner C and 20% Toner D were elastically superior to the world-renowned TLA. This study demonstrated the potential of utilizing waste toner as a bitumen modifier, providing an innovative, sustainable disposal option. Full article

In order to systematically study and develop a type of gussasphalt (GA) mix with superior performance, namely GA-10; the effect of Qingchuan Rock Asphalt (QRA) and Trinidad Lake asphalt (TLA) on the GA-10 mix was assessed based on the study of composite natural asphalt modified gussasphalt (CNAMGA) binder. Various analytical tests were used to evaluate the engineering properties, thermal stability and microstructure of CNAMGA mix. The results indicate that the stability of QRA modified binder and TLA modified binder in the normal temperature range and the high temperature range have been improved, and the temperature susceptibility is reduced. The optimal asphalt–aggregate ratio of the GA mix is determined to be 9.7%, which has good high-temperature stability, low-temperature crack resistance and construction workability. The QRA mix has better high-temperature stability than the TLA mix, whereas the low-temperature cracking resistance of the TLA mix is better than that of the QRA mix. The two kinds of GA-10 mix have similar construction workability. The fact that the abundant fine aggregates wrapped in binder fill the coarse aggregates surface contributes to the better adhesion of the GA asphalt concrete. The distribution of aggregate and binder is relatively uniform with fewer pores, and the overall proportion of the binder is greater than that of aggregate. Full article

Mastic asphalt (MA) has been particularly popular in recent years for bridge pavements due to many advantages such as easy application, good waterproofing properties, and high durability. However, the drawback of mastic asphalt in comparison to other asphalt mixtures is its lower resistance to permanent deformation. Trinidad Lake Asphalt (TLA) is often applied to make mastic asphalt resistant to permanent deformation. Practical experience demonstrates that serious failures may occur if MA pavement design and materials selection is not taken into account sufficiently. Therefore in this study, the influence of two parameters: zero shear viscosity (ZSV) of TLA-modified binder and mastic composition described by the filler–binder ratio, on the permanent deformation resistance of the MA mixture was evaluated. The primary purpose of determining the ZSV of the TLA-modified binders was to evaluate the rutting potential of the binders. The permanent deformation (rutting) resistance of the MA mixtures was evaluated based on static and dynamic indentation tests. The optimum content of TLA in the base bitumen and the optimum filler–binder ratio in the MA mixture were obtained based on multiple performance evaluations for modified binder, mastic and MA mixtures, i.e., 20% and 4.0, respectively. Full article

Increasing the content of reclaimed asphalt pavement material (RAP) in hot-mix recycled asphalt mixture (RHMA) with a satisfactory performance has been a hot topic in recent years. In this study, the performances of Trinidad lake asphalt (TLA), virgin asphalt binder, and aged asphalt binder were first compared, and then the modification mechanism of TLA on virgin asphalt and aged asphalt was explored. Furthermore, the RHMA was designed in accordance with the French norm NF P 98-140 containing 50% and 100% RAP, and their high-temperature stability, low-temperature cracking resistance, and fatigue performances were tested to be compared with the conventional dense gradation AC-20 asphalt mixture. The results show that the addition of TLA changes the component proportion of virgin asphalt binder, but no new functional groups are produced. The hard asphalt binder modified by TLA has a better rutting resistance, while the fatigue and cracking resistance is lower, compared to both aged and virgin asphalt. The high-modulus design concept of RHMA is a promising way to increase the RAP content in RHMA with acceptable performance. Generally, the RHMA with 50% RAP has similar properties to AC-20. And, when the RAP content reaches 100%, the high- and low-temperature performance and anti-fatigue performance of RHMA are better than AC-20 mixture. Thus, recycling aged asphalt using hard asphalt binder for hot-mixing recycled asphalt mixture to increase the RAP content is feasible. Full article

The application of various modifiers has emerged in recent years to improve conventional petroleum-based bitumen properties. The natural asphalt called Trinidad Lake Asphalt (TLA) has been applied very often due to its consistent properties, high viscosity and density, and superior rheological properties, and effective blending with other bitumen. However, most studies on TLA-modified binders always focused on physical and rheological properties in the original (unaged) condition, but the details about aging properties are often neglected. This study aimed to investigate the effect of short-term aging on the physical and rheological characteristics of the 35/50 base bitumen modified by the addition of two different TLA contents. The conventional physical tests and dynamic shear rheological tests were undertaken before and after aging to measure the penetration and softening point, complex shear modulus, and phase angle of the modified binders, as well as to calculate the zero shear viscosity using the Cross model fitting procedure. Based on the results of the above-mentioned comprehensive testing, the effect of aging on TLA-modified binder properties was evaluated using aging indices, as well as a direct comparison of results. The tests revealed that the short-term aging of TLA-modified binders did not worsen or reduce the pavement resistance to permanent deformation or the load-bearing capacity of the asphalt mixture. Full article

Mastic asphalt (MA) has been recognized as one of the most deformation-resistant and thus durable materials for bridge pavement. The performance properties of MA are highly dependent on the physical and rheological properties of the binder applied in the MA mixture. To modify the binder properties to obtain the expected performance of the MA mixture, Trinidad Lake Asphalt (TLA) is often applied. In this study, the TLA-modified binders to be used in mastic asphalt bridge pavement systems were evaluated to develop the optimum material combination using conventional and performance-related testing. Physical and rheological tests were carried out on TLA-modified binders with the different modifier content in the range of 10–50% on a weight basis. The tests revealed that the TLA modifier addition to the 35/50 base bitumen should be close to the value of 20%. Higher concentrations of TLA may make the binder very stiff and could induce low-temperature cracks in mastic asphalt. Full article

As bituminous binders greatly influence the engineering performance of gussasphalt concrete for bridge deck pavement, selecting appropriate bitumen is a critical procedure for mixture design. In this study, five different combinations of bituminous binder for potential use in the “Hong Kong–Zhuhai–Macao Bridge” project were prepared and tested. To meet the strict requirements of quality control, a new Guss-Mastic Asphalt (GMA) system was developed. Three key indices, Lueer fluidity, impact toughness, and dynamic stability, were used for GMA design and construction quality control. The test results show that the fluidity of the GMA mixtures was affected by the shear thinning phenomenon. After mixing for three hours, the Lueer value of all GMA mixtures met the requirements of pouring construction. Moreover, it was found that the influence of mixing time on GMA with styrene butadiene styrene (SBS) modified bitumen was different to other prepared mixtures. This difference is ascribed to the degradation of SBS during the blending process at an elevated temperature. Finally, the blended bitumen (30% Pen60/70 + 70% Trinidad lake asphalt (TLA)) was applied to the project of the Hong Kong–Zhuhai–Macao Bridge. Full article