Frank Mi-Way Ni

The main objective of this study was to evaluate the applicability of the “Quiet Pavement” concept under Florida’s unique weather and field conditions. The long-term field performance of three open-graded friction courses (OGFCs): FC-5 with PG 76-22 polymer-modified asphalt (PMA) binder (Control), FC-Q with ARB-12 binder, and FC-Q with PG 76-22 PMA binder was assessed using 16 years of comprehensive pavement data, including tire/pavement interaction noise (OBSI), rutting, cracking, raveling, friction, macrotexture (MPD), and ride quality (IRI). Results showed that FC-5 exhibited the highest initial noise levels and experienced the most severe surface deterioration, with crack ratings reaching failure thresholds and extensive raveling over time. FC-Q ARB-12 demonstrated stable, long-term performance, maintaining consistently lower noise, moderate macrotexture growth, and superior resistance to surface distress potentially because of its higher binder content. FC-Q PMA delivered moderate performance with more variability in noise, IRI, and surface distress indicators, falling between FC-5 and FC-Q ARB-12 with regard to performance. The observed performance justifies the adoption of the Quiet Pavement concept for Florida highways as an alternative of the traditional FC-5 mixture for reduced traffic noise and improved durability. The study also underscores the importance of ongoing monitoring in maximizing the benefits and lifespan of OGFC surfaces. Based on these results, FDOT has extended the Quiet Pavement study with new test sections using a finer 9.5 mm NMAS, seeking further improvements to the FC-Q mix design for even better performance in Florida’s challenging environment.

The Superpave mixture design method is currently the most prevalent design method for asphalt mixtures. However, its high-gyration levels often result in mixtures with lower asphalt binder content compared with earlier methods, leading to compaction and cracking issues and affecting the long-term performance and durability of asphalt pavements. To address these challenges, the concept of a low-gyration mixture was introduced by lowering designed number of gyrations and adjusting the volumetric requirements. Building on this concept, this project compared the performance of low-gyration asphalt mixtures (50 gyrations) with a Superpave mixture (100 gyrations) as the control mixture. This Superpave mixture is commonly used by the Florida Department of Transportation (FDOT). Full-scale accelerated pavement tests and laboratory tests were conducted at FDOT to evaluate the rutting, cracking, and durability performance of both mixtures. The results demonstrated improved compactability of the low-gyration mixture compared with the conventional Superpave mixture. At their target density levels, the low-gyration mixture exhibited better rutting resistance under field and laboratory conditions and showed lower sensitivity to air voids. Although improved cracking performance were observed in some low-gyration specimens, overall cracking and durability properties were similar between the two mixtures. The findings suggest potential benefits in pavement performance of low-gyration mixtures, particularly with regard to compactability, resulting in higher in-place density levels.

This study in Canada aimed to improve the performance of flexible pavements by comparing the in-place behavior of Lightweight Cellular Concrete (LCC) at three densities with traditional unbound granular material. The research investigated the effect of traffic load and testing temperature on pavement response and determined the structural layer coefficient for the 475 kg/m³ density. The structural layer coefficient for the LCC subbase at this density was 0.22. Results showed that pavements with LCC had over three times less stress at the top of the subgrade compared to the conventional granular material. The Weslea software, which uses a multi-layer elastic theory, appeared to overestimate stress responses for LCC pavements, and the research suggested a prediction modification for more accurate results. Overall, the study demonstrated that lightweight cellular concrete with different densities could improve pavement performance.

With the increasing price and carbon dioxide emission of cement comes the challenge of rigid pavement. One of the solutions to address this issue is minimizing the cementitious paste volume (CPV) of the concrete mix with the blended aggregates (BA) technique. This paper presents the effects of minimizing the CPV in Portland limestone cement (PLC) concrete with CPV reduction and BA application for Florida rigid pavement concrete. The findings indicated that reducing the CPV in the pavement concrete mix to some extent would not adversely affect the properties of the pavement concrete; the minimum CPV of PLC pavement concrete mixes can be reduced to 22.5% with no loss in the properties of fresh and hardened concrete. The other benefits of CPV reduction include low permeability and shrinkage strain. In summary, minimizing the CPV and utilizing the BA technique can be considered to design sustainable pavement concrete mixes with better pavement performance, lower materials costs, and lower global warming potential.

This study investigated the pore structure and its effects on mechanical properties of lightweight cellular concrete (LCC) in order to understand more and detailed characteristics of such structure. As part of investigation, environment scanning electron microscopes (ESEM) and industrial high-definition (HD) macro photography camera were separately used to capture and compare images of specimens. Physical properties of the pore structure, including pore area, size, perimeter, fit ellipse, and shape descriptors, were studied based on the image processing technology and software applications. Specimens with three different densities (400, 475, and 600 kg/m³) were prepared in the laboratory. Firstly, the effects of density on the characteristics of pore structure were investigated; furthermore, mechanical properties (compressive strength, modulus of elasticity and Poisson’s ratio, flexural strength and splitting tensile strength of LCC) were tested. The relationships among pore characteristics, density, and mechanical properties were analyzed. Based on the results obtained from the lab test—comparisons made between specimens with high-densities and those with low-densities—it was found significant variability in bubble size, thickness, and irregularity of pores. Furthermore, the increase of density is accompanied by better mechanical properties, and the main influencing factors are the thickness of the solid part and the shape of the bubble. The thicker of solid part and more regular pores of LCC has, the better mechanical properties are.

The simulation model used in this study is based on a construction project in Taiwan. In this study, STROBOSCOPE and EZStrobe were used as discrete-event simulation software to assess the potential risk of the construction in terms of time and cost. The construction process, the unit cost of the resources, and the operation time of each activity were modelled based on the actual construction procedure. A total of 30 replications was required for each scenario. Scenarios with real-world data inputs and eight other models were simulated using the software. The best scenario with the lowest cost and competitive time was selected as the base model for a sensitivity analysis. During the Sensitivity Analysis, the best model 8-R was generated by changing the number of labourers to 13 and Excavators to 3. Compared to the real-world project, the total costs were reduced by 11% and the total time was reduced by 58%. Moreover, the result of risk analysis based on scenario 8-R demonstrated that using a number of labourers, trucks, excavators, rollers, millers, and pavers less than the quantities that were used in the real-world data, the associated risk in term of cost and time will exceed the real-world project cost.

Pavement roughness has always been a concern for road users and highway agencies. The Directorate General of Highways (DGH), which administers the Taiwan Provincial Highways, stated that the maintenance lane-kilometres it manages increase daily. In recent years, the Taiwan government has been investing a great deal of money in social and health care services while decreasing annual funding for infrastructure. DGH is no exception to these budget-cutting efforts and now faces the challenge of how to maintain an acceptable level of pavement roughness with limited funding. With this challenge in mind, the main objective of this study was to explore pavement roughness under various maintenance funding levels for the Taiwan Provincial Highway. First, the researchers visited all five Taiwan pavement maintenance offices and several branches to collect roughness data, annual financial reports and expert opinions. Then, life-cycle cost analysis (LCCA), specifically RealCost LCCA software was used to estimate an annual minimum budget for DGH. Taiwan local and typical data were used in this analysis. The results of the LCCA conducted in this study indicated that DGH should be spending a minimum of 5.2 billion NTD per year on pavements to keep them in good condition.