During highway overhauls, asphalt pavement construction quality control is particularly important, directly impacting pavement durability, driving safety, and return on investment. To ensure comprehensive improvements in construction quality, we have proposed a comprehensive strategy encompassing five key dimensions: meticulous material control, process optimization, real-time quality monitoring, intelligent technology support, and a rigorous organizational management system. These strategies not only comply with industry standards but also incorporate extensive engineering experience to provide a systematic and practical solution for highway overhauls.
1. Full-Chain Material Control
During highway overhauls, material selection and control are paramount for quality assurance. We strictly adhere to the "Technical Specification for Highway Asphalt Pavement Construction" (JTG F40) to select appropriate asphalt grades and modifiers based on varying climatic conditions and traffic levels. For example, in hot and heavy-load areas, we select asphalt with a low penetration and a high softening point to enhance rutting resistance; in cold areas, we choose asphalt with a high ductility and a low brittle point to prevent pavement cracking. Furthermore, the selection of aggregates and fillers is crucial. Aggregates must meet a series of stringent specifications, such as crushing value and Los Angeles abrasion resistance. Harder materials, such as impact crushed stone or basalt, are preferred. For fillers, the moisture content and hydrophilicity of mineral powders must be strictly controlled to avoid asphalt spalling problems caused by the use of active materials such as fly ash.
While complying with environmental requirements, we also utilize recycled materials appropriately. The performance stability of recycled materials is verified through extraction tests and Marshall stability tests, and their inclusion ratio is strictly controlled (typically no more than 30%).
Next is the design and verification of the mixture proportions. We utilize Marshall design, Superpave design, or equilibrium design methods to optimize gradation, ensuring that various performance indicators, such as target void ratio, interstitial ratio, and saturation, meet regulatory requirements. For example, on heavily trafficked sections, we increase the proportion of coarse aggregate to enhance rutting resistance; on lightly trafficked sections, we increase the proportion of fine aggregate to improve surface smoothness. Finally, high-temperature rutting tests, low-temperature bending tests, and water stability tests are conducted to fully verify the comprehensive performance of the mix, ensuring it meets the quality requirements of highway overhauls.

2. Detailed Control of Construction Processes
During highway overhauls, meticulous control of construction processes is crucial for ensuring quality. This involves mixing and transportation, paving and compacting, as well as joint and edge treatment.
During the mixing and transportation stages, we strictly control the mixing temperature and time to ensure that the asphalt evenly coats the aggregate, avoiding whitening or segregation. Transport vehicles are also covered with insulating tarpaulins and coated with an insulating agent to minimize heat loss. The temperature of the mix delivered to the site must reach above 135°C; waste materials below this temperature are strictly prohibited.
The paving and compacting stages are equally important. We use a crawler paver for full-width paving to avoid longitudinal joints, and we strictly control the paving speed, loose paving thickness, and screed preheating temperature. In terms of rolling, we follow the principle of "close follow, slow pressure, high frequency and low amplitude", and adopt a combination of initial pressure, repeated pressure and final pressure to ensure that the compaction degree reaches more than 98% and the void ratio is controlled within 6%.
Furthermore, for joint and edge treatment, we use a hot jointing process for longitudinal joints and a flat jointing process for transverse joints to ensure smooth and dense joints. We use small vibrating tampers or handheld vibrators for tamping at the edges to prevent edge collapse caused by insufficient compaction.
3. Quality Inspection and Dynamic Monitoring
During the construction process, we use infrared thermal imaging cameras to monitor the paving temperature distribution in real time to prevent temperature segregation. We also use laser and continuous surface roughness meters to inspect the paved surface for smoothness, ensuring compliance with standards (IRI ≤ 1.5 m/km). Compaction is checked using nuclear density meters or core sampling, with at least one inspection point per 1,000 square meters.
In addition, we use drones equipped with high-definition cameras for aerial inspections. Using AI algorithms, we automatically identify potential pavement defects such as cracks, looseness, and oil seepage, and generate thermal maps to guide repair work. In terms of finished product quality acceptance, we strictly adhere to the "Highway Engineering Quality Inspection and Assessment Standard" (JTG F80/1), conducting random sampling tests on key indicators such as pavement thickness, flatness, skid resistance (construction depth ≥ 0.7mm, swing value BPN ≥ 45), and water permeability coefficient (≤ 120mL/min). Core samples are also subjected to indoor tests for Marshall stability, void ratio, and asphalt content to verify construction quality.
4. Intelligent Technology Innovation
Leveraging BIM and digital twin technology, we have constructed a detailed model of asphalt pavement construction. This model integrates key material parameters, construction parameters, and environmental data, enabling intuitive simulation and optimization of the construction process. For example, the digital twin platform can simulate and compare the compaction effects of different rolling combinations, assisting in selecting optimal process parameters. IoT sensors, such as temperature and pressure sensors, capture construction data in real time and upload it to a cloud platform for in-depth big data analysis, enabling early warning of potential quality issues.
Furthermore, the introduction of AI and machine learning technologies has further enhanced the intelligent level of pavement defect identification. We have developed an AI-powered defect recognition system. By training deep learning models, it accurately identifies pavement defects such as cracks, rutting, and potholes, and automatically proposes repair solutions. For example, in a project in Jiangsu, the system achieved over 95% defect recognition accuracy and increased repair efficiency by 30%. Furthermore, machine learning models are being used to predict pavement performance degradation trends, optimizing maintenance cycles and funding allocation, and promoting a shift in maintenance from a reactive repair approach to a proactive prevention approach.
5. Organizational Management and Safeguards
We prioritize personnel training and assessment to ensure that construction, supervision, and inspection personnel fully grasp the key points of quality control. Regular training covering material knowledge, construction techniques, inspection standards, and safety regulations continuously enhances the team's professional skills. We also establish a quality assessment and reward and punishment mechanism that closely links construction quality with individual performance and team bonuses, thereby motivating all employees to participate in quality management.
In terms of quality accountability and supervision, we clearly define the responsibilities of all parties involved and establish an electronic responsibility registration system to ensure full traceability of the entire process, from material procurement to project acceptance. By implementing a "double random, one public" sampling inspection model and dynamically adjusting the inspection frequency based on credit evaluation results, we ensure that high-risk enterprises are subject to strict supervision. Furthermore, we have brought in a third-party auditing firm to independently assess the use of maintenance funds and project quality, further strengthening quality supervision.
In terms of safety and environmental management, we have developed a detailed construction safety emergency plan and deployed dedicated safety officers to provide safety warnings and traffic control in the construction area to ensure safe and accident-free construction. We also strictly implement environmental protection measures such as watering to suppress dust, noise control, and waste recycling to minimize the environmental impact of construction and meet the standards and requirements of green construction.
6. Case Study and Effectiveness
A highway overhaul project in Jiangsu Province: By adopting SBS modified asphalt, optimizing grading design, and integrating intelligent rolling monitoring technology, the pavement compaction rate was significantly improved to 98.5%, rutting depth was reduced by 40%, effectively extending the pavement's service life, and reducing maintenance costs by 20%. A rural highway overhaul project in Zhejiang Province successfully implemented the "self-luminous road marking + solar lighting" technology, significantly reducing traffic accidents at night and lowering electricity consumption, achieving both economic and environmental benefits.
In summary, quality control of asphalt pavement construction during highway overhaul is crucial, encompassing every aspect of the process, including material selection, process design, construction execution, quality inspection, intelligent technology application, and organizational management. Through standardized material management, refined process control, intelligent technology empowerment, and systematic organizational support, we can significantly improve pavement construction quality, extend its service life, and reduce overall lifecycle costs. These practices provide solid support for building a strong transportation nation and also herald the future of asphalt pavement construction quality control towards a more intelligent, green, and sustainable approach.