“Of the 2.8 million miles of paved roads in the U.S., about 94 percent are surfaced with asphalt,” says the National Asphalt Pavement Association. As construction enthusiasts at Kilgore Companies, we’ve always marveled at the process of creating smooth, durable roads that withstand the test of time. Among the many materials used in roadway construction, hot mixed asphalt stands out as a reliable and versatile choice. Let’s dive into the advantages and disadvantages of harnessing the power of hot mixed asphalt in our roads, while also exploring the impact on jobs in construction.
Advantages of Hot Mixed Asphalt
Durability: Hot mixed asphalt boasts exceptional durability, making it a top choice for long-lasting roadways. Its ability to withstand heavy traffic loads and weather conditions makes sure that our roads remain intact for decades, reducing the frequency of costly repairs and reconstruction projects. This durability not only saves money but also minimizes disruptions to commuters and businesses.
Smooth Surface: The smooth surface created by hot mixed asphalt improves driving comfort and reduces vehicle wear and tear. This translates to lower maintenance costs for vehicle owners and enhances overall road safety by providing a stable driving surface.
Cost-Effectiveness: For cities and construction companies focused on maximizing their budgets, hot mixed asphalt is a cost-effective solution. Its lower initial cost, coupled with its durability, makes it a financially good option for large-scale road projects, allowing resources to be allocated efficiently across various infrastructure needs and jobs in construction.
Quick Installation: Despite the initial curing time, hot mixed asphalt offers a good advantage in terms of quick installation compared to other pavement materials. The efficiency of the installation process comes from several key factors:
Preparation and Planning: Before asphalt paving begins, preparation is essential. This includes site grading, ensuring proper drainage, and addressing any subgrade issues. Preparation sets the stage for a smooth and efficient paving operation.
Hot Mix Production: Hot mixed asphalt is prepared at asphalt plants, where aggregates (such as sand, gravel, and crushed stone) are combined with a binder (typically asphalt cement or bitumen) at temperatures ranging from 270°F to 325°F. The hot mix is then taken to the construction site in specialized trucks.
Paving Equipment: Construction crews use specialized paving equipment, such as asphalt pavers and rollers, to lay and compact the hot mixed asphalt. Modern asphalt pavers offer precise control over paving thickness and smoothness, ensuring quality across the pavement surface.
Efficient Workflow: During asphalt paving operations, coordination and efficiency are a must. Jobs in construction, such as crews work together to unload, spread, and compact the hot mix, minimizing downtime and maximizing productivity. Proper compaction is needed to achieve the desired density and structural integrity of the pavement.
Quality Control: Throughout the paving process, quality control measures are put in to monitor asphalt temperature, compaction levels, and overall pavement quality. Regular inspections and adjustments help ensure that the finished pavement meets engineering requirements.
By leveraging efficient workflows, advanced equipment, and quality control, construction teams can complete asphalt paving projects promptly, reducing overall project duration and minimizing disruptions to traffic flow. The combination of quick installation and subsequent curing time allows newly paved roads to be opened to the public efficiently while ensuring long-term durability and performance. According to nashuanh.gov, it takes around 2-3 weeks to 8 weeks or longer depending on the size and the conditions of the roads when paving a street from start to finish.
Recyclability: Sustainability is a growing concern in the construction industry, and hot mixed asphalt shines in this regard. Its recyclability allows for old asphalt pavements to be milled and reused in new mixtures, reducing the demand for virgin materials and promoting eco-friendly practices in road construction.
Disadvantages of Hot Mixed Asphalt
Weather Sensitivity: While hot mixed asphalt is designed to withstand different weather conditions, extreme temperatures, and moisture can still impact its performance. Cold weather can lead to brittleness and cracking if not properly maintained. This highlights the importance of proactive maintenance strategies to prevent weather-related damage.
Maintenance Requirements: Despite its durability, hot mixed asphalt requires maintenance to ensure optimal performance. This may include resurfacing, crack sealing, and patching to address wear and tear caused by traffic and environmental factors. While maintenance is needed to prolong the lifespan of asphalt roads, it does add to ongoing operational costs.
Environmental Impact: The production and use of hot mixed asphalt contribute to environmental challenges, including carbon emissions and energy consumption. Asphalt plants also emit pollutants during the mixing process, although advancements in technology are continuously improving environmental standards within the industry.
Limited Aesthetic Options: Unlike concrete, which offers a wide range of colors and finishes, hot mixed asphalt has limited aesthetic options. While colored asphalt exists, it’s not as commonly used in roadway construction, potentially limiting design choices for architects and urban planners seeking visual diversity in infrastructure projects.
Initial Curing Time: After hot mixed asphalt is laid and compacted, it undergoes a phase known as curing, during which it gains strength and durability. The duration of this curing period can vary based on several factors, including temperature, asphalt mix composition, and the thickness of the pavement layer.
During the initial curing time:
Strength Development: Initially, the asphalt mixture is pliable and fragile. As it cures, the binder in the mix gradually hardens, enhancing the pavement’s strength and load-bearing capacity. This curing process is needed to ensure that the road can withstand the stresses imposed by traffic and environmental factors.
Temperature Sensitivity: Temperature plays a significant role in the curing process. Warmer temperatures accelerate curing, allowing the asphalt to achieve its desired strength more quickly. Colder temperatures can prolong the curing time, requiring additional precautions to protect the newly laid pavement.
Traffic Restrictions: While hot mixed asphalt offers a decently quick installation process, it’s important to note that the road may not be ready for full traffic loads right after paving. During the initial curing period, traffic restrictions or temporary traffic management measures may be needed to prevent damage to the fresh asphalt surface.
Optimal Performance: Patience during the curing phase pays off in the long run. Allowing time for the asphalt to cure ensures that the pavement reaches its full potential in terms of durability, smoothness, and resistance to wear and tear. Construction teams and project managers must carefully plan for the curing time when scheduling road construction activities. By factoring in the expected curing duration based on local conditions and asphalt specifications, they can limit disruptions and make sure that the newly constructed roads meet performance standards from the outset.
Hot mixed asphalt presents many advantages, including durability, cost-effectiveness, and recyclability, making it a huge part of modern roadway construction. However, challenges such as weather sensitivity, maintenance requirements, and environmental considerations underscore the need for careful planning and management in road infrastructure projects and jobs in construction. By weighing these pros and cons, construction companies like Kilgore Companies can make informed decisions, contributing to the development of safer and more sustainable transportation networks for communities to thrive. Learn more on our website.