The duration required for bituminous pavement to reach a usable state after placement is a critical consideration in construction and maintenance. This timeframe hinges on factors like ambient temperature, pavement thickness, and the specific asphalt mix used. For instance, a thin overlay placed on a warm day will cure more rapidly than a thick section installed during cooler conditions.
Efficient curing times minimize traffic disruption and accelerate project completion. Understanding the factors influencing this process is essential for optimizing schedules, reducing delays, and ensuring the long-term performance of the pavement. Historically, inaccurate estimates of curing time have resulted in premature traffic loading, leading to pavement damage and costly repairs.
Subsequent sections will delve into the specific elements that dictate pavement curing, offering practical guidance on assessing readiness and mitigating potential risks associated with insufficient cure times. Discussion will include environmental considerations, mix design parameters, and accepted testing methodologies to determine suitable bearing capacity.
1. Temperature
Ambient temperature and pavement temperature exert a profound influence on the rate at which bituminous mixtures achieve sufficient stability for traffic. Elevated temperatures promote a more rapid reduction in viscosity and facilitate the dissipation of volatile components, leading to accelerated curing. Conversely, cooler conditions retard this process, potentially extending the required waiting period.
-
Ambient Air Temperature
The prevailing air temperature directly impacts the surface temperature of the newly placed asphalt. Higher air temperatures translate to increased surface temperatures, accelerating the evaporation of lighter oils and solvents within the asphalt binder. This evaporation process contributes to the hardening and strengthening of the pavement. Conversely, low air temperatures inhibit this process, prolonging the time required for the asphalt to reach its target stiffness. For example, paving operations conducted in summer months generally require shorter closure periods than those performed during the fall or winter.
-
Pavement Temperature During Placement
The initial temperature of the asphalt mix upon placement is a critical factor. Hotter mixes, within acceptable temperature ranges, will typically cure faster because the binder is more fluid and can compact more effectively. This improved compaction results in a denser pavement structure with reduced air voids, promoting greater stability. However, excessively high temperatures can lead to binder burn and premature aging, potentially negating the benefits of rapid curing. Proper temperature control during mixing, transport, and placement is thus essential for optimizing cure rates.
-
Subgrade Temperature
The temperature of the underlying subgrade also plays a role, albeit less direct than ambient air and pavement temperatures. A warmer subgrade can help maintain the temperature of the asphalt layer, particularly during the early stages of curing. This effect is more pronounced in thicker asphalt layers. Conversely, a cold subgrade can draw heat away from the asphalt, slowing the curing process. Insulating layers can sometimes be employed to mitigate the impact of subgrade temperature on asphalt curing rates, especially in regions with cold climates.
-
Diurnal Temperature Variation
The daily fluctuation in temperature, or diurnal variation, can affect the uniformity of curing. Wide swings in temperature can induce stress within the asphalt layer, potentially leading to cracking or other forms of distress. While some temperature variation is unavoidable, minimizing it through careful planning and timing of paving operations can promote more consistent and predictable curing. For example, avoiding placement during periods of extreme temperature change, such as late afternoon or early morning in certain climates, can contribute to improved pavement performance.
In summary, temperature is a dominating factor governing the “asphalt how long to dry” timeline. The interplay between ambient conditions, mix temperature, subgrade influence, and diurnal variation collectively dictate the speed and uniformity of hardening. Precise temperature control and awareness of environmental factors are therefore crucial for successful asphalt paving projects.
2. Asphalt Grade
The grade of asphalt binder directly correlates with the duration required for a newly paved surface to achieve sufficient stability. Asphalt grade, typically classified using a performance grading (PG) system, reflects the binder’s physical properties across a range of service temperatures. Softer asphalt grades, designed for colder climates, contain a higher proportion of volatile components, extending the time needed for these elements to dissipate and the pavement to harden. Conversely, stiffer grades, suited for warmer regions, exhibit a faster curing profile due to their lower volatile content.
A mismatch between the asphalt grade and the prevailing environmental conditions can lead to premature pavement distress. For example, utilizing a softer grade asphalt in a hot climate may result in permanent deformation or rutting as the pavement remains pliable for an extended period. Conversely, a stiffer grade used in cold conditions might become brittle and susceptible to cracking. Proper selection of asphalt grade is, therefore, a critical factor in optimizing cure times and ensuring long-term pavement performance. State Departments of Transportation (DOTs) typically specify asphalt grades based on regional climate data to mitigate these risks.
In summary, the asphalt grade is a primary determinant of the curing period, influencing both the rate of volatile dissipation and the pavement’s resistance to deformation under load. Selection of an appropriate grade, aligned with the project’s climate and traffic demands, is essential for achieving desired curing times and maximizing the service life of the asphalt pavement. Failure to account for asphalt grade during the planning phase can lead to extended closure times, increased construction costs, and premature pavement failure.
3. Layer Thickness
The thickness of the asphalt layer exerts a direct influence on the time required for it to cure adequately. Thicker layers inherently possess a greater volume of asphalt binder, which necessitates a longer period for volatile components to dissipate and for the pavement to achieve its designed strength and stability. The increased mass acts as an insulator, impeding the efficient transfer of heat from the pavement’s interior to the surrounding environment. This slower cooling rate prolongs the curing process, delaying the opening of the pavement to traffic. Conversely, thinner layers cool more rapidly, facilitating faster curing times.
The relationship between layer thickness and curing time is not linear; a doubling of the layer thickness will more than double the required curing duration. This is due to the complexities of heat transfer and binder properties. Real-world examples illustrate this effect: a thin overlay of 1.5 inches might be ready for traffic within a few hours under favorable weather conditions, while a full-depth pavement reconstruction with a 6-inch layer could require several days or even weeks to achieve adequate curing. In projects involving multiple asphalt lifts, each layer contributes to the overall curing time, and proper scheduling must account for the cumulative effect of these layers.
Understanding the correlation between layer thickness and curing time is crucial for effective project management. Overestimating curing times can lead to unnecessary delays and increased costs, while underestimating them can result in premature pavement failure and costly repairs. Engineers must consider the intended traffic load, environmental conditions, and asphalt mix design to accurately predict curing times and implement appropriate construction practices. Proper compaction techniques, coupled with accurate layer thickness control, are essential to optimize the curing process and ensure the long-term durability of the asphalt pavement.
4. Compaction
Achieving optimal density through compaction is paramount in determining the service life of asphalt pavements and directly influences the time required for the material to reach a state suitable for traffic. Inadequate compaction retards the hardening process, while proper compaction facilitates quicker stabilization.
-
Air Void Reduction
Compaction reduces the percentage of air voids within the asphalt mixture. Higher air void content hinders the hardening process by allowing greater oxidation of the binder and increasing its susceptibility to moisture damage. Efficient compaction expels these voids, creating a denser, more stable matrix that accelerates the time to structural integrity.
-
Interlock and Stability
Effective compaction increases the interlock between aggregate particles within the asphalt mix. This interlocking action provides structural stability and resistance to deformation under load. Poorly compacted asphalt lacks this interlock, resulting in a weaker pavement structure that takes longer to stabilize and is prone to rutting or shoving.
-
Thermal Conductivity
The density of asphalt affects its thermal conductivity. Properly compacted asphalt exhibits enhanced thermal conductivity, facilitating more uniform cooling and curing throughout the pavement layer. Conversely, lower density due to inadequate compaction inhibits heat dissipation, potentially prolonging the period required for the asphalt to harden uniformly, and increasing the risk of surface defects.
-
Moisture Resistance
Well-compacted asphalt demonstrates improved resistance to moisture infiltration. Excess moisture within the pavement structure can weaken the bond between the asphalt binder and aggregate, leading to stripping and premature failure. Sufficient compaction minimizes the pathways for moisture to penetrate the pavement, thereby reducing the risk of moisture-related damage and promoting more rapid stabilization of the asphalt.
Therefore, meticulous attention to compaction practices is crucial for ensuring that asphalt pavements achieve their intended density and structural properties. Proper compaction not only enhances the long-term durability of the pavement but also reduces the duration before it can withstand traffic loads, optimizing project timelines and minimizing disruptions.
5. Mix Design
The formulation of asphalt mixtures significantly influences the time required for stabilization. Mix design parameters dictate the proportions and properties of the constituent materials, impacting the rate at which the pavement achieves its design strength and resistance to deformation. An optimized mix design balances performance characteristics with practical considerations, directly affecting the paving schedule.
-
Aggregate Gradation
The size distribution of aggregate particles affects the density and stability of the asphalt mixture. A well-graded aggregate blend, with a balanced proportion of coarse, intermediate, and fine particles, promotes interlocking and reduces air voids. This denser structure enhances stability and accelerates the hardening process. Conversely, a poorly graded mix with excessive fines or a lack of intermediate sizes may exhibit higher air voids and reduced stability, prolonging the time necessary to reach adequate load-bearing capacity. For instance, gap-graded mixes, while offering benefits in certain applications, may require specialized curing techniques to achieve desired performance.
-
Asphalt Binder Content
The percentage of asphalt binder in the mix plays a crucial role in pavement performance and curing time. An optimal binder content provides sufficient coating of the aggregate particles, ensuring cohesion and flexibility. However, excessive binder can lead to bleeding or rutting, especially in hot weather, and may extend the curing period. Conversely, insufficient binder can result in a dry, brittle mix that is prone to cracking. Balancing the binder content is essential for achieving both durability and efficient curing. Mix design procedures, such as the Marshall or Superpave methods, aim to determine the optimum binder content based on performance criteria.
-
Modifier Additives
The inclusion of modifier additives, such as polymers or fibers, can significantly alter the properties of the asphalt mixture and affect its curing characteristics. Polymer-modified asphalt (PMA) often exhibits improved resistance to rutting and cracking, but may also require longer curing times due to the altered viscoelastic properties of the binder. Fiber reinforcement can enhance the tensile strength of the mix and reduce the risk of cracking, potentially leading to a faster stabilization. The selection and dosage of modifier additives must be carefully considered in relation to the project’s specific performance requirements and the desired curing timeline. Examples include the use of crumb rubber modifiers (CRM) to improve pavement flexibility and reduce noise.
-
Air Void Content Target
Mix design targets a specific air void content, typically in the range of 3-7% after compaction. The achieved air void content is directly related to compaction effort and significantly affects the asphalt how long to dry time. Higher air void contents negatively impact pavement performance, increasing oxidation and moisture damage, delaying stabilization. Mixes designed for lower air void content can reach required stability sooner.
In conclusion, the interplay of aggregate gradation, binder content, modifier additives, and air void content in the mix design dictates the curing behavior of asphalt pavements. Optimizing these parameters is essential for achieving a balance between performance characteristics and efficient construction schedules, ultimately influencing “asphalt how long to dry”.
6. Weather Conditions
Prevailing weather conditions represent a significant variable influencing the timeline for bituminous pavement to achieve adequate stability and load-bearing capacity. Ambient temperature, precipitation, and solar radiation interact to either accelerate or retard the curing process, necessitating careful consideration during construction planning and execution.
-
Rainfall
Precipitation during or immediately following asphalt placement can significantly extend the curing period. Water infiltration cools the pavement, impeding the evaporation of volatile compounds within the asphalt binder. Furthermore, water can displace the asphalt binder from the aggregate, weakening the pavement structure and delaying the development of sufficient strength. In extreme cases, heavy rainfall can completely halt paving operations and necessitate rework. Therefore, weather forecasts are critical for scheduling asphalt placement and minimizing the risk of rain-related delays.
-
Sunlight and Solar Radiation
Exposure to direct sunlight and solar radiation accelerates the curing process by increasing the pavement temperature. The radiant energy absorbed by the asphalt surface promotes the evaporation of lighter oils and solvents within the binder, leading to a more rapid increase in stiffness and stability. However, excessive exposure to sunlight can also cause premature aging and oxidation of the asphalt, potentially reducing its long-term durability. The angle of incidence and duration of sunlight exposure vary depending on the time of year and geographical location, influencing the rate of curing. For instance, pavements placed during summer months in areas with high solar radiation will typically cure faster than those placed during winter months in regions with less sunlight.
-
Wind Speed
Wind speed influences the rate of evaporation from the asphalt surface. Higher wind speeds promote convective heat transfer, accelerating the removal of volatile compounds and facilitating more rapid cooling and hardening of the pavement. However, excessively high winds can also cause localized cooling and uneven curing, potentially leading to surface cracking or other forms of distress. Wind speed can also affect the uniformity of compaction, particularly during the placement of open-graded asphalt mixes. Careful attention to wind conditions is therefore essential for ensuring consistent pavement quality and optimizing the curing process.
-
Humidity
High humidity levels can slow the evaporation of volatile components from the asphalt binder, thereby extending the curing period. Saturated air reduces the rate at which moisture can escape from the pavement surface, delaying the hardening process. Conversely, low humidity levels promote more rapid evaporation and faster curing. Humidity is often correlated with other weather conditions, such as temperature and precipitation, making it an important factor to consider when planning and executing asphalt paving projects. For example, paving operations conducted on a warm, humid day may require a longer closure period than those performed on a warm, dry day.
These multifaceted influences of weather underscore the importance of incorporating meteorological data into asphalt paving project management. Careful monitoring and forecasting of weather conditions enable informed decisions regarding scheduling, material selection, and construction practices, optimizing the cure time and ensuring long-term pavement performance.
7. Traffic Volume
The intensity and frequency of vehicular traffic significantly impact the period required for newly placed asphalt to achieve sufficient stability and resistance to deformation. Premature exposure to heavy loads can impede the hardening process and compromise pavement integrity.
-
Impact on Initial Set
High traffic volumes, particularly those including heavy vehicles, exert significant stress on newly placed asphalt before it has fully cured. This premature loading hinders the initial setting process, as the pavement is continually subjected to compressive and shear forces. The binder is displaced before it can effectively bond with the aggregate, leading to a weakened structure and increased susceptibility to rutting. Example: Opening a newly paved highway to truck traffic within hours of placement, versus allowing several days of curing under minimal traffic, demonstrates a marked difference in long-term pavement performance.
-
Compaction Interference
Uncontrolled traffic can interfere with the final stages of compaction. Even after initial rolling, the asphalt mixture continues to consolidate under traffic loading. However, this consolidation is not uniform, and concentrated wheel paths can lead to localized over-compaction and rutting, while areas between wheel paths remain under-compacted. This uneven compaction creates stress concentrations within the pavement and reduces its overall lifespan. Construction zones often utilize lane closures or detours to minimize traffic impact during this critical phase.
-
Temperature Sensitivity Amplification
The impact of traffic volume is amplified by temperature sensitivity. Newly placed asphalt is more susceptible to deformation at elevated temperatures. Heavy traffic exacerbates this vulnerability, leading to permanent deformation and rutting. Conversely, at lower temperatures, traffic can induce cracking in insufficiently cured asphalt. Careful consideration of temperature conditions, coupled with appropriate traffic management strategies, is essential for minimizing pavement damage during the initial curing period.
-
Curing Agent Effectiveness
When curing agents are employed, high traffic volume can diminish their effectiveness if the pavement is opened prematurely. Curing agents are designed to accelerate the hardening process, but their performance is optimized when the asphalt is allowed to cure undisturbed for a specified duration. Heavy traffic disrupts the chemical reactions that contribute to the curing process, reducing the overall benefit of the curing agent. This highlights the need for a balanced approach, considering both the use of curing agents and the implementation of appropriate traffic control measures.
These factors underscore the importance of managing traffic flow around newly paved surfaces. Implementing lane closures, detours, or reduced speed limits allows the asphalt sufficient time to cure and develop its designed strength, thus enhancing the longevity of the pavement and minimizing the need for costly repairs. Traffic considerations are integral to the planning phase of any asphalt paving project.
8. Curing Agents
Chemical additives, termed curing agents, are incorporated into asphalt mixtures to modify the rate at which the material achieves its intended strength and stability. The application of these agents offers a mechanism to reduce the duration before a paved surface can withstand vehicular traffic, addressing challenges associated with project timelines and traffic management.
-
Acceleration of Polymerization
Certain chemical compounds accelerate the polymerization process within the asphalt binder. These agents initiate cross-linking reactions between the binder molecules, forming a more rigid and interconnected network. This enhanced molecular structure leads to faster strength development and reduced susceptibility to deformation under load. Example: Polymeric additives based on epoxy or polyurethane chemistry can significantly reduce curing times by promoting rapid cross-linking. The implications include shorter road closures and reduced traffic congestion.
-
Volatile Component Reduction
Curing agents can facilitate the rapid evaporation of volatile organic compounds (VOCs) present in the asphalt binder. These compounds, while contributing to workability during placement, prolong the curing period and can pose environmental concerns. Agents that promote VOC release accelerate the hardening process and minimize the potential for long-term emissions. Example: Lime or cement kiln dust can react with certain components of the asphalt, reducing VOC emissions and promoting a faster setting time. This facet is significant from both an environmental and pavement performance perspective.
-
Improved Aggregate Adhesion
Surface-active agents can enhance the adhesion between the asphalt binder and the aggregate particles. Improved bonding reduces the risk of moisture damage and stripping, leading to a more durable and stable pavement structure. Enhanced adhesion also promotes a more uniform distribution of stress under load, reducing the potential for localized deformation. Example: Amine-based antistripping agents improve the bond between asphalt and aggregate, ensuring a stronger pavement that can bear traffic loads sooner. This is particularly beneficial in wet or humid climates.
-
Enhanced Early Strength
Some curing agents are specifically formulated to improve the early strength of asphalt mixtures. These agents promote rapid development of cohesion and stiffness, enabling the pavement to withstand traffic loads shortly after placement. Example: Certain calcium-based additives provide rapid setting by promoting crystallization within the asphalt matrix. This quick setting is advantageous in situations where traffic disruption must be minimized, such as emergency repairs or nighttime paving operations.
In summary, the strategic deployment of curing agents provides a means to manipulate the asphalt hardening timeline, mitigating delays and minimizing traffic interruptions. The selection of an appropriate agent necessitates a comprehensive understanding of the asphalt mix design, environmental conditions, and project-specific requirements. The ultimate goal is to balance the benefits of accelerated curing with the need to ensure long-term pavement performance and environmental sustainability. The correct use of these agents directly impacts the “asphalt how long to dry” time and is a key decision in road construction and maintenance.
9. Base Stability
Substructure integrity is a foundational element governing the setting characteristics of bituminous pavements. The bearing capacity and uniformity of the underlying base course directly influence stress distribution within the asphalt layer, impacting the rate at which it achieves suitable stability.
-
Support Uniformity
Variations in base course density and composition lead to differential settlement under load. Non-uniform support prolongs the cure period as the asphalt layer undergoes continuous micro-adjustments to accommodate underlying instabilities. A stable, consistently dense base minimizes these adjustments, allowing the asphalt to cure uniformly and reach load-bearing capacity more rapidly. Example: Paving over a patched or poorly compacted base will result in an extended and unpredictable cure duration, increasing the risk of premature pavement distress.
-
Moisture Management
Effective drainage within the base course prevents the accumulation of moisture beneath the asphalt layer. Excess moisture weakens the base and can migrate into the asphalt, disrupting binder adhesion and hindering the setting process. A well-draining base promotes a drier, more stable environment for the asphalt, accelerating the development of strength and resistance to deformation. Example: A granular base with inadequate drainage will trap water, leading to prolonged curing times and a higher susceptibility to stripping and rutting.
-
Material Composition and Consolidation
The material composition of the base course, including aggregate type and gradation, affects its consolidation characteristics. A well-graded, angular aggregate mixture will interlock effectively and resist deformation, providing a stable platform for the asphalt. Insufficient consolidation or the use of rounded aggregates can lead to a less stable base and prolonged asphalt how long to dry time. Example: The utilization of crushed stone versus river gravel in a base course demonstrates the impact of material selection on base stability and subsequent asphalt pavement performance.
-
Load Distribution Capacity
The ability of the base to spread wheel loads is directly linked to the asphalt’s setting. A strong base distributes concentrated loads over a wider area, reducing stress on the asphalt and preventing deformation while the binder hardens. A weak base transfers concentrated stress directly to the asphalt which extends the cure period. Example: A thick, dense-graded aggregate base will offer much better load distribution than a thin, open-graded base, affecting asphalt how long to dry time.
These interrelated facets underscore the critical role of the supporting layers in setting the stage for asphalt stability. Proper base preparation, material selection, and drainage control are not merely preliminary steps, but integral components dictating the pace and ultimate success of the asphalt setting process. Stable substructures enhance the likelihood of achieving optimal pavement properties and minimizing the time required for asphalt how long to dry before it can handle traffic.
Frequently Asked Questions
The following questions address common concerns regarding the duration required for asphalt to cure sufficiently for traffic loading. These answers provide insights into the factors influencing curing and best practices for ensuring pavement integrity.
Question 1: What is the typical timeframe for asphalt to fully cure?
The precise time for bituminous pavements to achieve a fully cured state is variable. It can span from a few hours to several days. This timeframe depends on factors like temperature, asphalt grade, layer thickness, and mix design. Curing is not a fixed duration, but a process dependent on numerous environmental and material characteristics.
Question 2: How does ambient temperature affect the pavement curing process?
Elevated ambient temperatures expedite the curing process by promoting the evaporation of volatile components and accelerating binder hardening. Conversely, cooler temperatures retard the process, extending the time needed for the asphalt to reach adequate strength. Temperature management strategies are often employed to mitigate the effects of adverse weather conditions.
Question 3: What role does layer thickness play in determining pavement curing time?
Thicker asphalt layers require longer curing times due to the increased volume of binder and slower heat dissipation. Thinner layers cool more rapidly and achieve stability faster. Layer thickness is a crucial consideration in project planning to accurately estimate the necessary closure period.
Question 4: Can traffic volume impact the asphalt how long to dry?
Yes, premature exposure to heavy traffic inhibits proper curing by stressing the uncured binder, leading to deformation. Traffic management during the initial cure significantly increases the overall pavement lifespan.
Question 5: Are there methods to accelerate the asphalt setting process?
Chemical curing agents can be incorporated into the asphalt mix to accelerate binder hardening. The selection of such agents depends on mix design and desired performance characteristics. Other strategies for influencing the curing process can include temperature control or altered compaction techniques.
Question 6: What are the consequences of opening asphalt pavements to traffic too soon?
Premature exposure to traffic loads can result in permanent deformation, rutting, and reduced pavement lifespan. Ensuring adequate curing is essential to achieve the intended structural integrity and durability of the asphalt pavement.
Accurate assessment of curing factors leads to informed project execution. Pavement readiness should be confirmed via established testing methodologies before opening the roadway to traffic.
The subsequent section will address best practices for determining asphalt readiness and avoiding premature loading.
Key Strategies for Optimizing Asphalt Curing
Successfully managing the curing period of asphalt pavements requires a proactive approach, incorporating best practices from planning through execution. Adherence to these strategies minimizes delays and maximizes the lifespan of the pavement.
Tip 1: Thoroughly Evaluate Weather Conditions: Project scheduling must account for weather patterns. Extended periods of rain or extreme temperature fluctuations negatively impact cure rates. Reschedule placement during favorable conditions.
Tip 2: Select the Appropriate Asphalt Grade: The grade must align with the anticipated service temperatures. Utilizing softer binders in hot climates can delay hardening, while stiffer binders can lead to premature cracking in cold environments. Ensure grade selection matches site-specific requirements.
Tip 3: Maintain Strict Compaction Control: Achieving optimal density is paramount. Utilize appropriate compaction equipment and techniques to minimize air voids and maximize aggregate interlock. Consistent compaction leads to faster stabilization.
Tip 4: Implement Traffic Management Strategies: Protect the pavement from premature traffic loading. Employ lane closures, detours, or reduced speed limits during the initial cure period. Controlled traffic is essential for allowing the binder to set properly.
Tip 5: Consider Curing Agents Judiciously: Curing agents can accelerate the hardening process, but should be used based on project requirements and mix design. Adhere strictly to manufacturer specifications for optimal results. Improper use can have adverse effects.
Tip 6: Ensure Base Course Stability: A stable and well-drained base course is critical. Address any base course deficiencies before asphalt placement. Subgrade issues will manifest as surface problems.
These targeted strategies enhance the probability of achieving desired asphalt setting rates and maximizing overall pavement durability. Adhering to these guidelines is paramount to successful paving projects.
The final section will summarize critical checkpoints for asphalt placement and inspection, solidifying best practices for the asphalt how long to dry.
Concluding Remarks
This exploration has highlighted the multifarious factors governing the time required for asphalt pavements to reach a stable, traffic-ready state. Pavement temperature, material composition, weather conditions, and construction practices collectively determine the duration of this critical process. An understanding of these variables and their interplay is essential for effective project planning and execution.
Recognizing the complex relationship between asphalt mix design and field conditions allows for informed decision-making, optimizing construction timelines and ensuring long-term pavement performance. Continued research and refinement of these practices will contribute to more predictable asphalt setting times and enhanced infrastructure resilience. Pavement engineers must prioritize this knowledge to ensure safe and durable roadways.
