Before new asphalt can be laid, its existing surface must first be cleared away using large machines like forklifts and bobcats. Select the best Arlington Asphalt Paving.
Sub-base layers provide your asphalt pavement with strength and stability, and getting this step right is absolutely critical to its lifespan.
Sub-base
Sub-base layers play a critical role in providing essential support and stability to asphalt pavements, helping prevent sinking and cracking over time. They typically consist of crushed stone layers depending on your pavement type – these essential layers help prevent cold weather damage to ensure that asphalt stays strong under traffic loads.
An effective sub-base must be compacted using either a plate compactor (Wacker plate) or roller to ensure there are no air pockets and that the sub-base has sufficient “tightness,” with few surface voids but rather a smooth-ish aggregate with finer textures.
Gradation and composition of aggregate for use as sub-base material are of vital importance when creating a permeable sub-base system, as this will have an impactful influence on load-carrying capacity, drainage, frost susceptibility, and permeability. Ideally, sub-base aggregate should consist of coarse material with minimum flat or thin particles and an abundance of rounder fragments rather than sharp-angled ones.
Once the sub-base has been appropriately compacted, your contractor will perform what is known as a ‘proof roll’ – an inspection with a heavy truck to see if there are any weak areas that need addressing before moving forward with further steps. Once tested successfully, it can go on to create its base course.
Base Course
Once the sub-base has been adequately prepared and compacted, an asphalt base course must be laid as a stable foundation for your new pavement. This layer must support traffic loads as well as weather conditions, resist rutting and settlement, and resist rutting and settlement. Your paving contractor may conduct a proof roll test on this base course to make sure it reaches 92%-98% density for maximum performance.
Asphalt base courses come in two primary forms: dense-graded and open-graded. DGB utilizes various aggregate sizes compacted together into an even surface, while an open-graded base (OGB) features more open structures with interconnected voids to allow water drainage freely.
Once the base course has been laid down, a heavy roller must be used to ensure all air pockets have been eliminated and asphalt compacted fully – this step is especially essential as a poorly compacted asphalt base may damage your new pavement surface.
Temperature controls must be strictly observed throughout the production of HMA, as overheating can compromise its structural integrity. Paving contractors should always work closely with HMA producers and understand their asphalt mix recipe; additionally, they must perform quality control testing using Marshall and Hveem test methods in order to verify that the material has been mixed, placed, and compacted correctly.
Surface Course
Once the subgrade has been cleaned up and graded, it’s ready for installation of its initial layer of asphalt – the base course. This layer should be installed directly over the compacted subgrade and provides a sturdy foundation for further pavement structures – as well as helping ensure water drains away without pooling up on your pavement and causing any further damage.
A base course consists of aggregate, sand, and crushed rock mixed or bound with asphalt (Asphalt Base Course). Its primary function is to distribute traffic and environmental loads evenly without creating excessive stresses or fatigue on unbound layers below it; for this to work effectively, it requires having high stiffness resistance deformation as well as easy mixing/placing capability.
Once the base course is installed, it must be compacted using a heavy roller known as proof rolling to ensure even coverage and to check for soft spots or unstable areas that should be repaired immediately if discovered. This step provides a substantial and long-term finished product.
Binder
Once the sub-base is in place, it must be graded and compacted to ensure a level surface to support asphalt paving. This includes checking for soft spots that need repair. Once this step has been completed, hot asphalt can be placed atop it – this layer features small aggregates such as crushed stone mixed with sand and asphalt binder for its jet-black hue and smooth rideability.
Once a custom mix of asphalt has been designed for a project, its production in an asphalt plant ensures it has the appropriate consistency and quality for this particular task. Asphalt mixtures typically consist of natural aggregates, recycled materials, and additives blended with bitumen, all mixed into an impregnable base called bitumen.
Asphalt is then transported to the construction site and spread evenly using specialized equipment, a crucial step to avoid unevenness that could cause further damage, such as potholes. Once dry, this mat can then be compacted again using rollers to improve density, reduce voids, and create a more resilient surface that is resistant to environmental elements like rainwater.
At this step, employees wearing personal protective equipment must adhere to all necessary procedures in order to remain safe from falling debris or other potential dangers. Such equipment could include safety vests, hard hats, long-sleeved shirts, steel-toe boots, and gloves.
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