In the entire production process of an asphalt mixing plant, weighing is a core link between raw material preparation and mixing. Its accuracy directly affects whether the mix proportions meet design requirements. Mix proportion accuracy not only affects operability during construction but also determines the durability and overall service life of the road.
While traditional single-stage weighing can meet the needs of foundation construction, the rise of high-grade projects such as expressways, airport roads, and heavy-duty freight roads has led to increasingly demanding mix proportion accuracy. Primary weighing is often affected by factors such as falling material inertia, conveyor belt residue, and temperature and humidity fluctuations, leading to inevitable errors.
Secondary dynamic weighing technology was developed precisely to meet these industry needs. By adding dynamic detection and automatic compensation steps after the initial weighing, it ensures accurate and stable mix proportions between batches even under high-speed continuous production conditions, thereby reliably ensuring the final quality of the asphalt mixture.
As previously mentioned, secondary dynamic weighing technology is a key means of ensuring mix accuracy in asphalt production and is essential for guaranteeing the quality of the finished product. So, how does it achieve this goal? Below, we’ll delve deeper into the system’s composition and operation.
A secondary dynamic weighing system adds real-time monitoring and intelligent compensation to primary weighing. Its key components include:
The key feature of this mode is simultaneous conveying, detection, and correction, enabling secondary precision adjustments without reducing production speed.
Before exploring the significant advantages of secondary dynamic weighing technology, we must first understand the basic operating mechanisms and limitations of traditional primary weighing technology.
Primary weighing typically involves a single measurement of aggregate, powder, and asphalt using a weighing hopper before the materials enter the mixing system to ensure that the initial mix proportions meet design requirements. However, this process only provides static weighing data, making it impossible to monitor material flow changes during transportation in real time, nor is it able to dynamically correct for deviations caused by equipment inertia, residue, or environmental factors.
Only by fully understanding the limitations of primary weighing can we fully appreciate why secondary dynamic weighing technology is a key solution for improving mix proportion accuracy.
After a single weighing operation, materials are conveyed to the mixer via the hopper or conveyor belt. Due to material inertia, over- or under-feeding may occur, resulting in a discrepancy between the weighed value and the actual amount delivered.
Fluctuations in temperature and humidity in the production environment, especially fluctuations in the moisture content of the material itself, can affect the readings of the weighing sensor, leading to unstable weighing data and reduced proportioning accuracy.
Over long-term use, the sensors of the belt scale, the tensioning devices of the belt conveyor, and related mechanical components will wear or loosen, reducing sensor sensitivity. This leads to the gradual accumulation of weighing errors and affects accuracy and stability.
Single-stage weighing only weighs materials before they are added, making it impossible to implement dynamic adjustments. As production progresses, errors cannot be corrected in a timely manner, causing proportioning deviations to gradually increase, ultimately affecting the overall quality of the mixture.
To address the limitations of primary weighing, secondary dynamic weighing technology achieves a quantum leap in mix accuracy and stability by adding real-time monitoring and intelligent compensation. Specific advantages include:
Traditional primary weighing typically has an error of approximately ±1% for aggregates and ±0.5% for powders and asphalt. Macroad‘s secondary dynamic weighing technology reduces aggregate error to ±0.5% and stabilizes the error at ±0.25% for powders and asphalt. This improved accuracy is crucial for the compactness and aging resistance of high-grade roads, such as highways.
In complex formulations involving multiple aggregates and mineral powders, secondary weighing can monitor and correct the proportions of each material individually, effectively preventing imbalances caused by cumulative errors, ensuring that each component strictly meets design requirements and improving the overall stability of the mixture.
Using dynamic weighing sensors installed along the conveyor path, secondary weighing monitors material weight changes in real time, promptly detecting over- or under-dosing caused by material inertia and instantly compensating for it.
High-precision sensors, combined with signal amplification and filtering technology, effectively suppress the impact of temperature, humidity, and material moisture content fluctuations on weighing results, ensuring continuous and stable data.
The intelligent control system analyzes historical data and provides real-time feedback to identify deviations caused by equipment status changes and automatically adjusts compensation strategies, extending equipment life while ensuring weighing accuracy.
The dynamic weighing mode, which monitors while conveying, enables instant correction of errors between batches, preventing error accumulation and ensuring highly consistent proportions even under long-term, high-load production.
Accurate material delivery not only improves product quality but also significantly reduces material waste caused by overdosing, reducing production costs. Taking a mixing plant with a daily output of 800 tons of asphalt as an example, secondary weighing can reduce asphalt waste by about 0.5% per day, which is equivalent to saving 4 tons of asphalt and more than 1,000 tons of raw material costs per year.
The above comparative analysis clearly demonstrates that secondary dynamic weighing technology not only successfully overcomes the shortcomings of traditional primary weighing but also achieves breakthroughs in accuracy, stability, and economic efficiency, becoming a key technical support for batching control in high-grade asphalt mixing plants.
Furthermore, Macroad’s series of asphalt mixing plants have successfully integrated a mature secondary dynamic weighing system. Leveraging its high-precision sensors and intelligent algorithms, it ensures a stable mix ratio in every batch, meeting the requirements of various project grades.
Secondary dynamic weighing technology doesn’t operate in isolation; instead, it collaborates deeply with multiple key systems within the asphalt mixing plant to create an efficient and accurate production closed loop. This inter-system collaboration not only ensures accurate mix proportions but also improves overall mixing quality and production efficiency.
Responsible for initial batching according to design requirements, providing a stable material base for primary weighing and subsequent secondary dynamic weighing.
As key channels for material transportation, they not only carry large amounts of material but also provide a stable conveying environment for dynamic monitoring by the secondary weighing sensors, ensuring accurate data collection.
Receives materials precisely proportioned by secondary dynamic weighing, achieving uniform, high-quality mixing and ensuring that the final asphalt mixture meets design standards.
By integrating secondary weighing technology with the Internet of Things (IoT), remote monitoring, real-time analysis of production data, abnormality alarms, and complete production record traceability are achieved, ensuring digital upgrades in production safety and quality management.
The efficient collaboration of this series of systems forms a complete closed-loop quality control chain. Secondary dynamic weighing technology, as the core link, ensures precise adjustment of mix proportions and consistent mixing quality, laying a solid foundation for the efficient and intelligent operation of modern asphalt mixing plants.
With the outstanding performance of secondary dynamic weighing technology in mix accuracy and production stability, its application value is becoming increasingly significant in various types of road projects. To better understand the practical impact of this technology, we need to analyze the different requirements for weighing technology in various road projects from the perspective of project needs, thereby clarifying which areas are most in need of secondary dynamic weighing systems.
| Basic municipal roads: | Primary weighing generally meets the needs of foundation construction, but in areas with high humidity or large fluctuations in material moisture content, secondary weighing can significantly improve mix stability and construction quality. |
| Expressways and high-grade highways: | The requirements for material mix accuracy are extremely stringent, and secondary dynamic weighing technology has become an industry standard for ensuring mix quality. |
| Airport roads: | Because asphalt mixtures must possess extremely high shear resistance and high-temperature resistance, any mix deviation can cause structural damage, making secondary weighing technology essential in airport road projects. |
| Roads in high-altitude and cold regions: | Low temperatures weaken the bond between asphalt and aggregate, necessitating even higher requirements for mix accuracy. Secondary weighing technology can effectively ensure material performance and pavement durability. |
Secondary dynamic weighing technology not only improves the current mix accuracy of asphalt mixing plants, but also becomes an important support for promoting intelligent production and digital management to a new stage. With the continuous advancement of artificial intelligence, big data and automation technology, the extended value and future trends of secondary weighing are mainly reflected in the following aspects.
The real-time material weighing data collected by the secondary weighing system not only reflects the accuracy of production proportions but also reveals subtle changes in equipment operating status. AI algorithms analyze this data to promptly identify potential risks such as equipment wear and sensor degradation. This enables predictive maintenance, avoids sudden failures, extends the life of critical components, and significantly reduces maintenance costs and the risk of production downtime.
The precise data generated by the secondary dynamic weighing system can be integrated into the big data platform, forming a full lifecycle quality data chain covering formulation design, weighing control, mixing, construction implementation, and maintenance management. Through data integration and analysis, managers can achieve quality traceability, process optimization, and risk warning, thereby improving overall project management and construction quality.
In the future, secondary weighing systems based on AI self-learning algorithms will be able to predict environmental changes. They will be able to proactively assess potential impacts of temperature, humidity, and material properties on weighing accuracy and automatically adjust initial weighing parameters, achieving truly dynamic intelligent batching. With the help of automated equipment and remote monitoring technology, asphalt mixing plants will gradually achieve unmanned production, greatly improving production efficiency and safety, and pushing the industry into a new era of intelligent manufacturing.
Secondary dynamic weighing technology is not only a hardware upgrade, but also an innovation in production philosophy. It enables asphalt mixing plants to maintain accurate, stable, and low-cost production despite the diverse environments, materials, and high-precision engineering requirements.
Faced with increasingly complex engineering requirements and changing construction environments, secondary dynamic weighing technology makes efficient and stable work possible, ensuring that every road can bear the heavy responsibility of the future. It is this power of precise control that drives the industry forward and lays a solid foundation for modern intelligent transportation.