To make your pavement last longer, you should consider bitumen-stabilized pavement. Learn about the different types of stabilizing agents, how to calculate stiffness modulus, and maintain a stabilized pavement. Here are a few of the top reasons. Listed below are some of the most common problems with asphalt-based pavements and the top solutions.
Factors to consider when choosing a bitumen stabilized pavement
When selecting a bitumen stabilized pavement for your project, there are several factors to consider. Choosing the right material for your project requires considering the purpose of your bitumen-stabilized pavement and traffic volume. Depending on the specific conditions, the durability and strength of your asphalt-stabilized layer may depend on different factors, including climate conditions. One other factor to consider is the cost of the additive.
One of the most important factors to consider is the rheological properties of the bitumen mixture. The composition of bitumen affects its durability. The more elastic bitumen is better for pavement applications, but it is not essential for all projects. The rheological properties of bitumen are affected by its amount of synthetic wax. For more information, check Global Technology now.
Properly stabilizing the soil is essential to a long-lasting pavement. While some agencies choose to dig out and replace the poor performing soils, the process may result in significant disturbance and disposal issues. Stabilization is an excellent choice for reducing these issues and improving the foundation’s structural support. Choosing a bitumen stabilized pavement for your project will benefit the environment and your budget.
Types of stabilizing agents
The type of stabilizing agent used in bitumen stabilized pavements largely depends on the traffic load and environmental conditions. Some stabilizing agents act as binder and cementitious agents, while others improve soils through chemical or physical reactions. Some admixtures require laboratory testing to verify their performance before they are used on a project, and others require field testing and good control in the application area.
Lime-flyash stabilization is best suited for soils with a plasticity index greater than 12 and is suitable for a wider range of soils. Lime-flyash stabilization has lower requirements on the fineness of soils, although durability studies have been limited. Hydrated lime is used in the form of a slurry or powder.
Depending on the stabilizing agent used, it is essential to understand its effect on the subgrade. Stabilized soil can improve subgrade strength, control moisture, and increase structural support. In addition, it reduces the permeability of soils and the tortuosity of water pathways, which can protect water-sensitive soils. While a stable subgrade is not a permanent solution, it is a worthwhile consideration.
Calculation of stiffness modulus
Various tests have been performed on bitumen-stabilized pavements to determine their stiffness modulus. The most common method to estimate this parameter is a deflection basin to determine the top surface stiffness. These measurements provide the equivalent resilient moduli of asphalt pavements. The resulting values are then used to modify the existing theory formula.
The stiffness modulus of bitumen-stabilized pavements is influenced by the thickness and density of the layers below. In addition, the higher the density of structural layers, the more likely the modulus ratio will be higher. However, a higher Poisson ratio is needed for highly plastic materials. If a subgrade is thin, the thickness of the surface layer will have to be less.
When comparing the top surface of a graded crushed stone transition layer with the top surface of a cement-stabilized crushed stone cushion, the calculated equivalent resilient modulus should be the same. In the same way, the thickness of the cement stabilized crushed stone layer should be within 12% of the top surface of the cushion. It is a relatively small deviation and meets the engineering application requirements.
Maintenance of a stabilized pavement
The stabilization process involved combining layers of pulverized materials with bitumen foam, and the mixture was then homogeneously mixed with water and cement. The process produced a bitumen-stabilized mix (BSM) that was graded and compacted. Cold recycling methods also require minimal maintenance. These methods are cost-effective and environmentally beneficial compared to new pavement materials, although they should be considered carefully due to their early life-cycle damage. The decision to use cold in situ recycling is based on the type of existing pavement, the expected traffic volumes in the future, and the availability of appropriate recycling plants.
Maintenance of a bitumen stabilized roadway involves proper base stabilization. It may be required for new road construction or part of a full-depth reclamation process to repair all levels of pavement damage. The stabilization process can be performed mechanically, chemically, or with asphalt additives. Often, a base stabilization project is a prerequisite for reconstructing new roads.
Generally, recycled roads require traffic reopening before installing the final wearing course. Until this process is completed, the roadway is exposed to the elements, which increases the risk of premature pavement failure. Common surface treatments for stabilized base courses are slurry, chip, micro-surfacing, and cape seals. Cold-mix overlays are common options, but best practices don’t change much for either.
